Methods - A total of 17 patients with PD participated (mean age 63.4 ± 10.3 years; Hoehn-Yahr score 2.5 ± 0.9, mean Unified Parkinson's Disease Rating Scale score 49.8 ± 13.7, mean disease duration 7.7 ± 5.1 years). They performed systematic walking speed manipulations under 4 conditions in a random order: (1) no cue, no visual flow, (2) no cue, visual flow, (3) cue, no visual flow and (4) cue, visual flow. Visual flow in the form of a virtual corridor that moved at the current walking speed was projected on a 2 × 2 m rear-projection screen. The cueing rhythm was set at − 10% of preferred stride frequency at each speed. Stride frequency was assessed using peaks in the trajectories of thigh sagittal plane segmental angles.
Results - Walking with RSC resulted in lower stride frequencies, and thus larger step lengths (p-values <0.05), regardless of walking speed. The presence of visual flow did not impair the use of RSC, as evidenced by the lack of differences between conditions 3 and 4 (p > 0.05).
Conclusion - Rhythmic somatosensory cueing may be a viable alternative for auditory cueing and is robust to changes in walking speed and visual distractors.