Neurocognitive ability EEG measurement method and system

• US 6,434,419 B1
• Filed: 06/26/2000
• Issued: 08/13/2002
• Est. Priority Date: 06/26/2000
• Status: Expired due to Fees

• Current Assignee: SAM Technology, Inc.
• Original Assignee: SAM Technology, Inc.
• Inventors: Smith, Michael E., Gevins, Alan S.
• Primary Examiner(s): Hindenburg, Max
• Application Number:
  US09/603,218
• Time in Patent Office: 778 Days
• Field of Search: 600/544, 600/545, 600/587
• US Class Current: 600/544
• CPC Class Codes: A61B 5/16 Devices for psychotechnics using teaching or educational appliances G09B1/00 - G09B7/00; Testing reaction times ; Devices for evaluating the psychological state
• CPC Class Codes: A61B 5/377 using evoked responses
• CPC Class Codes: A61B 5/4076 Diagnosing or monitoring particular conditions of the nervous system A61B5/4821, A61B5/4824 take precedence
• CPC Class Codes: A61B 5/411 Detecting or monitoring allergy or intolerance reactions to an allergenic agent or substance
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: G16H 20/70 relating to mental therapies, e.g. psychological therapy or autogenous training
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

An efficient, objective testing method and system for evaluating mental acuity and changes in mental acuity is described. The method and system are based on measuring an individual'"'"'s behavioral responses and brain function during a brief test of working memory and passive control condition. The method and system is designed to assess an individual'"'"'s overall cognitive ability (“general intelligence”), and whether that overall cognitive ability has been significantly affected by a variety of factors such as progressive disease processes, medication, stress, fatigue or training. The method and system can be used to determine whether drugs being evaluated to treat diseases or conditions affecting higher cognitive brain function have a significant positive effect on delaying or improving the symptoms of such a disease or condition, especially during clinical trials for drug approval and subsequent marketing. The method and system may also be employed as part of the successful diagnosis or ongoing treatment of neurological diseases or conditions that directly or indirectly affect human neurocognitive performance. The method and system may also be used to determine transitory changes in overall cognitive ability due to emotional stress or fatigue, and more long lasting changes in overall cognitive ability following training and educational programs.

Claims

1. The method of measuring a subject'"'"'s working memory, substantially free of bias from cultural and educational experience, to determine the subject'"'"'s overall cognitive ability (“

general intelligence”

), including the steps of;

(a) presenting an attention-demanding task to the subject, which engages the subject'"'"'s working memory processes, and, simultaneously;

(b) measuring the subject'"'"'s behavioral responses to the task and neuroelectric activity at the subject'"'"'s scalp using a set of electroencephalograph (EEG) electrodes and amplifier and analog/digital(A/D) converters to provide a set of digital data representing the subject'"'"'s behavioral responses and neuroelectric activity in response to the task;

(c) in a computer system, comparing the subject'"'"'s digital data representing behavioral responses and neuroelectric activity in response to the task to a set of digital data representing the behavioral responses and EEG derived neuroelectric activity responses of a normal group to the same task; and

(d) displaying the subject'"'"'s overall cognitive ability score or scores based upon the comparison of (c) with the normal group.

2. The method of claim 1, wherein in (a) a passive control condition is presented to the subject for comparison to the attention-demanding task.

3. The method of claim 1 employed to measure changes in the subject'"'"'s overall cognitive ability over a period of time, including performing the steps (a)-(c) to obtain a baseline cognitive ability score or scores and subsequently again performing the steps (a)-(c) to obtain a second cognitive ability score or scores and comparing the second and baseline cognitive ability scores.

4. The method of claim 1 employed to measure changes in the subject'"'"'s overall cognitive ability over a period of time, including performing the steps (a)-(c) to obtain a prior cognitive ability score or scores and subsequently again performing the steps (a)-(c) to obtain a subsequent cognitive ability score and comparing the prior and subsequent cognitive ability scores.

5. The method of claim 1 employed to measure changes in the subject'"'"'s overall cognitive ability over a period of time, including performing the steps (a)-(c) a plurality of times to obtain a prior set of cognitive ability scores and subsequently again performing the steps (a)-(c) to obtain a subsequent cognitive ability score or scores and comparing the subsequent cognitive ability score or scores with the prior set of scores.

6. The method of claims 2, 3, 4 or 5 employed to test the effect of medicine on a subject in which at least one score is obtained before administration of the medicine to the subject and at least another score is obtained after administration of the medicine to the subject.

