An Approach to an Automatic Pattern Recognition of the Electroencephalogram: Background Rhythm and Paroxysmal Elements

Abstract

The automatic analysis program for one derivation of E.E.G. described here is made up of two parts:1.) The first part consists of the study of background rhythm. A temporal analysis is made of the signal to identify the waves of which it is composed. Bursts of rhythms are recognised. Then the principal background rhythms are determined by the analysis of histograms of amplitude and frequency. The results are given as the percentage of the total waves, the mean frequency and amplitude and the coefficient of variation of these quantities.2.) The second part is the recognition of paroxysmal patterns. By successive applications of a set of criteria the parts of the E.E.G. which may contain spikes or spike-and-waves are extracted. The criteria are:— existence of large amplitude or slow waves,— comparison of the frequency of these suspect patterns with the background frequency,— comparison of the amplitude of these waves with the mean amplitude of the E.E.G.,— study of the rapid rhythms which, are superimposed on the show waves.This analysis is concluded by the printing of the number of isolated spikes or spike-and-waves that were observed.This program, orientated towards pattern recognition, is suitable for the study of the background patterns as well as the pattern recognition of paroxysmal bursts.