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What signal processors comprise an Event-Related Potential system for EEG?

What signal processors comprise an Event-Related Potential system for EEG?


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So my 30,000 ft. understanding of the EEG signal processing data flow is:

  1. Capture raw EEG data ("raw waveforms")
  2. Run these raw waveforms through a Signal Processing Framework that consists of 1+ "nodes"/processors, where each processor is doing some kind of transform on the raw waveform. In doing so, new information is unlocked from the raw waveform that was previously hidden
  3. Perform individual analyses on this unlocked data based on what suits your research/application

So first off, if the above understanding is misled in any way, please begin by correcting me!

Assuming I'm more or less correct, my specific application at hand is that I want to correlate certain raw waveforms with events (such as "thinking of a turtle", "moving head up and down", etc.). I believe Event-Related Potentials are what I'm looking for, but…

What I'm struggling with is: what does my "Signal Processing Network" need to look like in order to implement ERP? From an architectural perspective, I'm looking for this "network" to take raw waveforms in as input, and to output events, like the few I mentioned above.

Is FFT a player here? Some kinds of filters? What processors comprise an ERP system, and what does their respective "network" (data flow pipeline) look like?


Event-related potentials are an issue in many aspects of physiology, not just in EEG analysis, so this answer is more general.

The main problem is that electrical or other signals that are associated with some "event" are typically much lower in magnitude than the background noise in the system being examined. Electrocardiograms are the exception in this regard. The trick then is to get the event-related signal out of the noise.

This is done by multiple repetitions of the "event" combined with signal averaging. You mark the electrical record with the time of each event, line up portions of the record by the event markers, and average the lined-up signals around the multiple events. This can be the full waveform for sensory evoked potentials, or if you are examining action potentials in a nerve, the histogram of post-event occurrence times of action potentials.

The particular signal-processing mechanisms used have evolved with technology. I'm old enough to have known people who 60 years ago recorded electric neural activity on magnetic tape and processed the data, after analog-to-digital conversion, on what were then state-of-the art computers with 65,000 words of memory. Even then, there was discussion about the best technologies to use for specific purposes, as this 1959 MIT monograph indicates.

The main problem, the low level of event-related signals to the noise from other electrical activity, still remains 60 years later. The noise is biologic rather than technical, so more recent improvements have more to do with ease and speed of processing rather than the fundamental signal-to-noise problem. For event-related potentials, use whatever technology allows you to collect the electrical data along with linked notations of the event times, then to average the signals synchronized on the events to build up the signal out of the noise. In a standard clinical application of brainstem auditory evoked potentials to evaluate hearing, you may need to average over 500 or more stimulus presentations.

This signal-in-noise problem is also seen in functional magnetic resonance imaging (fMRI) of brain function, which must consider not only the signal over time but also differences among brain regions within individuals and differences among individuals. The Wikipedia page on fMRI goes into some detail on methods for getting specific signals out of the background noise. You should pay particular attention to the issue of "Block versus event-related design" on that page. My understanding is that for "events" of the type that you consider, like "thinking about a turtle," the block design works best in fMRI. The paper by Thierry et al, provided in the helpful answer by @Christiaan, shows how to apply this type of blocking approach to EEG measurements during presentation of visual stimuli.

The methods in that paper by Thierry et al also indicate the type of practical care that is used in professional analyses of this sort. The authors go into detail about the nature and placement of the electrodes, choice of which electrodes to use for analysis, signal-sampling rates, and so on. For example:

Scalp activity was digitized at a 1-kHz sampling rate from 64 Ag/AgCl electrodes distributed throughout the scalp according to the 10-20 convention using Cz as a reference. Impedances were kept below 7 kOhms. The electroencephalogram was filtered on-line between 0.01 and 200 Hz and off-line low pass at 35 Hz using a zero phase-shift digital filter. Eye blink artifacts were mathematically corrected, and signals exceeding $pm$ 75 $mu$V in any given epoch were automatically discarded.

Reading papers like this are probably the best way to learn about what's involved and to find people who can teach you how to do it.


ERPs are typically analyzed in terms of amplitude and latency. FFT is not really an option; it doesn't make sense. There may be some applications where it may be useful, but these are quite specific. For example, if repeated stimuli are presented and you are not averaging them, but you are collection an EEG, then FFT may help you to deduce whether stimulus frequency (e.g. 1/s) matches the response frequency and what the phase difference is between them. Note that FFT yields amplitude and phase data. But generally, again, ERPs are analyzed simply by taking amplitude and latency (Fig. 1)


Fig. 1. ERPs are characterized by taking the peaks, here the positive peak (P) at 100 ms (P1) and the negative peak (N) at 170 ms (N170). The amplitude of the N170 peak was analyzed and plotted. source: Thierry et al., (2007)

Reference
- Thierry et al., Nature Neuroscience (2007); 10: 505-11


EP2303112B1 - Method for processing a brain wave signal and brain computer interface - Google Patents

discloses a method to determine the hearing threshold in humans. Specific auditory stimuli and analysis of the related brain response signals are used. The stimuli comprise an auditory signal having a distinct characteristic such as a ramp in frequency or intensity.

discloses an EEG apparatus for analysis of quantified stimuli, including calculations of correlations between stimuli and brains signals.

discloses a method of cortical mapping, wherein subcutaneous electrodes are used to generate stimuli directly to brain cell areas, and electromyography is used to measure responses to those stimuli.

discloses a method and device for controlling equipment with the aid of electro-encephalograms (EEG) or electrocorticograms (ECoG). For this, different periodic stimuli are generated, each with a given base frequency. These periodic stimuli (frequency tagged stimuli) can be detected in the EEG or ECoG signals, amongst other by synchronizing the generation of stimuli and detection in the signal processing.

discloses thought analysis from brain wave data, such as EEG signals. Use is made of conceptual interpreters, whereby a test subject is presented with conceptual information and background stimuli. The brain wave data is subjected to signal processing using a stimulus model which represents attributes of stimuli.

  • Fig. 1 shows a schematic view of a brain computer interface according to an embodiment of the present invention
  • Fig. 2 shows a plots of noise tagged stimulus and the decomposition of the associated responses in a brain wave signal
  • Fig. 3 shows a fitting of an event related potential using an embodiment of the present invention
  • Fig. 4 shows time and frequency domain plots of tagged stimuli used in an experiment
  • Fig. 5 shows plots of correlation analysis of the tagged stimuli as shown in Fig. 4
  • Fig. 6 shows plots of rising and falling components of fits to the noise tagged stimuli of Fig. 4
  • Fig. 7 shows a flow diagram of an embodiment of the present method for processing a brain wave signal
  • Fig. 8 shows a flow diagram of a further embodiment of the present method for processing a brain wave signal
  • Fig. 9 shows plots of brain signals detected during a noise-tagging test with visual stimuli and
  • Fig. 10 shows a plot of one electrode signal of the plots of Fig. 9 .

  • a saw-tooth tone of 420Hz is used as a carrier
  • tags are applied to these tones using binary amplitude modulation, where for a binary zero the amplitude is reduced to 20% of its original value
  • two frequency tags at 42 and 70 Hz (for comparison with the noise tag)
  • two noise tags, called tag A and B, both 255 bits long with a 168 bit/s modulation rate, (≈1.5s noise tagging period)
  • a single tag was used for each epoch of 3s, i.e. 2 noise tag periods.
  • two tasks are used:
    • Perceptual - where only a single carrier and tag is used,
    • Serial Selective Attention - where the subject selectively attends (by counting) to one of the tags, which are presented in a random order.

    MATERIALS AND METHODS

    Five healthy persons took part in this study (3 female, 2 male, mean age 23.6 years, range 21–27 years). All subjects had previous experience as test persons in EEG and fMRI studies. They received a nominal compensation for their effort. All subjects gave informed consent in accordance with guidelines set by the Max-Planck-Institute.

    Subject Setup

    Conventional plastic-coated Ag/AgCl electrodes with iron-free copper leads 60 cm long were fixed on the subject's scalp by a stretchable plastic cap. Electrodes were mounted at positions Fz, F3, F4, C3, C4, P3, P4, O1 and O2 of the international 10/20 system. Fz was used as reference. Cables were twisted pairwise and led through a flexible silicon tube to the EEG amplifier located above the subject's head along the body axis in the scanner tunnel. In order to minimize movements, the subject's head was restrained using cushions. Cables and amplifier were fixed to the gantry by tape and weighed down by rice bags. Subjects wore mirror glasses in order to perceive the visual stimulation.

    Stimulation

    To elicit visual evoked potentials, a black/white checkerboard pattern of 16 × 16 patches (full field visual angle 11.5 degrees, 42 arc min per pattern) was inverted in intervals of 550 ms (a trial) ( 15 ). The ERTS package (Berisoft GmbH, Frankfurt, Germany) was used for stimulus display programming. The stimulation pattern was projected onto a screen in the scanner tunnel from an LCD projector located outside the scanner room. In experimental condition A, 256 trials were recorded without fMRI scanning. Condition B was designed as a blocked-fMRI experiment of 16 repetitions. Each block consisted of 16 sec checkboard stimulation, followed by a 16 sec display of a fixation point (corresponding to a total of 310 trials). Both conditions were run twice in each subject. A single trigger pulse was sent from the MR console to the stimulation PC to start an experimental block.

    EEG Recording

    A commercially available MR-compatible system (Schwarzer, Munich, Germany) was used for EEG recording. The battery-powered amplifier located in the scanner tunnel was connected via a 20 m fiber optic link to a standard PC in the MR console room equipped with a digital signal processor (DSP) board. The DSP board received trigger input from the stimulation PC which was recorded with the biosignals. The amplification factor of the system was 10000 ×, with a bandwidth of 0.073-70 Hz. Biosignals were sampled at 250 Hz using an unipolar recording with Fz as reference. Collected data were analyzed offline (see below).

    FMRI Scanning

    Functional imaging was performed using a Bruker Medspec 30/100 3.0T MR system. A bird cage quadrature coil was used. An in-house EPI implementation allowed the acquisition of the slices to be collected together at the beginning or end of the TR time, thus providing long pauses during which no MR signals were being recorded for the collection of the EEG data. Sequence parameters were: TE 30 ms, TR 1333 ms between successive acquisition of the same slice. Three slices were acquired with thickness 5 mm with 2 mm gap, 19.2 cm FOV, 64 × 64 matrix with 100 kHz sampling. The time period during which the images were acquired was 200 ms, leaving a 1133 ms period for MR relaxation and EEG acquisition. The three slices were centered along the sagittal direction of the calcarine fissure.

    EEG Data Evaluation

    FMRI Data Evaluation

    Subject movements were corrected in 2D (two translational and one rotational parameter) within and between both scans in condition B ( 16 ). Baseline filtering was achieved by estimating the baseline using low-pass filtering in the temporal domain (cut-off 0.05 Hz) and subtraction of the result from the data ( 17 ). System and physiological noise were partially removed by low-pass filtering in the temporal domain (cut-off 0.2 Hz) ( 17 ). Functional activation was detected by voxelwise univariate regression analysis using a box-car waveform shifted by 5 sec to match the lag of the hemodynamic response. The F-scores obtained were corrected for the effective degrees of freedom by analyzing the temporal auto-correlation ( 18 ). Assignment of significance was achieved by conversion of the F-scores into z-scores, thresholding the z-score map by eight, and assessment of the activated regions for their significance on the basis of their spatial extent ( 19 ). For graphical display, significantly activated brain areas were color-coded and overlaid onto T1-weighted anatomical scans obtained at the same positions as the functional data. In addition, z-score maps were registered with a T1-weighted high-resolution MR dataset of the same subject and transformed into Talairach space, in order to determine the coordinates of the fMRI activation centers.

    Dipole Fitting

    In order to demonstrate the close coupling of BOLD response and EEG activity, sources of the visual ERPs were localized using the ASA software package (ANT Software, Enschede, The Netherlands) on the basis of a realistically shaped three-shell boundary element model of the human brain and skull.


    Introduction

    Electroencephalography (EEG) is a well-established noninvasive method to record the electrical activity of the human brain using electrodes placed on the scalp. EEG is extensively used for clinical applications such as epilepsy diagnostics (Noachtar and Rémi, 2009), sleep staging (Campbell, 2009), diagnosis of hearing loss (Paulraj et al., 2015), anesthesia monitoring (Marchant et al., 2014), and brain-computer interfaces (Shih et al., 2012). Moreover, EEG serves as a fundamental research tool for understanding human brain function (Lopes da Silva, 2013). EEG signals are known for their high temporal resolution allowing to observe changes in neural activity at millisecond precision. Compared to neuroimaging techniques such as magnetic resonance imaging (MRI) or magnetoencephalography (MEG), EEG hardware is available at very low cost, relatively easy to use, and very flexible in its application. For instance, clinically useful EEG signals can already be acquired with as few as three electrodes (e.g., Jewett and Williston, 1971), but current clinical and research practice is the simultaneous acquisition from multiple scalp electrodes. The use of 20, 100, or even 200 electrodes is common and the resulting recordings are rich in spatial detail. However, multi-channel EEG is feasible only if a net or cap is used to keep sensors in place. Hence, the established EEG sensor and cap systems are bulky. They often come with loose wires, are clearly visible, and may not provide good signal quality over prolonged periods of time and if they do, they are not comfortable to wear. Here, we discuss recently developed alternatives to conventional EEG acquisition technology, with a particular focus on solutions that aim for daily-life application. We introduce the concept of transparent EEG as a new approach to acquire electrophysiological data with minimal inconvenience for the person that is monitored and show how this can be implemented using ear-EEG.

    The term mobile EEG has been used to describe the study of EEG-derived brain signals during motion (De Vos et al., 2014 Gramann, 2014). The role of the motor system has been recognized in cognitive neuroscience research: motor cognition, for instance, states that cognitive processing is embedded into actions and that the motor system contributes to cognitive processing (Jeannerod, 2008). Cognitive processes are different between rest and movement conditions (e.g., vision for action vs. vision for recognition, Goodale et al., 1991, or the interference of cognitive effort and gait stability, Al-Yahya et al., 2011) and the motor system even closely interacts with sensory processing (Schafer and Marcus, 1973). Accordingly the ecological validity of cognitive neuroscience research depends to a significant degree on the ability of studying the brain during natural motion (Ladouce et al., 2017). Even subtle motion, however, may distort signal quality. This drawback resulted in lab procedures that aim for highly artificial, motion-minimized recording situations. Yet, all behavior including speech is expressed as motion of (parts) of the human body. Thus, to study cognition during motion the availability of technology that tolerates motion appears advantageous. In this regard, EEG has a clear advantage over MRI or MEG since it can be made portable and has a higher motion tolerance. Several developments such as active or shielded electrodes (Metting van Rijn et al., 1990) and new sensor technology (Cömert and Hyttinen, 2015 Goverdovsky et al., 2015) may increase the degree of motion-tolerance even further. Here, we refer to mobile EEG as a technology that does not require the user to remain still. Mobile EEG systems are supposed to tolerate at least a modest degree of motion during signal acquisition, such as free walking at leisure pace (e.g., Debener et al., 2012). Not all mobile EEG solutions that tolerate user motion are mobile in the sense that they can easily be re-located. Indeed, mobile EEG research often combines EEG acquisition with motion-tracking and other recording modalities (Ojeda et al., 2014), which results in highly complex but stationary recording set-ups. This means that setups for mobile EEG are not necessarily portable.

    More recently developed EEG amplifier-sensor systems are small enough to fit into a trouser pocket. We refer to these small EEG systems that can easily be carried around as portable EEG. Interestingly, some portable EEG systems do not even require a computer, as recordings can be stored on the device or transmitted wirelessly to a smartphone (e.g., Stopczynski et al., 2014a Debener et al., 2015). It is important to note that portable EEG devices are not necessarily motion-tolerant. It remains to be seen whether recently developed portable EEG systems feature good signal quality during gross body motion.

    Most conventional EEG systems require skin abrasion and application of an electrolyte paste to achieve a low-impedance skin-electrode contact. The preparation of multi-channel EEG recordings and the cleanup afterwards is hence time consuming for both experimenter and participant. Typically hair washing is required after completion of an EEG recording session. To overcome these drawbacks, dry EEG sensor solutions have been developed. Some of these systems are now market-ready and do indeed require very little preparation time and no hair-washing afterwards (Zander et al., 2011 Fiedler et al., 2014). However, signal quality issues remain (Bertrand et al., 2013 Tautan et al., 2014 Mathewson et al., 2017), and the high-impedance skin-electrode contact of dry sensors may reduce motion-tolerance to a level below that of traditional wet EEG technology. Moreover, dry EEG systems require a constant pressure of electrodes onto the skin, and this pressure bears the risk of increasing discomfort and headaches. In order to avoid subsequent hair washing, electrolyte fluids as skin-contact elements have been developed (e.g., Alba et al., 2010). Several popular consumer EEG solutions are based on a similar idea. By using dry electrode caps, or by combining electrolyte fluids with a headset, a self-fitting of EEG sensors becomes feasible.

    This self-fitting characteristic appears important for several of the use cases presented below, and may be best described with the term wearable EEG. However, as mentioned above, wearable consumer-EEG systems, while portable, are not necessarily motion-tolerant. In 2012, we therefore introduced a consumer-EEG conversion kit and showed that low cost, wireless EEG can produce good EEG signal quality while walking outdoors—if combined with conventional cap EEG electrodes (Debener et al., 2012).

    Mobile EEG, portable EEG, and wearable EEG labels are not consistently used in the literature, and our short characterizations may not apply to all published uses of these terms. For daily-life applications, however, these and further characteristics have to be combined into a single, next generation EEG approach.

    We call this new approach transparent EEG. A transparent EEG is defined as a portable, motion-tolerant, self-applicable, highly unobtrusive, near invisible, and comfortable to wear EEG system. These requirements hold equally for sensor and amplifier technology. A transparent EEG should consist of sensors that are very small, near invisible and maintain good contact with the skin, preferably over many hours. All wires should be bundled and connect to an amplifier unit located in close proximity to the sensor array, to avoid long wires and minimize the risk of interference (Simakov and Webster, 2010). Accordingly, the amplifier must be head-mounted and should therefore be small enough in size to fit into glasses, behind the ear, or into in-ear devices similar to a modern hearing-aid. An amplifier used for transparent EEG should have low power consumption (or be easily and quickly rechargeable) and transmit signals wirelessly to a recording and signal-processing unit.

    Modern smartphone technology features wireless communication and sufficient on-board storage and computational power to support EEG acquisition and basic signal processing (Stopczynski et al., 2014b). Importantly, such a system would allow for undisturbed natural social interactions and natural daily activities, and should not be more of a hassle to use than a pair of glasses, a hearing aid or a smartwatch.

    In summary, a transparent EEG is a convenient EEG solution that allows to record brain signals relevant for a particular application with minimal disturbance to the users, short setup time, and long recording times. There is no exclusive way on how to implement a transparent EEG, but hardware miniaturization and convenient and unobtrusive sensor placement are critical. Consequently, transparent EEG has the potential to extend the usage of EEG to a wide variety of applications and situations that are not easily accessible with classical EEG solutions. In the remainder of this manuscript we argue that ear-EEG is one promising approach to implement transparent EEG and discuss our ear-EEG sensor approach using cEEGrid technology.

    Aiming toward transparent EEG, it has been found that good signal quality and wearing comfort can be achieved with miniaturized EEG electrodes (Nikulin et al., 2010). Likewise, a number of ear-EEG systems featuring miniaturized EEG sensors have been proposed in recent years (Looney et al., 2012, 2014 Kidmose et al., 2013 Lee et al., 2014 Bleichner et al., 2015 Debener et al., 2015 Norton et al., 2015). Looney et al. (2012) pioneered modern EEG acquisition by placing electrodes into the outer ear canal and the concha. While replicating their work (Bleichner et al., 2015), we noticed that the resulting amplitudes are much smaller than what can be expected from scalp-EEG, which is due to the small distance between electrodes. As described below, it is hence worthwhile to consider locations around the ear as an intermediary between scalp-EEG and in-ear EEG. For this article we define ear-EEG systems as devices that place all necessary EEG sensors (i.e., recording electrode, ground and reference) in the outer ear canal, the concha, or the area around the ear.

    By directly comparing simultaneously acquired scalp-EEG and ear-EEG signals, several independent laboratories have shown that ear-EEG can capture brain signals that are closely related to those recorded with scalp-EEG (Mikkelsen et al., 2015 Mirkovic et al., 2015 Bleichner et al., 2016 Zibrandtsen et al., 2016). In contrast to the classical EEG cap, ear-EEG sensors can be worn comfortably and are not more noticeable than hearing-aids or (in-ear) headphones. Ear-EEG sensors interfere much less with a participant's normal behavior and can be worn for many hours while maintaining good signal quality (Debener et al., 2015). First studies combining portable EEG systems with ear-EEG sensor technology and wireless smartphone-acquisition (Debener et al., 2015) have already been conducted, but commercially available portable EEG amplifier solutions are still too bulky to fit behind the ear. However, it is foreseeable that this will change in the near future (Zhang et al., 2013). These developments show that transparent EEG is well within reach. In the following section, we will present our ear-EEG approach in more detail.


    Mind Invasive Behavioral Modification Patents Patented at the United States Patent and Trademark Office, TODAY used for Involuntary Human Experimentation

    NOTE: Some, if not all of the patents listed are highly advanced, and are handheld, portable, land, sea, aerial drone, and space-based and continue to advance in research, TESTING, and development programs within the "Military Industrial Complex" thus making ongoing human experimentation a must.

    QUESTION: Has Brain Entrainment programming begun today focusing on a younger generation and on a larger scale?

    The fact is "Binaural Beats" reportedly influence the brain in more subtle ways through the entrainment of brainwaves.

    Manipulation of brainwaves is pivotal in mind control and the key for mass population control of which these technologies have their foundation through Operation Paperclip underground Nazi Mind Control ideology!

    The links, abstracts to patents provides a brief summary of the history of “Mind Control Technologies." This capability is also known as psycho-physical, or psychological electronic / Psychotronic as well as electromagnetic extremely low frequencies, frequency waves, resulting in the term Remote Neural Monitoring.

