Deep Brain Stimulation (DBS) Data Base Study

Deep Brain Stimulation (DBS) surgery is a treatment that can improve some of the motor symptoms associated with several movement disorder diseases. DBS is recommended for patients with Parkinson's disease who respond well to medication, but still experience frequent wearing off of medications with return of symptoms. Patients may also be experiencing troubling medication side effects such as dyskinesias, sleepiness, hallucinations, confusion, and behavioral/personality changes. DBS is also used for patients with Essential tremor who have undergone long trials of medication therapy and are still symptomatic. The goal of DBS surgery is to capture that best response to medication and hold it through the day. The Food and Drug Administration (FDA) approved DBS as a treatment for essential tremor in 1997 and for Parkinson's disease in 2002. The goal of DBS surgery is to improve the quality of life of patients and their families by reducing motor symptoms such as slowness, stiffness and tremor and possibly reducing medication. In order to help with our understanding of its effects, we will collect information on patients who will be undergoing or have undergone DBS surgery. St. Joseph's Hospital and Medical Center / Barrow Neurological Institute is one of only a few hospitals in the United States offering a new procedure known as asleep DBS surgery, performed under general anesthesia, as well as the traditional awake DBS procedure; therefore it is important that this new asleep surgery option be studied and compared to awake DBS surgery. Objectives include: * Comparison of data collected for both the awake and asleep DBS procedures during the pre-operative and post-operative periods including testing, diagnosis, surgical treatment, target accuracy, complications, motor function and quality of life outcomes. * Comparison of the differential effects of STN and GPi DBS on gait and balance control * Investigate the effects of DBS on the saccadic eye movements.