System for self-administration of electroencephalographic (EEG) neurofeedback training

A system for self-administered monitoring, displaying, analyzing and recording electrical activity of the brain provides indications of brain activity and a corresponding mental state of a user. A plurality of visual, auditory and tactile feedback mechanisms are integrated with the presentation of control and notification indications, to facilitate neurofeedback training of the user, The operational interface and sequencing is provided in such a manner as to provide the ability to the user to record, manage and control brain activity for different purposes including self-improvement, treatment, peak performance and recreation.

FIELD OF THE INVENTION 
The present invention pertains generally to EEG biofeedback for learning 
and controlling bio-electric characteristics of the brain which correspond 
to different mind states and conditions and, more particularly, to 
self-administered biofeedback systems which allow the user to provide 
interactive input in response to biofeedback neurologic signals to 
maintain or vary a mental state. 
BACKGROUND OF THE INVENTION 
EEG (brainwave) signals have been extensively studied in an effort to 
determine relationships between frequencies of electrical activity or 
neural discharge patterns of the brain and corresponding mental, emotional 
or cognitive states. Biofeedback of identified frequency bands of EEG 
signals is used to enable a person to voluntarily reach or maintain a 
target mental state. 
Frequency bands of EEG readings used in such biofeedback have been 
generally categorized in the approximate frequency ranges of: 
delta waves, 0 to 4 Hz; 
theta waves, 4 to 7 Hz; 
alpha waves, 8 to 12 Hz; 
beta waves, 12 Hz to 36 Hz, and 
sensorimotor rhythm (SMR) waves, 12 to 15 Hz. 
It is theorized that each of the major subbands of biofeedback EEG (delta, 
theta, alpha, beta) has unique bio-electric characteristics which 
correspond with unique subjective characteristics of an individual. The 
delta band is observed most clearly in coma and deep sleep, the theta band 
in light sleep and drowsiness, the alpha band in a variety of wakeful 
states involving creativity, calm and inner awareness, and the beta band 
in alert wakeful situations with external focus. In general, a dominant 
brain wave frequency increases with increasing mental activity. 
Many different approaches have been taken to EEG biofeedback to achieve 
mental state control. U.S. Pat. No. 4,928,704 describes a biofeedback 
method and system for training a person to develop useful degrees of 
voluntary control of EEG activity. EEG sensors are attached to cortical 
sites on the head for sensing EEG signals in a controlled environmental 
chamber. The signals are amplified and filtered in accordance with strict 
criteria for processing within time constraints matching natural 
neurologic activity. The signals are filtered in the pre-defined subbands 
of alpha, theta, beta and delta, and fed back to the monitored person in 
the form of optical, aural or tactile stimuli. 
U.S. Pat. No. 4,949,726 discloses an electrical device which is responsive 
to recorded brain waves to produce an electrical output which corresponds 
to detection of brain waves in predefined frequency ranges. The output of 
the device is connected to a device control apparatus to cause an output 
device to perform a function in accordance with detected brainwave 
signals. U.S. Pat. No. 5,024,235 describes an EEG neurofeedback apparatus 
which detects analog signals from the brain, converts readings to digital 
signals and compares the digital signals to a threshold amplitude to 
provide an auditory or visual indication to a person of whether or not the 
detected signals are within a predetermined frequency range. 
U.S. Pat. No. 5,241,967 describes a system for evoking EEG signals from a 
subject which applies a frequency signal to a stimulus generator for 
conversion to a stimulative signal such as a photic stimulus to the 
subject. The brain wave to be evoked is strongly synchronized by the 
stimulative signal applied to the subject to put the subject in the 
desired brain wave state. U.S. Pat. No. 5,365,939 describes a method for 
evaluating and treating an individual with EEG disentrainment feedback by 
selecting a reference site to determine a reference brain wave frequency, 
entraining the brain wave frequency in one direction until a first stop 
condition occurs, the entraining the brain wave frequency in an opposite 
direction until a second stop condition occurs. Different electrode sites 
are selected to fully test an individual for flexibility to EEG 
entrainment feedback treatment. And U.S. Pat. No. 5,406,957 describes an 
EEG Neurofeedback apparatus for training and tracking of cognitive states 
which measures bioelectric signals in bandwidth windows to produce a 
composite amplitude by a fast Fourier transform on an amplified signal. 
Selected bandwidths are displayed and monitored by computer to enable 
training of a person being monitored with audio or verbal feedback. 
