Method and apparatus for utilizing amplitude-modulated pulse-width modulation signals for neurostimulation and treatment of neurological disorders using electrical stimulation

• US 20040002635A1
• Filed: 02/04/2003
• Published: 01/01/2004
• Est. Priority Date: 02/04/2002
• Status: Abandoned Application

• Current Assignee: Great Lakes Biosciences LLC
• Original Assignee: Great Lakes Biosciences LLC
• Inventors: Esty, Mary L., Hargrove, Jeffrey B., Stokes, Theodore J.
• Application Number:
  US10/357,503
• Publication Number:
  US 20040002635A1
• Time in Patent Office: Days
• US Class Current: 600/300
• CPC Class Codes: A61B 5/374 Detecting the frequency distribution of signals, e.g. detecting delta, theta, alpha, beta or gamma waves
• CPC Class Codes: A61B 5/4076 Diagnosing or monitoring particular conditions of the nervous system A61B5/4821, A61B5/4824 take precedence
• CPC Class Codes: A61N 1/36021 for treatment of pain
• CPC Class Codes: A61N 1/36025 for treating a mental or cerebral condition

Abstract

A computing device-controlled system is described for the generation of amplitude-modulated pulse-width modulation (AMPWM) signals for use in treating neurological dysfunction via cranial neurostimulation, where the AMPWM signal is specifically designed to minimize the electrical impedance of the tissues of the head. A low-frequency carrier signal is determined for the AMPWM signal by measuring EEG activity at a reference site or sites, generally corresponding with the location of suspected brain dysfunction. Carrier signal frequency is variably related to critical frequency components of the EEG power spectral density, determined from statistical analysis of amplitudes and variability, and dynamically changed as a function of time to prevent entrainment. The AMPWM signal is presented to a subject via a plurality of neurostimulation delivery modes for therapeutic use.

Claims

1. A method of treating a neurological dysfunction, wherein said method comprises:

a) taking a first measurement of the EEG of a subject afflicted with at least one type of the neurological dysfunction in order to obtain EEG results;

b) evaluating the EEG results to determine whether any region of the brain of the subject possesses irregular activity as compared to other regions of the brain of the subject;

c) determining a dominant frequency of a region of the brain of the subject possesses irregular activity; and

d) administering an anti-neurological dysfunction therapy to the subject;

wherein the anti-neurological dysfunction therapy comprises inducing a neurostimulation signal directed to areas of the brain of the subject that correspond to the areas of the brain of the subject that possess irregular activity for a time sufficient to normalize the EEG of the areas of the brain of the subject that possess irregular activity; and

wherein additional EEG measurements from the areas of the brain of the subject that possess irregular activity are monitored during the administration of the therapy and wherein the neurostimulation signal is adjusted based on any detected changes in the additional EEG measurements.

2. The method of claim 1, wherein the step of evaluating the EEG results to determine whether any region of the brain of the subject possesses irregular activity further comprises the step of comparing EEG results from a region of the brain of the subject against EEG results from the remaining regions of the brain of the subject.

3. The method of claim 1, wherein the step of administering an anti-neurological dysfunction therapy to the subject results in alleviation of symptoms caused by the neurological dysfunctions.

4. The method of claim 1, wherein the step of taking the first EEG measurements further comprises the step of taking the first EEG measurements from more than one area of the scalp of the subject.

5. The method of claim 1, wherein the step of evaluating the EEG results to determine whether any region of the brain of the subject possesses irregular activity further comprises the step of using the obtained EEG results of step a) to produce a graphic image of the brain of the subject.

6. The method of claim 1, wherein the step of administering an anti-neurological dysfunction therapy to the subject further comprises a step of adjusting the EEG of the regions of the brain of the subject that possess irregular activity to match the predetermined frequency for that region of the brain.

7. The method of claim 1, wherein the neurological dysfunction is selected from the group consisting of traumatic brain injury, post traumatic stress disorder, post stroke paralysis, post traumatic brain injury paralysis, cerebral palsy, headache, depression, post chemotherapy cognitive, mood and fatigue disorder, fibromyalgia, memory loss, coma, and attention deficit disorder.

8. The method of claim 1, wherein the neurostimulation stimulation signal comprises a low frequency carrier signal and a high frequency pulse train.

