Abstract
For the purpose of topographical analysis concerning EEG in epilepsy, we developed a method of dynamic topography, in which interspike interval histogram and computerized topography of EEG were combined.
Twenty-four-channels EEGs including sixteen channels out of the international 10-20 system and eight channels on bilateral paramedian lines, were recorded by the monopolar derivation. At first, EEG spectral analysis was carried out using fast Fourier transformation technique. The spectral data in each frequency band of each channel were stored in data tape as an equipotential EEG topography of square roots of powerspectra. And then, interspike interval histograms were made in each channel and stored in data tape. Finally, both EEG topography and corresponding histogram were superimposed in one display, which was successively demonstrated on the monitor TV of twenty colors. A clinical application in case of focal epilepsy was presented.
Our display made it possible to analyze sequentially dynamic correlation between epiletogenic discharge and basic activity.
