Juvenile myoclonic epilepsy: a clinical and sleep EEG study.

Juvenile myoclonic epilepsy (JME) is characterized by myoclonic jerks on awakening, generalized tonic--clonic seizures (GTCS) and is associated with absence seizures in more than one third of cases. Fifteen patients with juvenile myoclonic epilepsy were studied with regard to their clinical profile, EEG data and sleep EEG findings. There was a delay in the diagnosis of JME (mean of 3.5 years) due to various reasons. Sleep deprivation was the most common precipitating factor for triggering seizures, followed by fatigue. Routine EEGs were abnormal in 73.33% of cases only and had misleading findings in 6.66%. Sleep EEGs were abnormal in 100% of cases with generalized spikes, polyspikes and slow wave discharges. Discharge rates on sleep EEGs typically increased significantly during the transition phase (i.e. the asleep to awakening stage) and we consider this to be a specific finding in appropriate clinical setting. Sleep EEGs are a more sensitive and specific tool for the diagnosis of JME while routine awake EEGs may miss or mislead.