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

BackgroundDeep brain stimulation (DBS) targeting the subthalamic nucleus (STN) is a widely adopted therapy for alleviating motor symptoms in Parkinsons Disease (PD). While electrode placement has been proposed as a key factor influencing motor outcomes, the specific relationship between electrode location and therapeutic effects on gait performance remain unclear. This study investigates the role of electrode placement in STN-DBS for improving gait in patients with PD (PwPD). MethodsWe conducted an observational study to evaluate overground gait performance in 49 PwPD who underwent bilateral STN-DBS surgery. Gait assessments were performed both prior to treatment initiation and six months post-implantation. We analysed changes in the mean values (mean set) and coefficient of variability (variability set) of ten commonly used spatio-temporal gait parameters, including stride length and walking speed. Additionally, we explored the association between gait outcomes and the spatial location of active contacts of the DBS electrodes. ResultsOur 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 was associated with 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. ConclusionsThis study provides empirical evidence on how STN-DBS, together with the spatial location of active lead contacts, impacts both the mean and variability of spatio-temporal gait parameters in PwPD. Importantly, our results highlight specific spatial targets within the STN that may optimize DBS implantation strategies to address patient-specific gait symptoms.