ABSTRACT
A 13-year-old boy patient had severe mental retardation and spastic quadriplegia due to fetal distress and hypoxic-ischemic brain damage in the perinatal period. He suffered from West syndrome at the age of 7 months, and subsequently was diagnosed as having symptomatic localization-related epilepsy. His intractable epileptic seizures were not controlled by combination of various antiepileptic drugs. After prescribing nitrazepam and zonisamide for more than 1 year, we added clobazam (CLB), which has been marketed in Japan since 2000, to this combination therapy. After the introduction of CLB, tonic seizures disappeared. However, gelastic seizures laughing with a stiff face and a wry mouth appeared frequently before falling asleep, and sleep disturbance worsened subsequently. It has not been reported previously that gelastic seizures are a side effect of CLB, although irritability and sleep disturbance have been described.