Subthalamic nucleus deep brain stimulation improves dyskinesias in Parkinson’s disease beyond levodopa reduction
Bilateral subthalamic nucleus deep brain stimulation (STN DBS) improves motor fluctuations and dyskinesias in patients with Parkinson's disease (PD). Dyskinesia improvement with STN DBS is believed to result entirely from levodopa reduction. However, some studies suggest that STN DBS may also directly suppress dyskinesias. To determine whether bilateral STN DBS improves dyskinesias beyond what would be expected from levodopa reduction alone, we analyzed pre-operative and post-operative dyskinesia scores (sum of MDS-UPDRS items 4.1 and 4.2) from 61 PD patients with bilateral STN DBS. A multiple regression model (adjusted for disease severity, disease duration, active contacts above the STN, use of amantadine, high pre-operative levodopa-equivalent dose (LED), sex, and interaction between active contacts above the STN and amantadine use) was created to describe the relationship between dyskinesia scores and LED prior to DBS. Using this model, a post-operative dyskinesia score was estimated from post-operative LED and compared to the actual post-operative dyskinesia score. The regression model was statistically significant overall (p = 0.003, R2 = 0.34, adjusted R2 = 0.24). The actual post-operative dyskinesia score (1.0 ± 1.4) was significantly lower than the score predicted by the model (3.0 ± 1.1, p < 0.0001). Dyskinesias after STN DBS improved more than predicted by levodopa reduction alone. Our data support the idea that STN stimulation may directly improve dyskinesias.
KeywordsParkinson’s disease Dyskinesias Deep brain stimulation Subthalamic nucleus
James Mossner receives research support from a TL1 training grant from the NIH (TL1TR002242). Dr. Patil has received grants from the National Institutes of Health (5R01GM111293-03, 5R01GM098578-08, 1U24NS107158-01, 1R01NS105132-01A1) and Taubman Medical Research Institute. Dr. Chou receives research support from the National Institutes of Health (NS091856-01, NS10061102, NS107158), participates as a site-PI in clinical trials sponsored by the Parkinson Study Group (STEADY-PD III, SURE-PD3, NILO-PD) receives royalties from UpTo Date and Springer Publishing and served as a consultant for Accordant, Boston Scientific and Sunovion.
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Compliance with ethical standards
It was obtained from all patients and the study was approved by the Medical Institutional Review Board of the University of Michigan.