Transient seizure remission in intractable localization-related epilepsy.

We sought to elucidate the clinical features of transient seizure remission in intractable cryptogenic or symptomatic localization-related epilepsy of childhood onset. Transient seizure remission has been reported to occur in mesial temporal sclerosis or focal cortical dysplasia, but few reports have focused on this phenomenon. We retrospectively scrutinized the temporal profiles of seizure frequency of 99 patients with intractable localization-related epilepsy by reviewing their medical charts. Ten patients (10%) had transient seizure remissions that lasted for 2 years or longer. When an appropriate antiepileptic agent was administered, seizure remission occurred within 1-18 months. Without any triggering factors, the seizures recurred abruptly in seven patients and gradually in three. Epileptiform discharges on electroencephalography disappeared during the transient remission in seven patients and reappeared in five of them after recurrence. After recurrence, no antiepileptic agent was able to control the seizures. In comparison with those without transient seizure remission, these 10 patients tended to have normal intelligence and a positive family history for epilepsy. Transient seizure remission occurs in a variety of pathologic changes and may be a result of an interaction between the progressive nature of some types of epileptogenic foci and an effect of the antiepileptic drugs.