Follow Up Study for Treatment of Parkinson's Disease With Deep Brain Stimulation

Parkinson's disease (PD), the second most prevalent neurodegenerative disease (after
Alzheimer's disease), affects more than a million Americans and is a common condition in the
Veteran population. Although there is currently no cure for the disease, many of the
symptoms of the disease can be effectively managed with medications and with deep brain
stimulation (DBS). This study seeks to build upon the original CSP#468 protocol by
providing an efficient long-term follow-up study. The objectives of this study are to:

determine whether the motor benefits of deep brain stimulation persist beyond two years of
follow-up in patients with Parkinson's disease; determine whether the target of stimulation
(GPi vs. STN) affects the durability of long-term motor improvement; define the impact of
DBS on long-term function and quality of life in patients with Parkinson's disease; identify
clinical features that predict favorable or unfavorable long-term outcome; and describe the
long-term performance of the DBS devices, including device durability, device explanation
rate, neurostimulator replacement frequency, and changes in stimulation parameters to
achieve optimum symptom control.

Inclusion Criteria:

- Participant in CSP#468

- Available and willing to be followed-up according to study protocol

Exclusion Criteria:

- DBS device explanted or permanently turned off without anticipated resumption of DBS
therapy.