Hypersensitivity in Tourette Syndrome

OBJECTIVE: This study will explore sensory phenomena associated with Tourette syndrome (TS). The first part will evaluate threshold levels versus perceived intensity of tactile and olfactory stimuli in areas reported to be hypersensitive in TS patients. The second part will use electromyography (EMG) to seek correlation between muscle activity and the perceived intensity of "urge" in focal areas of premonitory sensations. STUDY POPULATION: Twenty-six patients and 22 control subjects will be studied. Subjects can be of any race, gender, handedness, or age from 18 to 65 years. DESIGN: To determine olfactory and tactile threshold, n-butanol and Von Frey hairs will be presented in forced-choice modified method of limits paradigms. Perceived intensity will be examined using a generalized labeled magnitude scale (gLMS), whose word values are placed on a ruler for numerical reporting. Randomly arranged series of 7 stimuli for olfaction and touch will be presented in 4 sets, and subjects will report a number on the gLMS that corresponds to the intensity of each sensation. Both threshold and intensity will be measured in the peroneal nerve territory in all subjects, and at one other variable place, which will be matched 1:1 between patients and controls. The variable spot will consist of a patient's sensory tic site. Next, EMG activity will be measured from up to 8 muscles in the area of a sensory tic. Patients will report when a sensory tic is occurring, and will be asked to resist the motor tic for at least 12 seconds from that point. Total EMG activity will be measured in muscles surrounding the sensation at 1, 4, and 7 seconds before and after the tic. OUTCOME MEASURES: Outcome measures include the sensory threshold values for olfaction and touch and the reported intensity values. The outcome measures of the EMG study include the power of total EMG activity at time points before and after a tic.