    The list also encompasses Directed Energy Weapons, used in many formats and of which many victims of this official crime are reporting in widespread use for covert torture today, and in many cases, relentlessly around the clock or until death.

    US Patent # 5,123,899 (June 23, 1992)

    Method & System for Altering Consciousness, Gall, James

    Abstract --- A system for altering the states of human consciousness involves the simultaneous application of multiple stimuli, preferable sounds, having differing frequencies and wave forms. The relationship between the frequencies of the several stimuli is exhibited by the equation g = s.sup.n/4 .multidot.f where: f = frequency of one stimulus g = frequency of the other stimuli of stimulus and n=a positive or negative integer which is different for each other stimulus.

    OTHER CONSCIOUSNESS ALTERING PATENTS

    U.S. Patent, #5,123,899. June 23, 1992

    DESCRIPTION: A system for stimulating the brain to exhibit specific brain wave rhythms and thereby altering the subjects’ state of consciousness.

    U.S. Patent, #5,289,438. February 22, 1994

    DESCRIPTION: A system for the simultaneous application of multiple stimuli (usually aural) with different frequencies and waveforms. Electro Magnetic Field (EMF) monitoring / interference is one of the most insidious and secretive of all methods used by the agencies. Similarly, EEG cloning feeds back the results of EMF monitoring in an attempt to induce emotional responses (e.g. fear, anger, even sleep, etc.)

    PURPOSE: To Disorientate / Manipulate a Target

    US Patent # 4,777,529 (October 11, 1988)

    Auditory Subliminal Programming System, Schultz, Richard M., et al.

    Abstract --- An auditory subliminal programming system includes a subliminal message encoder that generates fixed frequency security tones and combines them with a subliminal message signal to produce an encoded subliminal message signal which is recorded on audio tape or the like. A corresponding subliminal decoder/mixer is connected as part of a user's conventional stereo system and receives as inputs an audio program selected by the user and the encoded subliminal message. The decoder/mixer filters the security tones, if present, from the subliminal message and combines the message signals with selected low frequency signals associated with enhanced relaxation and concentration to produce a composite auditory subliminal signal. The decoder/mixer combines the composite subliminal signal with the selected audio program signals to form composite signals only if it detects the presence of the security tones in the subliminal message signal. The decoder/mixer outputs the composite signal to the audio inputs of a conventional audio amplifier where it is amplified and broadcast by conventional audio speakers.

    THE QUESTION IS:

    How far into the future is the ban on psychotronic weapons?

    Or, at the very least full disclosure of the use of mind invasive advancements?

    Throughout the years, countless and untold numbers of people have been tested on without their knowledge or consent necessary to bring this technology to its highly effective current state of perfection. In light of this technology, now fully implemented, some recognized that diagnosis of victims today must also include or exclude, or patented mind invasive systems and devices as a covert contributor. However, due to high level government secrecy, some choose instead to look the other way in fear of the same fate.

    Painfully, many people have lost their families, jobs, and families and lives after torment by "Synthetic Telepathy" or "Artificial Telepathy," also patented and known as Weaponized Schizophrenia, the "Voice of God" by the DOD, Voice to Skull, the Frey Effect, Neural Decoding, Remote Neural Monitoring and ongoing. T esting on unsuspecting victims is how effectiveness has been determined and horrifically at the cost of human lives.

    Voice to Skull is a type of Neurophone invented by inventor Pat Flanagan as a teenager in 1958 at the age of 14. The device was confiscated by the US government, Flanagan was placed on "Secrecy Orders" and received the invention back 10 years later in 1968 and patenting.

    Alan Frey would later and perfect microwave technology having the same capability and beamed voice effect and is the widely used method along with ultrasounds, by handheld, portable, land, sea, aerial (drone), and space-based systems and devices.

    ** The Need for New Criteria of Diagnosis of

    Psychosis in the Light of Mind Invasive Technology **

    **THOUGHT TRANSMISSION CAPABILITY**

    HISTORY OF THE LIDA MACHINE AND EARLY DEVELOPMENT

    Many of these patents are microwave hearing based technology, used in electromagnetic mind control and Organized Stalking of individuals combined with Directed Energy Weapon coercive physical torture. They are portable, handheld, land, sea, aerial (drone) and microwave cellular tower and space-based.

    FOUNDATION OF MICROWAVE WEAPON HEARING

    Decades ago, a scientist, Allan Frey, found that if a microwave carrier were to be sliced and carried audio modulation, that modulation could be heard by someone in the signals path. The thin pulses of radio carrier wave cause current to flow through the nervous system - the result if a remote transmission no wires or contact is needed. Two examples are below with Abstracts following:

    “A hearing system” U.S. Patent #4,877,027, October 32, 1989, Wayne Brunkan.
    “A hearing device” U.S. Patent #4,858,612, August 22, 1989, Phillip L. Stocklin.

    Egg. The latter involves microwaves aimed at the auditory cortex. A mike turns the sounds to electrical signals which are treated so as to provide multi frequency microwaves which are applied to the brain area. Whatever sound the mike picks up (like a voice) is relayed to the target.

    NOTE: Again, many targets report relentless attacks from this patented Directed Energy Weapon system, inside and outside their homes, as a "slow kill" system used for damaging tissue and organ damage from the directional beam patent below:

    MIND CONTROL WITH SILENT SOUND EXPLAINED


    ARTIFICIAL TELEPATHY 101 / SYNTHETIC TELEPATHY PATENT AKA "HEARING VOICES"

    ARTIFICIAL TELEPATHY PATENT:

    The Microwave technological "Hearing Voices" effect is also known as the DOD "Voice of God" the Frey Effect, Voice-to-Skull, Artificial and Synthetic Telepathy, Remote Neural Monitoring, Neural Decoding, and Weaponized Schizophrenia. It is factually the capability to beamed voices of those at the helm of the technology directly into the victim's brain. It reportedly being used, past, present, and future in Black Ops cover-ups, to effectively discredit many targets enrolled into a heinous human guinea pig testing program, so monstrous most cannot believe it exists. Think of people reporting a voice of God or devil told them to kill someone, before or after a tragedy to include family and children to understand this great evil. The key is to strategically have test victims misdiagnosed as delusional and psychotic, as one of the biggest immoral, beyond evil nonconsensual technology testing program cover-ups ever known to man. Unbelievably these are little more than human monsters, and extremely disturbed psychopaths at the helm of patented technology, and not demons the public deceptively have been convinced are the culprits in deception and who think nothing of sacrificing human lives.

    COLD BLOODED BLACK OPS / HEARING VOICES EXPERIMENTATION


    DOD "Voice of God" TECHNOLOGY

    US Patent # 4,858,612 (August 22, 1989)

    Hearing Device, Stocklin, Philip L.

    Abstract --- A method and apparatus for stimulation of hearing in mammals by introduction of a plurality of microwaves into the region of the auditory cortex is shown and described. A microphone is used to transform sound signals into electrical signals which are in turn analyzed and processed to provide controls for generating a plurality of microwave signals at different frequencies. The multi-frequency microwaves are then applied to the brain in the region of the auditory cortex. By this method sounds are perceived by the mammals which are representative of the original sound received by the microphone.

    US Patent # 4,877,027 (October 31, 1989)

    Hearing System, Brunkan, Wayne B.

    Abstract --- Sound is induced in the head of a person by radiating the head with microwaves in the range of 100 megahertz to 10,000 megahertz that are modulated with a particular waveform. The waveform consists of frequency modulated bursts. Each burst is made up of 10 to 20 uniformly spaced pulses grouped tightly together. The burst width is between 500 nanoseconds and 100 microseconds. The pulse width is in the range of 10 nanoseconds to 1 microsecond. The bursts are frequency modulated by the audio input to create the sensation of hearing in the person whose head is irradiated.

    Microwaves and Behavior by Don Justesen,

    "American Psychologist Magazine"

    Microwave "Hearing Voices" "Frey Effect" named after Alan Frey

    Physical Control of the Mind by Brain Implants and Radio Frequencies

    American Psychologist, 1948, Page 3. Subminiature Radio EEG

    Telemeter for Studies of Disturbed Children.


    WASHINGTON POST ARTICLE

    Donald R. Justesen reported in "Microwaves and Behavior," American Psychologist, March 1975, that Sharp and Grove:

    It was demonstrated rigorously in an experiment conducted by Sharp and Grove, and published in an American Psychologist edition during 1975. . + Mind Control and Electromagnetic harassment victims.

    "Mind Control Technology" is the last thing powerful government agencies wants detailed and published. Today news agencies, politicians, government officials are under National Security gag orders.

    MIND CONTROL: IS IT FEASIBLE TO MANIPULATE THE HUMAN BRAIN?

    Don R. Justesen, 1975, Microwaves and Behavior, American Psychologist, March 1975, pg. 391 - 401 . Mind Control and Electromagnetic harassment victims.

    Below begins a detailed list of patents and in some cases detailed abstracts.

    MIND READING CAPABILITY IN EARLY STUDIES

    BY ONE INVENTOR - LAWRENCE PINNEO

    A Neurophysiologist and Electronic Engineer working for Stanford Research Institute (a military contractor) is the first “known” pioneer in this field.

    In 1974, he developed a computer system which correlated brain waves on an electroencephalograph with specific commands. By doing so, the capability to read minds or subvocal thought was accomplished.

    In the early 1990s, Dr. Edward Taub reported that words could be communicated onto a screen using the thought-activated movements of the computer cursor.

    BRAINWAVE SCANNERS / PROGRAMS:

    The EEG was first developed in 1920. As stated, later Lawrence Pinneo, a neurophysiologist and electronic engineer working for Stanford Research Institute (a military contractor) is the first "known" pioneer in the field of computer-based mind reading.

    In 1974 he developed a computer system which correlated brainwaves on an electroencephalograph with specific comments.

    BRAINWAVE MONITOR / ANALYZER (MIND READING)

    Mind reading software was first developed in 1994 by Dr. Donald York and Dr. Thomas Jensen.

    In 1994, the brainwave patterns of 40 subjects were officially correlated with both spoken words and silent thought. This was achieved by a neurophysiologist, Dr. Donald York, and a speech pathologist, Dr. Thomas Jensen, from the University of Missouri.

    They clearly identified 27 words /syllables in specific brain wave patterns and produced a computer program with a brain wave vocabulary.

    Using lasers/satellites, and high-powered computers, the agencies have now gained the ability to decipher human thoughts - and from a considerable distance. (instantaneously)

    DESCRIPTION: As personal scanning and tracking system involving the monitoring of an individual electromagnetic frequency, biometrics (Fractal DNA, iris, facial recognition, gait, iris, etc., via remote means e.g. Satellite. The results are fed to thought activated computers that possess a complete brainwave vocabulary via EEG.

    PURPOSE: Practically, communication with stroke victims and brain-activated control of modern jets are two applications. However, more often, it is used to mentally rape a Civilian target their thoughts being referenced immediately and/ or recorded for future use.

    EEG CLONING (Brainwave Manipulation of Emotions)

    DESCRIPTION: A system whereby the target’s electromagnetic frequency is monitored remotely and EEG results fed back to them (or others) to mimic emotional patterns e.g. fear, anger, etc. In other words supercomputer's clone your emotions then beam them back to you to induce fear or panic to control you.

    PURPOSE: To induce emotional / psychological responses. For example, the feedback of Delta waves may induct drowsiness since these are familiar when in deep sleep. Delta Programming is also used for Manchurian Candidates.


    HOW IS IT DONE?

    The magnetic field around the head, the brain waves of an individual can be monitored by satellite and drones. The transmitter is therefore the brain itself just as body heat is used for “Iris” satellite tracking (infrared) or mobile phones or bugs can be tracked as “transmitters.” In the case of the brain wave monitoring the results are then fed back to the relevant computers. Monitors then use the information to conduct “conversation” where audible Neurophone input is “applied” to the target / victim.

    MIND READING CAPABILITY TODAY

    The Department of Homeland Security, thought reading software is called MALINTENT, and another by Hewlett Packard is called Pre-crime.

    Both are in full use globally, to include Federal, State, and local agencies and through unified military operations within the US. The technology is designed to focus on a target and read the thoughts of targets of which some personnel use to degrade, demean, and mimic, as a form to technological harassment relentlessly. These operations typically do so while working in shifts around the clock. The technology can and is, past, present and future being used to nudge a person into crime to entrap a target, especially if unaware their thoughts are monitored and subliminally manipulated and influence used to unleash bogus investigations and placing the victim into the program for further human lab rat testing operations.

    If you are against tyranny, for example, you then can be placed on a “Watch List” for various reason then targeted by psychotronic weapons and psychophysical directed energy weapons, also known as the Active Denial System technology, in a massive technology testing program approved today for military and law enforcement testing. The mind reading technology has its origins in the Brainwave Monitor/ Analyzer as shown below:

    DHS SECURITY "MALINTENT" MIND READING TECHNOLOGY IN FULL USE WHEN PASSING THROUGH SECURITY AT AIRPORTS

    Psycho-physical "Mind Control" technology all have positive benefits for the good of humanity, however, today many of these patents are being used for nefarious goals, i.e., power & control.

    US Patent # 2,995,633 (August 8, 1961)

    Means for Aiding Hearing, Puharich, Henry & Lawrence, J.

    US Patent # 3,156,787 (November 10, 1964)

    Solid State Hearing System, Lawrence, Joseph & Puharich, Henry

    US Patent # 3,170,993 (February 23, 1965)

    Means for Aiding Hearing by Electrical Stimulation of the Facial Nerve System, Puharich, Henry & Lawrence, Joseph

    The "Neurophone" is one of the first officially patented "Hearing Voices effect technology.

    The link below gives the history of the inventor, Patrick Flanagan, at age 14, and how it was confiscated by the US government and returned for his patenting 10 years later.

    THE NEUROPHONE AND ADVANCED NEUROPHONE

    PURPOSE: Practically, the Neurophone could be used to communicate with the deaf but more often, it is used to terrorize targets. The tracked individuals here recorded/live threats, propaganda, etc. which those around them do not hear (delivered mainly via satellite laser). This harasses and discredit’s the targets especially if the problem is communicated to those unaware or the relevant technologies.

    US Patent # 3,393,279. July 16th, 1968
    US Patent # 3,647,970. March 7th, 1972

    The Neurophone was developed by Dr Patrick Flanagan in 1958. It’s a device that converts sound to electrical impulses. In its original form electrodes were placed on the skin but with defense department developments, the signals can be delivered via satellite. They then travel the nervous system directly to the brain (bypassing normal hearing mechanisms). Dr Flanagan’s “3D holographic sound system” can place sounds in any location as perceived by the targeted / tortured listener. This allows for a variety of deceptions for gullible victims.

    Today, the CIA, DIA (etc) use satellites and ground – based equipment to deliver verbal threats, deafening noise and propaganda using neurophone technology. Anything from TV’s/radio’s appearing to operate when switched off through to “Voices from God” and encounters with “telepathic” aliens are all cons using neurophone technologies to torment, deceive and (most importantly) discredit agency/targets. Naturally, the system can mimic anyone’s voice and automatic computer translations (into any language) are incorporated.

    Anecdotal evidence indicates that people like David Koresh, Martin Bryant and others could have been programmed then remotely triggered (or tricked) using harassment technologies like the neurophone. (Although most of the targets are intelligent and law-abiding). For example, John Lennon’s killer, Mark Chapman, reportedly heard voices before and after silencing the agency-hounded peace advocate. “God” apparently told him to confess verbally.

    To explain why others physically moving into the path of the laser (or whatever) do not pick up the signals, please note the following “possibilities”…

    a) Kirlean photography may be an ancillary system so it’s attuned to the targets personal energy field (their unique EM waves).

    b) The magnetite in our brains can act as a detectable fingerprint.

    c) Equally each of us has a unique bio electrical resonance frequency in our brains. EMF brain stimulation may be encoded so that pulsating EM signals sent to the targets brain cause audio-visual effects which only the target experiences. This, to me, is the best explanation.

    d) The individuals “vibrational pattern” could be used as a signal filter like a radio receiving only the sound modulating the frequency of the station it’s tuned to.

    e)The monitors simply adjust the volume downwards when you’re in a position where the signal could hit someone else’s body. Even if they heard it (briefly) they’d attribute it to another voice in the crowd etc.

    If it wasn’t so effective it would not be used to facilitate silent communications between U.S. Government agents/military personnel. And, by numerous reports, today used in relentless, ongoing, technological harassment of thousands of targets in a government program harassed around the clock as targeted victims from state-of-the-art operation centers nationwide, and many report globally. They system is also portable.

    US Patent # 3,393,279 (July 16, 1968)

    Nervous System Excitation Device, Flanagan, Giles P.

    Abstract --- A method of transmitting audio information via a radio frequency signal modulated with the audio info through electrodes placed on the subject's skin, causing the sensation of hearing the audio information in the brain.

    NOTE: This is said to be the original satellite delivered high tech Artificial Telepathy effect.

    US Patent # 3,629,521 (January 8, 1970)

    Hearing Systems, Puharich, Henry K.

    Abstract --- The present invention relates to the stimulation of the sensation of hearing in persons of impaired hearing abilities or in certain cases persons totally deaf utilizing RF energy. More particularly, the present invention relates to a method and apparatus for imparting synchronous AF or "acoustic" signals and so-called "transdermal" or RF signals. Hearing and improved speech discrimination, in accordance with one aspect of the present invention, is stimulated by the application of an AF acoustical signal to the "ear system" conventional bio-mechanism of hearing, which is delivered to the brain through the "normal" channels of hearing and a separate transdermal RF electrical signal which is applied to the "facial nerve system" and is detectable as a sensation of hearing. Vastly improved and enhanced hearing may be achieved.

    PSYCHO Acoustic Projector

    U.S. Patent, #3,566,347, February 23, 1971

    DESCRIPTION: A high directional beam radiated from a number of transducers and modulated by a speech, code, or noise beat signal. It may take the form of a radiator mounted on a vehicle, aircraft or satellite.

    PURPOSE: To produce aural/psychological disturbances and partial deafness.

    US Patent # 3,576,185 (April 27, 1971)

    Sleep-Inducing Method & Arrangement using Modulated Sound & Light, Meseck, Oscar & Schulz, Hans R.

    US Patent # 3,568,347 (February 23, 1971)

    Psycho-Acoustic Projector, Flanders, Andrew

    Abstract --- A system for producing aural psychological disturbances and partial deafness in the enemy during combat situations.

    US Patent # 3,647,970 (March 7, 1972)


    Method and System for Simplifying Speech Waveforms, Flanagan, G. Patrick

    Abstract --- A complex speech waveform is simplified so that it can be transmitted directly through earth or water as a waveform and understood directly or after amplification.

    US Patent # 3,773,049 (November 20, 1973)

    Apparatus for Treatment of Neuropsychic & Somatic Diseases with Heat, Light, Sound & VHF Electromagnetic Radiation, L. Y. Rabichev, et al.

    US Patent # 3,766,331 (October 16, 1973)

    Hearing Aid for Producing Sensations in the Brain, Zink, Henry R.

    Abstract --- A pulsed oscillator or transmitter supplies energy to a pair of insulated electrodes mounted on a person's neck. The transmitter produces pulses of intensity greater than a predetermined threshold value and of a width and rate so as to produce the sensation of hearing without the use of the auditory canal, thereby producing a hearing system enabling otherwise deaf people to hear.

    US Patent # 3,727,616 (March 17, 1973)

    Electronic System for Stimulation of Biological Systems, Lenskes, H.

    Abstract --- A receiver totally implanted within a living body is inductively coupled by two associated receiving coils to a physically unattached external transmitter which transmits two signals of different frequencies to the receiver via two associated transmitting coils. One of the signals from the transmitter provides the implanted receiver with precise control or stimulating signals which are demodulated and processed in a signal processor network in the receiver and then used by the body for stimulation of a nerve, for example, while the other signal provides the receiver with a continuous wave power signal which is rectified in the receiver to provide a source of electrical operating power for the receiver circuitry without need for an implanted battery.

    US Patent # 3,712,292 (January 23, 1973)

    Method & Apparatus for Producing Swept FM Audio Signal Patterns for Inducing Sleep, Zentmeyer, J.

    Abstract --- A method of producing sound signals for inducing sleep in a human being, and apparatus therefor together with representations thereof in recorded form, wherein an audio signal is generated representing a familiar, pleasing, repetitive sound, modulated by continuously sweeping frequencies in two selected frequency ranges having the dominant frequencies which occur in electrical wave patterns of the human brain during certain states of sleep. The volume of the audio signal is adjusted to mask the ambient noise and the subject can select any of several familiar, repetitive sounds most pleasing to him.

    US Patent # 3,837,331 (September 24, 1974)

    System & Method for Controlling the Nervous System of a Living Organism, Ross, S.

    Abstract --- A novel method for controlling the nervous system of a living organism for therapeutic and research purposes, among other applications, and an electronic system utilized in, and enabling the practice of the invented method. Bioelectrical signals generated in specific topological areas of the organism's nervous system, typically areas of the brain, are processed by the invented system so as to produce an output signal which is in some way an analog of selected characteristics detected in the bioelectrical signal. The output of the system, typically an audio or visual signal, is fed back to the organism as a stimulus. Responding to the stimulus, the organism can be trained to control the waveform pattern of the bioelectrical signal generated in its own nervous system.

    US Patent # 3,835,833 (September 17, 1974)

    Method for Obtaining Neurophysiological Effects, Limoge, A.

    Abstract --- A method and apparatus for obtaining neurophysiological effects on the central and/or peripheral systems of a patient. Electrodes are suitably positioned on the body of the patient and a composite electric signal is applied at the electrodes. The composite signal is formed by the super positioning of two signals: a first signal which is a rectified high-frequency carrier modulated in amplitude to about 100 percent by substantially square-shaped pulses whose duration, amplitude and frequency are chosen according to the neurophysiological effects desired, and a second signal which has a relatively white noise spectrum. The mean value of the first electric signal has a predetermined sign which is opposite the sign of the mean value of the second electric signal.

    US Patent # 3,884,218 (May 20, 1975)

    Method of Inducing & Maintaining Various Stages of Sleep in the Human Being, Monroe, Robert A.

