Role of the Sensory Experience in Generating Motor Tics in Tourette Syndrome

Objectives: We will investigate whether the sensory experience that precedes motor tics in Tourette syndrome is generated in the peripheral nervous system and whether it may result from altered sensory gating, and whether it is necessary to generate motor tics. Study Population: We will study 100 subjects. Thirty-five individuals with a diagnosis of Tourette syndrome who can describe a sensory experience preceding their tics, and 10 who deny a sensory prodrome for a total of 45 subjects. We will also study 55 Healthy volunteers ages 18-65.. Design: A Two-Part Study Part I: MEG recording We will determine the extent to which CNS responses to tactile and auditory stimuli habituate. Subjects will be presented with trains of stimuli, repeated 80 times. At the end of each of these blocks, a questionnaire will ascertain the subject s perception of these stimuli. CNS responses to the stimuli will be recorded using MEG and analyzed first for localization, and then for amplitude and frequency characteristics. Healthy volunteers will be included as a control group. Part II: rTMS inhibition We will test whether the sensory experience is necessary for generating a motor tic. We will inhibit the sensory experience using repetitive transcranial magnetic stimulation (rTMS) over the cortical region identified by prior and ongoing imaging studies in our group. Low intensity rTMS will be applied as a control. Sensory experiences and motor tics will be recorded before and after rTMS.. Staged Study: This will be a staged, exploratory study. In phase 1, we will study 20 adult subjects for part II. Data analysis of this phase will determine whether the procedures are well-tolerated and safe enough to allow for the inclusion of adolescent children, ages 14 and older. Phase 2 will involve completion of both parts, with 20 subjects each. Outcome Measures:\<TAB\> For part II, the outcome measures will be 1) inhibition of the sensory experience, and 2) the relationship between inhibition of sensory and motor phenomena. For part I, the outcome measure will be degree of habituation in TS subjects as compared to that in healthy volunteers.