Children's Medical Center Corporation

Braintech Corporation

Norman D Culver

Frank H Duffy

In a system for displaying multichannel EEG data, data values received from a matrix of EEG electrodes are stored in a random access memory. Digital values to be displayed are interpolated from the input values by addressing selected ones of the inputs from memory, multiplying those inputs by predetermined coefficients taken from a coefficient memory and summing the products. Each element of the display can be determined in that way within one frame time of the display apparatus. The data can be interpolated in real time for a flicker free display at a rate of over 25 frames per second. By displaying separate values associated with each display element as a distinct color, the dimensionality of the display can be increased. The numeric matrix which underlies the expanded topographic display can be stored digitally and further utilized in further operations and displays.

Apparatus and method for topographic display of multichannel data

Apparatus and method for topographic display of multichannel EEG data

Topographic displays of brain electrical activity are produced from matrices of data derived from evoked potential (EP) and steady-state responses of skull transducers. In different aspects, EP responses are displayed at a variable frame rate, the rate of data sampling is sufficient to capture rapid transient events, difference matrices are derived as the difference between matrices corresponding to two different brain conditions, the baseline of the EP responses is zeroed based on the average prestimulus response, and the steady-state response is analyzed by Fourier transforms. In other aspects, statistical comparison matrices representing statistical differences between corresponding elements in two matrices are generated, a coefficient-of-variance matrix is generated, additional display matrices are temporally interpolated, response waveforms are previewed and tagged for elimination from further processing, the topographic maps are displayed on a video monitor with appropriate scaling of the data to the tones of the display, and additional display points are interpolated between the measured data points for display.

Brain electricaL activity mapping

Information on brain electrical activity is derived from electrical-activity transducers spaced apart over the skull, the information is processed into a time sequence of matrices having elements representing the responses of the transducers, a succession of overlapping running-average matrices is generated each corresponding to an average of a plurality of the matrices in the time sequence, and the running-average matrices are displayed as a sequence of topographic maps. Expanded display matrices are generated from the data matrices by adding new matrix elements using three-point linear interpolation based on pre-stored coefficients corresponding to the location of each new matrix element with respect to the three closest transducer locations.

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Spotswood, NJ, United States of America

Norman D Culver