Left temporal rhythmic electrical activity: a correlate for psychosis? A case report

Summary.

It is well recognized that epileptic patients are at higher risk for acute or chronic psychotic states than non-epileptic subjects. Here we present intracranial depth electrode recordings during a psychotic episode in a 20-year-old woman who was referred for presurgical evaluation. Unrelated to her seizures, she presented acoustic hallucinations and delusions and became agitated for a duration of 18–24 hours. During this period, a new unusual pattern of sharp slow waves was seen semi-rhythmically every 2–3sec from left anterior neocortical temporal areas. Her condition responded well to a treatment with Haloperidol, but not with Benzodiazepines. Ictal and interictal scalp- and depth-EEG recordings outside the psychotic episode as well as MRI-based volumetry, PET, SPECT and neuropsychological testing gave evidence of bilateral temporal and frontal dysfunction. This case report suggests that psychosis in epileptic patients may be based on a bilateral cerebral dysfunction linked together in a pathological network, but with a focal (here: left temporal) driving mechanism.