Subthalamic nucleus deep brain stimulation in early stage Parkinson's disease

Abstract

Background: Deep brain stimulation (DBS) is an effective and approved therapy for advanced Parkinson's disease (PD), and a recent study suggests efficacy in mid-stage disease. This manuscript reports the results of a pilot trial investigating preliminary safety and tolerability of DBS in early PD.

Methods: Thirty subjects with idiopathic PD (Hoehn & Yahr Stage II off medication), age 50-75, on medication ≥6 months but ≤4 years, and without motor fluctuations or dyskinesias were randomized to optimal drug therapy (ODT) (n = 15) or DBS + ODT (n = 15). Co-primary endpoints were the time to reach a 4-point worsening from baseline in the UPDRS-III off therapy and the change in levodopa equivalent daily dose from baseline to 24 months.

Results: As hypothesized, the mean UPDRS total and part III scores were not significantly different on or off therapy at 24 months. Medication requirements in the DBS + ODT group were lower at all time points with a maximal difference at 18 months. With a few exceptions, differences in neuropsychological functioning were not significant. Two subjects in the DBS + ODT group suffered serious adverse events; remaining adverse events were mild or transient.

Conclusions: This study demonstrates that subjects with early stage PD will enroll in and complete trials testing invasive therapies and provides preliminary evidence that DBS is well tolerated in early PD. The results of this trial provide the data necessary to design a large, phase III, double-blind, multicenter trial investigating the safety and efficacy of DBS in early PD.

Keywords: Deep brain stimulation; Parkinson's disease; Subthalamic nucleus.

Figure 1. Study design

Study design indicating study visit duration and frequency. The baseline visit and all visits thereafter included 7 day medication washouts. Adapted from Charles et al., 2012 [13].

Figure 2. Kaplan-Meier Curve

Kaplan-Meier Curve comparing DBS+ODT group (solid line) to ODT group (dashed line). An event was defined as a four point worsening of the UPDRS-III score in the off medication state.