Physical therapy, delivered using various treatment approaches (e.g. treadmill training, balance training), is effective in reducing postural instability and improving spatiotemporal gait characteristics among individuals with PD who do not have DBS. To our knowledge, there are no studies to date that assessed the impact of PT for those with PD who have DBS. In fact, the current standard of care following STN-DBS does not include PT. Current care post-DBS includes pharmacologic management and monitoring of DBS settings, which are optimized based on Unified Parkinson's Disease Rating Scale motor subsection (UPDRS III) scores. Despite the introduction of substantial changes to neural activity in areas of the brain governing movement with DBS, formal movement training or assessment of functional mobility and safety are not provided after surgery. As such, patients may not experience significant improvements in postural stability and gait following surgery, and may be at increased risk for falls, fall-related complications, and development of a sedentary lifestyle. Physical therapy is a personalized intervention that can be used to address specific movement impairments that remain even when patients are on optimal regimens of medication and DBS. There is an urgent need to determine if PT is effective in improving postural stability and gait performance over time following STN-DBS. If the intervention is safe and feasible, future studies could evaluate the efficacy of PT for gait and balance deficits in this population before and/or immediately post-surgery, increasing the potential impact of this research.