[Symptoms and clinical course of epilepsy with myoclonic absences]

There is no comprehensive study so far in Japan on epilepsy with myoclonic absences (EMA), characterized by myoclonic absences (MA) as a specific seizure type. We retrospectively studied 9 patients (4 males and 5 females) with EMA confirmed by ictal video EEG and polygraph (EEG+EMG) recordings. The age at MA onset ranged from 18 to 92 months and the age at the last follow-up ranged from 3 to 39 years. The patients had IQ of 40 to 79. Eight patients had been free from seizures for more than one year at the last follow up. MA was controlled by valproate sodium monotherapy or combination of valproate sodium and ethosuximide with appropriate plasma levels. Generalized tonic clonic seizures and severe mental retardation were not necessarily associated with poor seizure outcome. Patients with long MA duration or MA status epilepticus were prone to be refractory to medication. EMA can be divided into two subgroups based on the seizure outcome, favorable and unfavorable. Further large-scale study is required.