[Event-related potential (P300) in two epileptic cases with continuous spike-waves during slow wave sleep].

We studied the P300 of two epileptic cases with almost continuous diffuse spike-wave discharges on sleep EEG: one with epilepsy with continuous spike-waves during slow wave sleep, and another with atypical benign partial epilepsy. These cases showed a marked prolongation of P300 latencies during nonconvulsive status epilepticus with continuous spike-waves during slow wave sleep. As they improved clinically and electroencephalographically, the latencies became normal. These findings indicate that P300 is a useful method to elucidate the pathophysiology of nonconvulsive status epilepticus with continuous spike-waves during slow wave sleep.