BIO-FEEDBACK APPARATUS

• US 3,821,949 A
• Filed: 04/10/1972
• Issued: 07/02/1974
• Est. Priority Date: 04/10/1972
• Status: Expired due to Term

• Current Assignee: Darrell D. Albright, Duane L. Callies, Elmer E. Green, Rex A. Hartzell, Wendell H. Spencer
• Original Assignee: Darrell D. Albright, Duane L. Callies, Elmer E. Green, Rex A. Hartzell, Wendell H. Spencer
• Inventors: Hartzell, Rex A., Callies, Duane L., Spencer, Wendell H., Albright, Darrell D., Green, Elmer E.
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US05/242,567
• Time in Patent Office: 813 Days
• Field of Search: 128/2.06,2.1B,2.1R,419-424 340/407
• US Class Current: 600/545
• CPC Class Codes: A61B 5/375 using biofeedback
• CPC Class Codes: A61B 5/7405 using sound

Abstract

An improved bio-feedback apparatus for sensing the brain-wave potentials produced by a subject wherein the sensed brain-wave potentials are processed through separate parallel processing channels of a controlling channel, each processing channel processing a preselected frequency range of the sensed brain-wave potential to provide subject-preceivable feedback signals indicative of signal presence within the preselected frequency of each processing channel. Each processing channel is constructed to provide predetermined signal amplitude and duration criteria for determining signal presence prior to initiating and terminating the feedback signals and, in one form, each processing channel is constructed to provide feedback signals indicative of the percentage of time during a subsequent predetermined epoch of time wherein a signal presence existed in the sensed brain-wave potential. In one form, the bio-feedback apparatus simultaneously produces audible feedback signals, each audible feedback signal having a separately identifiable tone indicative of signal presence within the preselected frequency range of the processing channels.

Claims

1. A bio-feedback apparatus for sensing the brain-wave potentials produced by a subject and providing feedback signals in response thereto, the apparatus comprising:

a brain-wave indicator detecting and sensing brain-wave potentials, and providing an output signal responsive thereto;

a preamplifier receiving the brain-wave indicator output signal and providing an amplified output signal responsive thereto;

a plurality of processing channels, each processing channel receiving the preamplifier output signal and providing a feedback signal responsive thereto, each processing channel comprising;

a passband filter, having a predetermined passband, receiving the preamplifier output signal and providing an output signal responsive to a frequency component of the received signal within the passband; and

means receiving the passband filter output signal and providing an output signal indicative of signal presence in the processing channel, including;

an oscillator, interposed in each processing channel, each oscillator in each processing channel receiving the passband filter output signal and generating an output signal having a distinct, separately identifiable frequency in response thereto, the oscillator output signals indicating signal presence in the processing channels;

a feedback indicator receiving the output signals indicative of the signal presence from each of the processing channels and providing subject-perceivable feedback signals responsive thereto, the feedback indicator including;

a summing amplifier receiving the oscillator output signal from each of the oscillators in each processing channel and providing a single output signal in response to the received oscillator output signals; and

an output indicator receiving the summing amplifier output signal and providing a subject-perceivable output indication responsive thereto.

2. The bio-feedback apparatus of claim 1 wherein the means receiving the passband filter means output signal is defined further to include:

a full-wave rectifier providing an output signal in response to a received input signal;

means connected to the full-wave rectifier receiving the passband filter output signal and providing an input signal to the full-wave rectifier;

a timing netwOrk receiving the full-wave rectifier output signal and providing a feedback control voltage in response to a received signal of a predetermined minimum duration thereby substantially eliminating feedback indications produced via relatively short duration sensed brainwave potentials; and

switch means having an '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' and an '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition connected to the timing network and the oscillator, the switch means receiving the feedback control voltage and being biased in the on condition in response thereto activating the oscillator in the '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition, the oscillator providing the output signal indicating signal presence in the processing channels.

