Deep Brain Stimulation (DBS) for Early Stage Parkinson's Disease (PD)

Inclusion Criteria: Patients must have a clinical diagnosis of probable idiopathic PD. Demonstrated response to dopaminergic therapy, defined as demonstrating at least 30% improvement in parkinsonian motor signs, based upon the UPDRS motor examination subscore, following the administration of their dopamine agonist (DA) drug(s) during the screening neurological examination. Hoehn and Yahr (H&Y) stage II when OFF medication. No contraindications to surgery. Age between 50 and 75 years old. Available for follow-up for four years. Informed Consent: The subject understands the risks, benefits, and alternatives to the study procedures and participation in the study. MRI within normal range for age. Levodopa or dopamine agonist therapy for greater than six months but less than or equal to four years. Exclusion Criteria: Evidence of an alternative diagnosis or secondary parkinsonism, as suggested by features unusual early in the clinical course: Prominent postural instability, freezing phenomena, or hallucinations unrelated to medications in the first 3 years after symptom onset; dementia preceding motor symptoms; supranuclear gaze palsy (other than restriction of upward gaze) or slowing of vertical saccades in the first year; severe, symptomatic dysautonomia unrelated to medications; documentation of a condition known to produce parkinsonism and plausibly connected to the subject's symptoms (such as suitably located focal brain lesions or neuroleptic use within the past 6 months) Uncontrolled medical condition or clinically significant medical disease that would increase the risk of developing pre- or postoperative complications (e.g., significant cardiac or pulmonary disease, uncontrolled hypertension). Evidence of dementia Major psychiatric disorder Previous brain operation or injury. Active participation in another clinical trial for the treatment of PD. Patients who have demand cardiac pacemakers or implantable cardioverter defibrillators (ICD's). Patients who have medical conditions that require repeat MRI scans or diathermy treatments. Evidence of existing dyskinesias or motor fluctuations.