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.