Influence of Gait Speed on Spatiotemporal Parameters in Advanced Parkinson’s Disease Following Subthalamic Nucleus Deep Brain Stimulation

BACKGROUND: Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor and non-motor symptoms. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a recognized treatment for advanced PD, yet its impact on gait parameters remains variable. The aim of this prospective study was to evaluate changes in spatiotemporal gait parameters following DBS-STN in patients with advanced PD. METHODS: Thirty patients with advanced PD underwent bilateral DBS-STN. Gait assessments were performed preoperatively and three months postoperatively using a pressure-sensitive treadmill under three walking speed conditions (slow, optimal and fast). Spatiotemporal gait parameters (as walking speed, double-stance phase, cadence, step length, stance phase duration) and derived values, such as asymmetry of both step length and stance phase, were analyzed with respect to the clinically better and worse limbs defined in accordance with Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS). RESULTS: No significant changes in walking speed, cadence, or double stance phase duration comparing gait characteristics pre- and postoperatively were found. Significant improvements were found in step length for the clinically worse limb at slow and optimal walking speeds and in stance phase duration for the clinically better limb at fast walking speed. Additionally, asymmetry in both step length and stance phase duration decreased at the fast walking speed after stimulation. For all other parameters evaluated in other walking speeds, the differences were not statistically significant. CONCLUSIONS: DBS-STN combined with medication had limited overall effects on spatiotemporal gait parameters in patients with advanced PD. However, when the clinically worse and better lower limbs were analyzed separately, selective improvements in step length and stance phase duration, along with reduced gait asymmetry at higher walking speeds were observed. These findings suggest that DBS may modulate specific components of gait control rather than global gait performance, highlighting the importance of individualized assessment in postoperative gait evaluation.