The effects of the everyday environment on epileptic activity in three mentally retarded individuals.

Three mentally retarded epileptic subjects with frequent epileptiform EEG paroxysms were monitored with simultaneous radio-telemetered EEG and video recording while they were exposed to their everyday environmental conditions. These conditions included prompts and reinforcement for performing vocational training tasks, speech therapy, eating and drinking, and cues for resting, waiting, playing, exercising, and relaxing. Epileptiform EEG activity and the occurrence of clinical seizures varied as a function of the particular environmental conditions. Epileptiform EEG discharges were longer in duration, and clinical seizures were more frequent in all 3 subjects during conditions which produced inactive behavior than during conditions which produced active behavior. The modulation of epileptiform activity by everyday environmental conditions carries implications for (1) the optimum structuring of the environment for mentally retarded patients with frequent, subtle seizures, and (2) the analysis of the effects of epileptiform discharges on behavior.