Inclusion  Clinical indications to proceed with DBS implantation, as determined by the clinical multidisciplinary movement disorders board, including: a) definitive diagnosis of essential tremor or dystonia, b) medically refractory disease, c) adequate performance on neuropsychological evaluation as determined by a licensed clinical neuropsychologist. The ability to comply with test directions, complete pre-operative task training, and provide informed consent. Age 18-80 years.  Exclusion  1. Inability to understand or perform the task outlined in the protocol during a pre-surgery training session. 2. Significant hearing loss.  3. Cortical venous anatomy that could potentially obstruct ECoG electrode placement, as determined by the surgeon, visualized on pre-op MRI or during surgery.