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.