Walking to the beat: the impact of non-invasive brain stimulation and music on gait in Parkinson's disease.

INTRODUCTION: Walking impairments in Parkinson's disease (PD), including reduced speed, cadence, and stride length, along with increased variability, impair mobility and raise fall risk. Conventional treatments may fail to address these deficits, underscoring the need for complementary non-invasive alternatives. METHODS: This study examined whether combining rhythmic auditory cueing with transcranial direct current stimulation (tDCS) over the supplementary motor area (SMA), a critical region for internally generated movement, would enhance gait performance in PD. Thirty-three participants with PD and thirty-two healthy controls completed two sessions (anodal vs. sham tDCS) with gait assessed during stimulation, immediately after stimulation, and 15 min after stimulation under two auditory conditions: walking in silence and walking to music paced 10% faster than baseline cadence. Spatiotemporal, variability, and stability gait parameters were analyzed using linear mixed-effects models. RESULTS: Rhythmic auditory cueing with music significantly increased cadence and speed during, immediately after, and especially 15 min after stimulation. Anodal tDCS produced faster cadence, as well as lower stride time variability and stride width, particularly in individuals with PD. Both music and anodal tDCS affected gait, with no interaction detected between them. Individuals with PD had greater gait variability overall and adjusted temporal gait parameters less to music than healthy controls did. Anodal stimulation reduced walking variability in PD, reducing the group differences observed under sham conditions. CONCLUSION: The findings suggest that rhythmic cueing and SMA stimulation target complementary mechanisms, highlighting the promise of combined tDCS-music interventions for gait rehabilitation in PD.