7. The method of claims 2, 3, 4 or 5 employed to test the effectiveness of a remedial program to improve cognitive functioning in which at least one score is obtained before administration of the remedial program to the subject and at least another score is obtained after administration of the remedial program.

8. The method of claims 2, 3, 4 or 5 employed to measure the effect of fatigue on a subject in which at least one score is obtained when the subject is in an alert, rested state and at least another score is obtained after the subject has been deprived of a normal amount of sleep or is otherwise fatigued.

9. The method of claims 2, 3, 4 or 5 employed to measure the effect of injury or disease on a subject in which at least one score is obtained when the subject is in a healthy, uninjured state and at least another score is obtained after the subject has been injured or contracted a disease.

10. The method of claims 2, 3, 4 or 5 employed to measure recovery from injury or disease in which at least one score is obtained after the subject has been injured or contracted a disease and at least another score is subsequently obtained.

11. The method of claims 2, 3, 4 or 5 wherein the task is not culturally biased as it does not involve reading a language.

12. The method of claims 2,3,4 or 5 and presenting the subject with at least two versions of the task, one version being relatively more difficult than the other version.

13. The method of claims 2, 3, 4 or 5 and additionally presenting the subject with control conditions in which the subject sits passively with eyes opened and the with eyes closed.

14. The method of claims 2,3,4 or 5 and measuring the subject'"'"'s neuroelectric activity in (b) while performing the task of (a) to determine one, or more, of the group selected from:

i. characterizing the subject'"'"'s level of alertness;

ii. characterizing the subject'"'"'s mental efforts and brain utilization;

iii. characterizing the subject'"'"'s sustained focused attention;

iv. characterizing the subject'"'"'s neurocognitive strategy;

v. characterizing the subject'"'"'s cognitive speed;

vi. characterizing the subject'"'"'s transient focused attention;

vii. characterizing how the subject'"'"'s brain and behavior respond to changes in mental workload by presenting more and less difficult versions of a task during the same test session;

viii. characterizing the subject'"'"'s quickness to adapt by presenting repeated trials of the same task during one test session.

15. The method of claims 2, 3, 4 or 5 and measuring the subject'"'"'s neuroelectric activity in (b) while performing the task of (a) to determine one, or more, of the group selected from:

i. characterizing the subject'"'"'s level of alertness by EEG measurement of the subject'"'"'s frontal delta power associated with slow horizontal eye movements, posterior theta and delta power, and ratios of posterior theta to alpha and delta to alpha powers;

ii. characterizing the subject'"'"'s mental effort and brain utilization by EEG measurement of the subject'"'"'s parietal and prefrontal alpha powers;

iii. characterizing the subject'"'"'s sustained focused attention by EEG measurement of the subject'"'"'s frontal midline theta power;

iv. characterizing the subject'"'"'s neurocognitive strategy by EEG measurement of left to right and anterior to posterior ratios of the subject'"'"'s alpha powers;

v. characterizing the subject'"'"'s cognitive speed by EEG measurement of the subject'"'"'s fronto-central P200 and P300 evoked potential peak latencies;

vi. characterizing the subject'"'"'s transient focused attention by EEG measurement of the subject'"'"'s fronto-central P200 and P300 evoked potential amplitudes;

vii. characterizing how the subject'"'"'s brain and behavior respond to changes in mental workload by presenting more and less difficult versions of the same task during the same test session and measuring differences between the difficulty levels, and the difficulty levels and resting, in neural activity measures i-vi; and

viii. characterizing the subject'"'"'s quickness to adapt by measuring changes in the neural activity measures i-vii as the subject continues to perform the attention demanding tasks during the same test sessions.

16. The method of measuring the working memory of a subject, substantially free of bias from cultural and educational experience, to identify existing deficits and to determine the changes in the subject'"'"'s working memory due to an underlying deleterious and/or progressive clinical condition, or due to any consequences of the administration of a medicine or remedial program, including the steps of:

(a) presenting to the subject an attention-demanding task, which engages the subject'"'"'s working memory processes;

(b) before administration of the medicine-or remedial program measuring the subject'"'"'s behavioral responses to the task questions and neuroelectric activity at the subject'"'"'s scalp using a set of electroencephalograph (EEG) electrodes and amplifiers and analog/digital (A/D) converters to provide a set of baseline digital data representing the subject'"'"'s behavioral responses to the task questions and neuroelectric activity in response to the task;

(c) in a computer system, comparing the subject'"'"'s behavioral and neuroelectric responses to the task questions to a normal group'"'"'s behavioral and neuroelectric responses to the task questions to obtain the subject'"'"'s baseline score;

(d) performing the steps (a)-(c) to obtain the subject'"'"'s score based upon a second or subsequent set of digital data and comparing the second or subsequent scores with the baseline score to obtain a measure of change of the subject'"'"'s working memory due to administration of the medicine or the remedial program or changes over time;

(e) displaying the subject'"'"'s changes in working memory based upon the comparison of the scores of (d).

