Automated Parkinson's Disease (PD) Motor Symptom Assessment for Deep Brain Stimulation (DBS) Programming

Inclusion Criteria: * Hoehn and Yahr stage 2 or worse when off medications * Average tremor and/or bradykinesia Unified Disease Rating Scale (UPDRS) score greater than 2 off meds * L-dopa responsive with clearly defined "on" periods, UPDRS motor III average tremor and bradykinesia improves by 25% * Stable on medical therapy for at least one month prior to study enrollment * Clinical approval to undergo unilateral DBS surgery targeting the STN or GPi * Available to participate for six months following DBS surgery Exclusion Criteria: * "Parkinson's plus" syndromes, secondary, or atypical Parkinson's syndromes (e.g. progressive supranuclear palsy, striato-nigral degeneration, multiple system atrophy, post-stroke, post-traumatic, or post-encephalitic Parkinson's. These patients have cardinal symptoms characteristic of PD but with additional symptoms indicating other organic brain dysfunction, such as gaze palsies, autonomic dysfunction, lack of response to L-dopa, these individuals tend not to improve with standard treatments for PD) * previous Parkinson's Disease surgery * medical contraindications to surgery or stimulation (e.g. uncontrolled hypertension, advanced coronary artery disease, other implanted stimulation or electronically-controlled devices including cardiac demand pacemaker, aneurysm clips, cochlear implants, or a spinal cord stimulator) (Note: for the subject who receives either a pacemaker and/or defibrillator after this study enrollment, he/she will be allowed to continue the study if the neurostimulator system can be adequately programmed to permit system compatibility) * contraindication to magnetic resonance imaging (e.g. indwelling metal fragments or implants that might be affected by MRI) * neuropsychological dysfunction (e.g. dementia) that would contraindicate surgery * intracranial abnormalities that would contraindicate surgery (e.g. stroke, tumor, vascular abnormality affecting the target area)