Repetitive visual stimulation to EEG neurofeedback protocols

• US 20030225340A1
• Filed: 05/30/2002
• Published: 12/04/2003
• Est. Priority Date: 05/30/2002
• Status: Active Grant

• Current Assignee: Thomas F. Collura
• Original Assignee: Thomas F. Collura
• Inventors: Collura, Thomas F.
• Granted Patent: US 7,269,456 B2
• Time in Patent Office: Days
• US Class Current: 600/545
• CPC Class Codes: A61B 5/375 using biofeedback
• CPC Class Codes: A61B 5/378 Visual stimuli
• CPC Class Codes: A61B 5/38 Acoustic or auditory stimuli
• CPC Class Codes: Y10S 128/905 Feedback to patient of biological signal other than brain electric signal

Abstract

An EEG neurofeedback and total evoked brain activity measurement methods utilize minimum ambient EEG activity as stimulant frequencies. A method of using repetitive stimulation in conjunction with EEG neurofeedback protocols is described. Electrodes, attached to a subject'"'"'s scalp, transmit electroencephalographic (EEG) signals from the subject. These signals are in response to the visual and/or auditory stimuli being displayed to the subject. The resultant EEG signals are then filtered at pre-defined frequencies or frequency bands. The output from the filtered EEG signals is then analyzed and monitored for short-term state changes. The invention also uses flicker stimulation, real-time signal filtration and feedback, feedback during audio and visual stimulation derived from filtered outputs, and fundamental and integral harmonics in combination with total evoked response.

Claims

1. A method of using repetitive stimulation in conjunction with EEG neurofeedback protocols, comprising the steps of:

securing electrodes to a subject'"'"'s scalp;

displaying stimuli to the subject;

receiving an electroencephalographic (EEG) signal from the subject while the stimuli is being displayed;

transmitting the resultant EEG signal to a filter;

filtering the EEG signal at a predefined frequency;

outputting the filtered EEG signal to a display monitor or other recorder;

capturing any screen images, waveforms, or envelope information;

analyzing the EEG signals; and

monitoring short-term state changes.

2. The method of claim 1 wherein visual stimuli is displayed to the subject.

3. The method of claim 2 wherein the visual stimuli displayed is presented using LED'"'"'s mounted in goggles or glasses positioned over the subject'"'"'s open eyes.

4. The method of claim 3 wherein the visual stimuli is in the form of a flickering light.

5. The method of claim 3 wherein the visual stimuli is in the form of square-wave light.

6. The method of claim 1 wherein auditory stimuli are presented to the subject.

7. The method of claim 6 wherein the auditory stimuli is presented using stereo head-phones positioned over the subject'"'"'s ears.

8. The method of claim 7 wherein the auditory stimuli is in the form of audible clicks.

9. The method of claim 1 wherein visual and auditory stimuli are displayed to the subject.

10. The method of claim 1 wherein the electrodes secured to the subject'"'"'s scalp are EEG electrodes.

11. The method of claim 1 wherein the EEG signal is narrow band filtered using custom-built analog or digital comb filters.

12. The method of claim 11 wherein the EEG signal is narrow band filtered at a frequency at the same rate as the stimuli.

13. The method of claim 12 wherein the EEG signal is narrow band filtered at a frequency of twice the rate as the stimuli.

14. The method of claim 13 wherein the EEG signal is narrow band filtered at a frequency of three times the rate of the stimuli.

15. The method of claim 14 wherein the EEG signal is narrow band filtered at a frequency of any integral harmonic of the rate of the stimuli.

16. The method of claim 11 wherein the filters are set to a time-constant chosen for the desired response characteristics.

17. The method of claim 16 further comprising an effective narrow bandwith which is sufficient to reject unrelated EEG activity.

18. The method of claim 17 wherein the output from the filters is combined to measure amplitude and latency of evoked activity.

19. The method of claim 18 wherein the EEG signals are displayed via a Signal Averager.

20. The method of claim 19 wherein a free-run EEG signal is superimposed on an averaged EEG signal to provide a single sweep display that synchronizes the two signals for visual comparisons.

21. The method of claim 20 wherein the images are captured using a photographic or digital method.

22. The method of claim 21 wherein the EEG signals are monitored continuously, in real-time.

23. The method of claim 22 wherein the EEG signals are recorded on an analog or digital strip chart recorder.

24. The method of claim 23 wherein all 4 banks of the comb filter are summed into one channel, to reveal the composite evoked potentials as an ongoing waveform.

25. The method of claim 24 wherein this waveform is plotted simultaneously with the raw EEG signal for a visual comparison.

26. A method of monitoring short-term state changes via EEG neurofeedback protocols, comprising the steps of:

securing electrodes to a subject'"'"'s scalp;

displaying stimuli to the subject;

receiving an electroencephalographic (EEG) signal from the subject while the stimuli is being displayed;

transmitting the resultant EEG signal to a comb filter;

narrow band filtering the EEG signal at center frequencies equal to the fundamental and integral harmonics of the stimulus rate;

outputting the filtered EEG signal to a multichannel analog or digital strip chart recorder to record the traces on moving paper;

slowing the chart speed so that the resulting trace reveals the signal envelope;

analyzing the EEG signals and amplitude; and

feeding individual filter channels to separate traces so they can be seen independently.

27. The method of claim 26 wherein the stimulus displayed is visual and is presented at a rate between 4 and 20 flashes/second.

28. The method of claim 26 wherein the stimulus displayed is auditory and is presented at a rate between 4 and 20 clicks/second.

29. The method of claim 26 wherein the stimuli displayed are both visual and auditory.

30. A method of measuring sensory and perceptual mechanisms of the brain, and training these mechanisms with feedback, comprising the steps of:

securing electrodes to a subject'"'"'s scalp;

displaying stimuli to the subject;

receiving an electroencephalographic (EEG) signal from the subject while the stimuli is being displayed;

transmitting the resultant EEG signal to a filter;

narrow band filtering the EEG signal at a predefined frequency;

reconstructing the total evoked brain activity by combining the filter outputs; and

feeding back in real-time of the total evoked response.

31. The method of claim 30 wherein the EEG signal is used to control a stimulator which produces a visual stimulus, wherein the control trains an increase or decrease in the evoked response.

32. The method of claim 30 wherein auditory feedback reflects the brain'"'"'s response to the stimulation and allows the subject to receive feedback regarding their current state of attention, wherein the feedback trains the sensory/perceptual pathways of the brain.

33. The method of claim 30 wherein the subject is trained via operant conditioning of the sensory/perceptual pathways of the brain by feedback in real-time of the evoked response.

34. The method of claim 30 wherein a control signal is derived from the brain'"'"'s response to stimulation, to affect a switch or actuator.