    Abstract --- A method of inducing sleep in a human being wherein an audio signal is generated comprising a familiar pleasing repetitive sound modulated by an EEG sleep pattern. The volume of the audio signal is adjusted to overcome the ambient noise and a subject can select a familiar repetitive sound most pleasing to himself.

    Malech's Remote Brainwave-Altering Machine

    US Patent Number 3,951,134 (April, 1976) - Represents an invention by Robert G. Malech

    Apparatus and method for remotely monitoring and altering brain waves

    Abstract -- Apparatus for and method of sensing brain waves at a position remote from a subject whereby electromagnetic signals of different frequencies are simultaneously transmitted to the brain of the subject in which the signals interfere with one another to yield a waveform which is modulated by the subject's brain waves. The interference waveform which is representative of the brain wave activity is re-transmitted by the brain to a receiver where it is demodulated and amplified. The demodulated waveform is then displayed for visual viewing and routed to a computer for further processing and analysis. The demodulated waveform also can be used to produce a compensating signal which is transmitted back to the brain to effect a desired change in electrical activity therein.

    Inventors: Malech Robert G. (Plainview, NY)

    Assignee: Dorne & Margolin Inc. (Bohemia, NY)

    Appl. No.: 494518

    Filed: August 5, 1974


    **HENDRICUS LOOS** - A MAJOR PLAYER IN NERVOUS SYSTEM MANIPULATION PATENTS

    US Patent # 5,935,054 (August 10, 1999)

    Magnetic Excitation of Sensory Resonances, Loos, Henry

    Abstract --- The invention pertains to influencing the nervous system of a subject by a weak externally applied magnetic field with a frequency near 1/2 Hz. In a range of amplitudes, such fields can excite the 1/2 sensory resonance, which is the physiological effect involved in "rocking the baby"


    US Patent # 6,017,302 (January 25, 2000)

    Subliminal Acoustic Manipulation of Nervous Systems, Loos, Hendricus

    Abstract --- In human subjects, sensory resonances can be excited by subliminal atmospheric acoustic pulses that are tuned to the resonance frequency. The 1/2 Hz sensory resonance affects the autonomic nervous system and may cause relaxation, drowsiness, or sexual excitement, depending on the precise acoustic frequency near 1/2 Hz used. The effects of the 2.5 Hz resonance include slowing of certain cortical processes, sleepiness, and disorientation. For these effects to occur, the acoustic intensity must lie in a certain deeply subliminal range. Suitable apparatus consists of a portable battery-powered source of weak sub-audio acoustic radiation.

    The method and apparatus can be used by the general public as an aid to relaxation, sleep, or sexual arousal, and clinically for the control and perhaps treatment of insomnia, tremors, epileptic seizures, and anxiety disorders. There is further application as a nonlethal weapon that can be used in law enforcement standoff situations, for causing drowsiness and disorientation in targeted subjects. It is then preferable to use venting acoustic monopoles in the form of a device that inhales and exhales air with sub-audio frequency.

    US Patent # 6,091,994 (July 18, 2000)

    Pulsative Manipulation of Nervous Systems, Loos, Hendricus

    Abstract --- Method and apparatus for manipulating the nervous system by imparting subliminal pulsative cooling to the subject's skin at a frequency that is suitable for the excitation of a sensory resonance. At present, two major sensory resonances are known, with frequencies near 1/2 Hz and 2.4 Hz. The 1/2 Hz sensory resonance causes relaxation, sleepiness, ptosis of the eyelids aka droopy eye syndrome (NOTE: Many programmed mind controlled Monarchs/Manchurians have droopy eyelid syndrome, is it due to radio frequency manipulation/influencing) a tonic smile, a "knot" in the stomach, or sexual excitement, depending on the precise frequency used. The 2.4 Hz resonance causes the slowing of certain cortical activities, and is characterized by a large increase of the time needed to silently count backward from 100 to 60, with the eyes closed.

    The invention can be used by the general public for inducing relaxation, sleep, or sexual excitement, and clinically for the control and perhaps a treatment of tremors, seizures, and autonomic system disorders such as panic attacks. Embodiments shown are a pulsed fan to impart subliminal cooling pulses to the subject's skin, and a silent device which induces periodically varying flow past the subject's skin, the flow being induced by pulsative rising warm air plumes that are caused by a thin resistive wire which is periodically heated by electric current pulses.

    HUMAN BODY ELECTRONIC TORTURE LIST OF AREAS TYPICALLY HIT AND THE GLOBAL EFFORT

    US Patent # 6,081,744 (June 27, 2000)

    Electric Fringe Field Generator for Manipulating Nervous Systems, Loos, Hendricus

    Abstract --- Apparatus and method for manipulating the nervous system of a subject through afferent nerves, modulated by externally applied weak fluctuating electric fields, tuned to certain frequencies such as to excite a resonance in neural circuits. Depending on the frequency chosen, excitation of such resonances causes in a human subject relaxation, sleepiness, sexual excitement, or the slowing of certain cortical processes. The electric field used for stimulation of the subject is induced by a pair of field electrodes charged to opposite polarity and placed such that the subject is entirely outside the space between the field electrodes. Such configuration allows for very compact devices where the field electrodes and a battery-powered voltage generator are contained in a small casing, such as a powder box.

    The stimulation by the weak external electric field relies on frequency modulation of spontaneous spiking patterns of afferent nerves. The method and apparatus can be used by the general public as an aid to relaxation, sleep, or arousal, and clinically for the control and perhaps the treatment of tremors and seizures, and disorders of the autonomic nervous system, such as panic attacks.

    US Patent # 6,167,304 (December 26, 2000)

    Pulse Variability in Electric Field Manipulation of Nervous Systems, Loos, Hendricus

    Abstract --- Apparatus and method for manipulating the nervous system of a subject by applying to the skin a pulsing external electric field which, although too weak to cause classical nerve stimulation, modulates the normal spontaneous spiking patterns of certain kinds of afferent nerves. For certain pulse frequencies the electric field stimulation can excite in the nervous system resonances with observable physiological consequences.

    Pulse variability is introduced for the purpose of thwarting habituation of the nervous system to the repetitive stimulation, or to alleviate the need for precise tuning to a resonance frequency, or to control pathological oscillatory neural activities such as tremors or seizures. Pulse generators with stochastic and deterministic pulse variability are disclosed, and the output of an effective generator of the latter type is characterized.

    US Patent # 3,967,616 (July 6, 1976)

    Multichannel System for & Multifactorial Method of Controlling the Nervous System of a Living Organism, Ross, Sidney A.

    Abstract --- A novel method for controlling the nervous system of a living organism for therapeutic and research purposes, among other applications, and an electronic system utilized in, and enabling the practice of, the invented method. Bioelectrical signals generated in specific topological areas of the organism's nervous system, typically areas of the brain, are processed by the invented system so as to produce a sensory stimulus if the system detects the presence or absence, as the case may be, of certain characteristics in the waveform patterns of the bioelectrical signals being monitored. The coincidence of the same or different characteristics in two or more waveform patterns, or the non-coincidence thereof, may be correlated with a certain desired condition of the organism's nervous system likewise, with respect to the coincidence or non-coincidence of different characteristics of a single waveform pattern. In any event, the sensory stimulus provided by the invented system, typically an audio or visual stimulus, or combination thereof, is fed back to the organism which associates its presence with the goal of achieving the desired condition of its nervous system. Responding to the stimulus, the organism can be trained to control the waveform patterns of the monitored bioelectrical signals and thereby, control its own nervous system. The results of the coincidence function permit results heretofore unobtainable.


    NOTE: These weapons were referred to by L. Brezhnev in 1975 when he told then U.S. President J. Carter that there should be a unilateral ban on certain secret weapons “more frightful than the mind of man has ever conceived.” And clearly there are many others that we are yet to learn about including advanced forms of infrasound weapons that can induce organ damage/illness from remote sources (esp. satellites).

    US Patent # 4,082,918 (April 4, 1978)

    Audio Analgesic Unit, Chang, Roland W., et al.

    Abstract --- An audio analgesic unit for use in masking sounds and substituting another sound which includes earmuffs to be used by a dental patient in which speakers are arranged and connected to a patient operated remote control unit to control the sound levels and a master control unit to override the patient remote control unit and operated by an operator, such as a dentist. A beeper indicates operation mode change.

    US Patent # 4,141,344 (February 27, 1979)

    Sound Recording System, Barbara, Louis J.

    Abstract --- In recording an audio program, such as music or voice, on a magnetic tape recorder an A.C. signal generator operating at a frequency below about 14 Hz provides an AC baseline for the audio program signal. This 14 Hz or lower AC signal is sensed by the listener's ear to create an Alpha or Theta state in his brain when the tape is played back.


    US Patent # 4,227,516 (October 14, 1980)

    Apparatus for Electrophysiological Stimulation, Meland, Bruce C., et al.

    Abstract --- Apparatus for the electrophysiological stimulation of a patient is provided for creating an analgesic condition in the patient to induce sleep, treat psychosomatic disorders, and to aid in the induction of electro-hypnosis and altered states of consciousness. The foregoing is achieved by repetitive stimuli in the patient for whom external influences, namely those of sight and sound, are intentionally excluded. The apparatus produces electrical stimulation of the patient in the form of a modulated wave which produces impulses in the delta, theta, alpha and beta regions of the brain's electrical activity, the electrical stimulation being accompanied by two sources of audio stimulation, one of which is a sinusoidal tone modulated by and synchronized with the electrical stimulation, and the other is derived from sound recordings.

    US Patent # 4,191,175 (March 4, 1980)

    Method & Apparatus for Repetitively Producing a Noise-like Audible Signal, Nagle, William L.

    Abstract --- A digital pulse generator and shift register repetitively produce bursts of digital pulses at a first adjustable repetition frequency. The repetition frequency of the pulses in each burst is also adjustable. A pink noise filter accentuates the lower burst frequency components near 7 hz and substantially attenuates all frequency components of the bursts above a first cut-off point near 10 Khz. A tunable band pass amplifier having a center frequency adjustable over a preselected range of frequencies optimally detectable by the average human ear accentuates the pink noise filter output near 2.6 Khz. The tunable amplifier drives an audible signal source with noise-like pulses of varying amplitudes and frequency components. A low pass amplifier may be connected to the pink noise filter to generate a train of pulses having a repetition frequency near 7 hz which pulses a light source in synchronism with the audible noise-like signal.

    US Patent # 4,315,501 (February 16, 1982)

    Learning-Relaxation Device, Gorges, Denis E.

    Abstract --- Disclosed is a device for relaxing, stimulating and/or driving brain wave form function in a human subject. The device comprises, in combination, an eye mask having independently controlled left and right eyepieces and a peripheral light array in each eyepiece, an audio headset having independently controlled left and right earpieces and a control panel which controls light and sound signals to the light arrays and earpieces, respectively. Various control functions allow simultaneous or alternating light and sound pulsations in the left and right light arrays and earpieces, as well as selective phasing between light and sound pulsations.

    US Patent # 4,335,710 (June 22, 1982)

    Device for the Induction of Specific Brain Wave Patterns, Williamson, John

    Abstract --- Brain wave patterns associated with relaxed and meditative states in a subject are gradually induced without deleterious chemical or neurological side effects. A white noise generator (11) has the spectral noise density of its output signal modulated in a manner similar to the brain wave patterns by a switching transistor within a spectrum modulator and converted to an audio signal by acoustic transducer. Ramp generator gradually increases the voltage received by and resultant output frequency of voltage controlled oscillator whereby switching transistor periodically shunts the high frequency components of the white noise signal to ground.

    US Patent # 4,354,505 (October 19, 1982)

    Method of and Apparatus for Testing and Indicating Relaxation State of a Human Subject, Shiga Kazumasa

    Abstract --- In a self-training biofeedback system, a physiological signal representing the state of relaxation of a person using the system is applied to a time counter to generate a binary count output representing the relaxation period. A visual indicator connected to the time counter provides the self-trained person with a quick display of the measured time period so he can gauge the depth of his relaxation.

    US Patent# 4388918 (June 21, 1983)

    Mental harmonization process, Filley, Charles C.

    Abstract --- A state of relaxation or mental harmonization in a subject is created by exposing a color solely to one field of vision of a subject and the complement of that color solely to the other field of vision of the subject while simultaneously exposing an audible tone solely to one ear of the subject and a harmonious tone solely to the other ear of the subject. The color and tones employed are subjectively comfortable and compatible. Preferably, the frequency difference between the two audible tones is one-half the frequency of the audible tone having the lowest frequency.

    US Patent # 4,508,105 (April 2, 1985)

    Shadow Generating Apparatus, Whitten, Glen, et al.

    Abstract --- Disclosed is an apparatus for inducing various brain wave patterns through visual stimulation. The apparatus comprises a pair of spectacles or other viewing apparatus having a liquid crystal display embedded in each lens. By repetitively activating and deactivating the liquid crystals, shadows are generated which are perceived by the subject individual wearing the viewing apparatus. Responding to the frequency of shadow generation, the subject's brain is thereby induced to generate sympathetic brain wave frequencies. The apparatus finds particular utility in the generation of alpha waves. Because learning is enhanced when the brain is in the alpha state, activities such as listening to tapes or lectures and the like can be carried out with greater facility. Shadow generation is accomplished through the use of a timing mechanism for each liquid crystal display and the frequency for each is adjustable over a wide range, permitting synchronous or asynchronous timing.


    US Patent # 4,395,600 (July 26, 1983)

    Auditory Subliminal Message System & Method, Lundy, Rene R., et al .

    Abstract --- Ambient audio signals from the customer shopping area within a store are sensed and fed to a signal processing circuit that produces a control signal which varies with variations in the amplitude of the sensed audio signals. A control circuit adjusts the amplitude of an auditory subliminal anti-shoplifting message to increase with increasing amplitudes of sensed audio signals and decrease with decreasing amplitudes of sensed audio signals. This amplitude controlled subliminal message may be mixed with background music and transmitted to the shopping area. To reduce distortion of the subliminal message, its amplitude is controlled to increase at a first rate slower than the rate of increase of the amplitude of ambient audio signals from the area. Also, the amplitude of the subliminal message is controlled to decrease at a second rate faster than the first rate with decreasing ambient audio signal amplitudes to minimize the possibility of the subliminal message becoming supra-liminal upon rapid declines in ambient audio signal amplitudes in the area. A masking signal is provided with an amplitude which is also controlled in response to the amplitude of sensed ambient audio signals. This masking signal may be combined with the auditory subliminal message to provide a composite signal fed to, and controlled by, the control circuit.

    US Patent # 4,573,449 (March 4, 1986)

    Method for Stimulating the Falling Asleep and/or Relaxing Behavior of a Person, Warnke, Egon F.

    Abstract --- A method and apparatus is provided with which a person suffering from sleeplessness can be more easily relaxed and may more rapidly fall asleep. In particular, sound pulses are emitted by an electro-acoustic transducer, according to the cadence of which, the person seeking to fall asleep is induced to breathe in and out over a predetermined period of time. By suitably selecting the pulse sequence frequency, the pitch and the amplitude of the sound pulses may be adjusted thereby enhancing the process of falling asleep.

    US Patent # 4,616,261 (October 7, 1986)

    Method & Apparatus for Generating Subliminal Visual Messages, Crawford, James R., et al.

    Abstract --- A system for generating a subliminal message during the display of a normal television program on a television receiver utilizes a personal computer to generate an RF carrier modulated with video signals encoding the subliminal message. The computer runs under the control of an application program which stores the subliminal message and also controls the computer to cause it to generate timing signals that are provided to a single pole double-throw switch. The source of the normal television program and the video output of the computer are connected to the two switch inputs and the switch output is connected to the television receiver antenna system. The timing signals cause the switch to normally display the conventional television program and to periodically switch to the computer output to generate the subliminal message. The video output of the computer includes horizontal and vertical synchronizing signals which are of substantially the same frequency as the synchronizing signals incorporated within the normal program source but of an arbitrary phase.

    US Patent # 4,717,343 (January 5, 1988)

    Method of Changing a Person's Behavior, Densky, Alan B.

    Abstract --- A method of conditioning a person's unconscious mind in order to effect a desired change in the person's behavior which does not require the services of a trained therapist. Instead the person to be treated views a program of video pictures appearing on a screen. The program as viewed by the person's unconscious mind acts to condition the person's thought patterns in a manner which alters that person's behavior in a positive way.

    US Patent # 4,692,118 (September 8, 1987)

    Video Subconscious Display Attachment, Mould, Richard E.

    Abstract --- An apparatus and method for introducing messages to the subconscious mind is disclosed, which includes a panel positioned adjacent a television screen, with the panel having non-distractive messages imprinted thereon, such that as the subject consciously focuses his attention on the video screen, his subconscious mind records the message from the panel that is within his peripheral vision.

    US Patent # 4,699,153 (October 13, 1987)

    System for Assessing Verbal Psychobiological, Correlates, Shevrin, Howard, et al.

    Abstract --- A system for assessing psychobiological conditions of a subject utilizes a plurality of words which are selected to be in four categories as critical stimuli. The words are presented by a tachistoscope to the subject in subliminal and supra-liminal modes of operation. Subliminal stimulation of the subject is achieved by presenting the selected words for an exposure period of approximately one millisecond. The supra-liminal exposure time is approximately thirty milliseconds. Prior to stimulation, the subject is diagnosed in accordance with conventional psychoanalytical techniques to establish the presence and nature of a pathological condition. The words are selected and categorized in four groups: pleasant words, unpleasant words, words related to a diagnosed conscious pathological condition, and words related to a diagnosed unconscious pathological condition. The brain wave responses which are evoked by the stimulation are collected via electrodes and analyzed in accordance with a trans-information technique which is based on information signal theory for establishing a probabilistic value which corresponds to the information content of the evoked responses.

    US Patent # 4,734,037 (March 29, 1988)

    Message Screen, McClure, J. Patrick

    Abstract --- A transparent sheet is disclosed having a message thereon. The sheet has a first side adapted to be attached facing a plate which is normally viewed by a viewer and a second side facing the viewer. The message is arranged to be readably intelligible from the second side but is not subliminally visible to the viewer when viewed from a normal viewing distance from the second side under normal viewing conditions. The message has a subliminal effect upon the viewer when viewed from the normal viewing distance from the second side under normal viewing conditions. A viewer can electively subject him or herself to subliminal messages while viewing television at leisure.

    US Patent # 4,821,326 (April 11, 1989)

    Non-Audible Speech Generation Method & Apparatus, MacLeod, Norman

    Abstract --- A non-audible speech generation apparatus and method for producing non-audible speech signals which includes an ultrasonic transducer or vibrator for projecting a series of glottal shaped ultrasonic pulses to the vocal track of a speaker. The glottal pulses, in the approximate frequency spectrum extending from 15 kilohertz to 105 kilohertz, contains harmonics of approximately 30 times the frequency of the acoustical harmonics generated by the vocal cords, but which may nevertheless be amplitude modulated to produce non-audible speech by the speaker's silently mouthing of words. The ultrasonic speech is then received by an ultrasonic transducer disposed outside of the speaker's mouth and electronically communicated to a translation device which down converts the ultrasonic signals to corresponding signals in the audible frequency range and synthesizes the signals into artificial speech.

    US Patent # 4,834,701 (May 30, 1989)

    Apparatus for Inducing Frequency Reduction in Brain Wave, Masaki, Kazumi

    Abstract --- Frequency reduction in human brain wave is inducible by allowing human brain to perceive 4-16 hertz beat sound. Such beat sound can be easily produced with an apparatus, comprising at least one sound source generating a set of low-frequency signals different each other in frequency by 4-16 hertz. Electroencephalographic study revealed that the beat sound is effective to reduce beta-rhythm into alpha-rhythm, as well as to retain alpha-rhythm.

    US Patent # 4,883,067 (November 28, 1989)

    Method & Apparatus for Translating the EEG into Music, Knispel, Joel, et al.

    Abstract --- A method and apparatus for applying a musical feedback signal to the human brain, or any other brain, to induce controllable psychological and physiological responses. A signal representing the ongoing electroencephalographic (EEG) signal of a brain preferably is obtained from the electrode location on the scalp known as CZ or P3 in clinical notation. A signal processor converts the ongoing EEG into electrical signals which are converted into music by synthesizers. The music is acoustically fed back to the brain after a time delay calculated to shift the phase of the feedback in order to reinforce specific or desired ongoing EEG activity from the scalp position of interest. The music is comprised of at least one voice that follows the moment-by-moment contour of the EEG in real time to reinforce the desired EEG activity. The music drives the brain into resonance with the music to provide a closed loop or physiological feedback effect. Preferably, the musical feedback comprises additional voices that embody psychoacoustic principles as well as provide the content and direction normally supplied by the therapist in conventional biofeedback. The invention contemplates numerous applications for the results obtained.


    US Patent # 4,889,526 (December 26, 1989)

    Non-Invasive Method & Apparatus for Modulating Brain Signals, Rauscher, Elizabeth A.

    Abstract --- This invention incorporates the discovery of new principles which utilize magnetic and electric fields generated by time varying square wave currents of precise repetition, width, shape and magnitude to move through coils and cutaneously applied conductive electrodes in order to stimulate the nervous system and reduce pain in humans. Timer means, adjustment means, and means to deliver current to the coils and conductive electrodes are described, as well as a theoretical model of the process. The invention incorporates the concept of two cyclic expanding and collapsing magnetic fields which generate precise wave forms in conjunction with each other to create a beat frequency which in turn causes the ion flow in the nervous system of the human body to be efficiently moved along the nerve path where the locus of the pain exists to thereby reduce the pain. The wave forms are created either in one or more coils, one or more pairs of electrodes, or a combination of the two.

    US Patent # 4,924,744 (May 15, 1990)

    Apparatus for Generating Sound through Low Frequency and Noise Modulation, Lenzen, Reiner

    Abstract --- In an apparatus for generating sound, there are provided a plurality of channels for generating sounds. Each of the channels includes a memory for storing waveform data, and at least one of the channels includes a noise generator so that various kinds of sounds including rhythm sound-effects sound, effects sound-vibrato etc. are generated. There is further provided a controller by which voice sound signal is passed through the channels so that artificial sound, voice sound etc. are generated. There is still further provided a circuit for adjusting an amplitude level of a whole sound which is obtained by mixing output sounds of the channels so that far and near sound is produced. Further, each of the channels includes left and right attenuators which divide a channel sound into left and right channel sounds. Still further, the apparatus comprises a low frequency oscillator for controlling a depth of frequency modulation, and a controller for writing sampling data of a predetermined waveform into serial addresses of a memory.