In many of the EEG biofeedback systems and methods of the prior art, it is 
necessary to interrupt data collection and analysis and/or the biofeedback 
process in order to perform set-up functions, to review component values, 
or to set protocols or adjust threshold levels. These functions are 
typically performed by a session administrator, which can ultimately 
diminish or otherwise adversely effect the nature and quality of 
biofeedback signals to a subject seeking to benefit from EEG training. 
Most of the neurofeedback systems of the prior art generate only a single 
form of each type of feedback stimuli, such as a single screen display, or 
a single auditory and tactile signal, thus inherently limiting the scope 
of biofeedback and physical (EEG) response. 
SUMMARY OF THE PRESENT INVENTION 
The present invention provides a method an apparatus for 
self-administration of electroencephalographic (EEG) neurofeedback 
training which records and analyzes electrical activity of the brain and 
produces an indication of a corresponding mental condition or state to a 
user. 
In accordance with one aspect of the invention, a system for 
self-administration of EEG neurofeedback training includes an EEG monitor 
having an EEG amplifier, an isolated computer interface, a microprocessor 
controller, and a peripheral breadboard area, EEG electrodes connected to 
the EEG module for attachment to the head of a user of the system, a 
connection from the EEG module isolated interface to a computer, the 
computer programmed with software of the system for monitoring, recording, 
reading, analyzing and displaying EEG signals, a monitor connected to the 
computer for display images of EEG signals processed by the computer and 
the system software. 
In accordance with another aspect of the invention, a method for 
self-administration of electronencephalographic (EEG) neurofeedback 
training through observation and control of displayed graphic images which 
correspond in real time to EEG signals obtained from a user of the system 
includes the steps of connecting electrodes of an EEG neurofeedback 
training system to the head of a user, the system having an EEG module 
connected to the electrodes and to a computer, the computer having 
software for receiving and analyzing signals received from the electrodes 
and generating screen displays in response to received EEG signals, the 
software further having control functions including user selection of 
types of screen displays including combinations of types of screen 
displays generatable by the software in response to EEG signals, and user 
selection of screen display parameters which correspond to received EEG 
signals, selecting a screen display for generation by the software and 
display on a monitor connected to the computer, selecting screen display 
parameters, and viewing the screen display generated by the software in 
response to received EEG signals. 
These and other aspects of the invention are herein described in 
particularized detail with reference to the accompanying Figures.

DETAILED DESCRIPTION OF PREFERRED AND ALTERNATE EMBODIMENTS 
With reference to FIG. 1, there is illustrated the basic components of the 
apparatus of the invention including an EEG module 10 having at least 
three EEG electrodes 11 connected thereto and attachable to the head H of 
a user. The EEG module 10 is connected by a serial data line 12 to a 
computer or data processor 20 which is connected to a display monitor 21, 
and/or addition biofeedback stimulative devices such as audio or vibratory 
headphones 221, light goggles 222, and/or tactile stimulator 223 as 
controlled by a feedback device controller 224 connected to computer 20. 
Computer 20 contains EEG analysis and biofeedback software 22 which 
performs EEG recording, analysis and biofeedback operations as described 
herein. 
The EEG module 10 includes a 2-channel EEG amplifier 13; a 
computer/controller 14, and on a peripheral breadboard area 15 a built-in 
electrode test and connection to additional indicators and controls 
indicated generally at 115; 2 auxiliary channels (GSR, Temp); 
analog-to-digital converter (1-8 channels); 8-bit digital input port; 
8-bit digital output port; optically isolated RS-232 port (9600 baud), and 
rechargeable batteries. The system uses an internal control structure that 
exploits the presence of two, independently operating computer units in 
the form of EEG module 10 and computer 20. The EEG module 10 is clocked by 
an internal interrupt timer that is responsible for initiating a 
processing cycle. The computer 20 is, for example, an Intel-based PC with 
a 486/50 or Pentium processor with Windows to include local storage and 
graphics, and also uses an internal interrupt timer responsible for 
initiating the processing cycle. The two computers, when operating 
concurrently, undertake a cyclic method of operation which facilitates two 
main computing functions: (1) the acquisition and transmission of data by 
the module, and the receipt of data, processing, and display by the user 
computer, and (2) the determination and transmission of control 
information by the user computer, and the receipt of this information by 
the module, which then carries out any of a number of possible 
user-feedback tasks. 
