STN vs. GPi deep brain stimulation for tremor suppression in Parkinson’s disease: A systematic review and meta-analysis

Congratulations to Drs. Joshua WongJamesKwo Wei David HoMatthew BroderickAdolfo Ramirez ZamoraLeonardo AlmeidaAparna Wagle-ShuklaChristina Wilson and Michael Okun on the publication of “STN vs. GPi deep brain stimulation for tremor suppression in Parkinson’s disease: A systematic review and meta-analysis” in the April supplement of Neurology..


Objective: To compare subthalamic nucleus (STN) deep brain stimulation (DBS) with globus pallidus interna (GPi) DBS for tremor suppression in Parkinson’s disease (PD).

Background: DBS is an effective surgical therapy that has been shown to provide significant benefit for motor symptoms in PD. Currently, two main structures targeted to treat motor complications in PD are the GPi and STN. Although some groups traditionally favor STN over GPi for tremor suppression, evidence demonstrating superiority in long term tremor control is limited.

Design/Methods: For this systematic review and meta-analysis, we searched MEDLINE for all randomized trials comparing STN vs GPi DBS in PD that were published before March 2017. We excluded studies with fewer than 10 patients in each study arm. Five studies were examined in a random effects model meta-analysis. We then conducted moderator variable analysis on the stimulation target to determine if there was a treatment effect difference for STN versus GPi.

Results: We compared DBS ON versus OFF and found a significant overall standardized difference mean effect: Effect Size = 0.36; 95% CI = 0.316 – 0.395; P < 0.0001. These findings indicate that DBS reduced tremor symptoms in PD patients with a medium effect size. Moderator variable analysis of STN vs GPI revealed two significant standardized effect sizes: (a) 23 STN comparisons: effect size = 0.38; 95% CI = 0.314 – 0.385; P < 0.0001 and (b) 23 GPi comparisons: effect size = 0.35; 95% CI = 0.30 – 0.40; P < 0.0001. A Z-test showed that effect sizes between the STN and GPi comparisons were not significantly different (P = 0.56).

Conclusions: DBS is effective in reducing tremor in PD patients regardless of stimulation target. There was no significant difference in the degree of tremor suppression in STN DBS versus GPi DBS.