Transcranial Magnetic Stimulation (TMS) for Individuals With Tourette's Syndrome

This study tests the efficacy of repetitive Transcranial Magnetic Stimulation (rTMS) in the treatment of Tourette's Syndrome (TS). It also examines measures of brain function to study the brain basis underlying TS. Despite major advances in the study and treatment of TS, patients often do not experience full remission from pharmacotherapy or behavioral therapy (Leckman 2002). rTMS is a non-invasive procedure that stimulates the brain using magnetic fields. This pilot study reported that rTMS may reduce TS symptoms (Mantovani et al., 2006). While promising, prior research has several limitations (e.g., relatively small sample sizes, and lack of sham \[placebo\] comparison). This study addresses the drawbacks of prior work, and will provide data that will help to determine whether rTMS can be useful for TS patients resistant to conventional therapies. 25 outpatients with TS who have been only partially responsive to conventional therapies will be randomly assigned to either active low frequency (1 Hz) rTMS or sham (placebo) stimulation. The active or sham stimulation will be applied to the supplementary motor area (SMA) daily for three weeks. If rTMS will be added onto ongoing pharmacotherapy, the doses must have been stable for four weeks prior to study entry. The SMA was selected because of its connections with brain areas implicated in TS. Pilot work indicates that stimulation of SMA with low frequency rTMS is beneficial in TS patients. Low frequency rTMS has the added benefit of a better safety profile (i.e. no risk of seizure) than high frequency rTMS. Rating scales for symptom change will be obtained at baseline, during the rTMS course, and at the end of three weeks of treatment. Patients will then be offered an open-label cross-over phase for an additional three weeks of daily active rTMS treatment. Patients who meet remission criteria in either phase or response criteria following the cross-over phase will continue routine clinical care under the supervision of their treating psychiatrist and will be invited back for assessment at 1, 3, and 6 months to determine the persistence of benefit. Excitability of the motor cortex has been reported to be abnormal in TS, and may relate to dysfunction in motor pathways. We will collect measures of motor cortex excitability (with single and paired-pulse TMS) at baseline and after each phase to study whether changes in these measures may be correlated with clinical improvement.