The supervisory functions of the system are identified as: Sequence Timing 
and Control, User Information and Instruction, and Spoken Report and 
Command. With reference to FIG. 2, the system uses an internal control 
structure that exploits the presence of two, independently operating, 
computer units. The first, computer 25 is clocked by an internal interrupt 
timer 26 that is responsible for initiating a processing cycle including 
an integrity check 251, analog data read 252, data transmission 253, data 
read 254, and output effects 255, including for example photic stimulator 
2551, auditory stimulator 2552, and/or tactile stimulator 2553. The second 
computer 28, which is for example a computer workstation including local 
storage and graphics, also uses an internal interrupt timer 29, that is 
responsible for initiating the processing cycle in accordance with the 
software of the invention, which includes for example the steps of loading 
the buffer at 291, performing computations at 292, decision procedure 293, 
creation of displays at 294, and sending of commands at 295. These two 
computers, when operating concurrently, undertake a cyclic method of 
operation that facilitates two main processes: (1) The acquisition and 
transmission of data by the module, and the receipt of data, processing, 
and display by the user computer, and (2) the determination and 
transmission of control information by the user computer, and the receipt 
of this information by the module, which then carries out any of a number 
of possible userfeedback tasks. 
The EEG module is powered by a rechargeable battery power circuit. When the 
unit is turned off, the power from the 9VDC adapter plugged into the 120 
VAC line is used to charge the internal battery. The circuit interrupts 
current from reaching the user, even with electrodes connected to the 
user. When the unit is turned on, the line is disconnected and the module 
operates from the batteries. This also insulates the user from the 
electrical energy which powers the module. The circuit thus uses AC line 
power to sustain the battery, which also remains connected to the 
wall-mounted power supply at all times, but without the risk associated 
with using line power to the module, thus eliminating any possibility of 
electrical shock to the user. 
Software 22 provides computing functions for data acquisition; graphic 
display (multiple modes); FFT frequency transform; EEG frequency band 
measurement; biofeedback task control and recording; file save and 
restore, graphing and summary capabilities. With the EEG module 10 and 
computer 20 connected and powered up, the software 22 is booted to 
generate an initial "open-input" noise display as shown in FIG. 3, 
representing the high frequency noise that is typically picked up by the 
EEG module 10 when it is sitting with nothing connected to the EEG module 
inputs. 
The electrodes 11 of the EEG module are attached to the user as, for 
example to the locations illustrated in FIG. 1, one electrode to each ear, 
and to at least one location on the scalp, with preferably one on each 
side of the forehead to provide "right active" and "left active" 
two-channel input, and neutral (or "indifferent") and "ground" EEG inputs. 
Generally, the active electrode will be attached to the head in a specific 
location (frontal, parietal, occipital, etc.), and the indifferent and 
ground electrodes will be attached to each ear. The active and indifferent 
electrodes are fed to either channel of the EEG module 10. For example, 
with the active electrode attached to the head, the indifferent electrode 
attached to the left ear, and ground attached to the right ear, the EEG 
module will measure brainwave activity between the head and the left ear 
as a reference, with the right ear being used as ground. Two active leads 
(right and left) provide two channel EEG monitoring. A dual ear clip can 
be used to provide connections on both the front and back of the ear. 
Using this electrode, a single channel recording (e.g., the left channel 
as shown) is obtained with only a single head connection. To add a second 
channel, a conventional earclip is added (e.g., to the right ear) and a 
second head connection ("right active") is attached. 
The program software 22 allows channel selection via the "1" and "2" 
buttons on the upper row of the toolbar shown in FIG. 3. The program 
starts up assuming a 1-channel module. If "2" is selected, the program 
assumes that the module is transmitting 2 channels of data. As represented 
by FIG. 3, one program screen display 30 generated by the software is 
divided vertically into two sides or window 31 and 32, denoted on the 
toolbar as "left" and "right". These two sides usually reflect the EEG 
activity from the respective sides of the brain. The work area consists of 
"tiled" regions that provide the various types of displays. The program 
generates the following alternative display windows: a report window in 
the upper left text window 33 presents text which explains what the system 
is doing, such as "programming module", or "collecting data". A "command 
window" in the upper right text window 34 presents text which requests 
user action such as "check module" or "relax for recording". 
The system is capable of displaying any combination of a set of selectable 
windows, which can be reconfigured and displayed, or hidden, at any time, 
including when the system is in operation. Moreover, the windows operate 
in concert, providing a user-interface that exploits the presentation of 
information in various forms, and with the information in a 
window-relating to, or controlling, the information in another window. 
