Deep Brain Stimulation (DBS) Frequency Effects on Gait in Parkinson's Disease(PD)

Effect of Frequency Change in Bilateral Subthalamic Nucleus (STN)-DBS on Gait Function in PD

In this study the investigators will evaluate the effect of both low and high frequency Deep Brain stimulation of the subthalamic nucleus (STN) in Parkinson's patients who have noted a change in their walking. The investigators' hypothesis is:

1. Stimulation at 60 Hertz (Hz) is associated with improved gait with increased stride length and faster time on the Stand walk sit test.
2. There is no worsening of the Unified Parkinson's Disease Rating Scale (UPDRS) at 60 Hz.

Inclusion Criteria:

• Be a patient at the Vanderbilt Movement Disorders clinic.
• Report a change in their gait.
• Be able to walk independently when off PD medications for 12-16 hours.
• Have a stable dose of PD medications for the prior three months .
• Not cognitively impaired, so as to give informed consent.
• MMSE > 24.

Exclusion Criteria:

• See inclusion criteria.