Some Clinical and EEG Aspects of Benign Juvenile Myoclonic Epilepsy

Abstract

Patients (12) with benign juvenile myoclonic epilepsy (BJME) representing 4% of the population of epileptics (n = 275) are presented. Only 2 patients (17%) had myoclonic jerks as the only seizure type. Seven (58%) had generalized tonic-clonic seizures (GTCS) and myoclonus. Three patients (25%) had absence seizures (AS), GTCS, and myoclonic jerks. EEG evidence of photosensitivity was found in 4 (33%). Auditory precipitation of seizures was found in 1 patient. As is the case with other primary generalized epilepsies, the onset of BJME seems to be age specific. In this series the mean age of onset in yr was 4.3 for AS, 14.75 for myoclonic jerks and 16.4 for GTCS. It took an average of 8.5 yr from the onset of BJME (range, 2-20 yr) and 6.5 yr from the onset of GTCS (range, 2 mo.-6 yr) until the condition was properly recognized. Patients (5) experienced at least 1 episode of myoclonic status epilepticus. Generalized, paroxysmal symmetric polyspike and slow wave discharges are the typical EEG finding. These complexes showed considerable interpatient variability. Sleep deprivation proved to be the most valuable activating procedure. Valproic acid monotherapy effectively controlled myoclonic jerks as well as associated GTCS in most patients.