9. The method of claim 8, wherein the high frequency pulse train is modulated by the low frequency carrier signal.

10. The method of claim 1, wherein the subject is a human being.

11. The method of claim 1, wherein the step of taking a first measurement of the EEG of a subject further comprises the step of taking separate readings at at least 21 different scalp locations.

12. The method of claim 1, wherein the time is from 1 second to 1 hour.

13. The method of claim 1, wherein the neurostimulation signal comprises a carrier frequency that comprises the dominant frequency and a frequency offset.

14. The method of claim 13, wherein the frequency offset is between −

10 and 20 Hertz.

15. The method of claim 8, wherein the neurostimulation signal is an AMPWM signal.

16. The method of claim 1, further comprising the step of administering multiple treatments of the method to the subject.

17. The method of claim 16, wherein the number of multiple exposures is between 1 and 40.

18. The method of claim 16, wherein a repeated use of the method is avoided within 24 hours of a previous use of the method.

19. The method of claim 1, wherein the method is used to treat more than one region of the brain of the subject that possesses irregular activity.

20. The method of claim 1, wherein the step of inducing the neurostimulation signal further comprises the step of inducing the neurostimulation signal through EEG sensors attached to the scalp of the subject.

21. The method of claim 1, wherein the step of inducing the neurostimulation signal further comprises the step of using an optical unit and the step of inducing the neurostimulation signal induced through photic stimulation;

and wherein said photic stimulation is produced by an optical unit worn by the subject, and wherein the optical unit comprises light emitting diodes, and wherein EEG sensors are attached to the scalp of the subject.

22. The method of claim 1, wherein the method is automated.

33. The method of claim 1, wherein the subject is sedated.

34. The method of claim 1, wherein the subject is medicated.

35. The apparatus of claim 12, wherein the subject is a human.

37. The method of claim 1, wherein step d) further comprises the step of entraining the EEG signals of the subject.

23. An apparatus for neurostimulating a subject, said apparatus comprising:

a) a computing device;

b) a neurostimulator that is operatively coupled to the computing device; and

c) a series of EEG sensors that are coupled to said neurostimulator.

24. The apparatus of claim 23, wherein the series of EEG sensors are configured (1) to be attached to the subject, (2) to measure EEG signals of the subject, and (3) to transmit neurostimulation signals to the subject, and wherein the EEG sensors comprise at least one positive contact, at least one negative contact, and at least one ground contact.

25. The apparatus of claim 23, wherein the apparatus is housed in a protective outer enclosure.

26. The apparatus of claim 23, wherein the neurostimulator comprises:

a) a biopotential acquisition unit comprising an electric circuit configured to acquire biopotential data from the EEG signals obtained by the EEG sensors attached to the subject, and to analyze and store the acquired biopotential and EEG data with computational means; and

wherein the biopotential acquisition unit is operatively coupled to the neurostimulator;

b) a transmission unit configured to transmit the biopotential and EEG data from the neurostimulator to the computing device;

c) an I/O unit configured to adjust for a time lag in the biopotential and EEG data being transmitted; and

d) at least one switching unit configured to manage a neurostimulation signal.

27. The apparatus of claim 23, wherein the neurostimulator further comprises an optical unit in which EEG sensors are contained, and wherein the optical unit further comprises a set of light generating units located in close proximity to the pupils of the subject when the optical unit are worn on the face of the subject.

28. The apparatus of claim 27, wherein the light generating units are light emitting diodes.

29. The apparatus of claim 26, wherein the neurostimulator further comprises:

a) at least one filtering unit;

b) an isolation amplifier; and

c) a microcontroller; and

wherein the EEG sensors are configured to transmit the EEG data directly to the biopotential acquisition unit; and

wherein the isolation amplifier is operatively coupled to the microcontroller and the biopotential acquisition unit; and

wherein the biopotential acquisition unit is configured to transmit the EEG data and biopotential data through at least one filtering unit and through an isolation amplifier.

30. The apparatus of claim 29, wherein the at least one filtering unit is selected from the group consisting of a circuit configured to filter data and a numerical filter.

31. The apparatus of claim 29, wherein the biopotential acquisition unit comprises a biopotential amplifier or a high resolution analog-to-digital converter.

32. The apparatus of claim 26, wherein the switching unit comprises a transistor.

36. The apparatus of claim 26, wherein the switching unit comprises an inductor configured to receive a stimulation signal from the neurostimulator which induce electrical current into the inductor, which further induces electrical current in the EEG sensors via electromagnetic coupling, and thereby into the subject.