The safety and efficacy of the two approaches to DBS surgery have been equivalent, and we are at a position of equipoise with regard to what to offer to patients. To date, there have been no randomized, controlled clinical trials comparing the efficacy and functional outcomes of the two DBS methods. After informed consent is obtained, the patients will undergo routine DBS pre-operative evaluation and diagnostic testing. This includes a pre-operative 3T-MRI with and without gadolinium as well as pre-operative medical clearance by the patient's PCP or general practitioner and/or other medical specialist if necessary. They will also receive a baseline clinical evaluation including both motor function (Unified Parkinson's Disease Rating Scale on and off antiparkinsonian medication) and quality of life (Parkinson's disease Questionnaire-39) if not already completed as part of the routine DBS candidacy evaluation within 2 months of surgery. Patients who elect to participate in this trial will undergo a routine pre-operative neurocognitive evaluation consisting of the following routine evaluative tests: Wechsler Test of Adult Reading, Mattis Dementia Rating Scale 2nd Edition, Wechsler Abbreviate Scale of Intelligence 2nd Edition; Wechsler Memory Scale 3rd edition, Digit Span, Stroop Neuropsychological Screening Test, Trail Making Test, Wisconsin Card Sorting Test, Controlled Oral Word Association Test, Animal Naming, Boston Naming Test, Wechsler Memory Scale 4th Edition, Logical Memory, Hopkins Verbal Learning Test - Revised, Brief Visuospatial Memory Test - Revised, Hooper visual Organization Test, Judgment of Line Orientation, Beck Depression Inventory, Beck Anxiety Inventory, Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease, Apathy Evaluation Scale; Epworth Sleepiness Scale, The subjects will then be randomized to 2 groups by using random numbers in an envelope system. We anticipate that 120 total patients will need to be enrolled in this pilot study (60 awake, 60 asleep), and thus the numbers 1-120 will be placed in envelopes. An odd number will correspond to the awake DBS procedure, and an even number will indicate an asleep DBS procedure.