Apparatus for and method of providing brainwave biofeedback

The present invention relates to an apparatus for and a method of providing brainwave biofeedback to a user while the user is simultaneously doing other tasks, for example, while the user is responding to a computer learning lab, working with another computer program, or playing a game. For example, a user could wear a headphone sensor unit, a virtual reality headset sensor unit, or a similar enclosure incorporating sensors made of comfortable compound sponges soaked in an electrolyte solution. The unit can detect brainwave signals which are then processed and interfaced with a computer. Audio and/or video feedback is provided to the user which indicates the user's focus or alertness. While the sensor unit could have therapeutic uses, the current embodiments relate to educational and recreational uses and for uses related to increasing personal performance.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an apparatus for and a method of providing 
brainwave biofeedback to a user while the user is simultaneously doing 
other tasks, for example, while the user is responding to a computer 
learning lab, working with another computer program, or playing a game. 
For example, a user could wear a headphone sensor unit, a virtual reality 
headset sensor unit, or a similar enclosure incorporating sensors 
comprised of comfortable compound sponges soaked in an electrolyte 
solution. The unit can detect brainwave signals which are then processed 
and interfaced with a computer. Audio and/or video feedback is provided to 
the user which indicates the user's focus or alertness. While the sensor 
unit could have therapeutic uses, the current embodiments relate to 
educational and recreational uses and for uses related to increasing 
personal performance. 
2. Discussion of the Prior Art 
The brain produces monitorable signals of from at least 1-40 Hertz (Hz). 
Signals of from about 1-4 Hz indicate a deep sleep state (delta); signals 
of from about 4-8 Hz indicate a reverie or daydreaming state (theta); 
signals of from about 8-13 Hz indicate an alert, but less mentally busy 
state (alpha); and, signals above 13 Hz indicate a vigilant state (beta). 
U.S. Pat. No. 3,998,213, to Price, teaches a self-adjusting holder for 
automatically positioning electroencephalographic ("EEG") electrodes. U.S. 
Pat. No. 4,537,198, to Corbett, teaches an electrode cap. U.S. Pat. No. 
5,348,006, to Tucker, teaches a head positioning pedestal. 
U.S. Pat. No. 5,406,957, to Tansey, teaches an apparatus and method for 
monitoring, analyzing, and utilizing brainwave data. 
SUMMARY OF THE INVENTION 
The present invention is for an apparatus and a method of detecting and 
providing instantaneous brainwave biofeedback so that a user can monitor 
his or her own level of focus or concentration or for monitoring by 
others, such as a parent or teacher. For example, while a student is using 
a computer to learn, brainwave signals are monitored and processed to 
provide immediate feedback on the same computer monitor to show the user 
at least one indicator of focus. Examples of indicators include an 
instantaneous EEG, a short-term concentration score, and a long-term 
concentration index. New methods of processing of brainwave signals are 
taught. 
Processed brainwave signals can be used as input to a separate program, 
running with any other computer program or activity where the indicator 
can be displayed. For example, if the user is "surfing" the INTERNET, 
brainwave feedback could be provided on a "thermometer" or "gas" gauge. 
Alternatively, the processed brainwave signals can be incorporated into 
another program. For example, if a user was playing a computer or video 
game, the better the user's focus, the more in focus the screen, the 
poorer the user's focus, the more out of focus the screen. Other screen 
adjustments could be made, such as changing the screen contrast, or the 
audio heard by the user could be varied. With a virtual reality helmet, 
brainwave feedback could be used to impact what the player sees and hears. 
To provide brainwave signals, a headset or virtual reality helmet with 
enhanced detection and a signal processing interface, for example, to a 
computer, can be provided. 
The brainwave sensor of this invention has been designed to provide easy to 
use, long-lasting, comfortable contact with the user's scalp and ears. The 
headset or helmet of the present invention may comprise a headband having 
at least one earpiece connected thereto, the earpiece having an ear pad, 
the ear pad having a sensor receiving receptacle therein, the sensor 
receiving receptacle having an ear lobe sensor unit detachably received 
therein, the ear lobe sensor unit and respective wearer's ear lobe being 
in a flush relation, the ear lobe sensor unit including an electrode 
having an electrode lead extending therefrom, and where the headband 
detachably receives a pair of scalp sensor units, each scalp sensor unit 
including an electrode having an electrode lead extending therefrom. 
Preferably, the scalp sensor unit includes a specially constructed 
compound sponge providing a flush relationship with the user's scalp 
through the hair, and simplified cleaning of dead skin from the scalp to 
facilitate electrical connections. 
