Nocturnal paroxysmal dystonia.

Sleep-related seizures characterised by choreoathetoid, dystonic and ballic movements occurred in 12 patients, repeatedly each night and over a period of years. The nocturnal attacks were short-lasting, responded well to carbamazepine and were sometimes associated with clearly or possibly epileptic seizures during night- or daytime. They resembled the paroxysmal kinesigenic dystonias of wakefulness. Similar dystonic-dyskinetic attacks, but of long duration and unresponsive to medication, were also observed in two other patients, in one 20 years before the onset of clinically apparent Huntington's chorea. Nocturnal paroxysmal dystonia represents a syndrome of sleep-related motor attacks which comprises two variants, respectively characterised by short and long-lasting seizures. Its precise nosological definition still awaits elucidation.