This provides the user with the ability to configure display and control 
screens that implement particular "protocols" for various purposes. 
FIG. 4 illustrates an EEG wave form display 40 which, in window 41, 
displays a scrolling raw wave form (in for example a one second epoch) set 
to refresh approximately twenty times per second. The wave form is drawn 
left to right across the display window and when it reaches the end, the 
drawing position starts over at the left side, replacing the previous data 
as it moves across the window, thereby displaying one second of EEG at all 
time, thereby continuously displaying one second of EEG monitoring, 
without disturbing the neurofeedback training session. This capability is 
essential in the application of self-administered biofeedback training 
because it eliminates the need for a dedicated operator or session 
administrator to monitor waveforms, independent of the subject's activity. 
Window 42 contains a Fast Fourier transform (FFT) display of a signal 
frequency spectrum of 1 to 30 Hz. This spectrum is updated four times per 
second and reflects the last one second of EEG data. A slowly changing 
"trend" envelope 43 is also superimposed to show the shape of the spectrum 
reflecting the last few seconds of EEG activity. This trend line is 
actually a "weighted" average of the past activity, using a wave length 
factor of approximately 0.6, so that the value of a point is, for example, 
0.4.times.(current value)+0.6.times.(previous value), to provide a 
"smoothing" function. FIG. 4 also illustrates the simultaneous and 
combined display of alternative graphical representations of monitored EEG 
waveforms, which is a fundamental concept of the invention. 
As shown in FIG. 5, the program further produces a "phase-space" 
two-dimensional display 50 using "rate of change" in place of the time 
axis, as commonly used in chaos analysis. The vertical axis is exactly the 
same as in the EEG wave form display, e.g., "amplitude" while the 
horizontal axis is the "first derivative" or "rate of change" of the EEG 
signal. This display produces very smooth coherent wave forms which appear 
as founded, open circles, while faster irregular activity will produce 
flatter shapes with more internal detail such as plot 51. 
As shown in FIG. 6, the program alternatively can produce a compressed 
spectral array (CSA) display 60 which generates a cascade of past FFT 
spectra covering the previous 100 seconds of EEG activity. As shown in 
FIG. 7, the program alternatively can produce a symmetrical laterally 
opposed bar graph plot display 70 which includes smoothing trend lines 71 
similar to that described in connection with FIG. 4. 
The program of the invention can alternatively produce a thermometer type 
display 80 as shown in FIG. 8, which includes each of the major EEG 
components or frequency band intensities as vertically oriented colored 
thermometers or "thermobars" 81 which vertically grow and shrink in 
real-time response to monitored EEG signals. In the thermometer type 
display of the invention, the EEG components or frequency bands 
represented by the individual thermometer columns are: .DELTA.delta: (1-3 
Hz), theta: (3-8 Hz), .alpha. alpha (8-12 Hz); SMR: (12-15 Hz), .beta. 
beta: (15-32 Hz). The parameters of the frequency bands represented by the 
thermometer columns can be adjusted or reset by the user. The 
"temperature" of each thermometer or thermobar 81 reflects the summed 
energy in the frequency bands. Thus, they represent a combination of all 
the frequencies and are not a simple real time amplitude. However, they 
are proportional to the amplitude of all of the components combined, 
because they are scaled in the same units as the FFT and mind-mirror 
windows, both of which reflect signal energy in the "root mean square" 
sense. 
In addition to displaying the EEG energy in each band, the thermometer 
display 80 of the invention is used to set up the biofeedback paradigms of 
the invention, which includes the identified components to be rewarded or 
to be discouraged, in the threshold values at which to elicit biofeedback 
signals. Each thermometer has superimposed on it two tick marks. The 
thicker top bar indicates the maximum value that a component has reached 
in a given current session. The thinner lower bar indicates the current 
threshold for the detection of activity in that band. With the "SND" mode 
enabled, every time the signal exceeds the threshold, there is generated 
an audible indication in the form of a spoken voice saying the name of the 
component, for example, "alpha", "beta". 
Initially, the thresholds are auto-set during "learn" mode at either 60% of 
the maximum value ("4+ components" and 40% of the maximum value for ("-4 
components") that have been reach in that session. Manual adjustment can 
then be easily done using the keyboard as described below. By displaying 
any combination of components, the thermometer display facilitates complex 
biofeedback paradigms with a single, simple, on-screen metaphor without 
interruption of EEG data collection and/or biofeedback to perform the 
setup function. 
