Preoperative Levodopa Response and Deep Brain Stimulation Effects on Motor Outcomes in Parkinson's Disease: A Systematic Review.

Background: The up‐to‐date literature systematically reviewing the predictive value of preoperative levodopa responsiveness after deep brain stimulation (DBS) surgery in motor outcomes in Parkinson's disease (PD) is lacking. Objective: To address this issue in patients with PD undergoing bilateral subthalamic nucleus (STN) or globus pallidus interna (GPi) DBS. Methods: We used the existing PRISMA consensus statement. A comprehensive review of literature from 1993 to May 2021 retrieved from PubMed was conducted. Results: The STN‐DBS responsiveness was significantly correlated with the preoperative levodopa responsiveness for the total score of UPDRS‐III at both 6‐ and 12‐month follow‐ups (P < 0.001). Such correlations were significant after controlling for age at time of surgery and disease duration. The significance of correlation disappeared for longer follow‐up times. For the sub‐scores of UPDRS‐III, a significant correlation between the preoperative levodopa responsiveness and STN DBS responsiveness was observed for rigidity, bradykinesia, and axial symptoms, but not for tremor (P = 0.002, 0.010, 0.007, and 0.542, respectively). The preoperative levodopa responsiveness was significantly correlated with GPi DBS responsiveness for the UPDRS‐III total score at a median follow‐up of 12 months (P = 0.030). Conclusion: The current study confirmed the value of preoperative levodopa responsiveness for prediction of the short‐term motor outcome after DBS (for both STN and GPi). The predictive value of levodopa responsiveness in short‐term outcomes for respective cardinal motor disabilities and the loss of its predictive value after STN DBS for long‐term motor outcomes were highlighted by this study. [ABSTRACT FROM AUTHOR]