Dystonia is a class of movement disorders characterized by sustained muscle contractions that produce abnormal postures, twisting movements, and other abnormal involuntary movements. For some moderately to severely affected patients, surgical treatment with deep brain stimulation (DBS) can reduce symptoms and improve function. However, the exact reason this surgery improves dystonia is not known.

This research study is being undertaken in the hope that it will determine which part(s) of abnormal brain circuits can be treated with DBS. This may be important for future diagnosis and treatment of this disorder.