3. The bio-feedback apparatus of claim 2 wherein each processing channel is defined further to include:

an amplifier receiving the preamplifier output signal and providing an amplified output signal in response thereto; and

sensitivity adjustment means connected to the amplifier controlling the threshold sensitivity setting of the amplifier connected thereto, the amplifier providing an amplifier output signal in response to a received preamplifier output signal having an amplitude exceeding the threshold setting of the sensitivity adjustment means connected thereto.

4. A bio-feedback apparatus for sensing the brain-wave potentials produced by a subject and providing the feedback signals in response thereto, the apparatus comprising:

a brain-wave indicator sensing the brain-wave potentials, and providing an output signal responsive thereto;

a preamplifier receiving the brain-wave indicator output signal and providing an amplified output signal responsive thereto;

a plurality of processing channels, each processing channel receiving the preamplifier output signal and providing a feedback signal responsive thereto, each processing channel comprising;

a passband filter, having a predetermined passband, receiving the preamplifier output signals and providing an output signal responsive to a frequency component of the received signal within the filter passband;

means receiving the passband filter output signal and providing an output signal indicating signal presence in the processing channel, including;

comparator means, having an upper and a lower amplitude threshold limit, receiving the passband filter output signal and providing an output signal in response to a received preamplifier output signal, the comparator means output signal being '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' when receiving a preamplifier output signal having an amplitude level within the upper and the lower amplitude threshold limits of the comparator means;

switch drive means receiving the comparator means output signal, having a biased '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' and a biased '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition, the switch drive means being biased in the '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition when receiving a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' comparator means output signal;

a threshold adjust means connected to the switch drive means receiving the switch drive means output signal in an '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition of the switch drive means and providing an output signal when receiving a switch drive means output signal of a predetermined minimum duration, the threshold adjust means output signal being terminated via the switch drive means output signal remaining switched to the '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' position for a predetermined minimum period of time; and

switch network means connected to the threshold adjust means having an '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' and an '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition, the switch network means biased in the '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition when receiving a threshold adjust means output signal indicating signal presence in the particular processing channel; and

feedback indicator means receiving the output signals indicative of signal presence from each of the processing channels and providing subject-perceivable feedback signals responsive thereto and indicative thereof.

5. The bio-feedback apparatus of claim 4 wherein the means in each processing channel receivIng the passband filter output signal and providing an output signal indicating signal presence in the processing channel is defined further to include:

amplitude discriminator means receiving the passband filter output signal and providing an output signal substantially proportional to the amplitude of the received passband filter output signal; and

comparator controller means receiving the amplitude discriminator output signal and providing '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' output signal in response to a received amplitude discriminator output signal having a predetermined duration indicating signal presence in the processing channel, the comparator controller output signal being connected to the feedback indicator means for providing subject perceivable feedback signals in response to a comparator controller means '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' output signal.

6. The bio-feedback apparatus of claim 5 wherein the means in each processing channel receiving the passband filter output signal and providing an output signal indicating signal presence in the processing channel is defined further to include:

zero crossing detector means receiving the passband filter output signal and providing a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' output signal in response to a negative going zero crossing of the passband filter output signal and a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' output signal in response to a positive going zero crossing of the passband filter output signal;

tachometer network means receiving the zero crossing detector means output signal providing an output signal substantially linearly proportional to the frequency of the received zero crossing detector means output signal; and

means receiving the tachometer network output signal and providing an oscillating output signal having a frequency corresponding to a multiple of the frequency of the sensed potential indicated by the tachometer network output signal; and

wherein the feedback indicator means receives the oscillating output signal corresponding to a multiple of the frequency of the sensed potential and provides a subject-perceivable feedback signal responsive thereto indicating signal presence in the particular processing channel.

7. The bio-feedback apparatus of claim 6 wherein the means in each processing channel receiving the passband filter output signal and providing an output signal indicating signal presence in the processing channel is defined further to include:

automatic gain control means receiving the amplitude discriminator output signal and the oscillating output signal corresponding to a multiple of the frequency of the sensed potential, the automatic gain control means controlling the volume of the received oscillating signal in response to the received amplitude discriminator output signal and providing an output signal corresponding to received oscillating signal having the volume thereof controlled in response to the received amplitude discriminator output signal;

feedback indicator means is defined further to include an audio output indicator receiving the automatic gain control output signal and providing audible subject-perceivable feedback signal responsive thereto.

