Deep Brain Stimulation (DBS) of the Pedunculopontine Nucleus (PPN)

This is a prospective, single-center randomized controlled trial designed to estimate the potential clinical benefit, and associated risks, of deep brain stimulation of the of the PPN and STN in patients with PD that are candidates for DBS for improvement of their motor symptoms and exhibit gait instability with falls. Patients will be enrolled and implanted with additional bilateral electrodes in the PPN. Each subject will be randomized 1:1 to one of the following sequences: Bilateral STN+PPN stimulation or Bilateral STN stimulation alone. The addition of a bilateral STN stimulation only group allows for the research of potential micro-lesioning effects of the PPN which might affect features of interest even in the absence of PPN stimulation.