Sixty hertz STN-DBS and L-Dopa reduces gait variability in parkinson's disease.

Abstract

Objective: We investigated the effects of Subthalamic Deep Brain Stimulation (STN-DBS) at high (180hz) and low frequency (60hz) and L-dopa on variability of spatiotemporal gait measures in an advanced PD cohort.

Materials and methods: This study consisted of PD subjects with chronic bilateral STN-DBS. Each combination of medication state (OFF/ON) and stimulation frequency (60 Hz/180Hz) were assessed and randomized across electrode contacts. Instrumented stand and walk tests were performed for each stimulation-medication condition and coefficient of variance (CV) was computed for each lower limb gait parameter. LM-ANOVA was employed for analysis.

Results: Twenty-two PD subjects with chronic DBS were recruited with an average age of 63.9(SD 9) years. L-dopa reduced variability in both spatial and temporal gait parameters: cadence (L/R, p < 0.0001), gait speed (L/R, p < 0.0001), toe off angle (L/R, p < 0.0001), SLS (L, p = 0.0002; R, p = 0.001), stance (L, p = 0.01, R, p < 0.0001;), step duration (L, p < 0.0001; R, p = 0.004), stride length (L/R, p < 0.0001), and foot swing (L, p = 0.0003; R, p < 0.0001). Low and high frequency DBS reduced variability in cadence, foot elevation midswing, speed, right foot strike angle, SLS, stand, step duration, stride length, and foot swing. 60 Hz STN-DBS synergistically reduced left foot mid-swing elevation variability (p = 0.02) when combined with medication.

Conclusion: This study demonstrates significant reduction in variability of spatial and temporal gait measures from L-dopa and STN-DBS. It further reveals a synergistic effect of 60Hz STN-DBS with L-dopa in reducing foot elevation midswing variability.