Spectral analysis of EEG in the late course of primary generalized myoclonic-astatic epilepsy. II. Cluster analysis of the power spectra.

Cluster analysis is applied to power spectra of the EEG of 38 patients with a primary generalized myoclonic astatic epilepsy (Gundel et al. 1981). The tendency of the data to form clusters within this group is indicated by a random experiment which has been performed with the data. The clustering algorithm divided the material in seven distinct groups which may be combined to three main types of power spectra. These types are power spectra with a 10 cps peak, a 4-7 cps peak and power spectra without remarkable rhythmization. The comparison of EEG types and clinical data shows a correlation of 4-7 cps rhythms with the occurrence of seizures. 4-7 cps rhythms are interpreted as a symptom of "centrencephalic" convulsibility.