8. The bio-feedback apparatus of claim 7 wherein the means providing an oscillating output signal in response to a received tachometer network output signal is defined further to include:

non-inverting amplifier means receiving the tachometer network means output signal and providing an amplified output signal in response thereto;

unity-gain inverting amplifier means receiving the non-inverting amplifier output signal and providing an inverted output signal in response thereto;

first diode bridge means connected to and receiving the non-inverting amplifier means output signal and the unity-gain inverting amplifier means output signal;

amplifier means having an output signal connected to the first diode bridge means;

second diode bridge means connected to the amplifier means providing an output signal driving the amplifier means;

inTegrator amplifier means connected to the first diode bridge means and providing a triangularly shaped output signal, the integrator amplifier means output signal being connected to the amplifier means controlling the amplitude of the triangularly shaped signal produced by the integrator amplifier means; and

signal converter means receiving the integrator amplifier means output signal and providing a sine-wave shaped output signal in response thereto, the signal converter means output signal being connected to automatic gain control means and providing the oscillating signal input connected thereto.

9. The bio-feedback apparatus of claim 6 wherein the means in each processing channel receiving the passband filter output signal and providing the output signal indicating signal presence in the processing channel is defined further to include:

bandpass controller means, having a high and a low threshold setting and providing a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' and a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' output signal, receiving the tachometer network means output signal and providing a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' output signal in response to a received tachometer network means output signal within the high and the low threshold setting of the bandpass controller means; and

wherein the comparator controller means receives the bandpass controller means output signal, the comparator controller providing a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' output signal in response to a received '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' bandpass controller means output signal indicating signal presence in the processing channel within the high and the low threshold settings of the bandpass controller means output signal.

10. The bio-feedback apparatus of claim 9 wherein the tachometer network means includes:

an oscillator means having an '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' and an '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition, the oscillator means receiving the zero crossing detector means output signal and being biased in the '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition in response thereto providing an oscillator means output signal; and

wherein the amplitude discriminator means is defined further to include;

discriminator amplifier means receiving the passband filter means output signal and providing an amplified output signal responsive thereto;

diode means connected to and receiving the discriminator amplifier means output signal, the diode means being forward biased and conducting when receiving a positive going discriminator amplifier means output signal and being reversed biased and nonconducting when receiving a negative going discriminator amplifier means output signal;

capacitor means receiving the discriminator amplifier means output signal and being charged in response thereto in a conducting condition of the diode means;

memory capacitor means receiving the charge on the capacitor means when connected thereto;

first gate means having an opened and a closed condition connected between the capacitor means and the memory capacitor means, the first gate means receiving the oscillator output signal via the tachometer network means and being biased open in response thereto connecting the capacitor means and the memory capacitor means;

switching means connected to the capacitor means having an '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' and an '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition and receiving the zero crossing detector means output signal, the switching means being biased in the '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition in response to a received zero crossing detector means output signal in the '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state discharging the capacitor means connected thereto; and

second gate means having an opened and a closed condition connected to the memory capacitor means and to the amplitude discriminator means, the charge on the memory capacitor means biasing the second gate means opened and providing the amplitude discriminator means output signal.

11. The bio-feedback apparatus of claim 10 wherein the tachometer network means is defined further to include:

switching means, having an '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' and an '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition, and receiving the tachOmeter oscillator means output signal and being biased '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' in response thereto;

function generator means connected to the switching means and having a portion charged in the '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition of the switching means, the charged portion being discharged in the '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition of the switching means, the function generator means providing an output signal proportional to the frequency of the sensed brain-wave potential in the discharging condition thereof;

memory capacitor means connected to the portion of the function generator charged in the '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition of the switch means and receiving the charge discharged from the function generator means when connected thereto; and

switching means connected to the function generator means and to the memory capacitor means, having an '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' and an '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition, the switching means receiving the oscillator output signal of the tachometer network means and being biased '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' in response thereto connecting the discharging function generator to the memory capacitor means.