    US Patent # 4,958,638 (September 25, 1990)

    Non-Contact Vital Signs Monitor, Sharpe, Steven, et al.

    Abstract --- An apparatus for measuring simultaneous physiological parameters such as heart rate and respiration without physically connecting electrodes or other sensors to the body. A beam of frequency modulated continuous wave radio frequency energy is directed towards the body of a subject. The reflected signal contains phase information representing the movement of the surface of the body, from which respiration and heartbeat information can be obtained. The reflected phase modulated energy is received and demodulated by the apparatus using synchronous quadrature detection. The quadrature signals so obtained are then signal processed to obtain the heartbeat and respiratory information of interest.

    US Patent # 5,017,143 (May 21, 1991)

    Method and Apparatus for Producing Subliminal Images, Backus, Alan, et al.

    Abstract --- A method and apparatus to produce more effective visual subliminal communications. Graphic and/or text images, presented for durations of less than a video frame, at organized rhythmic intervals, the rhythmic intervals intended to affect user receptivity, moods or behavior. Subliminal graphic images having translucent visual values locally dependent on background values in order to maintain desired levels of visual contrast.

    US Patent # 5,027,208 (June 25, 1991)

    Therapeutic Subliminal Imaging System, Dwyer, Jr., Joseph, et al.

    Abstract --- A therapeutic subliminal imaging system wherein a selected subliminal message is synchronized with and added to an existing video signal containing a supra-liminal message. A television receiver or video recorder can be used to provide the supraliminal message and a video processing circuit varies the intensity of that perceptible message to incorporate one or more subliminal images.


    US Patent # 5,036,858 (August 6, 1991)

    Method & Apparatus for Changing Brain Wave Frequency, Carter, John L., et al.

    Abstract --- A method for changing brain wave frequency to a desired frequency determines a current brain wave frequency of a user, generates two frequencies with a frequency difference of a magnitude between that of the current actual brain wave frequency and the desired frequency but always within a predetermined range of the current actual brain wave frequency, and produces an output to the user corresponding to the two frequencies. One apparatus to accomplish the method has a computer processor, a computer memory, EEG electrodes along with an amplifier, a programmable timing generator responsive to the computer processor for generating the two frequencies, audio amplifiers and a beat frequency generator driving a visual frequency amplifier.

    US Patent # 5,047,994 (September 10, 1991)

    Supersonic Bone Conduction Hearing Aid and Method, Lenhardt, Martin, et al.

    Abstract --- A supersonic bone conduction hearing aid that receives conventional audiometric frequencies and converts them to supersonic frequencies for connection to the human sensory system by vibration bone conduction. The hearing is believed to use channels of communications to the brain that are not normally used for hearing. These alternative channels do not deteriorate significantly with age as does the normal hearing channels. The supersonic bone conduction frequencies are discerned as frequencies in the audiometric range of frequencies.

    US Patent # 5,052,401 (October 1, 1991)

    Product Detector for a Steady Visual Evoked Potential Stimulator and Product Detector, Sherwin, Gary

    Abstract --- An automated visual testing system is disclosed which presents an alternating steady state visual stimulus to a patient through an optical system that modifies the stimulus image. As the image changes, the patient produces evoked potentials that change. The evoked potentials are detected by a product detector which produces the amplitude of the evoked potentials. The product detector includes filters which isolate the patient's evoked potentials, a modulator which detects the response using the stimulus source frequency and a demodulator that determines the amplitude of the response. The product detector detects the level of the steady state evoked potential signals even in the presence of substantial background noise and extraneous electroencephalograhic signals. These detectors can be used to monitor the evoked potential produced by visual, aural or somatic steady state stimuli. The components described above can be used to produce a system that can determine to which of several different displays an observer is paying attention by providing images that blink at different frequencies and product detectors for each of the stimulus frequencies. The product detector producing the highest output indicates the display upon which the observer is focused.

    US Patent # 5,128,765 (July 7, 1992)

    System for Implementing the Synchronized Superimposition of Subliminal Signals, Dingwall, Rober t

    Abstract --- An apparatus and system for the controlled delivery of a subliminal video and/or audio message on to a source signal from a video tape player or similar. The source signal is divided into audio and video portions. A video processor reads synchronization information from the source signal. A controller transmits a stored subliminal image at designated times to a mixer amplifier fully synchronized with the source signal. Concurrently, an audio subliminal message is applied to the source audio at a volume level regulated at some fraction to the source audio. The combined signals are transmitted to a monitor for undistracted viewing.

    US Patent # 5,134,484 (July 28, 1992)

    Superimposing Method & Apparatus Useful for Subliminal Messages, Willson, Joseph

    Abstract --- Data to be displayed is combined with a composite video signal. The data is stored in a memory in digital form. Each byte of the data is read out in sequential fashion to determine: the recurrence display rate of the data according to the frame sync pulses of the video signal the location of the data within the video image according to the line sync pulses of the video signal and the location of the data display within the video image according to the position information. Synchronization of the data with the video image is derived from the sync pulses of the composite video signal. A similar technique is employed to combine sound data with an audio signal. Data to be displayed may be presented as a subliminal message or may persist for a given time interval. The data may be derived from a variety of sources including a prerecorded or live video signal. The message may be a reminder message displayed upon a television screen to remind the viewer of an appointment. The data may be stored in a variety of different memory devices capable of high speed data retrieval. The data may be generated locally on-line or off-line and transferred to memory which stores the data necessary to create the message.

    US Patent # 5,135,468 (August 4, 1992)

    Method & Apparatus of Varying the Brain State of a Person by Means of an Audio Signal, Meissner, Juergen P.

    Abstract --- A method of varying the brain state of a person includes the steps of supplying the first audio signal to one ear of the person, supplying a second audio signal to the other ear of the person, and substantially continuously varying the frequency of at least one of the first and second audio signals to vary the brain state of the person.

    US Patent # 5,151,080 (September 29, 1992)

    Method & Apparatus for Inducing & Establishing a Changed State of Consciousness, Bick, Claus

    Abstract --- An electroacoustic device includes a sound generator as well as a system for producing synthetic human speech, connected to a modulation stage for superimposing the output signals thereof. The superimposed output signals are applied via an amplifier stage to one of a headphone system or loudspeaker system.

    US Patent # 5,159,703 (October 27, 1992)

    Silent Subliminal Presentation System, Lowery, Oliver

    Abstract --- A silent communications system in which non-aural carriers, in the very low or very high audio frequency range or in the adjacent ultrasonic frequency spectrum, are amplitude or f requency modulated with the desired intelligence and propagated acoustically or vibrationally, for inducement into the brain, typically through the use of loudspeakers, earphones or piezoelectric transducers.

    US Patent # 5,170,381 (December 8, 1992)

    Method for Mixing Audio Subliminal Recordings, Taylor, Eldon, et al.

    Abstract --- Audio subliminal recordings are made in which in addition to using a primary carrier, such as music, two audio channels are used to deliver subliminal messages to the brain. On one channel, accessing the left brain hemisphere, the message delivered is meaningfully spoken, forward-masked, permissive affirmations delivered in a round-robin manner by a male voice, a female voice and a child's voice. On the other channel, accessing the right brain, directive messages, in the same voices, are recorded in backward-masked (or meta-contrast). The three voices are recording in round-robin fashion with full echo reverberation. The audio tracks are mixed using a special processor which converts sound frequencies to electrical impulses and tracks the subliminal message to synchronize the subliminal message in stereo with the primary carrier. The processor maintains constant gain differential between the primary carrier and the subliminal verbiage and, with the subliminal verbiage being recorded with round-robin, full echo reverberation, ensures that none of a message is lost. The primary carrier should be continuous music without breaks or great differences in movements.


    US Patent # 5,175,571 (December 29, 1992)

    Glasses with Subliminal Message , Tanefsky, Faye, et al.

    Abstract --- A pair of subliminal imaging spectacles is provided with a matched pair of visual subliminal images designed and placed so as to merge into one image due to the stereoscopic effect of human vision and thus to impart a subliminal message to the wearer.


    US Patent # 5,194,008 (March 16, 1993)

    Subliminal Image Modulation Projection and Detection System and Method, Mohan, William L., et al.

    Abstract --- Weapon training simulation system including a computer operated video display scene whereon is projected a plurality of visual targets. The computer controls the display scene and the targets, whether stationary or moving, and processes data of a point of aim sensor apparatus associated with a weapon operated by a trainee. The sensor apparatus is sensitive to non-visible or subliminal modulated areas having a controlled contrast of brightness between the target scene and the targets. The sensor apparatus locates a specific subliminal modulated area and the computer determines the location of a target image on the display scene with respect to the sensor apparatus

    US Patent # 5,213,562 (May 25, 1993)

    Method of Inducing Mental, Emotional and Physical States of Consciousness, Monroe, Robert A.

    Abstract --- A method having applicability in replication of desired consciousness states in the training of an individual to replicate such a state of consciousness without further audio stimulation and in the transferring of such states from one human being to another through the imposition of one individual's EEG, superimposed on desired stereo signals, on another individual, by inducement of a binaural beat phenomenon.

    US Patent # 5,215,468 (June 1, 1993)

    Method and Apparatus for Introducing Subliminal Changes to Audio Stimuli, Lauffer, Martha A., et al.

    Abstract --- A method and apparatus for introducing gradual changes to an audio signal so that the changes are subliminal. The changes can involve tempo and volume, for example, and can take the form of a gentle gradient having ever increasing/decreasing ramp-like changes over a sufficient duration, or a more complex program involving several gentle gradients. In the preferred embodiment, an enhanced audio play-back device such as a portable audio cassette recorder can be programmed to subliminally alter the characteristics of a standard pre-recorded tape containing music, for example. As a motivational tool during walking, jogging or other repetitive exercise, the tempo is gradually increased over a period of time to encourage a corresponding gradual (and subliminal) increase in physical exertion by a user whose rate of movement is proportional to the tempo of the music. The tempo can be either manually changed in conjunction with a subliminal program, or by itself in an override mode, or by itself in a version of the present-inventive audio play-back device which allows only manual tempo alternation. In an alternate embodiment, a special pre-recorded tape contains subliminal changes in tempo, for example, for play-back on a standard audio cassette recorder (which operates at one speed, only) to cause the same effect as the preferred embodiment.

    US Patent # 5,221,962 (June 22, 1993)

    Subliminal Device having Manual Adjustment of Perception Level of Subliminal Messages, Backus, Alan L., et al.

    Abstract --- A method and apparatus for presenting subliminal visual and/or audio messages which allows user verification of message content and presence, as well as proper adjustment of message obviousness while accounting for ambient conditions and user sensitivities is disclosed. This method and apparatus also presents synchronized reinforced sensory input of subliminal messages. This is performed by simultaneously overlaying images received from a VCR over a plurality of television signals. This apparatus directs overlay images over RF television signals having both audio and video components.

    US Patent # 5,224,864 (July 6, 1993)

    Method of Recording and Reproducing Subliminal Signals that are 180 Degrees Out of Phase With, Blake F.

    Abstract --- A subliminal recording includes both subliminal message and mask signals applied to both tracks of a two track recording medium. The subliminal message signals are identical in content, and are recorded in an out-of-phase relationship. The mask signals are recorded in phase. The resulting recording may be utilized in the conventional manner for subliminal recordings. By combining the composite signals in an inverted relationship, the mask signals cancel while the subliminal message signals are additive, thus allowing the presence of the subliminal message signal to be confirmed on the recording.


    US Patent # 5,270,800 (December 14, 1993)

    Subliminal Message Generator, Sweet. Robert L.

    Abstract --- A combined subliminal and supraliminal message generator for use with a television receiver permits complete control of subliminal messages and their manner of presentation. A video synchronization detector enables a video display generator to generate a video message signal corresponding to a received alphanumeric text message in synchronism with a received television signal. A video mixer selects either the received video signal or the video message signal for output. The messages produced by the video message generator are user selectable via a keyboard input. A message memory stores a plurality of alphanumeric text messages specified by user commands for use as subliminal messages. This message memory preferably includes a read only memory storing predetermined sets of alphanumeric text messages directed to differing topics. The sets of predetermined alphanumeric text messages preferably include several positive affirmations directed to the left brain and an equal number of positive affirmations directed to the right brain that are alternately presented subliminally. The left brain messages are presented in a linear text mode, while the right brain messages are presented in a three dimensional perspective mode. The user can control the length and spacing of the subliminal presentations to accommodate differing conscious thresholds. Alternative embodiments include a combined cable television converter and subliminal message generator, a combine television receiver and subliminal message generator and a computer capable of presenting subliminal messages.

    US Patent # 5,245,666 (September 14, 1993)

    Personal Subliminal Messaging System, Mikell, Bruce T.

    Abstract --- A personal subliminal messaging system includes a wide range linear subliminal modulator (43), a digital audio recording or play device (46), a microphone (51) to pick up the sound at the ear, and an earpiece (50) to deliver the subliminal message. The sound level at the user's ear is detected and measured. After rise time and decay conditioning of the varying dc control signal, the wide range linear modulator (43) uses this signal to control the level of the message to the earpiece (50). The user adjusts the system for a liminal of a subliminal level. The psychoacoustic phenomena of Post Masking is used to increase the integrity of the message in subliminal messaging systems.

    US Patent # 5,289,438 (February 22, 1994)

    Method & System for Altering Consciousness, Gall, James

    Abstract --- A system for altering the states of human consciousness involves the simultaneous application of multiple stimuli, preferable sounds, having differing frequencies and wave forms. The relationship between the frequencies of the several stimuli is exhibited by the equation g = 2.sup.n/4 .multidot.f where: f = frequency of one stimulus g = frequency of the other stimuli or stimulus and n = a positive or negative integer which is different for each other stimulus.

    US Patent # 5,330,414 (July 19, 1994)

    Brain Wave Inducing Apparatus, Yasushi, Mitsuo

    Abstract --- A random signal generator outputs a random noise signal to a band pass filter which selectively passes frequency components in the frequency range of a desired brain wave from a subject. The output of the band pass filter is supplied to an automatic level controller. The automatic level controller sets the output of band pass filter to a predetermined amplitude. Then, the output of the automatic level controller is fed to a stimulating light generator, which converts the output of the automatic level controller into a light signal for stimulating the subject in order to induce the desired brain wave from the subject. The light signal is then emitted into the subject's eyes.

    US Patent # 5,352,181 (October 4, 1994)

    Method & Recording for Producing Sounds and Messages, Davis, Mark E.

    Abstract --- A method and recording for use in achieving Alpha and Theta brain wave states and effecting positive emotional states in humans to enhance learning and self-improvement, is provided which includes a medium having a musical composition recorded thereon with an initial tempo decreasing to a final tempo and verbal phrases, comprising between approximately 4 and approximately 8 words, recorded in synchrony with the decreasing initial tempo.


    US Patent # 5,356,368 (October 18, 1994)

    Method & Apparatus for Inducing Desired States of Consciousness, Monroe, Robert E.

    Abstract --- Improved methods and apparatus for entraining human brain patterns, employing frequency following response (FFR) techniques, facilitate attainment of desired states of consciousness. In one embodiment, a plurality of electroencephalogram (EEG) waveforms, characteristic of a given state of consciousness, are combined to yield an EEG waveform to which subjects may be susceptible more readily. In another embodiment, sleep patterns are reproduced based on observed brain patterns during portions of a sleep cycle entrainment principles are applied to induce sleep. In yet another embodiment, entrainment principles are applied in the work environment, to induce and maintain a desired level of consciousness. A portable device also is described.

    US Patent # 5,392,788 (February 28, 1995)

    Method and Device for Interpreting Concepts and Conceptual Thought , Hudspeth, William J.

    Abstract --- A system for acquisition and decoding of EP and SP signals is provided which comprises a transducer for presenting stimuli to a subject, EEG transducers for recording brainwave signals from the subject, a computer for controlling and synchronizing stimuli presented to the subject and for concurrently recording brainwave signals, and either interpreting signals using a model for conceptual perceptional and emotional thought to correspond EEG signals to thought of the subject or comparing signals to normative EEG signals from a normative population to diagnose and locate the origin of brain dysfunctional underlying perception, conception, and emotion.

    US Patent # 5,479,941 (January 2, 1996)

    Device for Inducing Altered States of Consciousness, Harner, Michael

    Abstract --- A rotating device for producing altered states of consciousness in a subject is provided. The subject's body rotates about a point in the center of the body support means at a speed between about 10 and about 60 revolutions per minute. In a preferred embodiment, the direction of rotation is periodically reversed.


    US Patent # 5,480,374 (January 2, 1996)

    Method and Apparatus for Reducing Physiological Stress, Van Dick, Robert

    Abstract --- Physiological stress in a human subject is treated by generating a weak electromagnetic field about a grounded electrode by the application of pulses of between 5 and 50 microseconds each at a pulse rate of between 0.5K and 10K pulses per second to a power electrode, the power electrode and grounded electrode being coupled to high voltage pulse generation means. A subject is positioned within the weak electromagnetic field for a period of time sufficient to cause an increase in his or her alpha or theta brain wave levels.


    US Patent # 5,522,386 (June 4, 1996)

    Apparatus for Determination of the Condition of the Vegetative Part of the Nervous System, Lerner, Eduard

    Abstract --- Apparatus for use in the determination of the condition of the vegetative part of the nervous system and/or of sensory functions of an organism, i.e. a human being or animal. The apparatus comprises devices for generating and supplying to said organism at least one sensory stimulus chosen from a group of sensory stimuli, such as visual, sound, olfactory, gustatory, tactile or pain stimuli, and devices for measuring the skin potential and the evoked response of the organism to a stimulus. The measured data are processed by processing devices for automatically controlling the supply of at least one stimulus for providing a non-rhythmical sequence of stimuli. Preferably, pairs of stimuli are supplied for developing a conditioned reflex.


    US Patent # 5,507,291 (April 16, 1996)

    Method & Apparatus for Remotely Determining Information as to Person's Emotional State, Stirbl, et al.

    Abstract --- In a method for remotely determining information relating to a person's emotional state, an waveform energy having a predetermined frequency and a predetermined intensity is generated and wirelessly transmitted towards a remotely located subject. Waveform energy emitted from the subject is detected and automatically analyzed to derive information relating to the individual's emotional state. Physiological or physical parameters of blood pressure, pulse rate, pupil size, respiration rate and perspiration level are measured and compared with reference values to provide information utilizable in evaluating interviewee's responses or possibly criminal intent in security sensitive areas.


    US Patent # 5,539,705 (July 23, 1996)

    Ultrasonic Speech Translator and Communication System, Akerman, M., et al.

    Abstract --- A wireless communication system, undetectable by radio-frequency methods, for converting audio signals, including human voice, to electronic signals in the ultrasonic frequency range, transmitting the ultrasonic signal by way of acoustic pressure waves across a carrier medium, including gases, liquids and solids, and reconverting the ultrasonic acoustic pressure waves back to the original audio signal. This invention was made with government support under Contract DE-ACO5-840R2l400, awarded by the US Department of Energy to Martin Marietta Energy Systems, Inc.


    US Patent # 5,551,879 (September 3, 1996)

    Dream State Teaching Machine, Raynie, Arthur D.

    Abstract --- A device for enhancing lucidity in the dream state of an individual. The device includes electronic circuitry incorporated into a headband for the user to wear while sleeping. The circuitry includes a detector for fitting adjacent to the eye of the sleeping individual, for detecting Rapid Eye Movement (REM), which occurs during the dream state. The detector emits a signal that is evaluated by additional circuitry to determine whether or not REM sleep is occurring. If REM sleep is occurring, a signal is generated to operate a recorded, which typically plays prerecorded messages through the headphones engaging the ear of the sleeping individual.


    US Patent # 5,562,597 (October 8, 1996)

    Method & Apparatus for Reducing Physiological Stress, Van Dick, Robert C.

    Abstract --- Physiological stress in a human subject is treated by generating a weak electromagnetic field about a quartz crystal. The crystal is stimulated by applying electrical pulses of pulse widths between 0.1 and 50 microseconds each at a pulse repetition rate of between 0.5K and 10K pulses per second to a conductor positioned adjacent to the quartz crystal thereby generating a weak electromagnetic field. A subject is positioned within the weak electromagnetic field for a period of time sufficient to reduce stress.

    US Patent # 5,586,967 (December 24, 1996)

    Method & Recording for Producing Sounds and Messages to Achieve Alpha & Theta Brainwave States, Davis, Mark E.

    Abstract --- A method and recording for the use in achieving alpha and theta brainwave states and effecting positive emotional states in humans, is provided which includes a medium having a musical composition thereon with an initial tempo decreasing to a final tempo and verbal phrases recorded in synchrony with the decreasing tempo.

    US Patent # 5,644,363 (July 1, 1997)

    Apparatus for Superimposing Visual Subliminal Instructions on a Video Signal, Mead, Talbert

    Abstract --- A subliminal video instructional device comprises circuitry for receiving an underlying video signal and presenting this signal to horizontal and vertical synchronization detection circuits, circuitry for generating a subliminal video message synchronized to the underlying video signal, and circuitry for adding the subliminal video message to the underlying video signal to create a combination video signal.

    US Patent # 5,649,061 (July 15, 1997)

    Device and Method for Estimating a Mental Decision, Smyth, Christopher

    Abstract --- A device and method for estimating a mental decision to select a visual cue from the viewer's eye fixation and corresponding single event evoked cerebral potential. The device comprises an eye tracker, an electronic biosignal processor and a digital computer. The eye tracker determines the instantaneous viewing direction from oculometric measurements and a head position and orientation sensor.

