Parental generalized EEG alpha activity predisposes to spike wave discharges in offspring.

Familial and twin studies have shown that the individual variability of the normal human electroencephalogram (EEG) is largely genetically determined. In epileptology, these genetic parameters of the EEG background activity are almost totally neglected. The aim of the present study has been to investigate whether a special genetic type of background activity might be related to the pathogenesis of epilepsy. EEG recordings of parents of 257 epileptic children were evaluated retrospectively. Some 156 healthy adults served as controls. Special attention was paid to alpha activity extending to the frontal region, both in bipolar and in referential recordings (Alpha I). Alpha I was found significantly more often in parents of children with primary generalized epilepsy (18%) compared with parents of children with focal epilepsy (8%) or controls (9%). In a second step, parental EEGs of children with different EEG patterns associated with epilepsy were studied. Alpha I was found significantly more often in parents of children with focal sharp waves and generalized spikes and waves (26%) than in parents of probands with focal sharp waves without additional generalized spikes and waves (8%) or in controls (9%). Parents of probands with theta rhythms and spikes and waves had alpha I significantly more often (18%) than parents of probands with theta rhythms without additional spikes and waves (8%) or controls (9%). The findings reveal a clear correlation between the type of EEG background activity in parents and the EEG characteristics in their children, thus pointing to common mechanisms.