[Demonstration of an interpolation method for determining approximate maximum and minimum points as a prerequisite for EEG analysis in the time domain using computers with limited memory capacity].

Abstract

The EEG analysis in the time domain provides several advantages compared to the power spectra analysis, based on a FFT. There is the possibility to differentiate frequency, amplitude and other elementary characteristics of the wave form. This technique of EEG analysis is based on the definition of distinct characteristics of the wave form. Problems for calculating the frequency distribution arise--according to Harner, 1977--due to the fact, that the digitalization rate has to be very fast to reach an adequate resolution. On the other hand a high digitalization rate of 5 ms or below produces problems concerning the limited memory capacity of laboratory computers, especially if more than one derivation should be analysed simultaneously, to make further topological analyses possible. Three procedures of EEG analysis to calculate frequency distributions are shown, two of them are based on an interpolation technique to calculate adjusted minima-maxima. The results of these procedures using two different digitalization rates, were compared and discussed to respect similarity of resulting frequency distributions.