Walking Speed Reliably Measures Clinically Significant Changes in Gait by Directional Deep Brain Stimulation

Area of Science:

• Neurology
• Biomedical Engineering

Background:

• Gait dysfunction in Parkinson's disease (PD) is a significant unmet need, often only partially addressed by levodopa.
• Deep brain stimulation (DBS) shows promise for PD gait symptoms, but its efficacy is not always systematically assessed.
• Walking speed is a potential quantitative measure for evaluating DBS effectiveness during programming.

Purpose of the Study:

• To investigate the reliability and functional impact of gait changes using directional DBS in the subthalamic nucleus.
• To assess comfortable walking speed as a measure of DBS efficacy in Parkinson's disease patients.

Main Methods:

• Nineteen Parkinson's disease patients received unilateral subthalamic nucleus DBS with directional leads.
• Comfortable walking speed was measured preoperatively and across 10 stimulation configurations during device activation.
• Statistical analyses included repeated measures ANOVA and intraclass correlation coefficients to assess reliability and significance.

Main Results:

• Mean comfortable walking speed significantly improved with DBS ON compared to DBS OFF and minimum DBS ON speeds.
• Changes in walking speed were primarily driven by modifications in step length, not cadence.
• Walking speed assessment demonstrated high reliability (Intraclass Correlation Coefficient ≥0.949) across stimulation configurations.

Conclusions:

• Acute assessment of walking speed is a reliable and clinically meaningful metric for evaluating gait function during DBS.
• Directional subthalamic DBS can acutely improve gait dysfunction in Parkinson's disease.
• Next-generation directional DBS technologies offer potential for personalized gait enhancement in PD.