The software can alternatively generate one dimensional trends of each of 
the biofeedback EEG frequency bands to show current and past activity of a 
component in a plot of value vs. time over a period of 120 seconds, as 
shown by the display 90 in FIG. 9. After the plot reaches 120 seconds, it 
clears and redraws. The plot window displays only those components which 
are currently selected, i.e. that would be displayed in the "thermometer" 
window. Trend values are saved in a disk file so that any number of 
successive two minute periods can be saved to the file for later display 
and analysis. All components are calculated and saved to a trend file 
whether they are displayed or not. 
Alternatively, a two dimensional trend displays plots components against 
each other, such as, for example, alpha vs. beta as shown in the display 
100 of FIG. 10. This plot uses the first two of the currently selected 
components in order from low frequency to high frequency, i.e., delta, 
theta, alpha, SMR, beta. 
The system software can alternatively generate a "highway" type display 110 
shown in FIG. 11 which is similar to an EEG spectrum, used for ADD 
protocols with theta, SMR and beta as three colored bars, with the center 
bar proportional to SMR, the left bar proportional to theta, and the right 
bar proportional to beta. The software generates the rectangular lines 111 
which surrounding the boxes to provide a visual indication of current 
threshold values. 
Alternatively, the system software can produce a "pac man" type display 120 
shown in FIG. 12 which will advance one point for each target hit. Since 
what constitutes a "hit" is determined by the set up of the thermometer 
system, the exact criteria for causing the "pac man" to move can be set up 
in any desired fashion, such as an alpha or beta wave reinforcement. 
Alternatively, the system software can produce a "pac man" with words or 
"word man" wherein the pac man will eat his words, as shown by display 130 
in FIG. 13. This is very useful in working with people who wish to work 
with their EEG brain waves while reading. The word man display moves from 
level to level continuing to read from a file automatically "turning the 
pages" as the levels proceed. The user may type any text into a DOS text 
file and, by copying that file into a pac man file and restarting the pac 
man screen, the text is dynamically incorporated into the display. 
As shown by display 140 of FIG. 14, the system of the invention can also 
produce an interactive biofeedback display which is generally in the form 
of an expressive facial image 141, the features of which are determined by 
the monitored EEG activity. This aspect of the invention allows the user 
to control the facial expression on the screen using the EEG waveforms. 
The angle of the eyebrows 142, and the angle of the smile (or frown) 143 
are controlled by two EEG components. Thus, a range of expressions, 
including "happy," "mischievious," "hopeful," and "angry" can be produced 
by the different combinations of these facial features. 
The face works in any mode, including training mode. Typically, the mouth 
is used to reflect a component we wish to encourage, and the eyebrows are 
used to reflect a component we wish to discourage. The degree of angle of 
the mouth, or of the eyebrows, is made relative to the threshold value. 
The center point of the mouth is set by the threshold value, and the 
outside of the mouth is set by the component controlling it. Thus, a mouth 
value below threshold is a frown, and a value above threshold is a smile. 
If the "threshold" values are not set, then they are taken to be zero. 
Thus, the mouth value would always be a smile, of varying extent. 
In the case of the eyebrows, the controlling component sets the outer 
("lateral") points, while the threshold sets the inner ("medial") points. 
Thus, a value below threshold "lifts" the eyebrows, and a value above 
threshold "lowers" the eyebrows. "Lifting" the eyebrows means that the 
center of the eyebrows is higher than the outsides, resulting in a 
"positive" affect. "Lowering" the eyebrows can also be called "scowling," 
in which the center of the eyebrows is lower than the outsides. Similar to 
the mouth, if there is no threshold value, then the eyebrows are always 
relatively "lowered." 
In the following examples, the mouth is controlled by the alpha (8-12) 
amplitude, and the eyebrows are controlled by the theta (4-7) amplitude. 
In accordance with some "ADD" protocols, we want to encourage alpha, and 
discourage theta. As alpha increases, the "smile" grows. On the other 
hand, as theta increases, the eyebrows "scowl." Other facial expression 
parameters can be incorporated into this display of the invention such as 
wide open or squinting eyes, moving nose, ears and other facial lines or 
contours which contribute to an overall expression such as dimples, 
wrinkles and cheek bone profiles. Also, digitized images of an actual user 
could be generated and digitally altered from memory to alter the 
described facial components according to monitored EEG signals. 
