Method for the analysis and utilization of P300 brain waves

• US 5,137,027 A
• Filed: 06/12/1990
• Issued: 08/11/1992
• Est. Priority Date: 05/01/1987
• Status: Expired due to Term

• Current Assignee: Joel P. Rosenfeld
• Original Assignee: Joel P. Rosenfeld
• Inventors: Rosenfeld, Joel P.
• Primary Examiner(s): Howell, Kyle L.
• Assistant Examiner(s): Akers, Scott R.
• Application Number:
  US07/537,319
• Time in Patent Office: 791 Days
• Field of Search: 128/731, 128/732, 128/733, 128/741, 128/744, 128/745, 128/746, 128/660.05
• 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 5/164 Lie detection
• CPC Class Codes: A61B 5/377 using evoked responses
• CPC Class Codes: A61B 5/383 Somatosensory stimuli, e.g. electric stimulation

Abstract

A control question method for evaluating whether or not a subject has previously performed a given act. The subject is preliminarily questioned about the given and other unrelated acts, and then is serially repetitively presented with an odd-ball paradigm comprised of such given facts as well as irrelevant facts. Event-related potentials concurrently generated by the subject are electroencephalographically sensed and analyzed for P3 content and the P3 waves generated by each paradigm repeat are compared. Based on selected criteria, a conclusion regarding prior act performance is made. Computer means are utilized to regulate the paradigm presentation and to interpret and analyze the P3 responses.

Claims

1. A method of evaluating at least one of either (a) the attention level of a subject towards one class of stimuli in the presence of a second class of stimuli, or (b) evaluating the attention absorbing capacity of said second class of stimuli by said subject in the presence of said first class of stimuli, said method comprising the steps of sequentially:

(a) first exposing said subject to one first run of a Bernoulli-random series comprising one class of sensorially perceivable stimuli said series being comprised of about 100 to about 300 stimuli members all stimuli members of said series having an equal time duration which is in the range of about 1.5 to about 2,000 milliseconds, each stimulus member of said series being separated from adjacent stimuli members of said series by an equal time interval which is in the range of about 1.5 to about 20 seconds, said series being comprised of two groups, one said group being a minority and comprising about 5 to about 50 percent of said series and the remaining group being a majority and comprising the balance of up to 100 percent of said series, while concurrently electroencephalographically sensing from at least one scalp site of said subject the event related potentials produced by said subject in response to said exposing during said first run;

(b) first determining for each subject exposure by the stimulus members of said one minority group during said first run;

(1) the prestimulus electroencephalographic potential for a first measured millisecond time interval which interval is in the range of about 50 to about 500 milliseconds and which interval exists prior to said exposure, and

(2) the maximum voltage amplitude for the P3 wave produced over a second measured millisecond time interval which interval is in the range of about 50 to about 500 milliseconds said P3 wave maximum amplitude being measured within a time period in the range of about 300 to about 1200 milliseconds measured from the start of said exposure; and

(c) exposing said subject to a second class of sensorially perceivable stimuli while simultaneously also secondly exposing said subject to a one second run of said Bernoulli-random series comprising said one class of stimuli with the individual members of said series being maintained in the same order as in said first run thereof while concurrently electroencephalographically sensing from at least one scalp site of said subject the event related potentials produced by said subject in response to said second exposing of said second run;

(d) secondly determining for each subject exposure by the stimulus members of said one minority group during said second exposing of said second run minority stimulus;

(1) the prestimulus electroencephalographic potential for a first measured millisecond time interval which interval is in the range of about 50 to about 500 milliseconds and which interval exists prior to said exposure, and

(2) the maximum voltage amplitude for the P3 wave produced over a second measured millisecond time interval which intervals is in the range of about 50 to 500 milliseconds, said P3 wave maximum amplitude being measured within a time period in the range of about 300 to about 1200 milliseconds measured from the start of said exposure; and

(e) comparing the resulting amplitude wave forms so obtained from each of said steps (b) and (d) relative to a predetermined criterion, thereby to evaluate differences in the measured values obtained in step (d) relative to step (a).

2. The method of claim 1 wherein said stimuli are auditory, wherein one said class thereof differs in frequency from said second class thereof by a value in the range of about 50 to 100 cycles per second and the signals have a strength of about 50 to 70 db.