The cardinal motor features of Parkinson's disease (PD) include bradykinesia, rest tremor, and rigidity. Though non-motor features have been recognized for centuries, only recently has the prevalence and impact of non-motor symptoms become the focus of intense study. Disturbances of sleep are among the most common non-motor manifestations of PD; approximately two-thirds of PD patients experience sleep dysfunction of some kind. Given that sleep contributes to the regulation of many physiological processes, sleep disturbance has a significant impact on quality of life in PD, and places high strain on caregivers. Though numerous symptomatic therapies exist, the treatment of sleep disorders in PD is limited by a lack of adequately powered, randomized studies providing high quality evidence. Although deep brain stimulation (DBS) is primarily used to treat PD motor symptoms and reduce the need for dopaminergic medications, several studies have shown that DBS provides benefit for non-motor symptoms, including sleep disturbance. Few studies have used an objective measure to assess the impact of DBS on sleep in PD, and none have done so by studying sleep in the home environment. Existing studies have largely been limited to a single night of sleep recording in a sleep lab. Furthermore, no studies have assessed sleep both on and off medication, before and after DBS implantation. This study will enroll patients undergoing evaluation for DBS implantation. Sleep will be assessed before DBS implantation, both while patients continue their usual medication regimen and while withholding medications. After DBS implantation and programming, sleep will again be assessed with stimulation on, both while continuing medications and subsequently while withholding medications.