    The electronic processor continually estimates the cerebral electroencephalogramic potential from scalp surface measurements following corrections for electrooculogramic, electromyogramic and electrocardiogramic artifacts. The digital computer analyzes the viewing direction data for a fixation and then extracts the corresponding single event evoked cerebral potential. The fixation properties, such as duration, start and end pupil sizes, end state (saccade or blink) and gaze fixation count, and the parametric representation of the evoked potential are all inputs to an artificial neural network for outputting an estimate of the selection interest in the gaze point of regard. The artificial neural network is trained off-line prior to application to represent the mental decisions of the viewer. The device can be used to control computerized machinery from a video display by ocular gaze point of regard alone, by determining which visual cue the viewer is looking at and then using the estimation of the task-related selection as a selector switch.


    US Patent # 5,784,124 (July 21, 1998)

    Supraliminal Method of Education, D'Alitalia, Joseph A., et al.

    Abstract --- A method of behavior modification involves having a patient view supraliminal video messages superimposed upon an underlying video presentation. The video messages incorporate messages wherein at least some of the messages link a desired modified behavior to positive feelings of the patient. A supraliminal message generator and superimposer iteratively selects individual messages for display from the sequence of messages, decompressing the messages as required, and places the selected messages in a buffer memory of a video generation device. A processor of the supraliminal message generator and superimposer then fades the selected message from an invisible level to a visible level on the video display, and then fades the selected message from the visible level back to the invisible level.


    US Patent # 5,868,103 (February 9, 1999)

    Method and Apparatus for Controlling an Animal, Boyd, Randal

    Abstract --- An apparatus for controlling an animal wherein the animal receives a control stimulus of the release of a substance having an adverse effect upon the animal as a corrective measure. The apparatus includes a transmitter for producing a transmitted field, and a releasable collar for attaching to the neck of the animal. The collar includes a receiver for receiving the transmitted field and for producing a received signal, a control circuit for determining when the received signal indicates that the animal requires a corrective measure and for producing a control signal, a container for containing the substance having an adverse effect upon the animal, and a mechanism for releasing the substance from the container into the presence of the animal upon the production of the control signal by the control circuit. In use, the transmitter is set to produce the transmitted field and the collar is attached to the neck of the animal. As the animal moves about, the receiver in the collar receives the transmitted field and produces a received signal. The control circuit determines when the received signal indicates that the animal requires a corrective measure. A control signal is produced by the control circuit when the determination is made that the animal requires a corrective measure. Upon the production of the control signal, the substance having an adverse effect upon the animal is released from the container and into the presence of the animal.


    US Patent # 5,922,016 (July 13, 1999)

    Apparatus for Electric Stimulation of Auditory Nerves of a Human Being, Wagner, Hermann

    Abstract --- Apparatus for electric stimulation and diagnostics of auditory nerves of a human being, e.g. for determination of sensation level (SL), most conformable level (MCL) and uncomfortable level (UCL) audibility curves, includes a stimulator detachably secured to a human being for sending a signal into a human ear, and an electrode placed within the human ear and electrically connected to the stimulator by an electric conductor for conducting the signals from the stimulator into the ear. A control unit is operatively connected to the stimulator for instructing the stimulator as to characteristics of the generated signals being transmitted to the ear.


    US Patent # 6,039,688 (March 21, 2000)

    Therapeutic Behavior Modification Program, Compliance Monitoring and Feedback System, Douglas, Peter, et al.

    Abstract --- A therapeutic behavior modification program, compliance monitoring and feedback system includes a server-based relational database and one or more microprocessors electronically coupled to the server. The system enables development of a therapeutic behavior modification program having a series of milestones for an individual to achieve lifestyle changes necessary to maintain his or her health or recover from ailments or medical procedures.

    The program may be modified by a physician or trained case advisor prior to implementation. The system monitors the individual's compliance with the program by prompting the individual to enter health-related data, correlating the individual's entered data with the milestones in the behavior modification program and generating compliance data indicative of the individual's progress toward achievement of the program milestones.

    The system also includes an integrated system of graphical system interfaces for motivating the individual to comply with the program. Through the interfaces, the individual can access the database to review the compliance data and obtain health information from a remote source such as selected sites on the Internet. The system also provides an electronic calendar integrated with the behavior modification program for signaling the individual to take action pursuant to the behavior modification program in which the calendar accesses the relational database and integrates requirements of the program with the individual's daily schedule, and an electronic journal for enabling the individual to enter personal health-related information into the system on a regular basis.

    In addition, the system includes an electronic meeting room for linking the individual to a plurality of other individuals having related behavior modification programs for facilitating group peer support sessions for compliance with the program. The system enables motivational media presentations to be made to the individuals in the electronic meeting room as part of the group support session to facilitate interactive group discussion about the presentations. The entire system is designed around a community of support motif including a graphical electronic navigator operable by the individual to control the microprocessor for accessing different parts of the system.

    US Patent # 6,052,336 (April 18, 2000)

    Apparatus and Method of Broadcasting Audible Sound Using Ultrasonic Sound as a Carrier, Lowrey, Austin, III

    Abstract --- An ultrasonic sound source broadcasts an ultrasonic signal which is amplitude and/or frequency modulated with an information input signal originating from an information input source. If the signals are amplitude modulated, a square root function of the information input signal is produced prior to modulation. The modulated signal, which may be amplified, is then broadcast via a projector unit whereupon an individual or group of individual’s located in the broadcast region detect the audible sound.


    US Patent # 5,954,629 (September 21, 1999)

    Brain Wave Inducing System, Yanagidaira, Masatoshi, et al.

    Abstract --- Sensors are provided for detecting brain waves of a user, and a band-pass filter is provided for extracting a particular brain waves including an .alpha. wave included in a detected brain wave. The band-pass filter comprises a first band-pass filter having a narrow pass band, and a second band-pass filter having a wide pass band. One of the first and second band-pass filters is selected, and a stimulation signal is produced in dependency on an .alpha. wave extracted by a selected band-pass filter. In accordance with the stimulation signal, a stimulation light is emitted to the user in order to induce the user to relax or sleeping state.


    US Patent # 5,954,630 (September 21, 1999)

    FM Theta-Inducing Audible Sound , Masaki, Kazumi, et al.

    Abstract --- An audible sound of modulated wave where a very low-frequency wave of about 20 hertz or lower is superposed on an audio low-frequency wave effectively stimulates FM theta in human brain waves to improve attention and concentration during mental tasks when auditorily administered. The audible sound is also effective in stimulation of human alpha wave when the very low-frequency wave lies within the range of about 2-10 hertz. Such audible sound is artificially obtainable by generating an electric signal which contains such a modulated wave, and transducing it into audible sound wave.


    US Patent # 6,006,188 (December 21, 1999)

    Speech Signal Processing for Determining Psychological or Physiological Characteristics, Bogdashevsky, Rostislav, et al.

    Abstract --- A speech-based system for assessing the psychological, physiological, or other characteristics of a test subject is described. The system includes a knowledge base that stores one or more speech models, where each speech model corresponds to a characteristic of a group of reference subjects. Signal processing circuitry, which may be implemented in hardware, software and/or firmware, compares the test speech parameters of a test subject with the speech models.

    In one embodiment, each speech model is represented by a statistical time-ordered series of frequency representations of the speech of the reference subjects. The speech model is independent of a priori knowledge of style parameters associated with the voice or speech. The system includes speech parameterization circuitry for generating the test parameters in response to the test subject's speech. This circuitry includes speech acquisition circuitry, which may be located remotely from the knowledge base. The system further includes output circuitry for outputting at least one indicator of a characteristic in response to the comparison performed by the signal processing circuitry. The characteristic may be time-varying, in which case the output circuitry outputs the characteristic in a time-varying manner. The output circuitry also may output a ranking of each output characteristic.

    In one embodiment, one or more characteristics may indicate the degree of sincerity of the test subject, where the degree of sincerity may vary with time. The system may also be employed to determine the effectiveness of treatment for a psychological or physiological disorder by comparing psychological or physiological characteristics, respectively, before and after treatment.

    Patent # 6,011,991 (January 4, 2000)

    Communication System & Method Including Brain Wave Analysis, Mardirossian, Aris

    Abstract --- A system and method for enabling human beings to communicate by way of their monitored brain activity. The brain activity of an individual is monitored and transmitted to a remote location (e.g. by military drone or satellite). At the remote location, the monitored brain activity is compared with pre-recorded normalized brain activity curves, waveforms, or patterns to determine if a match or substantial match is found. If such a match is found, then the computer at the remote location determines that the individual was attempting to communicate the word, phrase, or thought corresponding to the matched stored normalized signal.


    US Patent # 6,122,322 (September 19, 2000)

    Subliminal Message Protection, Jandel, Magnus

    Abstract --- The present invention relates to a method and to a system for detecting a first context change between two frames. When a second context change between a further two frames occurs within a predetermined time interval, the frames accommodated within the two context changes are defined as a subliminal message. An alarm is sent to an observer upon detection of a subliminal message.


    US Patent # 6,135,944 (October 24, 2000)

    Method of Inducing Harmonious States of Being, Bowman, Gerard D., et al.

    Abstract --- A method of inducing harmonious states of being using vibrational stimuli, preferably sound, comprised of a multitude of frequencies expressing a specific pattern of relationship. Two base signals are modulated by a set of ratios to generate a plurality of harmonics. The harmonics are combined to form a "fractal" arrangement.


    US Patent # 6,239,705 (May 29,2001)

    Intra-Oral Electronic Tracking Device, Glen, Jeffrey

    Abstract --- An improved stealthy, non-surgical, biocompatible electronic tracking device is provided in which a housing is placed intra-orally. The housing contains microcircuitry. The microcircuitry comprises a receiver, a passive mode to active mode activator, a signal decoder for determining positional fix, a transmitter, an antenna, and a power supply. Optionally, an amplifier may be utilized to boost signal strength.

    The power supply energizes the receiver. Upon receiving a coded activating signal, the positional fix signal decoder is energized, determining a positional fix. The transmitter subsequently transmits through the antenna a position locating signal to be received by a remote locator. In another embodiment of the present invention, the microcircuitry comprises a receiver, a passive mode to active mode activator, a transmitter, an antenna and a power supply. Optionally, an amplifier may be utilized to boost signal strength. The power supply energizes the receiver. Upon receiving a coded activating signal, the transmitter is energized. The transmitter subsequently transmits through the antenna a homing signal to be received by a remote locator.

    US Patent # 6,258,022 (July 10,2001)

    Behavior Modification, Rose, John

    Abstract --- Behavior modification of a human subject takes place under hypnosis, when the subject is in a relaxed state. A machine plays back a video or audio recording, during which the subject is instructed to activate a device to create a perceptible stimulation which is linked, through the hypnosis, with a visualization of enhanced or improved performance. After the hypnosis, the user can reactivate the device at will, whenever the improved performance, such as an improved sporting performance, is desired. This will again create the perceptible stimulation and thus induce the required visualization.


    US Patent # 6,292,688 (September 18, 2001)

    Method and Apparatus for Analyzing Neurological Response to Emotion-Inducing Stimuli, Patton, Richard

    Abstract --- A method of determining the extent of the emotional response of a test subject to stimuli having a time-varying visual content, for example, an advertising presentation. The test subject is positioned to observe the presentation for a given duration, and a path of communication is established between the subject and a brain wave detector/analyzer.

    The intensity component of each of at least two different brain wave frequencies is measured during the exposure, and each frequency is associated with a particular emotion. While the subject views the presentation, periodic variations in the intensity component of the brain waves of each of the particular frequencies selected is measured. The change rates in the intensity at regular periods during the duration are also measured. The intensity change rates are then used to construct a graph of plural coordinate points, and these coordinate points graphically establish the composite emotional reaction of the subject as the presentation continues.


    US Patent # 6,426,919 (July 30, 2002)

    Portable and Hand-Held Device for Making Humanly Audible Sounds, Williams, Gerosa.

    Abstract --- A portable and hand-held device for making humanly audible sounds responsive to the detecting of ultrasonic sounds. The device includes a hand-held housing and circuitry that is contained in the housing.

    The circuitry includes a microphone that receives the ultrasonic sound, a first low voltage audio power amplifier that strengthens the signal from the microphone, a second low voltage audio power amplifier that further strengthens the signal from the first low voltage audio power amplifier, a 7-stage ripple carry binary counter that lowers the frequency of the signal from the second low voltage audio power amplifier so as to be humanly audible, a third low voltage audio power amplifier that strengthens the signal from the 7-stage ripple carry binary counter, and a speaker that generates a humanly audible sound from the third low voltage audio power amplifier.


    US Patent # 6,487,531 (November 26, 2002)

    Signal Injection Coupling into the Human Vocal Tract, Tosaya, Carol

    Abstract --- A means and method are provided for enhancing or replacing the natural excitation of the human vocal tract by artificial excitation means, wherein the artificially created acoustics present additional spectral, temporal, or phase data useful for (1) enhancing the machine recognition robustness of audible speech or (2) enabling more robust machine-recognition of relatively inaudible mouthed or whispered speech.

    The artificial excitation (a) may be arranged to be audible or inaudible, (b) may be designed to be non-interfering with another user's similar means, (c) may be used in one or both of a vocal content-enhancement mode or a complimentary vocal tract-probing mode, and/or (d) may be used for the recognition of audible or inaudible continuous speech or isolated spoken commands.


    US Patent # 6,488,617 (December 3, 2002)

    Method and Device for Producing a Desired Brain State, Katz, Bruce

    Abstract --- A method and device for the production of a desired brain state in an individual contain means for monitoring and analyzing the brain state while a set of one or more magnets produce fields that alter this state. A computational system alters various parameters of the magnetic fields in order to close the gap between the actual and desired brain state. This feedback process operates continuously until the gap is minimized and/or removed.


    US Patent # 6,506,148 (January 14, 2003)

    Nervous System Manipulation by EM Fields from Monitors, Loos, Hendricus

    Abstract --- Physiological effects have been observed in a human subject in response to stimulation of the skin with weak electromagnetic fields that are pulsed with certain frequencies near 1/2 Hz or 2.4 Hz, such as to excite a sensory resonance. Many computer monitors and TV tubes, when displaying pulsed images, emit pulsed electromagnetic fields of sufficient amplitudes to cause such excitation.

    It is therefore possible to manipulate the nervous system of a subject by pulsing images displayed on a nearby computer monitor or TV set. For the latter, the image pulsing may be imbedded in the program material, or it may be overlaid by modulating a video stream, either as an RF signal or as a video signal. The image displayed on a computer monitor may be pulsed effectively by a simple computer program. For certain monitors, pulsed electromagnetic fields capable of exciting sensory resonances in nearby subjects may be generated even as the displayed images are pulsed with subliminal intensity.


    BIOSCIENTIST JOHN J. MCMURTREY - THE MICROWAVE HIGH-TECH "HEARING VOICES" EFFECT OF BEAMED MICROWAVE TECHNOLOGY

    Research and studies reveal factually that technology known as Neurophone, Microwave Voice to Skull/Hearing Voices Effect, Artificial or Synthetic Telepathy, Frey Effect, Neural Decoding or Artificial, Synthetic, or Subliminal Hearing Voices as shown capable by the patents, 100% mimic, precisely the definition of textbook Nazi Psychiatry Schizophrenia.

    Some believe that schizophrenia factually is a term coined, similar to "non-lethal" weapons, which are factually deadly, used strategically by agencies wanting to continue ongoing testing of technology which has been around for decades. In fact, research was ongoing before some of the first patents in the 60s and used on unsuspecting individuals. The Associations of Psychiatry, in both the US and Canada, were among the first agencies documented to be running massive technology testing programs.

    Today, many, many people are, or have been, erroneously misdiagnosed as a result of disbelief of the reality of this, again, patented subliminal message carrying technology and verbal assault from operation centers, which carries the operator(s) voice, through radio waves, today from the state-of-the-art operations, directly into the human brain designed to technologically harass the targeted individual and push the target over the edge.

    Many are also are being misdiagnosed due to a lack of any ability to investigate or confirm the reality of what is happening today by physicians of what the target is proclaiming or that it is factually the result of patented technology.

    MICROWAVE CONGRUENCE - Is in agreement or harmony compatibility, i.e., "The results show microwaves are quite good congruence with decades of human experimentation studies"

    The microwave radio frequency technology can be used to beam voices directly into the human brain of which no one can hear except the target and is then strategically used discredited as schizo!

    SURFING THE APOCALYPSE - CAPABILITIES FOR CONTROL

    US PATENT 6,506,148 - NERVOUS SYSTEM MANIPULATION BY ELECTROMAGNETIC FIELDS FROM MONITORS

    WORKS HAND-IN-HAND WITH VERBAL TECHNOLOGICAL HARASSMENT TO PUSH A TARGET OVER THE EDGE

    Physiological effects have been observed in a human subject in response to stimulation of the skin with weak electromagnetic fields that are pulsed with certain frequencies near 1/2 Hz or 2.4 Hz, such as to excite a sensory resonance. Many computer monitors and TV tubes, when displaying pulsed images, emit pulsed electromagnetic fields of sufficient amplitudes to cause such excitation. It is therefore possible to manipulate the nervous system of a subject by pulsing images displayed on a nearby computer monitor or TV set.

    For the latter, the image pulsing may be imbedded in the program material, or it may be overlaid by modulating a video stream, either as an RF signal or as a video signal. The image displayed on a computer monitor may be pulsed effectively by a simple computer program. For certain monitors, pulsed electromagnetic fields capable of exciting sensory resonances in nearby subjects may be generated even as the displayed images are pulsed with subliminal intensity. (Courtesy of rense.com)

    US PATENT 4,717,343 -- METHOD OF CHANGING A PERSON'S BEHAVIOR

    SUBCONSCIOUS PROGRAMMING

    A method of conditioning a person's unconscious mind in order to effect a desired change in the person's behavior which does not require the services of a trained therapist. Instead the person to be treated views a program of video pictures appearing on a screen. The program as viewed by the person's unconscious mind acts to condition the person's thought patterns in a manner which alters that person's behavior in a positive way.

    SOURCE: Judy Wall, Mike Coyle and Jan Wiesemann.

    Paranoia Magazine Issue 24 Fall 2000 -Article -'Technology to Your Mind' - By Judy Wall

    US PATENT 5,270,800 --SUBLIMINAL MESSAGE GENERATOR

    THOUGHTS MATERIALIZE WHICH THE TARGET BELIEVE ARE HIS/HER OWN AND EVEN MIMIC THE TARGET'S VOICE

    A combined subliminal and supraliminal message generator for use with a television receiver permits complete control of subliminal messages and their manner of presentation. A video synchronization detector enables a video display generator to generate a video message signal corresponding to a received alphanumeric text message in synchronism with a received television signal. A video mixer selects either the received video signal or the video message signal for output.

    The messages produced by the video message generator are user selectable via a keyboard input. A message memory stores a plurality of alphanumeric text messages specified by user commands for use as subliminal messages. This message memory preferably includes a read only memory storing predetermined sets of alphanumeric text messages directed to differing topics. The sets of predetermined alphanumeric text messages preferably include several positive affirmations directed to the left brain and an equal number of positive affirmations directed to the right brain that are alternately presented subliminally. The left brain messages are presented in a linear text mode, while the right brain messages are presented in a three dimensional perspective mode. The user can control the length and spacing of the subliminal presentations to accommodate differing conscious thresholds.

    Alternative embodiments include a combined cable television converter and subliminal message generator, a combine television receiver and subliminal message generator and a computer capable of presenting subliminal messages.

    SOURCE: Judy Wall, Mike Coyle and Jan Wiesemann.

    Paranoia Magazine Issue 24 Fall 2000 -Article -'Technology to Control Your Mind' - By Judy Wall

    US PATENT 5,123,899 -- METHOD AND SYSTEM FOR ALTERING CONSCIOUSNESS

    MONARCH, MANCHURIAN PROGRAMMING / HYPNOSIS CAPABILITY

    A system for altering the states of human consciousness involves the simultaneous application of multiple stimuli, preferable sounds, having differing frequencies and wave forms. The relationship between the frequencies of the several stimuli is exhibited by the equation g=s.sup.n/4 .multidot.f where: f=frequency of one stimulus g=frequency of the other stimuli of stimulus and n=a positive or negative integer which is different for each other stimulus.

    ALSO SEE US PATENT 5,289,438

    A PATENT WHICH CHANGES THE PERCEPTION

    MAGAZINE ARTICLE FOCUSING

    ON METHOD AND SYSTEM FOR ALTERING CONSCIOUSNESS

    SOURCE: Judy Wall, Mike Coyle and Jan Wiesemann.

    Paranoia Magazine Issue 24 Fall 2000 - 'Technology to Control Your Mind' - By Judy Wall

    US PATENT 4,877,027-- HEARING SYSTEM

    TECHNOLOGICAL HEARING VOICES EFFECT BEAMED DIRECTLY INTO THE HUMAN BRAIN LEADING TO MISDIAGNOSIS OF VICTIM

    Sound is induced in the head of a person by radiating the head with microwaves in the range of 100 megahertz to 10,000 megahertz that are modulated with a particular waveform. The waveform consists of frequency modulated bursts. Each burst is made up of ten to twenty uniformly spaced pulses grouped tightly together. The burst width is between 500 nanoseconds and 100 microseconds. The pulse width is in the range of 10 nanoseconds to 1 microsecond.

    The bursts are frequency modulated by the audio input to create the sensation of hearing in the person whose head is irradiated.

    US PATENT 6,011,991-- COMMUNICATION SYSTEM AND METHOD INCLUDING BRAIN WAVE ANALYSIS AND/OR USE OF BRAIN ACTIVITY

    RADIO FREQUENCY IS USED TO CREATE SADNESS, EMOTIONAL CONFUSION, FEAR, PANIC, ANGER, ETC., AND PUSH VICTIM OVER THE EDGE STRATEGICALLY

    A system and method for enabling human beings to communicate by way of their monitored brain activity. The brain activity of an individual is monitored and transmitted to a remote location (e.g. by satellite). At the remote location, the monitored brain activity is compared with pre-recorded normalized brain activity curves, waveforms, or patterns to determine if a match or substantial match is found. If such a match is found, then the computer at the remote location determines that the individual was attempting to communicate the word, phrase, or thought corresponding to the matched stored normalized signal.

