Paroxysmal myoclonic dystonia with vocalisations: new entity or variant of preexisting syndromes?

From among 1377 patients with movement disorders, four patients had an unusual movement disorder characterised by paroxysmal bursts of involuntary, regular, repetitive, rhythmic, bilateral, coordinated, simultaneous, stereotypic myoclonus and vocalisations, often associated with tonic symptoms, interference with voluntary functioning, presence of hyperactivity, attention and learning disabilities, and resistance to treatment with haloperidol and other drugs. This symptom complex may represent a new disease entity, referred to here as paroxysmal myoclonic dystonia with vocalisations or a variant or combination of other movement disorders such as Gilles de la Tourette, myoclonic, or dystonic syndromes.