 This study will use transcranial magnetic stimulation TMS and electrical stimulation of nerves to examine how the brain controls muscle movement in focal hand dystonia writers cramp. Normally, when a person moves a finger, the brains motor cortex prevents the other fingers from moving involuntarily. Patients with focal hand dystonia have difficulty with individualized finger movements, possibly due to increased excitability of the motor cortex. Musicians, writers, typists, athletes and others whose work involves frequent repetitive movements may develop focal dystonia of the hand. 