    US PATENT 4,858,612 - HEARING DEVICE

    MICROWAVE HEARING VOICES AKA ARTIFICIAL TELEPATHY, ALSO KNOWN AS "FREY EFFECT" AFTER ALAN FREY, NEUROSCIENTIST

    A method and apparatus for simulation of hearing in mammals by introduction of a plurality of microwaves into the region of the auditory cortex is shown and described. A microphone is used to transform sound signals into electrical signals which are in turn analyzed and processed to provide controls for generating a plurality of microwave signals at different frequencies. The multifrequency microwaves are then applied to the brain in the region of the auditory cortex. By this method sounds are perceived by the mammal which are representative of the original sound received by the microphone.

    US PATENT 3,951,134 - APPARATUS AND METHOD FOR REMOTELY MONITORING AND ALTERING BRAINWAVES

    CAN CREATE ASSASSINS, MONARCHS / MANCHURIANS, ETC, VIA DELTA PROGRAMMING

    Apparatus for and method of sensing brain waves at a position remote from a subject whereby electromagnetic signals of different frequencies are simultaneously transmitted to the brain of the subject in which the signals interfere with one another to yield a waveform which is modulated by the subject's brain waves.

    The interference waveform which is representative of the brain wave activity is re-transmitted by the brain to a receiver where it is demodulated and amplified. The demodulated waveform is then displayed for visual viewing and routed to a computer for further processing and analysis. The demodulated waveform also can be used to produce a compensating signal which is transmitted back to the brain to effect a desired change in electrical activity therein.

    US PATENT 5,159,703 - SILENT SUBLIMINAL PRESENTATION SYSTEM

    CAN BE USED TO INFLUENCE, MANIPULATE, BRAINWASH, IMPLANTED SUBLIMINAL SUGGESTIONS WHILE SLEEPING

    A silent communications system in which nonaural carriers, in the very low or very high audio frequency range or in the adjacent ultrasonic frequency spectrum, are amplitude or frequency modulated with the desired intelligence and propagated acoustically or vibrationally, for inducement into the brain, typically through the use of loudspeakers, earphones or piezoelectric transducers.


    SILENT SOUND PROGRAMMING

    US PATENT 5,507,291- METHOD AND AN ASSOCIATED APPARATUS FOR REMOTELY DETERMINING INFORMATION AS TO A PERSON'S EMOTIONAL STATE

    USED TO DETERMINE IF PSYCHO-PHYSICAL ELF TECHNOLOGY IS WORKING ON TARGET OR HAVING THE DESIRED EFFECT

    In a method for remotely determining information relating to a person's emotional state, an waveform energy having a predetermined frequency and a predetermined intensity is generated and wirelessly transmitted towards a remotely located subject. Waveform energy emitted from the subject is detected and automatically analyzed to derive information relating to the individual's emotional state.

    Physiological or physical parameters of blood pressure, pulse rate, pupil size, respiration rate and perspiration level are measured and compared with reference values to provide information utilizable in evaluating interviewee's responses or possibly criminal intent in security sensitive areas.

    US PATENT: US5629678 - IMPLANTABLE TRANSCEIVER

    MICROCHIP / VERICHIP IMPLANTS

    Apparatus for Tracking And Recovering Humans.

    US PATENT FOR BARCODE TATTOO - US PATENT 5,878,155

    USED SIMILAR TO RADIO FREQUENCY ID CHIP / MICRO-CHIP IMPLANT

    Method for verifying human identity during electronic sale transactions. A method is presented for facilitating sales transactions by electronic media. A bar code or a design is tattooed on an individual. Before the sales transaction can be consummated, the tattoo is scanned with a scanner (such as the symbol ls4278).

    Characteristics about the scanned tattoo are compared to characteristics about other tattoos stored on a computer database in order to verify the identity of the buyer. Once verified, the seller may be authorized to debit the buyer's electronic bank account in order to consummate the transaction. The seller's electronic bank account may be similarly updated.


    US PATENT 5,539,705 - ULTRASONIC SPEECH TRANSLATOR AND COMMUNICATIONS SYSTEM

    ONE OF SATELLITE TECHNOLOGICAL HARASSMENT EFFORTS FROM OPERATION CENTERS

    A wireless communication system undetectable by radio frequency methods for converting audio signals, including human voice, to electronic signals in the ultrasonic frequency range, transmitting the ultrasonic signal by way of acoustical pressure waves across a carrier medium, including gases, liquids, or solids, and reconverting the ultrasonic acoustical pressure waves back to the original audio signal. The ultrasonic speech translator and communication system (20) includes an ultrasonic transmitting device (100) and an ultrasonic receiving device (200). The ultrasonic transmitting device (100) accepts as input (115) an audio signal such as human voice input from a microphone (114) or tape deck.


    US PATENT 5,629,678 - PERSONAL TRACKING AND RECOVERY SYSTEM

    AS STATED BELOW

    Apparatus for tracking and recovering humans utilizes an implantable transceiver incorporating a power supply and actuation system allowing the unit to remain implanted and functional for years without maintenance. The implanted transmitter may be remotely actuated, or actuated by the implantee. Power for the remote-activated receiver is generated electromechanically through the movement of body muscle. The device is small enough to be implanted in a child, facilitating use as a safeguard against kidnapping, and has a transmission range which also makes it suitable for wilderness sporting activities. A novel biological monitoring feature allows the device to be used to facilitate prompt medical dispatch in the event of heart attack or similar medical emergency. A novel sensation-feedback feature allows the implantee to control and actuate the device with certainty.


    US PATENT 5,760,692 - INTRA-ORAL TRACKING DEVICE

    An intra-oral tracking device adapted for use in association with a tooth having a buccal surface and a lingual surface, the apparatus comprises a tooth mounting member having an inner surface and an outer surface, the inner surface including adhesive material.


    US PATENT 5,868,100 - FENCELESS ANIMAL CONTROL SYSTEM USING GPS LOCATION INFORMATION

    SIMILARLY USED FOR HUMANS AS RFID / MICROCHIP IMPLANTS

    A fenceless animal confinement system comprising portable units attached to the animal and including means for receiving GPS signals and for providing stimulation to the animal. The GPS signals are processed to provide location information which is compared to the desired boundary parameters. If the animal has moved outside the desired area, the stimulation means is activated. The signal processing circuitry may be included either within the portable unit or within a separate fixed station.


    US PATENT 5,905,461 - GLOBAL POSITIONING SATELLITE TRACKING DEVICE

    SATELLITE SURVEILLANCE, VIA, CHIPPED CREDIT CARD, PHONE, VEHICLE TRACKING, ANYWHERE

    A global positioning and tracking system for locating one of a person and item of property. The global positioning and tracking system comprises at least one tracking device for connection to the one of the person and item of property including a processing device for determining a location of the tracking device and generating a position signal and a transmitter for transmitting said position signal.

    US PATENT 5,935,054 - MAGNETIC EXCITATION OF SENSORY RESONANCES

    USED TO CREATE EXTREME AGITATION SADNESS, ANGER, FEAR, WHILE TARGET IN HYPNOTIC STATE

    The invention pertains to influencing the nervous system of a subject by a weak externally applied magnetic field with a frequency near 1/2 Hz. In a range of amplitudes, such fields can excite the 1/2 sensory resonance, which is the physiological effect involved in "rocking the baby".


    US PATENT 5,952,600 - ENGINE DISABLING WEAPON

    USED TO DISABLE A TARGET'S VEHICLE WHICH COULD BE HAZARDOUS

    A non-lethal weapon for disabling an engine such as that of a fleeing car by means of a high voltage discharge that perturbs or destroys the electrical circuits.

    US PATENT 6,014,080 - BODY WORN ACTIVE AND PASSIVE TRACKING DEVICE

    AS STATED

    Tamper resistant body-worn tracking device to be worn by offenders or potential victims for use in a wireless communication system receiving signals from a global positioning system (GPS).


    US PATENT 6,017,302 - SUBLIMINAL ACOUSTIC MANIPULATION OF NERVOUS SYSTEMS

    AS STATED EARLIER, USED FOR MANY REASONS AND RESULTS IN PTOSIS, AKA DROOPY EYE SYNDROME.

    In human subjects, sensory resonances can be excited by subliminal atmospheric acoustic pulses that are tuned to the resonance frequency. The 1/2 Hz sensory resonance affects the autonomic nervous system and may cause relaxation, ptosis of the eyelid, drowsiness, or sexual excitement, depending on the precise acoustic frequency near 1/2 Hz used.

    The effects of the 2.5 Hz resonance include slowing of certain cortical processes, sleepiness, and disorientation. For these effects to occur, the acoustic intensity must lie in a certain deeply subliminal range. Suitable apparatus consists of a portable battery-powered source of weak sub-audio acoustic radiation.

    The method and apparatus can be used by the general public as an aid to relaxation, sleep, or sexual arousal, and clinically for the control and perhaps treatment of insomnia, tremors, epileptic seizures, and anxiety disorders. There is further application as a nonlethal weapon that can be used in law enforcement standoff situations, for causing drowsiness and disorientation in targeted subjects. It is then preferable to use venting acoustic monopoles in the form of a device that inhales and exhales air with sub audio frequency.


    US PATENT 6,051,594 - METHODS AND FORMULATIONS FOR MODULATING THE HUMAN SEXUAL RESPONSE

    SEXUAL STIMULATION PATENTS USED AND ENJOYED BY MEN IN OPERATION CENTERS

    The invention is directed to improved methods for modulating the human sexual response by orally administering a formulation of the vasodilator phentolamine to the blood circulation and thereby modulating the sexual response on demand.


    US PATENT 6,052,336 - APPARATUS AND METHOD OF BROADCASTING AUDIBLE SOUND USING ULTRASONIC SOUND AS A CARRIER

    THIS TECHNOLOGY IS ALSO DEPLOYED VIA DRONES USED AS PART OF "SLOW KILL" OPERATIONS

    An ultrasonic sound source broadcasts an ultrasonic signal which is amplitude and/or frequency modulated with an information input signal originating from an information input source. If the signals are amplitude modulated, a square root function of the information input signal is produced prior to modulation. The modulated signal, which may be amplified, is then broadcast via a projector unit, whereupon an individual or group of individuals located in the broadcast region detect the audible sound.

    MANY TARGETED INDIVIDUALS REPORT, AS PART OF ORGANIZED STALKING EFFORTS, ALSO KNOWN AS GANG STALKING, BEING TERRORIZED BY PORTABLE DEVICES PROVIDED TO THE COMMUNITY AROUND THE VICTIM SET-UP IN NEIGHBOR'S HOMES WHERE OFFICIAL PERSONNEL HAVE MOVED IN FOR SURVEILLANCE.

    THE DEVICES, AS WELL AS AERIAN METHODS, ARE CAPABLE OF BEAMING, DIRECTED ENERGY WEAPONS, AND ULTRASONIC WEAPONS, SONIC WEAPONS CAUSING NEUROLOGICAL DAMAGE, FROM DRONES INTO THE VICTIM'S HOME. THE DEVICES CAN ALSO CARRY THE VOICES OF THE OPERATORS THROUGH THE WALL VIA PORTABLE MICROWAVE RADIO WAVE FREQUENCIES DEVICES AND SYSTEMS.

    WEAPONS OF "SOFT AND SLOW KILL " USED BY IN COVERT MILITARY AND LAW ENFORCEMENT EFFORTS DESIGNED TO SILENCE VICTIMS AND PROVIDED TO COMMUNITY ORGANIZED STALKING OPERATIVES.


    DUAL USE OF RADIO FREQUENCY DIRECTED ENERGY WEAPON AND IMAGER - US PATENT 8049173 B1

    ABSTRACT: There is disclosed an dual use RF directed energy weapon and imager. A generator may provide a first beam of RF electromagnetic energy which may be directed to an object by a beam director. An imager may form an image of the object. The imager may share an aperture defined by the beam director.

    MULTIFUNCTIONAL RADIO FREQUENCY DIRECTED ENERGY SYSTEM - COVERT TORTURE WEAPON SYSTEM

    UNITED STATES PATENT - 7629918 B2

    ABSTRACT: A RFDE system includes an RFDE transmitter and at least one RFDE antenna. The RFDE transmitter and antenna direct high power electromagnetic energy towards a target sufficient to cause high energy damage or disruption of the target. The RFDE system further includes a targeting system for locating the target. The targeting system includes a radar transmitter and at least one radar antenna for transmitting and receiving electromagnetic energy to locate the target. The RFDE system also includes an antenna pointing system for aiming the at least one RFDE antenna at the target based on the location of the target as ascertained by the targeting system. Moreover, at least a portion of the radar transmitter or the at least one radar antenna is integrated within at least a portion of the RFDE transmitter or the at least one RFDE antenna.


    Methods

    1 Ethics statement

    The study was approved by the Human Research Protections Program of the University of California San Diego. All participants were asked to read and sign an informed consent form before participating in the study.

    2 System diagrams for a collaborative BCI

    A collaborative BCI and a conventional BCI differ in many respects. A conventional BCI mainly aims to help the individual with motor disability to communication with the environment, whereas a collaborative BCI is specifically designed for improving human performance of healthy users. The basic design and operation of a collaborative BCI is shown in Figure 1. Similar to a conventional BCI [1], a collaborative BCI consists of three major parts: a data-recording module, a signal processing module, and a command translation module. Consequently, there are three major procedures in system operations. First, brain signals from a group of users are acquired by multiple EEG recording devices, and then are synchronized with common environmental events. Second, integrated EEG and event data are processed for extracting features for decoding users' intentions. Third, extracted features are directly translated to operation commands, which can also be used to provide sensory feedbacks to the users. Compared to a single-subject BCI, the complexity of system input from multiple users will lead to technical challenges in both data recording and signal processing procedures.

    To implement a collaborative BCI, there are several specific requirements for hardware and software designs due to the employment of multiple users. First, multiple EEG recording systems need to work independently and simultaneously. Second, multiple-subject data need to be received and synchronized with respect to the common environmental events. Third, multiple-subject data recording and data processing procedures have to be performed in (near) real time. Ideally, the system can be implemented using a centralized paradigm similar to a conventional BCI (Figure 2a). In this paradigm, EEG data from multiple subjects are received and recorded, then thrown into a conventional BCI module for signal processing and command translation using a data server. A centralized paradigm is optimal for designing a collaborative BCI system however, practicality of system implementation may be limited by heavy loads of data transmission and high computational costs caused by advanced signal processing and machine learning techniques [26], [27], [28], as well as low hardware/software robustness due to the involvement of multiple BCI subsystems.

    (A) a centralized paradigm (B) a distributed paradigm.

    To find a remedy to these problems associated with the centralized paradigm, we propose a distributed paradigm to facilitate the implementation of a collaborative BCI. As shown in Figure 2b, the whole system consists of multiple distributed BCI subsystems and a simplified data server. For each subject, a BCI subsystem works independently each subsystem has its capability in EEG data acquisition and processing. In this paradigm, the amount of data transmitted between subsystems and the data server, as well as the computational cost for data processing, are significantly reduced. Because the data server only functions as an ensemble classifier for integrating classification results sent by the subsystems, the system robustness can be improved as well. The single-person BCI has been well studied in previous studies. Therefore this distributed paradigm is a more practical solution for implementing a collaborative BCI. The only disadvantage of the distributed paradigm is that costs of subsystem hardware might increase due to the employment of a data processing platform for each subject. In practice, portable data processing platforms such as a digital signal processor (DSP) platform can be integrated into the EEG recording device to reduce the overall system cost, and improve system practicality [29]. A collaborative BCI using the distributed regime can be considered a distributed computing system, in which each BCI subsystem solves the classification task independently in order to achieve a common goal (e.g., predicting motor response). Details of data analysis approaches for both paradigms will be discussed in the data analysis section.

    3 BCI experiment

    This BCI study adopted a motor action paradigm reported in [10]. In the experiment, a visually guided reaching or gazing was employed as a motor response task. For the purpose of improving human performance, brain activities in the PPC, which occurred before actual motor response, were extracted for predicting the directions of upcoming movements. As shown in Figure 3, the response time (RT) of a cue-guided reaching movement consists of five stages: target identification, visual-motor transmission, motor planning, motor execution, and motor control. These processes occur sequentially in the visual cortex, the PPC, the premotor cortex, the primary motor cortex, and the nerve-muscle pathways. Through directly extracting embedded information from the PPC and bypassing the motor related procedures, this BCI system could accelerate a motor response by using an artificial limb.

    3.1 Subjects.

    An EEG and a behavior experiments were run separately on two groups of subjects. Twenty right-handed participants (12 males and 8 females, mean age 25 years) with normal or corrected-to-normal vision participated in the EEG experiment. Another group of 18 subjects participated in the behavior experiment (12 males and 6 females, mean age 23 years).

    3.2 Stimuli and procedure.

    A delayed saccade-or-reach task was used in the EEG study, allowing us to look for direction information in the EEG during the phase of movement planning. The experiment was comprised of nine conditions differing by movement types (saccade to target, reach without eye movement, or visually guided reach) and movement directions (left, center, or right). Each task was indicated to the subject by, first, giving an effector cue telling the type of action to be performed, followed by a direction cue and, finally, by an imperative action cue. Subjects were seated comfortably in an armchair at a distance of 40 cm from a 19-inch touch screen. A chin rest was used to help them maintain head position.

    Subjects used their right hands to perform the reaching tasks. At the beginning of each trial, the subject's forearm rested on the table with an index finger holding down a key on a keypad placed 30 cm in front of screen center. The sequence of visual cues in each trial is shown in Figure 4a. At the beginning of a trial, a fixation cross (0.65°×0.65°) was displayed at the center of the screen plus three red crosses (0.65°×0.65°) indicating potential target positions. The left and right targets had a vertical distance of 6° and a horizontal distance of 15° from the central fixation cross the central target was 12° upwards. After 500 ms, an effector cue (0.5°×0.5°, rectangle, ellipse indicating hand and eye movements respectively, see Figure 4c) appeared at the screen center for 1000 ms. Next, a central direction cue (0.65°×0.65°, ⊣, ⊥, ⊢ for left, center, and right respectively) was presented for 700 ms. Subjects were asked to maintain fixation on the central cue until they started their responses, to perform the indicated response as quickly as possible following the disappearance of the direction cue (and reappearance of the fixation cross), and finally to return to their initial (key-down) position. There was a 400–600 ms interval for rest before the next trial started. Total trial duration amounted to 3500–4000 ms.

    (A) an EEG trial (B) a behavior trial (C) visual cues used to indicate effector and direction of a task.

    The behavior experiment was designed to measure the actual RT of a reaching movement using the same paradigm except that there was no delay after the direction cue, i.e., the direction cue was also used as the Go cue (see Figure 4b). In this experiment, subjects were instructed to response as fast as possible after the appearance of the direction cue.

    3.3 Data Recording.

    In the EEG experiments, EEG data were recorded using Ag/AgCl electrodes from 128 scalp positions distributed over the entire scalp using a BioSemi ActiveTwo EEG system (Biosemi, Inc.) referenced to the CMS-DRL ground. Eye movements were monitored by additional bipolar horizontal and vertical EOG electrodes. All signals were amplified and digitized at a sample rate of 256 Hz. Three cue presentation events and two manual response events (“button release” and “screen touch”) were recorded on an event channel synchronized to the EEG data by DataRiver software (A. Vankov). EEG and behavioral data were recorded from 20 subjects on different days using the exactly same target presentation sequences. Some practice blocks were run before starting the EEG recording. For each subject, the experiment consisted of four blocks (with breaks in between) each including five runs of 45 trials. Within each block, there was a 20-second rest between runs. A total of 900 trials were equally distributed between the nine tasks, which were presented to the subject in a pseudorandom sequence.

    In the behavior experiment, only the events were recorded for obtaining the actual RT for a reaching response. For each subject, the experiment consisted of three blocks with a total of 675 trials equally distributed among the nine tasks.

    3.4 Data preprocessing.

    This study focused on the estimations of planned direction of movement. For simplicity, we only used “left” and “right” conditions for “hand” tasks for further analysis. The same analysis could be applied to data under “eye” and “both” conditions. Epochs from the response delay period, 0 to 700 ms following the onsets of direction cues, were extracted from the continuous data, and labeled by movement directions. The period [−100 ms 0 ms] was used as the baseline for each trial. Electrodes with poor skin contact were identified by their abnormal activity patterns and then removed from the data.

    We used independent component analysis (ICA) as an unsupervised spatial filtering technique to remove artifacts arising from eye and muscle movements. For each subject, all trials were band-pass filtered (1–30 Hz), concatenated, and then decomposed using the EEGLAB toolbox [30]. To retain the low-frequency EEG activities, ICA weights of the decomposition were applied to original unfiltered data before artifact removal. To extract the direction-specific activity of the ERPs, we compared the spatiotemporal patterns of EEG corresponding to different movement directions. As shown in Figure 5, we found a hemispheric asymmetry over the parietal cortex during the delay period (0–700 ms) in which motor planning can be presumed to have continued until the cued movement onset (appeared after 700 ms). Two lateral electrodes representing PPC activities showed a significant contralateral negativity and ipsilateral positivity with respect to the intended movement direction (Figure 5b). Across all subjects, difference waves between reaching left and reaching right conditions showed two peaks located at 210 ms and 320 ms after the direction cue. ERP scalp maps of two conditions and their difference at these two selected frames were illustrated in Figure 5a.

    (A) Grand average 128-channel scalp maps of ERPs and difference waves (left-right) across all subjects at 210 ms and 320 ms. Black dots indicate positions of two selected electrodes near the PPC. (B) Average ERP waveforms across all subjects on two PPC electrodes in left- and right-reaching conditions and their difference. Dash lines mark peaks of difference waves at 210 ms and 320 ms. ERPs at two PPC electrodes show significant differences between left and right conditions using a paired t-test across subjects (left PPC: p<10 −5 at 210 ms and p<10 −6 at 320 ms, right PPC: p<10 −6 at 210 ms and p<10 −4 at 320 ms). The shaded intervals indicate areas where differences between left and right conditions are significant (p<0.05).