Further, the present invention comprises a brainwave biofeedback apparatus 
to be worn by a user on the user's head, the apparatus having a scalp 
portion passing over a scalp portion of the user's head, the apparatus 
further comprising at least one scalp sensor unit, the at least one scalp 
sensor unit being detachably receivable by the scalp portion, the at least 
one scalp sensor unit having a scalp electrode cup and a compound sponge 
assembly, the scalp electrode cup including a scalp electrode having a 
scalp electrode lead extending therefrom, the compound sponge assembly 
including an absorbent sponge portion and a scalp contact and cleaning 
portion, the scalp contact and cleaning portion to engage said user's 
hair, the absorbent sponge portion being partway received by the scalp 
electrode cup. This apparatus can also include at least one earpiece 
having an ear pad, the ear pad having a sensor receiving receptacle 
therein, the sensor receiving receptacle having an ear lobe sensor unit 
detachably received therein, the ear lobe sensor unit having a lobe 
electrode cup and a lobe sponge, the lobe electrode cup including a lobe 
electrode having a lobe electrode lead extending therefrom, the lobe 
sponge including an ear lobe engaging portion, the lobe sponge being 
partway received by said lobe electrode cup.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
With reference to FIGS. 1-4, a headset 10 and its ear lobe sensor units 40 
and scalp sensor units 50 are shown. Headset 10 includes a headband 20 and 
a pair of earpieces 30, although a single earpiece could be used. Each 
earpiece 30 has a pad 32 with a headphone speaker 36 therein. Headphone 
speakers can provide an audio signal to a wearer, as in any conventional 
headphone. As desired, the brainwave signals can be detected and amplified 
and processes can be used to affect what the wearer hears through speakers 
36. 
Pad 32 has a recessed portion 34 at a location where the pad would engage a 
wearer's ear lobe. An ear lobe sensor unit 40 fits within recessed portion 
34. The geometry of the ear lobe engaging portion of unit 40 ensures that 
ear lobe sensor unit 40 has maximum contact with the wearer's ear lobe. 
Alternatively, other locations on the ear may be contacted by specially 
shaped sponges or an ear pad made from conducting sponge, foam, or other 
electrical conducting material covering a larger portion of the ear. 
Sensor units 40 and 50 have respective electrode leads 42 and 52 which are 
received by input/output interface unit 60, which also receives 
input/output cable 62. Input/output cable 62 is, for example, connected to 
a biofeedback processor or computer serial port. Unit 60 may, for example, 
include signal processing circuitry. 
Scalp sensor unit 50 includes an electrode cup 53 having, for example, a 
diameter "d" of about one inch (2.5 cm) and a height "h" of about 5/8 inch 
(1.6 cm). This height provides a "deep well" for retaining moisture in a 
cosmetic sponge 55 received partway therein. Cup 53 could have a lid 
placed thereover. The lid would have an opening therein through which 
sponge 55 would extend outward. The lid would help prevent drops of 
moisture from dripping on the wearer of headset 10. 
Electrode cup 53 has a slit 54 terminating in a hole 54h to permit an 
electrode lead 52 to be received by cup 53. Cup 53 is shown having an 
electrode 51 received therein with an electrode lead 52 extending 
therefrom. Strain relief, such as shrink wrap, not shown, can be provided 
around lead 52 where it passes tightly through slit hole 54h. While 
electrode 51 is shown positioned against the cup bottom, other electrode 
positioning is envisioned. 
Cup 53 securely receives a cosmetic sponge 55, which may be a dense rubber 
or latex. A firm structured sponge is desired to retain shape. For 
example, red rubber sponge by A. J. Siris Products Corporation of 
Patterson, New Jersey has a desired structure. Sponge 55 and sponge 45, 
explained later, will absorb enough salt water to be effective for over 
three hours. Alternatively, cup 53 can include an opening so that salt 
water can be added during use, or headset 10 can include a salt water 
reservoir with tubes to provide salt water to sponges 55 and 45. 
Alternatively, a reservoir could be provided within each cup 53. 
Sponge 55 is shown having a larger portion 57 external of cup 53. Scalp 
sensor unit 50 generally engages the hair of a wearer. To improve 
connectivity, sponge 55 has a woven fiber portion 56 attached thereto. For 
example, the fiber scrub portion of a no-scratch scrub sponge by 3M under 
the trademarked name "SCOTCH-BRITE", catalog number 520/521, when placed 
on the scalp and moved back and forth, has been found to effectively 
penetrate the hair and remove dead scalp skin cells to improve electrical 
connectivity. 
Cup 53 is shown having a hook and loop type fastener 54, such as the 
trademarked separable fastener material "VELCRO", attached outside the cup 
bottom. This is used to attach the scalp sensor unit 50 to headband 20 at 
a desired location, which will vary with different users. Being able to 
remove the cups permits rewetting of the sponges. Other attachment means 
are envisioned. For example, fastener 54 could be replaced with a snap. A 
plurality of snap receivers could be attached to headband 20 and the cup 
53 snapped into the desired receiver. If there is a lid on cup 53, the 
fiber portion 56 could be attached to the external portion of sponge 55. 