17. The method of claim 16, wherein in (a) a passive control condition is presented to the subject for comparison to the attention-demanding task.

18. The method of claim 16 employed to test the effect of a medicine on a subject in which the baseline score is obtained before administration of the medicine to the subject and the second or subsequent score is obtained during or after administration of the medicine to the subject.

19. The method of claim 16 employed to test the effectiveness of a remedial program to improve cognitive functioning in which the baseline score is obtained before administration of the remedial program to the subject and the second or subsequent score is obtained during or after administration of the remedial program.

20. The method of claims 16-19 wherein the task is not culturally biased as it does not involve reading a language.

21. The method of claims 16-19 and presenting the subject with two versions of the task, one version being relatively more difficult than the other version.

22. The method of claims 16-19 and additionally presenting the subject with a control condition in which the subject sits passively with eyes opened and eyes closed.

23. The method of claim 16 employed to measure changes in the subject'"'"'s working memory over a period of time to test an underlying deleterious and/or progressive clinical condition, including performing the steps (a)-(c) to obtain a prior score and subsequently again performing the steps (a)-(c) to obtain a subsequent score and comparing the prior and subsequent scores.

24. The method of claim 16 employed to measure changes in the subject'"'"'s working memory to test an underlying deleterious and/or progressive clinical condition over a period of time, including performing the steps (a)-(c) a plurality of times to obtain a set of scores and subsequently again performing the steps (a)-(c) to obtain a subsequent score and comparing the subsequent score with the set of scores.

25. The method of claims 16-19 and measuring the subject'"'"'s neuroelectric activity in (b) while performing the task of (a) to determine one, or more, of the group selected from:

i. characterizing the subject'"'"'s level of alertness;

ii. characterizing the subject'"'"'s mental efforts and brain utilization;

iii. characterizing the subject'"'"'s sustained focused attention;

iv. characterizing the subject'"'"'s neurocognitive strategy;

v. characterizing the subject'"'"'s cognitive speed;

vi. characterizing the subject'"'"'s transient focused attention;

vii. characterizing how the subject'"'"'s brain and behavior respond to changes in mental workload by presenting more and less difficult versions of a task during the same test session;

viii. characterizing the subject'"'"'s quickness to adapt by presenting repeated trials of the same task during one test session.

26. The method of claims 16-19 and measuring the subject'"'"'s neuroelectric activity in (b) while performing the task of (a) to determine one, or more, of the group selected from:

(i) characterizing the subject'"'"'s level of alertness by EEG measurement of the subject'"'"'s frontal delta power associated with slow horizontal eye movements, posterior theta and delta power, and ratios of posterior theta to alpha and delta to alpha powers;

(ii) characterizing the subject'"'"'s mental effort and brain utilization by EEG measurement of the subject'"'"'s parietal and prefrontal alpha powers;

(iii) characterizing the subject'"'"'s sustained focused attention by EEG measurement of the subject'"'"'s frontal midline theta power;

(iv) characterizing the subject'"'"'s neurocognitive, strategy by EEG measurement of left to right and anterior to posterior ratios of the subject'"'"'s alpha powers;

(v) characterizing the subject'"'"'s cognitive speed by EEG measurement of the subject'"'"'s fronto-central P200 and P300 evoked potential peak latencies;

(vi) characterizing the subject'"'"'s transient focused attention by EEG measurement of the subject'"'"'s fronto-central P200 and P300 evoked potential amplitudes;

(vii) characterizing how the subject'"'"'s brain and behavior respond to changes in mental workload by presenting more and less difficult versions of the same task during the same test session and measuring differences between the difficulty levels, and the difficulty levels and resting, in neural activity measures i-vi; and

(viii) characterizing the subject'"'"'s quickness to adapt by measuring changes in the neural activity measures i-vii as the subject continues to perform the attention demanding tasks during the same test session.