Paroxysmal dyskinesia on waking: two case reports.

Until recently, paroxysmal hypnogenic dyskinesia was thought to be a rare movement disorder characterized by intermittent dystonia and/or choreoathetoid movements that occur during non-rapid eye movement sleep, with consciousness preserved once the patient is awakened during the episodes. Recent investigations have revealed that most, but not all, paroxysmal hypnogenic dyskinesia cases are actually frontal lobe epilepsy. Here, we present two cases with paroxysmal choreoathetoid movements on waking during non-rapid eye movement sleep. Although they did not respond to antiepileptic drugs, they did respond to antidopaminergic drugs. This supports the opinion that non-epileptic paroxysmal hypnogenic dyskinesia does exist.