Ear lobe sensor unit 40 has an electrode cup 43 which is similar to cup 53. 
As with unit 50, cup 43 receives an electrode 41 and has an electrode lead 
42 extending therefrom. Fastener 44, for example, "VELCRO", is shown which 
may be used to secure cup 43 within sensor receiving receptacle 34. A snap 
or other attachment means may also be used. 
Cosmetic sponge 45 is shown having a trapezoidal shaped cross-section. This 
shape permits maximum engagement with a wearer's ear lobe. The upper 
portion 47 engages the ear lobe cartilage and the wider lower portion 48 
engages the lower, softer part of the ear lobe. Shown is the angle 
".alpha." of approximately 15.degree.. Alternatively, the sponge could be 
custom shaped to fit a desired place on the ear; for example, a U-shaped 
sponge could fit around the ear lobe cartilage. 
Input/output interface unit 60 receives audio signal(s) through 
input/output cable 62 and provides those audio signal(s) to headphone 
speakers 36. While more or less electrodes can be employed as desired, 
each of the four electrodes 41/51 provides a signal to interface unit 60 
through respective electrode lead 42/52. Processed or unprocessed 
electrode signals may be passed through cable 62. Cable 62 is preferably 
shielded. Also, instead of cable 62, radio waves, infrared light, or other 
transmission means may be employed to interface the headset 10 with, for 
example, the biofeedback processor. It is envisioned that programs 
contained in an EPROM or a computer will be used to make calculations and 
provide indications of alertness. 
Electrodes 41/51 may be, for example, acrylonitrile-butadiene-styrene 
("ABS") plastic impregnated with graphite and covered with silver/silver 
chloride, although, other electrode materials may be used. Cosmetic sponge 
45/55, soaked in a saline or other electrolyte solution, conducts 
electricity to the electrodes from the ear lobe or scalp, as appropriate. 
To demonstrate possible processing of the signals from the four electrodes 
41/51, a signal from right ear lobe electrode 41 may be an electrically 
grounded signal, a signal from left ear lobe electrode 41 may be a neutral 
reference signal, a first signal "S1" from right head electrode 51 may be 
provided, and a second signal "S2" from left head electrode 51 may be 
provided. It is noted that the ear lobes are not the only place on the 
wearer's body to place ground and obtain a neutral reference signal; 
although placing all the electrodes into a headset or helmet is more 
convenient for the user. The in-phase components of signals S1 and S2 are 
added after pre-amplification. A particular low frequency band, DC to 12 
Hertz or portions thereof, is extracted by digital or analog filtering or 
by a Fast Fourier Transform. A signal representing the magnitude or power 
of this output is divided by a similarly derived signal representing the 
magnitude or power for a wider frequency band, DC to at least 32 Hertz. 
This ratio, representing sleep and daydreaming brainwaves divided by total 
brainwaves, is then subtracted from or divided into a desired fixed 
number, for example, the number 32, with the resulting number providing a 
biofeedback indicator of increased alertness. 
Instead of using the DC to 12 Hertz band, the ratio of a 12-128 Hertz band 
(or portions thereof) to a DC to 128 Hertz band (or portions thereof) can 
be evaluated to provide a biofeedback indicator of alert and vigilant 
brainwaves divided by total brainwaves. In this situation, the closer the 
ratio is to unity, the better the alertness of the testee, while the 
closer the ratio is to zero, the less the alertness of the testee. 
This biofeedback indicator can be provided to a computer program through, 
for example, a serial or game port, so that the computer monitor provides 
an indication of alertness or lack thereof. For example, in a Windows 
environment, or a similar environment such as a Computer Learning Lab, an 
alertness program could be running along with an educational program. As 
seen in FIG. 5, a user is learning to add and subtract. A window 
designated by the numeral 2 is shown providing an indication of alertness. 
The alertness program will sample brainwaves at a sampling rate sufficient 
to provide real-time feedback, for example, at a sampling rate of twenty 
times per second. Instead of displaying the instantaneous values as the 
indication of alertness, the display can represent an average of values 
over a preselected time interval. As another possibility, the display can 
be differential, representing the change in alertness, either more or less 
alert at prior sessions or at prior times in the same session. The 
indication of alertness can also be used to provide audio feedback through 
headphone speakers 36, for example, by a volume change. 