    3.5 Feature extraction and classification.

    The goal of this study is to demonstrate the efficacy of a collaborative BCI, rather than the EEG dynamics associated with all different task conditions. Therefore, the analysis below focuses only on the classification performance of predicting the intended movements based on the directional EEG information generated in the parietal cortex. To this end, two lateral electrodes over the PPC areas were selected for feature extraction based on the significance of ERP difference between left and right conditions. Figure 6 shows ERP waveforms at two PPC electrodes for all subjects. The direction-related asymmetry in the PPC was highly reproducible across subjects. Through time-frequency analysis, we found that the ERP difference was mostly contributed by EEG components with a frequency band lower than 12 Hz. To reduce feature dimension, EEG signals were downsampled by calculating the mean of five continuous data points without overlapping. For feature extraction, within a selected time window, EEG amplitudes were normalized at each time point to have a range of [−1 1] across trials and conditions, and then normalized amplitudes from two PPC electrodes were concatenated into a feature vector: (1)

    Solid lines indicate the reaching left condition, and dash lines indicate the reaching right condition.

    For classification, a support vector machine (SVM) classifier with an RBF kernel was implemented in the MATLAB® Bioinformatics Toolbox. The RBF kernel was optimized according to average classification performance across all subjects. To facilitate the training procedure, the scaling factor in the RBF kernel was fixed at 10 for all SVM classifiers. In this study, 10×10-fold cross validation was run to estimate classification performance for all classification tasks.

    4 Collaborative BCI data analysis

    For each subject, classification of “left” versus “right” trials was performed using a standard machine-learning paradigm. For a collaborative classification based on data from multiple subjects, we propose three approaches to fuse the information from multiple subjects: (1) ERP averaging across subjects, (2) feature combination (e.g., concatenating features from multiple subjects), and (3) voting using an ensemble classifier. All these approaches can be implemented in the centralized paradigm, but for the distributed paradigm, only the voting approach is practical because data from each subject are processed separately in each of the BCI subsystems.

    4.1 ERP averaging.

    A widely used method for analyzing ERP has been to average EEG measurements over an ensemble of trials within a subject or across subjects [22]. Ensemble averaging can enhance the SNR of ERP given a linear mixing model: (2)

    where ERP(t) is a constant signal (i.e., the evoked brain response) and Noise(t) is a random signal with zero mean (i.e., the background EEG activity) in different trials. In a collaborative BCI system, multiple trials can be obtained through collecting single-trial data from multiple subjects. Therefore, the ensemble averaging method can be implemented across subjects: (3)

    where i is subject index and m is the total number of subjects.

    4.2 Feature combination.

    According to ERP studies, the model in equation (2) is not true when considering a more complicated ERP model, which involves multiple components [22]: (4)

    where ERP is assumed to consist of n components, with independent amplitude modulation indicated by and latency jitter indicated by . Under this circumstance, ensemble averaging might lose information due to individual differences among subjects. For example, latency jitter might cancel out ERP signals when two adjacent components have different polarities. Therefore, to maintain intact information from all the subjects, the feature combination method might be more suitable for a collaborative system.

    In the machine learning theory, feature combination can improve overall classification accuracy due to independence between features. Recently, following the wide employment of machine learning techniques in BCI studies, feature combination methods have been introduced in EEG classification [5], [27]. For simplicity, we use a feature concatenating method, which is easy to implement: (5)

    where the combined feature vector is a concatenation of feature vectors from m subjects.

    Theoretically, feature combination is optimal for a collaborative BCI. However, considering the fact of a BCI system that training data is always limited and feature combination will significantly increase the dimensionality of feature space, the feature combination method might encounter an overfitting problem. For example, the dimension of features from a single subject is 50 in equation (1) when using the time window of [0 ms 500 ms], which will be increased to 1000 for 20 subjects. However, the number of the training samples remains the same as in the single subject condition (100 trials per condition). Therefore, the performance gain of feature combination will be weakened due to a small training-set size.

    4.3 Voting.

    Ensemble classifiers have been widely used in the area of machine learning [31]. An ensemble classifier consists of multiple sub-classifiers and a voting system. In the case of a binary classification where two classes are labeled as +1 and −1 respectively, the procedure for a weighted voting can be described as follows: (6)

    where w, i. is the subject specific weight and y, i. is the output of a sub-classifier. In our study, an SVM classifier was trained as a sub-classifier for each subject, and the training accuracy was used as the voting weight.

    As mentioned before, the voting method is the only solution for a collaborative BCI using the distributed paradigm. Ideally, if there is no interaction between subjects, the voting method is supposed not to lose useful information for classification.

    4.4 Training and testing.

    Realization of training and testing procedures of a collaborative BCI depends on the method used in feature extraction. The ERP averaging and Feature concatenating methods have to be realized on a centralized computer infrastructure where original EEG data from different subjects can be collected and processed. The Voting method can be realized either on a centralized or a distributed system.

    In the collaborative BCI regime, a ‘single-trial’ actually comprised multiple epochs from multiple subjects following the same task stimulus. A 10×10-fold cross validation was used to assess classification performance. For the ERP averaging method, features of each trial were obtained by averaging feature vectors (Equation (1)) across subjects. An SVM classifier was then trained with the training set and applied to classification of the testing set. The Feature concatenating method used a similar way except that features were obtained by concatenating feature vectors from individuals (Equation (5)). In the Voting method, an SVM sub-classifier was used for training and testing for each subject separately. The collaborative classification was then performed using Equation (6).

    4.5 Number of subjects.

    The number of subjects is an important parameter for a collaborative BCI. In general, more subjects can provide more information for improving classification. Generally, when average performance is poor, any subject who has classification accuracy higher than the chance level can improve the overall performance of a collaborative BCI. However, the system costs (including hardware, software, and human resources) will also increase when more subjects are involved. Therefore, a tradeoff between the system performance and system cost should be made according to the specificity of the application.

    To answer the question of how many subjects are needed to implement a satisfactory collaborative BCI, we evaluated system performance with respect to the number of subjects. For each number n (from 1 to 20), a random combination (n out of 20 subjects) was repeated 500 times for calculating classification accuracy using cross validation. All of the three collaborative approaches were calculated for comparison using data within the time window of [0 ms 400 ms]. A one-way Analysis of Variance (ANOVA) was used to investigate the effect of ‘number of subjects' on classification performance. Furthermore, for each collaborative condition (n from 2 to 20), the two-sample T-test (500 samples for the collaborative method vs. 20 samples for the individual method) was used as a post-hoc test to evaluate if the performance of a collaborative BCI was significantly better than that of an individual BCI.

    4.6 Prediction time.

    In an application regime such as a target detection task, response time is always a critical parameter for evaluating human behavioral performance. In the motor action paradigm used in this study, we aimed to improve human performance through accelerating a motor decision-making, compared to RT. Therefore, it would be interesting to find out how fast a collaborative BCI can predict the direction of an upcoming reaching movement.

    The actual mean RT for the hand reaching tasks measured in the behavior experiment was 464±62 ms across 18 subjects. As discussed before, response direction can be determined through extracting brain activities related to the visuomotor transmission procedure. According to prediction time, the system improves the overall performance when response direction can be accurately predicted at any time point earlier than the RT. To explore the system's capability of accelerating motor decision-making, we evaluated the system performance at different time durations used for feature extraction. Time windows with zero onset and different offsets starting from 100 ms and ending at 500 ms, incrementing with an interval of 10 ms, (i.e., 0–100 ms, 0–110 ms, …, 0–500 ms) were used to calculate accuracy-time curves. To show interaction between the prediction time and the number of subjects, different numbers of subjects (1, 5, 10, 15, and 20) were included for comparison.


    Mapping of different functions

    The configurability of the developed SAC architecture can be leveraged to realize multiple biomedical signal processing operations on it, because the majority of the functions include multiplication and addition. Mapping methodologies for these commonly used functions are presented in this section. The target functions, also optimized for the proposed hardware, are classified broadly into two categories: Variable and Fixed coefficient functions. The coefficients of variable functions depend on the characteristic parameters of the function. For example, bandwidth, gain and number of taps determine the coefficients of FIR filter. In contrast, the fixed coefficient functions have constant coefficients and they undergo fixed steps resulting in constant coefficients. Therefore, it is redundant for the user to explicitly provide constant coefficients to the hardware and is eliminated by means of simple state machines. The architecture contains state machines for all the target functions. Based on the control word, one of the state machines becomes active and controls the function execution.

    Variable coefficient functions

    The multiplication, squaring, addition and multiply-accumulate (MAC) functions are based on the common equation: (sum _^ <11>a_icdot b_i) . A special case of MAC, where (a_i) = 1, represents the addition operation. For multiplication (a_i) (and/or (b_i) ) is 0 for i>0 and for squaring, (a_i) = (b_i) is done in the multiplication. The 12 RUs, marked #1, 4, 7, 10, 13, 16, 19, 21, 24, 27, 30 and 33, receive external data and computation takes eight clock cycles. It is possible to map this operation by choosing a different set of 12 RUS anywhere in the architecture but with a higher latency.

    DWT Mapping a Discrete Wavelet Transform Algorithm, b 2-D DWT Mapping on the SAC Architecture

    The mathematical equation for FIR filtering, differentiation and moving average can be readily expressed as a MAC operation. However, the 2-D convolution includes the product of data and coefficient matrices as (Z(i,j) = sum _^sum _^X(i-m,j-n).Y(m)(n)) , where (N_1 imes N_2) is the matrix size. The convolution consist of multiply-accumulate with spatially shifted input samples. The spatial shifts in the input matrix can be handled by careful interpretation of input rows in the memory [12]. By doing so, the 2-D convolution yields to 1-D convolution operation of length (N_1 imes N_2) . The generalized equation of FIR filtering, Differentiation, Moving Average and 2-D convolution thus becomes (sum _^ x[n-i]cdot b_i) , where (Nge N_1 imes N_2) . This output is based on the previous inputs and require memory elements. The architecture supports thirty-six taps for these set of functions. The external data (x[n]) is supplied on RU #1 and RUs can be connected in chain structure using the configuration and bypass multiplexers. The 2-D convolution requires input ports equal to the number of rows in the transform mask. The mask size of up to (6 ( imes) 6) can be mapped on the proposed hardware.

    Fixed coefficient functions

    Functions grouped in this category perform computations using a state machine. The state machine transforms the algorithm into a series of sequential steps. The fixed coefficients are stored in register files.

    COrdinate Rotation DIgital Computer (CORDIC) [27]

    It is derived from the general rotation transform and provides an iterative method of performing vector rotations by arbitrary angles using only shift and add operations. Generalized version of the algorithm is given by Eq. 4 [28] and includes hyperbolic and nonlinear functions, logarithm, square root computations in addition to the standard trigonometric functions.

    The top level hardware architecture for the CORDIC is shown in Fig. 6a. The ‘X and Y Computing Block’ computes the x and y variables, whereas the ‘Angle Accumulator Computing Block’ computes the z variable. The computation uses an adder or a subtractor and result from the previous iteration. The right-shift operation ( (>>) ) can be viewed as multiplication with (2^<-i>) . The SAC architecture performs multiplication where the 9-b coefficient register is loaded with the content (2^<-i>) in the (i^) iteration. The data register is loaded with the x, y or z variable (or (alpha) value) and the subsequent additions are carried out in the CU. [25] provides the seed value for various functions along with m and (alpha) .

    DWT Mapping a Flow Chart of 2-D DWT State Machine, b DWT Mask Manipulation, c Data Stored in Interleaved Manner in the Circular Memory with the Write and Read Pointers. The updated columns are indicated by grey filled text

    Tile #1 and tile #3 are used for CORDIC mapping (Fig. 6b). The RUs are not connected with each other in both the tiles except for RU #19-21– ( angle) 28-30 forming a 6 RU chain. The seed values x (_0) , y (_0) , z (_0) are fed into RU #1, 10 and 13 from the three read ports of circular memory (Fig. 6c). The y variable is computed first followed by z and x throughout the iterations. As y or z needs to undergo direction decision logic for next iteration, this process is overlapped with x computation so that no clock cycles are wasted. y (_1) is computed using y (_0) and x (_0) from RU #1 and RU #13, respectively, and the result stored in RU #19. At the same time, all the RUs pushes forward its data register content to the next RU in the chain. The arctan data is forced on RU #10 through internal multiplexer (CM10_int). Variable z (_1) is computed using RU #11 (z (_0) ) and RU #10 (arctan) and z (_1) is stored in RU #19, whereas y (_1) shifts to RU #20. Using RU #15 (x (_0) ) and 3 (y (_0) ), variable x (_1) is computed and stored in RU #19. At this stage, y (_1) , z (_1) and x (_1) are in RU #21, RU #20 and RU #19. y (_2) is computed using RU #21 and RU #19, z (_2) using RU #21 and RU #10 and x (_2) using RU #21 and RU #29. It should be noted that, previous value is present in RU #21 for x , y and z. The second variable of the equation (x or y) lies in RU #19, RU #10 and RU #29. Same sequence is followed with a state machine that follows a defined pattern. The algorithmic state machine shown in Fig. 7 consists of six states and depicts the RU coefficients loaded in each state during CORDIC computation. The coefficients for RUs used in CORDIC algorithm mapping are applied through the CORDIC input of coefficient multiplexers. A CORDIC multiplexer shown in Fig. 5 is connected to the coefficient multiplexer CORDIC input of RU #19 and RU #29. The multiplexer has 2 (^i) terms in binary as inputs and its select line is controlled by the state machine and takes 24 cycles for each iteration. It stores results internally in RUs and does not use additional memory.

    The 2-D Discrete Wavelet Transform

    2-D DWT translates to two consecutive matrix multiplication between the input and DWT mask coefficients. The results of matrix multiplication can be directly realized as multiply-accumulate operation and thus can be supported by the SAC architecture. The DWT decomposes a signal into four frequency sub-bands, namely LL (approximation (cA) matrix), LH (horizontal (cH) matrix), HL (vertical (cV) matrix) and HH (diagonal (cD) matrix). A generic mapping methodology is discussed that supports twenty-eight wavelets with filter size <8 [26]. The DWT algorithm first computes low pass filtering followed by down sampling by a factor of 2. The resultant vector is convolved with high pass filter and the LL DWT matrix is retained (with 75% compression) after another down sampling by a factor of 2. Additionally, periodic padding [29] is done on either side of the input samples and intermediate results to ensure spatial continuity on boundaries. The DWT computation steps are shown in Fig. 8a wherein the row wise convolution is carried out on a 14 ( imes) 8 padded image and an intermediate matrix, Y is generated. Columns 0-3 of padded image are same as columns 5-8 of the actual image. Thus, the convolution filter mask is modified by swapping the first four terms with the last four terms. This eliminates the use of excess memory elements required to store the padding. Furthermore, the mask advances by two steps as opposed to one step in the conventional convolution performing down sampling along with the intermediate matrix generation. The second set of convolution is performed on transposed padded Y matrix.

    The proposed architecture supports 8 ( imes) 8 block 2-D DWT operation with the mapping scheme are indicated in Fig. 8b. The five states of the DWT state machine are shown in Fig. 9a. The intermediate matrix (Y) rows are computed in the first state and the other four states compute the first row of DWT matrix. Convolution filter coefficients provided by the state machine are input to RU #1, RU #4, RU #7, RU #10, RU #13, RU #16, RU #31 and RU #34 and are multiplied with the first row of image matrix to generate the first element of Y matrix. Similarly, the rest of the seven elements of first row of Y matrix are generated in 64 cycles. RU #19-RU #26 holds the first row which requires padding on either sides. This is done by means of convolution mask rearrangement. The convolution filter is rearranged by moving the first four coefficients towards the end. By doing this, the padded elements which are at the bottom of unpadded image gets multiplied with the respective coefficients yielding the same result as padded image with the unmodified filter mask (Fig. 9b). The mask manipulation enables computing cA elements without external padding on the intermediate matrix which further permits storing the intermediate matrix. The circular memory write pointer is used to write 8 ( imes) 8 (= 64) input data which is stored column-wise in different sections of the memory in an interleaved manner (Fig. 9c) for simplifying the reading operation. It also ensures moving the convolution mask by 2 steps, a scheme adopted in the mapping to eliminate down sampling later. Consequently, multiple read ports ensure reading all columns simultaneously resulting in computation of Y matrix to be computed in eight clock cycles.

    Flow Chart of 2-D DCT State Machine

    The 2-D discrete cosine transform (DCT)

    Matrix computation (of an image) requires two matrix multiplication operations : DCT = DCT (_) * Image * (DCT (_) ) (^T) , where transform matrix (DCT (_) ) becomes constant for a fixed mask size. Matrix multiplication can be realized on the proposed architecture by loading row and column elements of the two matrices in place of coefficients and data registers, respectively. The architecture supports 8 ( imes) 8 block wise DCT and provides a compression of (approx) 84% (10 of 64 output samples are retained). The DCT mapping datapath is similar to the DWT mapping methodology shown in Fig. 8b. The first matrix multiplication or the intermediate matrix Int (_) = DCT (_) * Image, row wise image data and first row of DCTmat are forced on RU #1, RU #4, RU #7, RU #10, RU #13, RU #16, RU #31 and RU #34 as data and coefficient, respectively. The results form the first row of Int (_) that is periodically stored from RU #19-RU #26 and has to be further multiplied with DCT (_) (^T) .

    The row coefficients of the transform matrix are forced on coefficient registers of RU #19-RU #26 and the resultant DCT(0,0) is obtained. On forcing subsequent DCT (_) rows in the coefficient of RU #19-RU #30 chain, the remaining elements of the first row of DCT are obtained. It should be noted that, Int (_) stored in RU #19-RU #26 shifts down the RU chain every 8 clock cycles. This is incorporated by the state machine (Fig. 10) that consists of 5 states traversed four times, fully or partially to obtain Int (_) and DCT in successive computations. The state sequence differs with the iteration#, because the number of elements computed in the DCT matrix decreases by one with every row resulting in an upper triangular matrix. The Int (_) matrix is computed in state #1 and DCT matrix is computed in states #2-5. The image data is stored column wise in an interleaved manner in circular memory similar to data storage in DWT mapping discussed earlier.


    METHODS

    Subjects and Surgery

    All experiments were performed with two male rhesus monkeys (juvenile monkey Tm, 4 kg adult monkey Tb, 6 kg). Surgical and training procedures have been described elsewhere (Premereur, Vanduffel, & Janssen, 2011). Figure 1B shows a representative recording position for monkey Tb. In both monkeys, the recording area comprised the posterior part of the lateral bank of the IPS, corresponding to LIPd and LIPv (Lewis & Van Essen, 2000). All procedures were performed in accordance with the National Institutes of Health Guide for the Care and Use of Laboratory Animals and were approved by the ethical committee at the Katholieke Universiteit Leuven Medical School.

    Methods. (A) Visually guided saccade task with multiple distractors. Green dot: saccade target. Gray dots: distractors. Dotted circle: RF. (B) Recording positions. Coronal MRI section with green crosshairs indicating a representative recording position. (C) Average RT plotted as a function of go time. Line thickness represents standard error black line shows the fit of a weighted combination of a unimodal anticipation and an exponential function to the data.

    Methods. (A) Visually guided saccade task with multiple distractors. Green dot: saccade target. Gray dots: distractors. Dotted circle: RF. (B) Recording positions. Coronal MRI section with green crosshairs indicating a representative recording position. (C) Average RT plotted as a function of go time. Line thickness represents standard error black line shows the fit of a weighted combination of a unimodal anticipation and an exponential function to the data.

    Stimuli and Tests

    In the visually guided saccade task with a single distractor, all parameters were identical to the multiple-distractor task, except that a single (green) target stimulus and a single (gray) distractor appeared either inside or outside the LIP RF. Therefore the single-distractor task consisted of four conditions: target and distractor inside RF, target inside RF and distractor outside RF, target outside RF and distractor inside RF, and target and distractor outside the RF.

    In the memory-guided saccade task, a green saccade target appeared either inside or outside the RF for 200 msec after a 450-msec period of fixation. After the disappearance of the target, the monkey had to maintain central fixation until the fixation point dimmed, hereby cueing the monkey to saccade to the remembered target position. We used the same distribution of random go-times as in the visually-guided saccade task.

    The passive fixation task consisted of a fixed 800-msec period of fixation, after which a static colored grating (1.5° in diameter, spatial frequency: 1 cycle/deg, red–blue sine wave gratings, mean luminance of red: 30 cd/m 2 , mean luminance of blue: 100 cd/m 2 ) was presented for 600 msec inside the RF on 80% of the trials. In the other 20% of the randomly interleaved trials, a bitmap figure with the same luminance and color as the background of the monitor (and therefore invisible to the animal: equal to no stimulus presentation) was presented in the RF of the neuron. This trial structure was used to obtain the exact same timing parameters in both conditions (Grating vs. No Grating). The animal was rewarded for maintaining fixation until 500 msec after stimulus offset.

    Recording Procedure

    We employed standard recording procedures as described in Premereur et al. (2011). A photocell was attached to the monitor to detect the onset of a white square in the bottom right corner of the screen (covered with black tape to obscure it from the monkeys' view) that appeared in the first video frame containing a stimulus (distractor, saccade target, or go signal). LFP and spiking activity were recorded with the same tungsten electrode. LFP signals were amplified and filtered between 1 and 170 Hz (Frequency Devices, Ottawa, IL). Eye position signals (EyeLink 1000, SR Research, Mississauga, Ontario, Canada), neural activity, and photocell pulses were digitized and processed on a digital signal processor at 20 kHz (C6000 series Texas Instruments, Dallas, TX). We searched for responses in MUA by placing saccade targets at various locations in the contralateral hemifield. Formal testing started once a spatially selective multi- or single-unit target response was observed. Thus, the selection of LIP neurons was based on the presence of spatially selective target responses, but sites with significant memory delay period activity were found at nearby locations, consistent with previous LIP studies (e.g., Falkner, Krishna, & Goldberg, 2010). The tasks were presented in a sequence with, if possible, multiple repetitions, always in the same order: visually guided saccade task with multiple-distractors (120 trials), passive fixation task (100 trials), and memory saccade task (80 trials). In 15 sites, the task sequence also contained the single-distractor saccade task after the memory saccade task.

    Data Analysis

    All data analysis (unless mentioned otherwise) was performed using custom-written Matlab (The MathWorks, Natick, MA) programs.