As represented by the facial expression in display 150 of FIG. 15, both the 
alpha and the theta are relatively low. As a result, the face is not 
really smiling, but the eyebrows are lifted in response to the low theta. 
The face is hopeful, since the user is capable of keeping the theta low, 
but has not yet demonstrated enhanced alpha. As further shown by FIG. 15, 
the facial expression can be simultaneously displayed with any of the 
previously described biofeedback display formats such as the thermometer 
array 152, which readings of course correspond in real time to the 
elements of the facial expression. Such combined displays can be 
reconfigured or hidden at any time, including when the system is in 
operation. The display windows operate in concert to maximize the feedback 
effectiveness of the combined formats. This feature provides the user with 
the ability to configure display and control screens which implement 
particular protocols for various purposes. 
In the display 160 of FIG. 16, the "happy" face is produced as a result of 
high alpha readings, and low theta readings. The mouth is smiling, and the 
eyebrows are lifted. Since this is what we want to see, the face is happy 
to see it. This image is also shown simultaneously displayed with the 
corresponding thermometer readings of alpha and theta. In the 
"mischievous" facial expression display 170 of FIG. 17 the alpha is high, 
but the theta is also high. As a result, the face is smiling, but the 
eyebrows are "scowling." The result is a mischievous look, telling the 
user that they still need to lower that theta| This message is emphasized 
by the corresponding thermometer display showing the theta column above 
the threshold level. 
In the "angry" facial expression display 180 of FIG. 18, the "angry" face 
results from low alpha, so the face is frowning. Also, the theta is high, 
causing the eyebrows to lower. As a result, we have a very unhappy face, 
telling the user that this is not at all what is desired| 
As can be seen from these examples, the dynamic facial expression displays 
of the invention provide an extraordinary modality of biofeedback, in 
which the brainwave components are reflected in the apparent emotion of 
the visual image, providing a very direct and easy-to-comprehend display. 
The facial expression display of the invention has special value, in that 
it has been shown that people everywhere express emotions in the same 
basic ways. Ekman & Friesen (1982) showed that people from different 
cultures interpret photographs depicting emotions in the same ways, 
including people as far apart as natives of New Guinea, and American 
college students. (Ekman P., & Friesen, W. V. (1982) Measuring facial 
movements with the facial action coding system. In P. Ekman (Ed.), Emotion 
in the human face. Cambridge University Press. (pp. 99, 101), and 
Eibl-Eibesfeldt, I. (1989) Human ethology, New York: Aldine de Gruyter. 
(pp. 98, 102, 116), incorporated herein by reference. Furthermore, 
Eibl-Eibesfeldt (1989) found that the eyebrow flash, a momentary raising 
of the eyebrows lasting about 1/6 second, accompanied by a smile, is 
universally recognized in every culture studied, including New Guinea, 
Samoa, Africa, Asia, South America, and Europe. This has been found to be 
universally recognized as a nonverbal display of happiness and surprise. 
This evidence has been taken to show that we come into the world 
genetically prepared to express and recognize emotion via facial 
expression. The present invention exploits this natural ability to assist 
in neurofeedback training by generating facial expressions which 
correspond and respond to detected EEG signals. By generating 
representations of facial expressions as displays for EEG biofeedback, the 
invention utilizes a basic, genetically defined communication mechanism to 
convey the content of the biofeedback signal. 
On the tool bars of the various displays of the invention, there are 
provided two control buttons for each EEG component (delta, theta, alpha, 
alpha+, and beta) The top button has the Greek symbol for that component 
on it. Pressing that button will "toggle" the display and processing of 
that component. The corresponding "thermometer" display will appear or 
disappear, to indicate this. 
Beneath each component button is a "+/-" button, that cycles that component 
through one of three states: 
"ignore"=0: 
display, but do not process for biofeedback 
"reward"=+: 
if the value exceeds threshold, send a signal. 
Also, if the value is below threshold, inhibit any signal that might be 
sent, due to another component. 
"inhibit"=-: 
if the value is below threshold, send a signal. 
Also, if the value is above threshold, inhibit any signal that might be 
send, due to another component. 
The mode of each component is designated by the appearance of a "0", "+", 
or "-" on the corresponding thermometer bulb. 
