Electroencephalographic system and method using factor structure of the evoked potentials
AssigneeNew York University
InventorErwin R. John
Life of this patent
Estimating the term…
Abstract
In an electroencephalographic method and system for the quantitative analysis of brain waves, a programmed sequence of stimuli is automatically presented to a subject to evoke averaged evoked responses (AER's). The AER's are automatically analyzed by factor analysis in which each waveshape is reconstituted, as closely as possible, by a set of "basis waveshapes" (factors) held in memory. The "factor scores" (contributions of each factor) are Z transformed as a comparison against results from a normal population, and displayed as color-coded topographic maps of the head.
Claims14
The method of analyzing the brain waves of a human subject to determine the presence, degree and type of evoked potential abnormality, the method consisting of the steps, in sequence, of:
- removably securing a plurality of electrodes i to the scalp of the patient, automatically presenting a sequence of stimuli to the patient to evoke brainwave potentials (EP) at the electrodes;
- detecting the said EP brainwaves, amplifying the detected brainwaves, converting the amplified brainwaves into digital form, averaging the digitized brainwaves to produce average evoked responses (AER) for analysis in a digital processing computer system having computer memory;
- decomposing the average evoked responses (AER) by factor analysis, in which each AER from each electrode is compared to pre-formulated factor waveforms stored in the computer memory to determine the amount of voltage that each pre-formulated factor waveform contributes to said AER to thereby produce a factor score a.sub.ij, quantifying the contribution of each factor j to the AER from any electrode i;
- subjecting the results of the said factor score to Z-transform, wherein each of said factor scores is compared to norms stored in the computer memory to produce a factor Z-score, corresponding to a determination of waveshape normalcy and the degree of abnormality of each of said AER's and
- displaying the said normalcy and degree of abnormality on a color-coded topographic map comprising a head diagram in which each area of the head represents an electrode location and the colors represent normalcy and the degree of abnormality reflected by the factor Z-score.
A system for analyzing the brainwaves of a human subject to determine the presence, degree and type of evoked potential abnormality, the system consisting of:
- a plurality of electrodes, means for removably securing the plurality of electrodes to the scalp of the patient, stimuli means for automatically presenting a sequence of stimuli to the patient to evoke brainwave potentials (EP) at the electrodes;
- amplifier means for amplifying the evoked brainwaves, A/D converter means for converting the amplified brainwaves into digital brainwave form, averaging means for averaging the digitized brainwaves to provide average evoked responses (AER) for analysis in a digital processing computer system;
- computer means having a computer memory and calculation means for analyzing the average evoked responses by factor analysis, said computer means comparing each AER from each electrode to pre-formulated factor waveforms stored in the computer memory to determine the voltage that each pre-formulated factor waveform contributes to each AER said comparison producing a factor score a.sub.ij quantifying the contribution of each factor to the AER from any electrode;
- Z-transform computer means for subjecting the said factor score to Z-transform, statistical computing means for automatically comparing each of said factor scores to norms stored in the computer memory to produce a factor Z score providing a determination of normalcy versus the degree of abnormality;
- and
- display means to display the said normalcy and degree of abnormality on a color coded topographic map comprising a head diagram in which each area of the head represents an electrode location and the color represents normalcy and the degree of abnormality reflected by the factor Z score.
Dependencies are inferred from the claim text.