Deep Brain Stimulation Effective Long Term in Improving Motor Function in Parkinson Disease

Deep brain stimulation (DBS) of the subthalmic nucleus (STN) and globus pallidus (GPi) provided significant short-term and long-term improvement in motor function for people with Parkinson disease (PD), with DBS of the STN shown to be slightly more effective, according to an abstract presented at the American Academy of Neurology’s 73rd Annual Meeting being held virtually April 17-22, 2021.

In prior research, DBS has been associated with a myriad of benefits for patients with PD, ranging from improvements in social, occupational, and psychosocial function to decreasing risk of disease progression. However, it has been cited to lose efficacy over time.

Examining the 2 main types of DBS studied in PD, surgery within the STN and GPi, the researchers of the present study sought to examine the long-term outcomes of both approaches for patients with the condition.

“There are no published studies from prospective randomized trials examining outcomes beyond 3 years comparing STN to GPi DBS,” said the study authors.

They derived patient data from the CSP468 VA/NINDS multicenter randomized controlled trial, which included a subset of patients originally randomized to GPi or STN DBS. Participants were followed up to 10 years, with completed visits conducted 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).

Baseline characteristics were cited as comparable, with participants of the STN-DBS and GPi-DBS groups assessed for the primary outcome of change in Unified Parkinson’s Disease Rating Scale (UPDRS) motor subscale in the OFF medication/ON stimulation state.

Compared with baseline, at which the score was 43.2, motor function was significantly improved and maintained at each completed visit for both the GPi-DBS group (2 years, 25.8; P < .001; 7 years, 35.4; P < .001; 10 years, 34.0; P = .10) and STN-DBS group (2 years, 27.7, P < .001; 7 years, 34.4; P < .001; 10 years, 28.3; P < .001), respectively.

Furthermore, the authors noted that improvements were generally similar between both groups over time, but with a trend favoring STN-DBS (P = .09).

Based on subscales of motor symptoms, tremor showed the greatest reduction over time followed by rigidity, with bradykinesia subscores also showing greater improvement at 7 and 10 years with STN-DBS (P = .03).

UPDRS I,  II, and IV scores and quality of time based on motor diaries exhibited significant long-term improvement regardless of group.

Conversely, Parkinson's Disease Questionnaire-39 total score no longer showed improvement at 7 or 10 years for either group. Both groups had significant medication reduction with no target difference over time (P = 0.70).

Speaking on the study findings, the researchers called it “remarkable” considering the progressive nature of PD. “This is the longest follow up describing DBS outcomes comparing the 2 targets in a randomized cohort,” they concluded.

Reference

Ostrem J, Weaver F, Follett K, et al. 10 year clinical outcomes of subthalamic nucleus versus pallidal deep brain stimulation for Parkinson’s disease: VA/NINDS CSP #468F. Presented at: The American Academy of Neurology’s 73rd Annual Meeting; April 17-22, 2020.