For example, to encourage high alpha, while discouraging theta, press the 
alpha+ button once, to change it to "+". Then, press the theta button 
twice, changing it to "-". A reward signal will be sent only if the alpha+ 
component is above threshold, and the theta component is below threshold. 
If two components are assigned "+", then they must both be above threshold 
for a reward signal; similarly, two "-" components must both be below 
threshold. 
The combination of "+" and "-" modes, as set up for all components is 
called a "paradigm." 
The system of the invention has two basic operating modes for biofeedback. 
These are initiated by the two buttons "Lrn" and "Trn," or the "Learn" and 
"Train" items under the "Compute" menu heading. 
"Learn" mode is as follows: 
At the initiation of Learn mode, all counters, maxima, and thresholds are 
set to zero. The system acquires EEG, and measures the size of each 
component. It adjusts the maximum, and threshold, for each component, and 
updates these continually. No feedback is provided to the user, and no 
threshold crossings are counted. 
At the initiation of Train mode, the maxima and thresholds are fixed. The 
system will provide feedback based on the paradigm set up, and will not 
adjust the thresholds. 
The normal use is as follows: 
1) Set up the desired paradigm. This can be done as the system is running 
in Learn mode, if desired, or before. 
2) Use Learn mode to allow the BrainMaster to learn the values of your EEG 
components. 
3) Use Train mode to allow the BrainMaster to provide you with feedback, 
and to count, your threshold crossings. 
Although feedback is provided only when the selected paradigm is satisfied, 
all threshold crossings are counted with the counters. This allows the 
user to see the amount of each component being generated, regardless of 
the specific paradigm. 
The system further includes a "reset" control, which is a picture of a 
computer with a red arrow pointing to it. This button can be used to reset 
the counters, and scores to zero, without changing the thresholds. The 
function is useful when teaching use of the feedback control screens, 
since it will reset the screens to zero counts, without change to the 
setup of any of the component controls, or their values. 
Normally, when a "reward" is registered, the computer will "beep" or 
"ding," depending on its hardware configuration. If the "Snd" button is 
selected, the system will attempt to send sounds to a SoundBlaster.TM. (or 
equivalent) sound card. To use this mode, a SoundBlaster.TM. or functional 
equivalent must be installed in the computer. Preferably, the sound is a 
pleasant "sine" wave, with aesthetically chosen "attack" and "decay" 
characteristics, for a rapid, yet nondistracting, sound. The pitch of the 
sound is proportional to the amplitude of the component, starting at a 
base frequency that is different for each component. Any or all of the 
components can be active in this mode, allowing the user to play up to 
five "voices" via the EEG. 
In this mode, for each component selected (visible in the "thermometer" 
window), a tone is generated whenever the component is above its 
threshold. If the threshold is kept at zero, the sound will always be 
heard. Thus, when training a component, the sound serves both as an audio 
indicator that the component is above threshold, and as an indication of 
the size of the component. 
When processing a component for reward, but without sound, the user simply 
deselects "Snd" from the "thermometer" window. It will continue to be used 
for feedback processing, but the proportional pitch sound for that 
component will not be generated. 
In accordance with a preferred embodiment of this aspect of the invention, 
the base frequencies and delta increments used for Proportional Pitch 
feedback are as follows: 
______________________________________ 
Component: 
Base Frequency (Hz): 
Delta per unit increase (Hz): 
______________________________________ 
Delta 100 5 
Theta 200 10 
Alpha 800 20 
High Alpha 
1300 20 
(SMR) 
Beta 1500 30 
______________________________________ 
The system of the invention also automatically maintains a file "summary" 
in the current directory. This file contains a textual summary of the EEG 
component values, their means, and standard deviations, for 2-minute 
intervals, or whenever the "reset" button is pressed. This file contains 
time-stamps with each record. In addition, when any of the number keys (1 
through 9) are pressed, the file posts the exact time and date, and 
records the number. This allows the user to save time-markers for 
important events. By making a standard use of the numbered markers, up to 
9 different types of events can be accurately time-logged, and the summary 
file compiled indefinitely. 