12. The bio-feedback apparatus of claim 11 wherein the function generator means is defined further to include:

capacitor means connected to the switching means and being charged in the '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition of the switching means;

a resistive network bleed path connected to the capacitor means having a relatively low time constant;

a resistive network bleed path connected to the capacitor means having a relatively high time constant; and

diode means, having a forward biased and a reverse biased condition, connected to the high time constant resistive network bleed path, the capacitor means discharging through the high time constant resistive network bleed path in a forward biased condition of the diode means and through the low time constant resistive network bleed path in a reverse biased condition of the diode means, the discharging curve of the capacitor means being linearly proportional to the frequency of the sensed brain-wave potential.

13. The bio-feedback apparatus of claim 12 wherein the function generator means is defined further to include:

a resistive network bleed path connected to the capacitor means having an intermediate time constant; and

diode means connected to the intermediate time constant resistive network bleed path, the capacitor means discharging through the high and the intermediate time constant resistive networks in a forward biased condition of the diode means connected therein, the capacitor means discharging through the intermediate and the low time constant resistive networks in a reverse biased condition of the diode means connected to the high time constant resistive network, and the capacitor means discharging through the low time constant resistive network in a reverse biased condition of the two diode means.

14. The bio-feedback apparatus of claim 9 wherein the comparator controller means is defined further to include:

first comparator means, having a predetermined threshold setting, receiving the amplitude discriminator output signal and providing an output signal in a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' state in response to a received amplitude discriminator output signal having an amplitude level exceeding the threshold setting of the first comparator means;

second comparator means receiving the first comparator means output signal and connected to the capacitor means, having a predetermined threshold setting and providing a comparator controller means output signal in a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state in response to the capacitor means connected thereto being discharged to a potential exceeding the threshold setting of the second comparator means; and

capacitor means connected to the second comparator means and to the bandpass controller means discharging in a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' state of the first comparator means output signal and in a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' state of the bandpass controller means output signal.

15. The bio-feedback apparatuS of claim 14 wherein the bandpass controller means is defined further to include:

dual-comparator means, having a predetermined high and a low threshold limit, receiving the tachometer network means output signal and providing a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' output signal when receiving a tachometer network means output signal within the high and the low threshold limit; and

gate means receiving the dual-comparator means output signal and the first comparator means output signal from the comparator controller means, the gate means being connected to the second comparator means of the comparator controller means and connecting a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' output signal to the capacitor means when receiving a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' dual-comparator means output signal.

16. The bio-feedback apparatus of claim 9 wherein the bandpass controller means includes:

gate means inverting the bandpass controller means output signal and providing a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' output signal in response to a received tachometer network means output signal within the high and the low threshold setting of the bandpass controller means; and

wherein the feedback indicator means is defined further to include;

mixer amplifier means receiving the automatic gain control means output signals connected thereto and providing an amplified output signal responsive thereto;

relay means interposed between the mixer amplifier means and the automatic gain control means output signal of each processing channel, the relay means connecting each automatic gain control means output signal to the mixer amplifier means in an energized condition thereof; and

drive transistor means connected to the relay means having an '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' and an '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition and energizing the relay means in the '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition thereof, the drive transistor means receiving each comparator controller means output signal and each output signal of the gate means of each bandpass controller means;

diode means connected between the drive transistor means and the comparator controller means output signal and between the drive transistor means and the output signal of the gate means of each bandpass controller means, the drive transistor means being biased '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' in response to a received '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' output signal of the gate means of the bandpass controller means and a received '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' amplitude discriminator means output signal.

