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

Theta rhythms in the EEG: a genetic trait in childhood epilepsy

Rhythmic theta activity maximally expressed in the parietobasal leads is a characteristic interictal EEG pattern in infants and children with primarily generalized "corticoreticular" seizures, including febrile convulsions. It is a strictly age-dependent electroencephalographic expression of a widespread genetic disposition to convulsions. If it coincides with photosensitivity, it leads to a considerable risk of spikes and waves. As epidemiological and family studies have shown, it is most likely polygenically determined and genetically independent of both photosensitivity and focal sharp waves. In epileptic patients the persisting expression of parietal theta rhythms beyond childhood bears prognostic significance. As one among many factors the "theta trait" is of importance in the "multifactorial" pathogenesis of epilepsy.

Interdependence of different genetic EEG patterns in siblings of epileptic patients

The present study is based on the data of a more extensive investigation of the genetics of spike-wave epilepsies of childhood with minor seizures (Doose and Baier 1987). It evaluated EEG findings in 271 siblings of patients by means of log-linear methods. The risk of siblings to manifest spikes and waves during rest or hyperventilation is distinctly increased if they are positive for 4-7 Hz rhythms, and to a lesser degree, if they are photosensitive. Moreover, siblings of female patients seem to be at a higher risk of manifest spikes and waves than siblings of males. 4-7 Hz rhythms of the EEG background activity and photosensitivity are mutually independent symptoms of an increased liability to manifest spikes and waves. These findings are discussed in the context of a 'multifactorial' background of spikes and waves.