    LFP Analysis

    For every trial, the time–frequency power spectrum was calculated using Morlet's wavelet analysis techniques (Tallon-Baudry & Bertrand, 1999), with spectro-temporal resolution equal to 7, after filtering with a 50-Hz notch filter (FieldTrip Toolbox, Donders Institute, Nijmegen, the Netherlands). Power was normalized per trial by dividing the power trace per frequency by the average power for this frequency in the 300-msec interval before stimulus onset. To exclude trials containing possible artifacts in the LFP recordings, maximum and minimum values of the continuous LFP signal and of the time–frequency spectrum were calculated per trial, and trials with minimum signal values below the 5th percentile or maximum values above the 95th percentile were removed. Furthermore, the data set was split in two, and all population analyses were repeated for both halves of the population of recording sites to check for consistency. If inconsistent findings were found, due to one trial or recording site with extreme values, this trial/recording site was removed. We analyzed the LFP power in standard frequency bands: high gamma (80–170 Hz), medium gamma (50–80 Hz), low gamma (25–50 Hz), beta (12–25 Hz), and alpha (8–12 Hz). Lower frequencies were excluded from our analyses, as our trials were on average only 1.5 sec in length. LFP power was averaged across trials and over frequencies to extract the average power per frequency band over time. LFP data were not corrected for averaged visually evoked potentials (VEPs), but removing the VEP yielded similar response patterns. LFP analyses using multitaper methods also revealed similar response patterns. All statistics on LFP data were obtained using permutation tests, where real data were randomly distributed over all the different conditions 10,000 times, and the differences between two conditions were then calculated for every permutation for comparison with the actual difference between conditions. Differences between conditions were calculated based on the response in the 0–500 msec interval after stimulus (target or distractor) onset. Presaccadic enhancement in LFP power was assessed by comparing power in the 100-msec interval before the saccade with power in the interval 200–100 msec before the saccade.

    Correlation Neural Activity/RT

    We calculated the trial-by-trial correlation between RT and LFP power per frequency band around the time of the go signal (−150 before until 50 msec after go time). Because both neural activity and RT can increase or decrease over time and can therefore exhibit spurious correlations, we “detrended” the power in each frequency band by trialwise subtracting the average power in that frequency band across trials in the interval from 150 msec before until 50 msec after the time of the go cue. The same detrending procedure was employed for RT by trialwise subtraction of the average RT for that go time. Thus, the correlations were computed on the residuals of LFP power and RT after subtraction of the means.

    Spike-field Coherence

    Spike-field coherence (SFC) was calculated between spiking (SUA or MUA) and LFP activity using the Chronux toolbox (chronux.org Bokil, Andrews, Kulkarni, Mehta, & Mitra, 2010). LFP-data were corrected for the average VEP by trialwise subtraction of the average VEP for a given site and condition. We calculated the temporal dynamics of the average SFC after target onset in the same frequency bands as for the LFPs, in time bins of 350 msec with a 10-msec step width. Because of the large bin width used to calculate the SFC, only trials with a go time of 900 msec or longer were included, and significant differences between conditions were tested using permutation tests in the entire 0–900 msec interval. Increases in coherence after stimulus onset were tested for significance with nonparametric permutation tests by comparing baseline coherence (−300–0 msec) with coherence in the 0–200 msec interval. Time bandwidth product and number of tapers were set at 3 and 5, respectively. We randomly extracted the same number of trials for every condition. An extra control analysis was performed to eliminate any possible influence of firing rate differences upon observed differences in SFC. Therefore, we equalized firing rates over time using a procedure similar to the one proposed by Gregoriou, Gotts, Zhou, and Desimone (2009). Spike trains in both Target-in and Target-out conditions were binned in 1-msec segments, convolved with a Gaussian kernel (sigma = 10 msec), and averaged across trials for each condition. Average baseline activity was calculated as the average spike rate in the 300 msec before target onset. We calculated the difference in spike rates between each time bin and the baseline activity and divided this value by the maximum rate for this time bin. This normalization allowed us to estimate for each bin the probability that spikes would need to be removed from the higher firing rate signal. Spikes in the original spike trains were randomly removed based on this calculated probability value. Equalizing spikes over time in this way typically resulted in a reduction in absolute coherence values by 1–12%. Note that spike rates not only differ over time but also between conditions (Target-in vs Target-out). By equalizing the firing rates toward baseline activity, we also corrected for spike rate differences between conditions.

    Microsaccades

    We calculated the number of microsaccades as a function of time after stimulus onset. A microsaccade was defined as an increase in the velocity of the eye trace exceeding three times the standard deviation of the velocity in the delay period (typically in the range of 50° per second) within the electronically defined fixation window.


    What signal processors comprise an Event-Related Potential system for EEG? - Biology

    A Brain Computer Interface (BCI) provides a communication system to control external device(s) in which messages or commands are sent to external world through brain signals. These signals do not pass through the brain’s normal output pathways of nerves and muscles. Rather, BCI provides an alternate method to its user to interact with the world. For example, Electroencephalogram (EEG) based BCI messages are encoded in EEG activity of brain. For people with amputation or severe neuromuscular disability, who may lack normal output channels, BCIs prove to be useful for controlling external devices [ 1 ]. The world of BCI is growing day by day, with applications ranging from control of upper/lower limb prosthesis and wheel chairs to control of multimedia applications and smart phones for people suffering from stroke [ 2 , 3 ]. Table 1 shows some researches in which upper limb prosthesis or cursor is controlled using motor imagery. Movements of a prosthesis are commonly controlled through manipulating the motion of rotary actuator (electric motor) in a BCI system.

    Examples of research for prosthesis or cursor control using motor imagery.

    BCI system consists of input signals (electrophysiological activity recorded from scalp of user), a signal processor (filtering the signal for desired frequency and extracting features for best representation of user intent), a translating algorithm or classifier (that anticipates the human intent from the selected feature), and finally a control algorithm that controls the device attached to the system [ 1 ].

    Mental activity, such as imagination of movement and movement itself or decision making, results in excitation of Neural Networks which cause changes in electrical potentials that can be recorded by sensors [ 2 ]. This electrical potential is recorded using invasive (placement of sensor under the scalp through surgery) or noninvasive (placement of sensors on the scalp) sensors. The invasive method provides a higher signal to noise ratio however, it is cost-wise expensive and involves risk due to surgery. There is a variety of changes in electrical potentials that can be extracted from real time recorded EEG signals [ 10 ] which can be either evoked potentials or induced potentials. This includes Event Related Potentials (ERP), P300 Evoked Potentials [ 11 ], Slow Cortical Potentials, Visual Evoked Potentials, and Mu and Beta Rhythms over the sensorimotor cortex [ 12 ].

    In this research, noninvasive electrode equipment is used for recording EEG signals form scalp. The EEG signal data set was recorded using a 14-channel electrode headset (Emotiv headset) from right-handed, neurologically intact volunteers. This research is a follow-up of our previous research in which Mu and Beta Rhythms (8� Hz) were used. Power Spectral Density (PSD) was used for analysis of filtered data followed by logistic regression for classification of finger movements [ 13 ]. PSD describes the distribution of power of signal over its frequency. The band power of Power Spectral Density [ 14 ] of finger movements of one hand occurring over the motor cortex is used as a feature to classify them. The Mu and Beta Rhythms that occur over the motor cortex provide us with information related to the movement [ 15 , 16 ].

    A variety of classification techniques are used in BCI systems such as Neural Networks (NN), Support Vector Machines (SVM), Discriminant Analysis, and Bayesian Classifiers. As an extension of our previous research logistic regression is used as a classifier, and output of the classifier is used for generating command signals to control upper limb prosthesis [ 17 – 19 ].

    Our previous research [ 13 ] compared different classifiers, namely, Multilayer Perceptron, Linear Discriminant Analysis (LDA), Quadratic Discriminant Analysis (QDA), and logistic regression to achieve highest classification accuracy [ 20 , 21 ]. Two-stage logistic regression gave the highest classification accuracy of 74% for four finger movements (thumb, index finger, index and middle finger combined, and fist). Weka 3.6.9 (data mining software with collection of machine learning algorithms) and Matlab were used to process the signals in earlier research.

    In the current research our emphasis is on the use of embedded system to process EEG data for generating command signals for upper limb prosthesis. Arduino Uno is used as the embedded system to filter signals (between 8 and 30 Hz), extract features (PSD), and differentiate between three finger movements. In this research, we are using three targeted finger movements (thumb, index finger, and fist) instead of four (as were in our previous research). The reason to restrict ourselves to three movements only is that embedded system is not able to distinguish between the index finger movement and index-middle finger combined movement.

    2. Materials and Methods 2.1. Section I: Experimental Protocol and Data Acquisition

    The data was acquired from four subjects (one female and 3 male) who volunteered to undergo data recording protocol. One of the male subjects (described as category I in Results) has a habit of high involuntary eye blinking frequency. The other three subjects are described as category II in Results. The age of subjects is between 22 and 45 years. The process of data acquisition from the subjects is approved by the departmental ethical review board. The volunteers are healthy with no known neurological disabilities. The data was acquired using Emotiv headset at 128 Hz sampling frequency. Emotiv has 14 noninvasive electrodes placed according to the international 10-20 system shown in Figure 1 [ 13 ]. The data was acquired for four movements, i.e., thumb, fist, index finger, and index-middle finger combined movements. The movements are shown in Figure 2 [ 13 ]. Three out of these acquired movements (thumb, index finger, and fist movement) data were used for this research.

    Finger movements that were recorded. (a) Thumb movement. (b) Fist movement. (c) Index finger movement. (d) Two-finger (index and middle) combined movement [ 13 ].

    During data acquisition, the subjects were comfortably sitting in a chair and were asked to perform the movements shown on the computer screen. For each subject the acquired data of one trial contained 10 seconds of data for each movement, which makes 1280 samples per movement. The total samples in one recorded trial are 1280 × 4 = 5120 . There were a total of 60 recorded trials for each subject, out of which 13 trials for each subject were rejected on the basis of visual inspection. Rest of the 47 data trials for each subject were used. For this research samples of only three movements (thumb, index finger, and fist) were used instead of four movements. Thus, for this research 47 × 1280 × 3 = 180480 samples have been used for one subject. The data acquisition protocol is shown in Figure 3 .

    Data acquisition protocol.

    2.2. Section II: Embedded System

    The aim of this research was to design an embedded system that can be used to classify and control upper limb prosthesis finger movements using acquired EEG signals. 𠇊rduino Uno” is the embedded system used to fulfill the aim of this research. The attributes of embedded system (Arduino Uno) are given in Table 2 .

    Attributes of embedded system.

    The data was given as input to Arduino Uno, which was programmed to process the input (filtering and classification). Basing upon the result of classification, generate a signal that controls motors connected to upper limb prosthesis fingers. Stages of the system from data input to device control are shown in Figure 4 .

    Stages of system from data input to device control.

    Data processing steps included digital filtering with a high pass and low pass filter to retain 8� Hz of frequencies. Filtration was followed by feature extraction (calculation of band power from PSD of the remaining frequencies) from the data. The feature vector was then given as input to a logistic regression classifier network for classification of three finger movements. Based on the classification, a command signal is generated and sent to a motor drive circuitry (H-Bridge in this case) to actuate the respective motor to start the finger movement of upper limb prosthesis.

    This research was carried out using data already acquired from the subjects. Data set of each trial consisted of 10 seconds of data of 14 channels at the sampling rate of 128 Hz. From each of the 47 trials, 250 ms of data was extracted and converted to text files. The data was saved offline on an SD card in text file and given as input to Arduino Uno. The SD card was interfaced with the controller using Serial Peripheral Interface (SPI). SPI operates in full duplex mode with a Master Out Slave In Pin, Master In Slave Out Pin, Serial Clock Pin, and Chip Select Pin. The Arduino acted as Master, while the SD card acted as Slave. The Arduino first enabled the SD card through Chip Select. The clock was set at a baud rate of 9600. The Pin configuration of connection between SD card and Arduino Uno is shown in Table 3 .

    Connection between SD card and Arduino.

    As discussed earlier in this section, 250 ms of data was extracted from each trial, converted, and saved in text file. During processing, first 250 ms of data is read by the embedded system, processed, and classified. Then, next 250 ms of data of next trial is read and processed and the loop continues for classification until the data reaches its end.

    2.3. Section III: Filtration Techniques

    Filtering the data to extract Mu and Beta band of frequencies (8� Hz) is carried out as this band contains maximum information related to finger movements. To execute this through embedded system, 250 ms of EEG data was digitally filtered using a Butterworth filter between 8 and 30 Hz of order 2. The reason for using Butterworth filter was its flat response with zero ripples. The coefficients of the Butterworth filter were taken from Matlab 𠇋utter” command and are shown in Tables 4 and 5 .

    High pass filter coefficients.

    Low pass filter coefficients.

    Filtration was done using these coefficients in the filter difference equation defined by [ 21 ] (1) a 1 ∗ y n = b 1 ∗ x n + b 2 ∗ x n - 1 + b 3 ∗ x n - 2 - a 2 ∗ y n - 1 - a 3 ∗ y n - 2 , where y is the output, x is the input, and n is the n th element of the output.

    Before passing the data through filter, it was padded. Later, after the forward and reverse filtering, the data was truncated back to its original number of samples. Filtration was done in both forward and reverse direction. The data was first passed through high pass filter of order 2 and 8 Hz𠂜ut-off frequency and the resultant was passed through a low pass filter of order 2 and 30 Hz cut-off frequency.

    2.4. Section IV: Feature Extraction

    Power Spectral Density of each channel of the filtered signal was calculated. Each channel of filtered signal was divided into 4 windows of 62.5 ms each. A hamming window was created. The formula for hamming window is given in [ 22 ] (2) w n = 0.54 - 0.46 ∗ cos ⁡ 2 π n N - 1 , where N is the maximum number of points of the sampling window.

    The window function was then multiplied with the signal to shape it into hamming window. Fast Fourier transform of the windowed signal was then calculated. Formula for Fast Fourier transform is given in [ 22 ] (3) X k = ∑ n = 0 N - 1 x n e - i 2 π k n / N   k = 0 , … , N - 1 .

    The absolute value of the resultant is computed and divided by the normalization factor of the window.

    The normalization factor of the window is given by [ 22 ] (4) U = 1 L ∑ n = 0 N - 1 w n 2 .

    This gives us the Power Spectral Density of the window, which can be represented as in ( 5 ) [ 3 ]. After the PSD of each window is calculated, the corresponding values of all windows are added and averaged, leaving us with a vector of 8 constituents. Each value of this vector is then further divided by 2 π to scale the values. (5) p x x = X f 2 F s L U , where Fs is sampling frequency, L is length of segment, U is window normalization constant given by ( 4 ), and X ( f ) is data after FFT.

    The power values are averaged to give the band power of one channel of data. The process is repeated for all the 14 channels. In the end, we are left with a feature vector of 14 values, each representing the band power of 8� Hz frequency of the channel. Figure 5 shows the topography plots of the raw data of randomly selected data samples of each movement. It can be seen that in each plot the electrodes F3 and FC5 contribute to rise in contours. These channels are basically located above the sensorimotor cortex. The contours due to these two electrodes have been magnified to show the difference in the topographies of the movements. The difference is also highlighted in the periodogram graphs that are shown from Figures 6 – 8 on channels F3 and FC5 of different movements. These graphs show the power concentration, in the 8� Hz band, of different movements.

    Topography plots of movements. FC5 and F3 electrodes have been magnified to show the difference in the topographies of the movements.

    Finger movement periodogram of channels F3 and FC5.

    Thumb movement periodogram of channels F3 and FC5.

    Fist movement periodogram of channels F3 and FC5.

    2.5. Section V: Classification

    As discussed earlier, our previous research had shown highest classification accuracy by using linear regression classifier. Therefore, for this research we used two-stage logistic regression classifier to calculate classification accuracy for three finger movements. For the logistic regression classifier, the probability of the first class is given by [ 23 ] (6) P G = 1 = exp ⁡ B T ∗ F exp ⁡ B T ∗ F + 1 , where F is the feature vector and B T are the coefficients of logistic regression.

    The criterion for selection of class is [ 24 , 25 ] (7) G x = c l a s s   1   if   P r > 0.5 G x = c l a s s   1   if   P r < 0.5 .

    In the two-stage model, the first classifier (referred to as network I) distinguished between class 1, which is thumb and finger movements, and class 2 which is fist movement. In the 2nd stage a second classifier (referred to as network II) distinguished between thumb and finger movement. The classifier model is shown in Figure 9 . Training of the classifier was done using data set of all subjects (75% for training and 25% for testing) in “Weka” and coefficients of logistic regression were calculated for further use in classification using the embedded system. 31 randomly chosen samples for each movement were tested for classification in embedded system keeping in mind the data handling capability [ 26 ].

    Two-stage logistic regression classifier used for the system.

    2.6. Section VI: Device Control

    Upper limb prosthesis used for this research was developed in the department for carrying out the experiments. Figure 10 shows a picture of upper limb prosthesis.

    Prosthesis controlled by the embedded system.

    Prosthesis contains two motors connected to two fingers and placed at the palm. Finger joints are connected with each other with the help of a flexible metal wire which is connected with a motor. Motor rotation will cause winding or unwinding of the flexible metal wire resulting in opening or closing of fingers. Both motors were connected to motor drive which was taking command signal from Arduino Uno. The embedded system generated a control signal based on the classification of finger movements. This control signal was sent to the motor drive circuitry to actuate the motor for desired motion. One of the motors is attached to Output Pins 4 and 6 (for thumb movement) and the other is attached to Output Pins 2 and 3 (for finger movement). Motion of motors according to classification is shown in Table 6 .

    Motion of motors according to classification.

    To train the two-stage logistic regression classifier data set of all subjects (category I and category II) is used as discussed in Section 2.5 . 75% data is used for training and 25% data is used for testing. “Weka” (data mining software) was used and coefficients of logistic regression were calculated for further use in embedded system.

    Results of our research comprise two categories. In category I (subject having a habit of high involuntary eye blinking frequency), 31 randomly chosen data samples from each movement were used for testing using embedded system. In category II (subjects other than category I), 31 randomly chosen data samples from each movement were used for testing using embedded system.

    Table 7 shows the classification accuracy of each stage of classifier (network I and network II) using data set of all subjects (category I and category II) as discussed in Section 2.5 .

    Network classification accuracy of a two-stage logistic classifier network.

    Table 8 shows the confusion matrix of category I data set tested over 31 randomly chosen samples for each movement and Table 9 shows the category II data set tested over 31 randomly chosen samples for each movement.

    Confusion matrix of category I data set.

    Confusion matrix of category II data set.

    Table 10 shows the per class classification accuracy of randomly chosen samples from category I and category II. Percentage accuracies are calculated on the basis of confusion matrices shown in Tables 8 and 9 .

    The aim of this research was to investigate the design of an embedded system for control of upper limb prosthesis as an extension of our previous research. As evident from Table 1 , research using BCI system for control of prosthesis is focused on spatially distant motor movements. Our focus in this research was to control prosthesis with finger movements which have less spatial distance as compared to earlier researches.

    Finger movements have the same origin in brain leading to extremely small spatial difference between them. Our endeavor was to pick up the small difference of brain activity recorded in the form of electrical potential and classify it with higher accuracy. It was seen from the topography plots shown in Figure 5 that finger movements have the same origin in brain. The minor differences in the topographies were highlighted when the data under electrodes F3 and FC5 was interpolated and plotted in a magnified manner.

    Band power of Power Spectral Density of Mu and Beta Rhythms was chosen as feature vectors. PSD is used as a feature vector in 70% of the research which focuses on motor controls. The periodogram of the movements was plotted for the channels above sensorimotor cortex to visualize the differences.

    The development of the embedded system was focused on to design a control for upper limb prosthesis that has small size and light weight and is easy to carry onboard system for prosthesis user. The acquired data was saved on SD card rather than on the controller to depict a real time data processing and classification. 70% mean classification accuracy was achieved with 2-stage logistic regression classifier using an Arduino Uno based embedded system. It should also be noted that the index and middle finger combined movement could not be classified with higher accuracies since the spatial distance is very less. This accuracy needs to be increased further for developing better control of prosthesis and practical implementation.

    The challenge is to create an online model that can process and classify the real time data. However, implementation of the model on patients requires a more robust system suggested subsequently. A headset with greater number of channels especially above the motor cortex is required for recording more comprehensive signals. It is also recommended to use an embedded system with higher computational speed which can process signals in real time.

    It can also be seen from our results that eye blinking during data acquisition induces ocular artefacts which result in lower classification accuracies. For a better and higher classification accuracies a signal with higher signal to noise ratio is required. Different techniques for removing ocular artefact may be used for future work.

    Overall the research shows that upper limb prosthesis control can be achieved even with signals that are taken from closely situated body part with an average accuracy of 70% (calculated on the basis of classification accuracy of category II randomly chosen samples as mentioned in Table 10 ).

    The designed embedded system in this research is capable of controlling the prosthesis based on the model developed earlier. A two-stage classifier has been designed and implemented over the embedded systems. The classifier is capable of distinguishing between three movements of finger, thumb, and fist. The mean classification accuracy of 70% is attained by the developed system. Further work to improve the classification accuracy using advanced embedded system can be undertaken for enhanced prosthesis control.


    Results

    Figure 7 shows the accuracy of single-trial classification for all 20 subjects using a single-subject classification paradigm. The classification accuracy increased in accordance to the increase of the time window length used for feature extraction. With window length shorter than 150 ms, the average accuracy was around the chance level (mean±standard deviation: 51.1±5.9%). After 150 ms, the accuracy increased gradually and reached 67.0±7.5% at 500 ms. The tendency of performance improvement is consistent with the differences in time courses of ERP waves between left and right conditions, which reflect temporal dynamics of the PPC activities during directional movement planning. There was a large individual variability in single-trial classification accuracy: <60% in four subjects, 60–70% in 10 subjects, and >70% in six subjects. These results indicate that EEG activities near the PPC can provide useful information for predicting the intended movement direction. Although single-trial classification performance for single subject is low, it provides a substantial basis for building a collaborative BCI.



Comments:

  1. Shaktilmaran

    What a nice sentence

  2. Westin

    Yes, correctly.



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