A sample summary file as generated by the system may be as follows: 
______________________________________ 
Pass: 1: Duration: 72 seconds 
Tue Jun 25 23:47:28 1996 
delta theta alpha 
smr beta 40 Hz 
______________________________________ 
min: 0 0 0 0 0 0 
max: 26 24 14 8 17 0 
mean: 14.41 4.92 7.37 2.89 6.58 0.00 
var: 14.89 5.91 8.00 3.24 7.02 0.00 
______________________________________ 
Pass: 1: Duration: 3 seconds 
Wed Jun 26 22:20:20 1996 
delta theta alpha 
smr beta 40 Hz 
______________________________________ 
min: 13 5 3 2 6 0 
max: 26 7 4 2 7 0 
mean: 19.50 6.00 3.50 2.00 6.50 0.00 
var: 20.55 6.08 3.54 2.00 6.52 0.00 
______________________________________ 
Pass: 2: Duration: 4 seconds 
Wed Jun 26 22:20:27 1996 
delta theta alpha 
smr beta 40 Hz 
______________________________________ 
min: 13 4 3 2 6 0 
max: 26 7 9 4 7 0 
mean: 17.33 5.33 5.33 2.67 6.67 0.00 
var: 18.38 5.48 5.94 2.83 6.68 0.00 
______________________________________ 
Pass: 3: Duration: 10 seconds 
Wed Jun 26 22:20:42 1996 
delta theta alpha 
smr beta 40 Hz 
______________________________________ 
min: 13 3 2 1 6 0 
max: 26 9 9 7 9 0 
mean: 16.56 5.56 4.78 3.33 7.00 0.00 
var: 17.14 5.83 5.55 3.83 7.06 0.00 
______________________________________ 
Note: 2: Wed Jun 26 22:35:25 1996 
Note: 1: Wed Jun 26 22:35:28 1996 
Note: 9: Wed Jun 26 22:35:32 1996 
______________________________________ 
Pass: 1: Duration: 10 seconds 
Wed Jun 26 22:35:35 1996 
delta theta alpha 
smr beta 40 Hz 
______________________________________ 
min: 13 2 2 2 6 0 
max: 26 12 11 8 8 0 
mean: 15.44 5.44 6.67 3.89 6.89 0.00 
var: 15.95 6.06 7.35 4.31 6.93 0.00 
______________________________________ 
The invention automatically maintains a set of "trend" files in the current 
directory. These are started anew, and are overwritten every time the 
program is started. They are named "trend0", "trend1", "trend2", and so 
on. They contain the amplitudes of each of the EEG components, written 
every second, and terminated by a &lt;CR&gt; &lt;LF&gt;. Each file contains 120 
entries, and thus lasts two minutes. When a file is completed, it is 
finished, and the next numbered file is then created and written to. A 
trend file can be read at any time, even if it is the current file, since 
the BrainMaster program "closes" the file after each write, and "reopens" 
it to append data. These files are designed to be easily read and 
interpreted by another program, so that it can obtain up-to-date 
information about the EEG components being recorded. 
The invention as thus described provides a novel interactive EEG 
biofeedback system which can be self-administered by a user to obtain 
direct EEG information and self-train EEG in response to the information 
displayed. By generating and displaying a variety of dynamic EEG signal 
monitoring display formats, singularly or simultaneously, the system 
provides a user with a selectable any single or combined EEG display 
paradigm, in order to achieve optimum self-training results. The novel 
battery-powered EEG module provides excellent mobility for connection to 
any suitable processor and display monitor. 
A user of the system can carry out a sequence of operations suited to a 
specific task, including using the EEG waveform window to monitor raw EEG 
data, using the FFT of Mind Mirror windows to see the EEG frequency bands, 
using the thermometer window to monitor EEG components and set up and 
monitor progress of training, and using any of the other described 
displays to perform biofeedback procedures, and to review trends and 
summaries. 
The system also provides certain EEG training supervisory functions so that 
training sessions can be self-conducted under programmed supervision, 
including but not limited to: (1) Instructing the user to apply electrodes 
and turn on the amplifier module; (2) Instructing the user to inspect and 
confirm the raw EEG; (3) Instructing the user to allow baseline EEG 
recording to proceed; (4) Instructing the user to inspect the baseline EEG 
frequency bands for appropriateness; (5) Entering the training mode and 
taking baseline component values for setting of thresholds, and (6) 
Instructing the user to initiate the performance of the 
biofeedback-related tasks. The supervisory function of the system is 
facilitated by internal timers in the EEG module to determine the time for 
each segment, and using the Report and Command display windows to provide 
the user with appropriate textual information. These functions may also be 
implemented using "spoken word" commands in the form of synthesized or 
stored speech, so that the biofeedback instrument can perform sufficient 
control and instructional activity to facilitate self-administered 
monitoring and biofeedback.