Psychomotor epilepsy and psychosis. II. Electroencephalographic findings (sphenoidal electrode recordings).

The EEG findings in waking, sleep, and sphenoidal electrode recordings in 96 patients with partial epileptic seizures with complex symptoms, who, after a median interval of 18 years developed paranoid/hallucinatory psychosis, were compared with the findings from a group of patients without psychosis, who had had the same type of epilepsy in median 24 years. There were no significant differences between the two groups with regard to median age at onset of epilepsy or complex partial seizures, age, or duration of epilepsy at time of examination. The psychotic patients had a significant preponderance of temporal medio-basal spike foci, recorded on the sphenoidal electrode, indicating deep temporal lobe dysfunction as an important factor in the pathogenesis of psychosis. A significant higher frequency of bilateral and multiple spike foci, together with a significant frequency of slow-wave admixture to the waking background EEG activity, indicated more extensive and severe epileptogenic lesions in the psychotic patients. There was no correlation between psychosis and unilateral EEG-foci in either temporal lobe.