Premonitory sensory phenomenon in Tourette's syndrome.

We administered a questionnaire designed to probe for premonitory sensations associated with motor tics to 50 patients with Tourette's syndrome (TS). Premonitory sensations were reported by 46 (92%) patients, and the most common sensation was an urge to move and an impulse to tic ("had to do it"). Intensification of premonitory sensations, if prevented from performing a motor tic, was reported also in 37 patients (74%), 36 patients (72%) reported relief of premonitory sensations after performing the tic, and 27 of 40 (68%) described a motor tic as a voluntary motor response to an involuntary sensation, rather than a completely involuntary movement. The "just right" sensation correlated with the presence of co-morbid obsessive-compulsive disorder. We conclude that premonitory sensations are an important aspect of motor tics and some patients perceive motor tics as a voluntary movement in response to an involuntary sensation.