Optimal stimulation sites of the subthalamic nucleus for the treatment of gait symptoms of Parkinson’s disease

Abstract

AbstractDeep brain stimulation (DBS) targeting the subthalamic nucleus (STN) is a widely adopted therapy for mitigating motor symptoms in Parkinson’s Disease (PD). Although the electrode placement site has been proposed as a significant factor influencing motor outcomes, the specific relationships between electrode location and therapeutic effects on gait performance remain unclear. This study seeks to identify optimal stimulation sites within the STN to effectively address gait symptoms in patients with PD (PwPD). We assessed overground gait performance in 49 PwPD who underwent bilateral STN-DBS surgery, both before treatment initiation and six months post-implantation, comparing the results to 51 asymptomatic individuals. Our evaluation focused on treatment-induced changes in the mean (mean set) and coefficient of variability (variability set) of ten commonly used spatio-temporal gait parameters, such as stride length and walking speed. We also examined their correlation with the location of the active contacts of the DBS electrodes utilized for therapeutic stimulation. Our findings indicate that DBS treatment resulted in a significant reduction in stride time, stance time, swing time, and step time, in addition to an increase in the variability of double limb stance time, stride time, stance time, and step time. Furthermore, we observed that the location of the active contacts resulted in alterations in mean step length, stride length, and walking speed, as well as changes to cadence, stride time, stance time, and step width. We identified the postero-superior region of the STN as the most effective region for improving the mean set, whereas the antero-superior region of the STN emerged as the most effective region for improving the variability set. This study provides empirical evidence on how STN-DBS, in tandem with the location of active lead contacts, impacts both mean and variability of spatio-temporal gait parameters in PwPD. Importantly, our results indicate specific STN spatial targets for DBS implantation to address patient specific gait symptoms.