To report extended long-term outcomes of DBS of the GPi and STN for patients with Parkinson disease (PD) in the landmark CSP468 VA/NINDS multicenter randomized controlled trial.

There are no published studies from prospective randomized trials examining outcomes beyond 3 years comparing STN to GPi DBS.  Here we present outcomes after DBS (out to 10 years in some patients).

A subset of patients originally randomized to GPi or STN DBS were followed up to 10 years with visits completed at 2 years (GPi n=85; STN n=70), 7 years (GPi n=68; STN n=49), and 10 years (GPi n=49; STN n=28). The primary outcome was change in UPDRS motor subscale in the off medication/on stimulation state between targets and included multiple secondary outcomes.

Baseline characteristics were comparable. Improvement in motor function compared to baseline was maintained at 2, 7, and 10 years for GPi(43.2 to 25.8, p less than 0.001; 35.4, p less than 0.001; and 34.0, p=0.10) and STN(43.2 to 27.7, p less than 0.001; 34.4 p less than 0.001, and 28.3 p less than 0.001), respectively. Improvements were generally similar between targets over time, but with a trend favoring STN(p = 0.09). The tremor subscales showed the greatest reduction overtime followed by rigidity subscores.  Bradykinesia subscores showed greater improvement at 7 and 10 years with STN DBS(p=0.03). UPDRS I,  II, and IV scores and quality of time based on motor diaries also showed significant long-term improvement regardless of target. PDQ39 total score no longer showed improvement at 7 or 10 years (either target). Lastly, both targets had significant medication reduction with no target difference over time (p=0.70).

DBS therapy had a significant and stable effect on motor function regardless of target over 10 years. This is remarkable, given that PD is a progressive neurodegenerative disease. This is the longest follow up describing DBS outcomes comparing the two targets in a randomized cohort.