17. The bio-feedback apparatus of claim 9 wherein the feedback indicator means is defined further to include:

amplifier means having an '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' and an '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition receiving the comparator controller means output signal and being biased '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' in response to a comparator controller means output signal in the '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state;

meter means receiving the tachometer network means output signal, providing a visual feedback signal indicating the frequency of the sensed brain-wave potential; and

relay means interposed between the tachometer network means and the meter means, connecting the tachometer network means output signal to the meter means in an energized condition thereof, the relay means connected to the amplifier means and being energized in a biased '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition of the amplifier means.

18. The bio-feedback apparatus of claim 5 wherein the means in each processing channel receiving the passband filter output signal and providing an output signal indicating signal presence in the processing channel is defined further to include:

data reduction controller means receiving the comparator controller means output signal indicating signal presence in the processing channel, and having a portion monitoring signal presence in the processing channel over a predetermined epoch period of time. and providing an output signal indicating the percentage of time signal presence existed in the processing channel during a subsequent predetermined period of time, an epoch period of time; and

wherein the feedback indicator is defined furTher to include a portion receiving the output signal indicating the percentage of time signal presence existed in the processing channel and providing a feedback indication in response thereto.

19. The bio-feedback apparatus of claim 18 wherein the data reduction means is defined further to include:

delay oscillator means generating an output signal;

analog switch means receiving the comparator controller means output signal and the delay oscillator means output signal, the analog switch means providing the delay oscillator output signal when receiving a comparator controller means output signal in a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state;

delay signal controller means receiving the delay oscillator means output signal via the analog switch means and recording the received delay oscillator means output signal for the predetermined epoch period of time; and

means receiving the delay signal controller means output signal and the comparator controller means output signal providing an output signal indicating the average percentage of time signal presence existed in the processing channel for the preceding predetermined epoch period of time in response to the received comparator controller means output signal and the received delay signal controller means output signal; and

wherein the feedback indicator means includes a portion receiving the output signals indicating the average percentage of time signal presence existed in each processing channel and provides a subject-perceivable feedback signal response thereto.

20. The bio-feedback apparatus of claim 19 wherein the portion of the feedback indicator means providing the output signal indicative of the average percentage of time signal presence existed in the processing channel is defined further to include:

counters for counting up to a predetermined number and counting down to zero, the counters providing a digital output signal indicative of the count registered therein and having a count-up mode, a count-down mode, and a hold mode, the counters positioned in the count-up mode in response to a received count-up signal and positioned in the count-down mode in response to a received count-down signal;

overvoltage controller means providing a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' and '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' output signal, and having an upper and a lower threshold limit, the overvoltage controller means receiving the delay signal controller means output signal and providing a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' output signal in response to a received delay signal controller means output signal within the upper and the lower threshold limits; and

counter controller means connected to the counters and receiving the overvoltage controller means output signal and the comparator controller output signal, the counter controller means providing an output count-up signal in response to a comparator controller means output signal in the '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state and an overvoltage controller means output signal in the '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' stage, and an output count-down signal in response to a received comparator controller means output signal in a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' state and an overvoltage controller means output signal in a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state, the digital output signals of the counters providing the output signal indicating the average percentage of time signal presence existed in the processing channel.

21. The bio-feedback apparatus of claim 20 wherein the portion of the feedback indicator means providing the output signal indicative of the average percentage of time signal presence existed in the processing channel is defined further to include:

a digital/analog converter receiving the counters output signal and providing an analog voltage output signal responsive thereto indicating the percentage of time signal presence existed in the processing channel.

22. The bio-feedback apparatus of claim 21 wherein the feedback indicator means includes:

meter drive network means receiving the digital/analog converter output signal and providing an output signal responsive thereto; and

meter means receiving the meter drive network means output signal and providing a visual feedback indicating the average percentage of time signal presence existed in the processing channel connected thereto in response to the received meter drive network output signal.

