The purpose of this research project is to gain a better understanding of changes in brain function that occur over time in a cohort of patients who either have Tourette Syndrome (TS) or are at risk for developing TS. Specifically, we intend to study families with individuals who do and do not have TS by performing repeated measures of the functional properties of the brain using transcranial magnetic stimulation (TMS). TMS is a noninvasive, easily tolerated relatively inexpensive technology that employs a handheld magnetic coil (with the approximate field strength of a clinical MRI scanner) to activate neurons in order to study their function. As a result of the information gained from this study, we hope to determine whether TMS can be used to predict: 1) which at risk children will develop TS or Obsessive Compulsive Disorder (OCD); 2) which children are more likely to have more severe symptoms; and 3) how individuals are likely to respond to medications. In addition, we hope this investigation will help us understand the biological processes that underlie the manifestation and progression of TS symptoms. These study results should provide a framework for understanding data from ongoing genetic and environmental/epidemiological studies of TS, and thus may serve as a measure of symptom severity and treatment response. If we can identify abnormalities which reliably precede symptom onset or correlate well with symptom severity, this knowledge may be helpful for counseling families, for identifying candidates for early treatment, and for choosing classes of medications. Donald L. Gilbert, M.D., Assist. Professor of Pediatrics and Neurology, Director, Tourette’s Syndrome and Movement Disorders Clinic, Children’s Hospital Medical Center, Cincinnati, OH Award: $71,995 Tourette Association of America Inc. – Research Grant Award 2002-2003