Dystonic tics in patients with Tourette's syndrome.

Dystonic tics, in contrast to clonic tics, are relatively slow and temporarily sustained twisting, pulling, or squeezing movements producing briefly maintained abnormal postures. Because dystonic tics often present diagnostic difficulties, we studied these motor tics in 156 patients with Tourette's syndrome (TS). In addition to clonic motor and vocal/phonic tics, seen in all patients, 89 (57%) of them exhibited one or more dystonic tics. The most common dystonic tics were oculogyric deviations (43 patients), blepharospasm (23), and dystonic neck movements (11). Blinking (110) and facial twitching (86) were the most common clonic tics. Except for possibly a greater familial occurrence, a higher frequency of previous head trauma, and associated attention deficit disorder, the group of patients with dystonic tics did not significantly differ in any of the major clinical variables from those TS patients without dystonic tics. We conclude that dystonic tics are typical motor manifestations of TS and that patients with these motor tics are not different from those with more typical clonic tics.