23. The bio-feedback apparatus of claim 21 defined further to include:

clock pulse generator means generating a clock pulse output signal therefrom; and

wherein the counters are further defined to provide output signals in the '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' state in response to a count being registered thereon and to provide output signals in the '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state in response to a zero count being registered thereon, the counters being positioned in the count-up mode in response to a received count-up signal and a clock pulse and in the count-down mode in response to a received count-down signal and a clock pulse; and

wherein the counter controller means receives the clock pulse output signal and the counters output signal, the counter controller means being defined further to include;

gate means receiving the clock pulse output signal, the comparator controller means output signal, the overvoltage controller means output signal and the counters output signals and providing an output count-up signal and a clock pulse in response to a comparator controller means output signal in the '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state and an overvoltage controller means output signal in a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' state, an output count-down signal and a clock pulse in response to a received comparator controller means output signal in a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' state and an overvoltage controller means output signal in a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state, in response to at least one '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' counters output signal, and providing an output count-up signal and a clock pulse in response to received counters output signal in the '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state and a received comparator means output signal in a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state.

24. The bio-feedback apparatus of claim 18 wherein the brain-wave indicator means includes:

means detecting and sensing the brain-wave potentials produced at at least two preselected scalp sites, the brain-wave indicator means providing a controlling channel output signal indicating the sensed brain-wave potential at each scalp site; and

wherein the preamplifier means receives the controlling channel output signals and provides amplified output signals responsive thereto; and

wherein the bio-feedback apparatus includes;

an amplitude equalizer, having a portion varying received signals about a preset amplitude reference axis, receiving and varying the amplified controlling channel output signals about the predetermined common amplitude reference axis providing the equalized amplified controlling channel output signals therefrom; and

wherein processing channels include a plurality of processing channels receiving each controlling channel output signal and providing a feedback signal responsive to each received controlling channel output signal indicating signal presence in the processing channel.

25. The bio-feedback apparatus of claim 24 wherein the feedback indicator means is defined further to include:

first audio means providing subject-perceivable audible feedback signals responsive to a received signal input thereto;

second audio means providing subject-perceivable audible feedback signals responsive to a received signal input thereto; and

switch means connected to and receiving the feedback signals of each controlling channel output signal, the switch means connected to the first and the second audio means and having one switch position connecting the feedback signal from one controlling channel output signal to the first audio means and the feedback signal from one other controlling channel output signal to the second audio means, and one other switch position connecting the feedback signals from one of the controlling channel output signals to the first and the second audio means.

26. A bio-feedback apparatus for sensing the brain-wave potentials produced by a subject and providing feedback signals in response thereto, the apparatus comprising:

a brain-wave indicator detecting and sensing the brain-wave potentials, and providing an output signal responsive thereto;

a processing channel receiving the brain-wave indicator output signal and providing a feedback signal responsive thereto, the processing channel comprising;

frequency discriminator means having a predetermined passband, receiving the brain-wave indicator output signals and providing an output signal responsive to the frequency component of the received signal within the passband of the frequency discriminator means;

means receiving the frequency discriminator means output signal and providing an output signal indicating signal presence in the processing channels;

a data reduction controller means receiving the output signal indicating signal presence in the processing channel and providing an output signal indicating the percentage of time signal presence exists in the processing channel for a subsequent predetermined epoch period of time, the data reduction controller means including;

delay oscillator means generating an output signal;

analog switch means receiving the output signal indicating signal presence in the processing channel and the delay oscillator means output signal, the analog switch means providing the delay oscillator means output signal in response to a received output signal indicating signal presence in the processing channel;

delay signal controller means receiving the delay oscillator means output signal from the analog switch means and recording the received delay oscillator means output signal for the predetermined epoch period of time and providing an output signal responsive thereto; and

means receiving the delay signal controller means output signal indicating signal presence in the processing channel during the predetermined epoch period of time and providing an output signal indicating the average percentage of time signal presence existed in the processing channel for the predetermined epoch period of time, including;

counters for counting up to a predetermined number and counting down to zero, the counters providing a digital output signal indicating the count registered therein and having a count-up mode, a count-down mode, a hold mode, the counters being in the count-up mode when receiving a received count-up signal and being in the count-down mode when receiving a count-down signal;

overvoltage controller means providing a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' and a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' output signal, and having a predetermined upper and a lower threshold limit, the overvoltage controller means receiving the delay signal controller means output signal and providing a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' output signal in response to a received delay signal controller means output signal within the upper and the lower threshold limits of the overvoltage controller means; and

