[Mental deterioration in childhood epilepsy. II. Investigation of intelligence of right-handed epileptic children with right-hemispheric dominance of language].

To clarify the pathogenesis of mental deterioration in epilepsy, we investigated the intelligence of right-handed epileptic children with right hemispheric dominance of language. On dichotic listening test, all 13 patients with right-handedness, 7 to 20 years of age, showed a left ear dominance suggesting right hemispheric dominance of language. Among 13 patients, 9 showed mental retardation, and 6 patients of them showed mental deterioration during the clinical course of epilepsy. Eight patients showed findings suggesting brain damage in the left hemisphere either in clinical feature, EEG or CT. A relationship was suspected between the right-hemispheric dominance of language and the epileptic focus in the left hemisphere. The usefulness of dichotic listening test was suggested both in disclosure of the brain damage and the investigation of mental retardation in childhood epilepsy.