--Disease Characteristics-- Lennox-Gastaut syndrome Slow spike and wave pattern on electroencephalogram At least 60 seizures with atypical absence and drop attacks within 1 month Seizure types allowed in addition to those above: Tonic Tonic-clonic Myoclonic Minor motor Absence of progressive lesion confirmed by computerized tomography or magnetic resonance imaging No change documented by physical exam subsequent to imaging No generalized status epilepticus within 3 months while complying with drug therapy No seizures resulting from progressive disease, e.g.: Active infection Neoplasm Metabolic disorder No anoxic episode requiring resuscitation within 1 year --Prior/Concurrent Therapy--