counter controller means connected to the counters and receiving the overvoltage controller means output signal indicative of signal presence in the processing channel, the counter controller means providing an output count-up signal when receiving an over-voltage controller means output signal in the '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' state indicating signal presence in the processing channel, and an output count-down signal when receiving an overvoltage controller means output signal in a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state, the count registered in the counters indicating the percentage of time signal presence existed in the processing channel during the predetermined epoch period of time; and

feedback indicator means receiving the output signal indicating the percentage of time signal presence existed in the processing channel and providing a subject-perceivable feedback signal responsive thereto.

27. The bio-feedback apparatus of claim 26 wherein the means providing the output signal indicating the average percentage of time signal presence existed in the processing channel is defined further to include:

a digital/analog converter receiving the counters output signal and providing an analog voltage output signal responsive thereto indicating the percentage of time signal presence existed in the processing channel.

28. The bio-feedback apparatus of claim 27 defined further to include:

clock pulse generator means generating a clock pulse output signal therefrom; and

wherein the counters are further defined to provide output signals in the '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' state in response to a count being registered thereon and to provide output signals in the '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state in response to a zero count being registered thereon, the counters being positioned in the count-up mode in response to a received count-up signal and a clock pulse and in the count-down mode in response to a received count-down signal and a clock pulse; and

wherein the counter controller means receives the clock pulse output signal and the counters output signal, the counter controller means being defined further to include;

gate means receiving the clock pulse output signal, the comparator controller means output signal, the overvoltage controller means output signal and the counters output signals and providing an output count-up signal and a clock pulse in response to an output signal indicative of signal presence in the processing channel and an overvoltage controller means output signal in a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' state, an output count-down signal and a clock pulse in response to a received overvoltage controller means output signal in a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state, in response to at least one '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' counters output signal, and providing an output count-up signal and a clock pulse in response to a received output signal indicative of signal presence in the processing channel, in response to received counters output signals in the '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state.

29. A bio-feedback apparatus for sensing the brain-wave potentials produced by a subject and providing feedback signals in response thereto, the apparatus comprising:

brain-wave indicator means detecting and sensing the brain-wave potentials and providing an output signal responsive thereto;

preamplifier means receiving the brain-wave indicator means output signal and providing an amplified output signal responsive thereto;

passband filter means, having a predetermined passband, receiving the preamplifier output signal and providing an output signal responsive to a frequency component of the received signal within the filter means passband;

zero crossing detector means receiving the passband filter means output signal and providing a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' output signal in response to a positive going zero crossing of the passband filter means output signal and a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' output signal in response to a negative going zero crossing of the passband filter means output signal;

tachometer network means receiving the zero crossing detector means output signal providing an output signal proportional to the frequency of the received zero crossing detector means output signal;

means receiving the tachometer network means output signal and providing an oscillating output signal having a frequency corresponding to a multiple of the frequency of the sensed potential indicated by the tachometer network means output signal;

amplitude discriminator means receiving the passband filter means output signal and providing an output signal substantially proportional to the amplitude of the received passband filter means output signal;

comparator controller means receiving the amplitude discriminator means output signal and providing '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' output signal in response to a received amplitude discriminator means output signal having a predetermined minimum duration, in one position thereof;

bandpass controller means having a predetermined high and a predetermined low threshold setting and providing a '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' AND a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' output signal, receiving the tachometer network means output signal and providing a '"'"''"'"''"'"''"'"'low'"'"''"'"''"'"''"'"' output signal in response to a received tachometer network means output signal within the high and the low threshold settings of the bandpass controller means, the bandpass controller means output signal connected to the comparator controller means and the comparator controller means providing the output signal therefrom in the '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state of the bandpass controller means output signal; and

feedback indicator means connected to the comparator controller means receiving the comparator controller means output signal and providing subject-perceivable feedback signals in response to a received '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' comparator controller means output signal.