Statistical analysis can also be run on the raw or processed EEG data. For 
example, if a user was using a learning program for a thirty minute study 
session, indicators of alertness during the first ten minutes, middle ten 
minutes, and last ten minutes could be provided. Also, results for 
different study sessions could be compared and instantaneous indicators 
provided. Further, if used in a multiple student environment, indicators 
of alertness for each of the plurality of students could be simultaneously 
provided to a teacher's monitor. 
Also, the alertness indicator can be incorporated directly into a computer 
program. FIG. 6 demonstrates a simple maze that a user must solve. As long 
as the user's alertness indicator is at a satisfactory level, the screen 
will be in focus as seen in FIG. 6. However, if while trying to solve the 
maze, the user's alertness indicator falls below a satisfactory level some 
or all of the maze will go out of focus, as seen in FIG. 7. Also, a fixed 
indicator number does not have to be used to set the out of focus 
condition. For example, assuming an alertness indicator range of zero to 
one, with one being the most alert, the monitor could be a total blur near 
zero, totally focused near one, and variable in between. For example, the 
screen would be more in focus at 0.7 than 0.6. Alternatively, or in 
addition, screen brightness, screen contrast, percentage of total image 
displayed, and/or the volume, clarity, or characteristics of audio output 
can be varied based upon the alertness indicator. 
Further, an indication of alertness can be processed by a video interface, 
which further transforms the output of a video adaptor board as a function 
of the alertness indicator, such that, for example, a user playing a video 
game, could have game play affected by the alertness indicator, in manners 
similar to those described above, without changing the video game program. 
Other processing of the brainwave signals is envisioned. For example, the 
EEG derived from two sites on the head, for example, C3 and C4 or Fz and 
Pz, and a neutral reference site, for example, the ear lobe, is amplified 
and filtered to eliminate low frequency artifacts by using a low frequency 
filter at about 2 Hertz. The two signals are then combined by digital or 
analog circuit means to form separate sum and difference signals, which 
respectively contain the in-phase and out-of-phase information from these 
signals. Software contained in an EPROM or computer program analyzes the 
resulting two signals by a Fast Fourier Transform and/or digital filtering 
into specified 1-34 Hertz bands, using, for example, a desired upper 
cut-off frequency. From the summed signals, the software then recombines 
selected frequency bands to form an in-phase low frequency signal with a 
pre-specified bandwidth comprising frequencies between 2 to 11 Hertz. From 
the difference signals, the software derives an out-of-phase high 
frequency signal, comprising some portion of the frequencies between 11 
and 45 Hertz. The user would try to increase the out-of-phase high 
frequency EEG output and simultaneously inhibit the in-phase low frequency 
EEG output to enhance alertness. 
As another example, it may be desired to analyze the brainwave signals, 
which are derived from a site or sites on the head and from a neutral 
reference, such as the ear lobe, from about 2 to 32 Hertz to provide a 
testee feedback to minimize emotional thoughts and feelings. Software 
contained in an EPROM or in a computer program calculates the frequency 
below which a preselected percentage ("N%") of EEG energy is contained. 
For example N can be in the range of 20% to 80%. Typically, the higher the 
frequency, the better the concentration, the lower the frequency, the 
better the relaxation. For example, with sensors located at the temporal 
area, for example, T3, T5, or F7, decreasing the frequency will minimize 
emotional thoughts and feelings. With this testing, additional or 
different scalp sensor units 50 may be employed at additional or different 
locations, such as for sampling at temporal or frontal areas of the brain. 
Plastic extensions from the headband 20 can be provided to facilitate 
placement. 
Also, using an alertness indicator, a computer program can direct a user to 
attempt to change from one state of alertness to another. For example, 
assuming N of 60%, a user could be requested to concentrate on a preset 
screen display to have 60% of the brainwave energy above a frequency of 13 
Hertz for a preselected time period. The time to achieve this criterion 
could be recorded. Then, the screen display could be changed to a 
different desired display and the user requested to relax so that 60% of 
the brainwave energy is below a frequency of 8 Hertz for a preselected 
time period. Again, the time to achieve this more relaxed criterion could 
be recorded. Feedback would be provided to the user when the desired state 
was reached and their ability to subsequently sustain that state can be 
measured by various statistical means. By repeating this procedure, the 
user can learn to make rapid and effective transitions between states of 
alertness in order to develop flexibility of attention. This training 
should help users achieve and sustain desired states of concentration 
and/or relaxation. By omitting the feedback from the procedure, the user's 
ability to flexibly switch his or her states of alertness or attention 
could be measured, for example, by deriving an average response time for 
several trials. 
The foregoing detailed description is given primarily for clearness of 
understanding and no unnecessary limitations are to be understood 
therefrom for modifications will become obvious to those skilled in the 
art upon reading this disclosure and may be made without departing from 
the spirit of the invention or the scope of the appended claims.