To assess long-term effectiveness of unilateral deep brain stimulation (DBS) in Parkinson’s disease (PD) patients with up to one year of follow-up.

DBS is an established therapy for improving motor symptoms in select PD patients. Despite the common approach of simultaneous bilateral DBS implantation, there is value in a unilateral approach, with benefit up to 5 years. Considering the asymmetric phenomenology in PD, unilateral DBS may be a preferable initial option for select patients.

We analyzed 180 patients (121 GPi / 59 STN) with unilateral DBS. The mean (SD) Unified Parkinson’s Disease Rating Scale part III motor scores (UPDRS-III) were: 35.7 (11.7) preoperatively, 25 (10.7) at 3-6 months postoperatively, and 26 (12) at 10-14 months postoperatively. The mean UPDRS-III at 3-6 and 10-14 months were significantly different from baseline (p = 0.000). A total of 66 patients with bilateral leads were selected for further comparison. Their mean (SD) UPDRS-III scores were: 37 (12) preoperatively, 24 (9) at 3-6 months postoperatively, and 27.3 (10.5) at 10-14 months postoperatively. The mean UPDRS-III at 3-6 and 10-14 months post-implantation were also significantly different from baseline. There was no significant difference in the percent improvement of UPDRS-III between unilateral and bilateral DBS at 3-6 and 10-14 months postoperatively (p= 0.208 and 0.762 respectively).

Patients with unilateral DBS show significant improvement in motor symptoms at 3-6 and 10-14 months postoperatively. The degree of improvement is not significantly different from patients who underwent bilateral DBS.