30. The bio-feedback apparatus of claim 29 wherein the tachometer network means includes:

an oscillator means having an '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' and an '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition, the oscillator means receiving the zero crossing detector means output signal and being biased in the '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition in response thereto providing an oscillator means output signal; and

wherein the amplitude discriminator means is defined further to include;

discriminator amplifier means receiving the passband filter means output signal and providing an amplified output signal responsive thereto;

diode means, having a forward biased and a reverse biased condition, connected to and receiving the discriminator amplifier means output signal, the diode means being forward biased and conducting when receiving a positive going discriminator amplifier means output signal and being reversed biased and nonconducting when receiving a negative going discriminator amplifier means output signal;

capacitor means receiving the discriminator amplifier means output signal and being charged in response thereto in a conducting condition of the diode means;

memory capacitor means receiving the charge on the capacitor means when connected thereto;

first gate means having an opened and a closed condition connected between the capacitor means and the memory capacitor means, the first gate means receiving the oscillator output signal via the tachometer network means and being biased open in response thereto connecting the capacitor means and the memory capacitor means;

switching means connected to the capacitor means having an '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' and an '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition and receiving the zero crossing detector means output signal, the switching means being biased in the '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition in response to a received zero crossing detector means output signal in the '"'"''"'"''"'"''"'"'high'"'"''"'"''"'"''"'"' state discharging the capacitor means connected thereto; and

second gate means having an opened and a closed condition connected to the memory capacitor means and to the amplitude discriminator means, the charge on the memory capacitor means biasing the second gate means opened and providing the amplitude discriminator means output signal.

31. The bio-feedback apparatus of claim 30 wherein the tachometer network means includes:

switching means, having an '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' and an '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition, and receiving the tachometer oscillator means output signal and being biased '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' in response thereto;

function generator means connected to the switching means and having a portion charged in the '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition of the switching means, the charged portion being discharged in the '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition of the switching means, the function generator means providing an output signal proportional to the frequency of the sensed brain-wave potential in the discharging condition thereof;

memory capacitor means connected to the portion fo the function generator charged in the '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' condition of the switch means and receiving the charge discharged from the function generator means when connected thereto; and

switching means connected to the function generator means and to the memory capacitor means, having an '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' and an '"'"''"'"''"'"''"'"'off'"'"''"'"''"'"''"'"' condition, the switching means receiving the oscillator means output signal of the tachometer network means and being biased '"'"''"'"''"'"''"'"'on'"'"''"'"''"'"''"'"' in response thereto connecting the discharging function generator to the memory capacitor means.

32. A bio-feedback apparatus for sensing the brain-wave potentials produced by a subject and providing feedback signals in response thereto, the apparatus comprising:

brain-wave indicator means detecting and sensing the brain-wave potentials at two preselected sites, and providing a controlling channel output signal indicating the sensed brain-wave potential at each site;

preamplifier means receiving the controlling channel output signals and providing amplified output signals responsive thereto;

a plurality of processing channels, some of the processing channels receiving one of the controlling channel output signals and providing a feedback signal responsive thereto, some of the other processing channels receiving one other of the controlling channel output signals and providing a feedback signal responsive thereto, each of the processing channels comprising;

frequency discriminator means, having a predetermined passband, receiving the preamplifier output signal and providing an output signal responsive to a predetermined frequency component of the received preamplifier output signal having a frequency within the passband of the frequency discriminator means; and

means receiving the frequency discriminator means output signal and providing an output signal indicating signal presence in the processing channel, comprising;

first audio means providing subject-perceivable audible feedback signals responsive to a received signal input thereto;

second audio means providing subject-perceivable audible feedback signals responsive to a received signal input thereto; and

switch means receiving the feedback signals of each controlling channel output signal and connected to the first and the second audio means, the switch means having one switch condition connecting the feedback signal from one controlling channel output signal to the first audio means and the feedback signal from one other controlling channel output signal to the second audio means, and one other switch condition connecting the feedback signals from one of the controlling channel output signals to the first and the second audio means.