The clinical syndrome of primary tic disorder associated with dystonia: a large clinical series and a review of the literature

Background: The co-occurrence of tics and dystonia as an idiopathic condition has only rarely been reported. We report a series of patients with tics and persistent dystonia, with the aim of determining the prevalence and clinical characteristics of this syndrome.

Methods: Analysis of clinical database of patients with tic disorders.

Results: From our database of 224 patients with tics, 20 had co-occurrence of tics and dystonia as a primary disorder. Six patients had Tourette's syndrome, and 2 had idiopathic chronic motor/phonic tics. Twelve of the 20 had adult onset of tics (9 with motor/phonic tics and 3 with motor tics). Dystonia was focal in 12 patients (cervical most common) and segmental in 8. A sensory geste was present in 8. Mean age of tic onset and dystonia was 28.3 ± 19.7 and 40.5 ± 15.3 years, respectively. Tics preceded dystonia in 12, dystonia preceded tics in 4, and 1 patient had simultaneous onset of tics and dystonia. In 3 patients, symptoms' sequence could not be determined. Only 8 patients required treatment for their tics. Botulinum toxin was the mainstay of dystonia treatment (16 patients), whereas 6 received trihexyphenidyl. Six patients each had depression and obsessive compulsive symptoms, and 5 had attention-deficit and hyperactivity disorder.

Discussion: We have further characterized the syndrome of a primary condition of tics associated with persistent focal/segmental dystonia. Apart from the presence of dystonia, our data suggest that these patients are differentiated from pure tic disorders by a later age of onset, lesser severity of tics, and lower frequency of associated features.