Automatic evoked potential detection

Claim 1

A machine-implemented method comprising: deriving for the same patient a first set of averaged brain waveforms in the absence of a stimulus and a second set in the presence thereof; seeking a test measure related to averaged spectral characteristics of the first and second sets of averaged brain waveforms and to their variance; and evaluating the test measure relative to one or more levels determined as a function of the number of averaged brain waveforms to ascertain the likelihood that the patient exhibited or failed to exhibit a significant evoked potential in response to said stimulus.

Claim 11

A method comprising deriving a first and a second set of a subject's averaged brain waveforms, one in the absence and the other in the presence of a stimulus, finding therefrom a test measure of the discrepancy therebetween, and ascertaining, on the basis of spectral characteristics of the averaged waveforms rather than only the number of waveforms which have been averaged, whether the subject exhibits a significant evoked potential in response to the stimulus to a predetermined risk of false positive and false negative results.

Claim 12

A method comprising deriving a first and a second set of a subject's averaged brain waveforms, one in the absence and the other in the presence of a stimulus, finding therefrom a test measure of the discrepancy therebetween, and ascertaining, on the basis of spectral characteristics of the averaged waveforms rather than only the number of waveforms which have been averaged, whether the subject exhibits a significant evoked potential in response to the stimulus to a predetermined risk of false positive and false negative results.

Claim 13

A system comprising: means for deriving for the same subject a first set of averaged brain waveforms in the absence of a stimulus and a second set in the presence thereof; means for seeking a test measure related to averaged spectral characteristics of the first and second sets of averaged brain waveforms and to their variance; and means for testing the test measure relative to one or more levels determined as a function of the number of averaged brain waveforms to ascertain the likelihood that the subject exhibited or failed to exhibit a significant evoked potential in response to the stimulus.

Claim 14

A system comprising: means for deriving for the same subject a first set of averaged brain waveforms in the absence of a stimulus and a second set in the presence thereof; means for seeking a test measure related to averaged spectral characteristics of the first and second sets of averaged brain waveforms and to their variance; and means for testing the test measure relative to one or more levels determined as a function of the number of averaged brain waveforms to ascertain the likelihood that the subject exhibited or failed to exhibit a significant evoked potential in response to the stimulus.

Claim 23

A method comprising the steps of: (a) deriving a first brainwave in the absence of a stimulus; (b) sampling the brainwave to produce digital samples DP(i) of the brainwave to form an epoch n=1, repeating to form an epoch n=2, and repeating to form a total of N epochs, where n=1, 2, . . . , N, and forming the N epochs into a group K; (c) finding for the group K produced in the immediately preceding step an averaged waveform K; (d) deriving a second brainwave for the same subject in the presence of the stimulus; (e) repeating steps (b) and (c) for the second brainwave; (f) repeating the sequence of steps (a) through (e) for successive first and second brainwaves to produce for each a respective sequence of groups K=2, K=3, . . . , K=K(min), and producing for each repetition a respective pair of averaged waveforms K, a respective spectral measure P(K) for the absence of the stimulus and a respective spectral measure P'(K) for the presence of the stimulus; (g) finding a test measure V(K) as a function of the difference between said spectral measure P(K) and P'(K) derived from said waveforms and of the variance thereof; (h) finding an acceptance level Va(K) and a rejection level Vr(K) as respective functions of at least the number of groups K for which said spectral measures have been found; (i) evaluating the test measure relative to said acceptance and rejection levels to determine if the difference between the first and second averaged waveforms, as reflected in said test measure V(K), is likely to correspond to the presence of a significant evoked potential in response to said stimulus, or to the absence of said potential, or to an uncertainty as to the presence or absence of said potential; (j) in case the determination results in a finding of uncertainty, repeating the sequence of steps (a) through (i) using successively incremented values of K(min) in step (f) until step (i) yields a determination of either the likely presence of said potential or steps (a) through (i) have been repeated a selected maximum number of times such that K=K(max); and (k) producing a tangible representation of said determination.

Claim 24

A method comprising the steps of: (a) deriving a first brainwave in the absence of a stimulus; (b) sampling the brainwave to produce digital samples DP(i) of the brainwave to form an epoch n=1, repeating to form an epoch n=2, and repeating to form a total of N epochs, where n=1, 2, . . . , N, and forming the N epochs into a group K; (c) finding for the group K produced in the immediately preceding step an averaged waveform K; (d) deriving a second brainwave for the same subject in the presence of the stimulus; (e) repeating steps (b) and (c) for the second brainwave; (f) repeating the sequence of steps (a) through (e) for successive first and second brainwaves to produce for each a respective sequence of groups K=2, K=3, . . . , K=K(min), and producing for each repetition a respective pair of averaged waveforms K, a respective spectral measure P(K) for the absence of the stimulus and a respective spectral measure P'(K) for the presence of the stimulus; (g) finding a test measure V(K) as a function of the difference between said spectral measure P(K) and P'(K) derived from said waveforms and of the variance thereof; (h) finding an acceptance level Va(K) and a rejection level Vr(K) as respective functions of at least the number of groups K for which said spectral measures have been found; (i) evaluating the test measure relative to said acceptance and rejection levels to determine if the difference between the first and second averaged waveforms, as reflected in said test measure V(K), is likely to correspond to the presence of a significant evoked potential in response to said stimulus, or to the absence of said potential, or to an uncertainty as to the presence or absence of said potential; (j) in case the determination results in a finding of uncertainty, repeating the sequence of steps (a) through (i) using successively incremented values of K(min) in step (f) until step (i) yields a determination of either the likely presence of said potential or steps (a) through (i) have been repeated a selected maximum number of times such that K=K(max); and (k) producing a tangible representation of said determination.