Event-related potential (P300) in epilepsy.

The P300 component of auditory event-related potential was studied in 39 patients with temporal lobe epilepsy (TLE), 26 with idiopathic generalized epilepsy (IGE) and 28 controls. The age-corrected P300 latencies were significantly longer in TLE patients compared with those in IGE patients and controls. Neither the duration of epilepsy nor clinical manifestation was related to the P300 component in the same epileptic syndrome. The age-corrected P300 latencies recorded from Cz were significantly prolonged in TLE patients with bilateral temporal EEG foci compared with those with unilateral focus. The effects of anti-epileptic drugs on the P300 component were not significant. Our findings imply that prolonged P300 latency in TLE patients, especially in those with bilateral EEG foci is due to damage of the hippocampus, which is potentially an epileptogenic focus.