Effects of visual and auditory cues on gait initiation in people with Parkinson's disease

Objective: To evaluate the effects of auditory and visual cues on gait initiation in people with Parkinson's disease. Subjects: Fourteen subjects with Parkinson's disease were recruited from community support groups, seven of whom reported having experienced freezing when walking. Design and setting: This study was a repeated measures analysis of gait initiation performance during a single visit to a university-based motion laboratory. Following baseline trials, auditory and visual cue conditions were presented in random order. The auditory cues were rhythmic sounds with an interval matching the subject's average step time. The visual cues were high-contrast transverse lines on the floor adjusted for the subject's first step length and overall height. Main measures: Kinematic recordings enabled calculation of the timing and length of steps as well as overall velocity. The timing and magnitude of weight shift and push-off force were obtained from a force platform. Results: The magnitudes of first and second step lengths, of push-off force and of overall gait velocity were significantly greater in the visual cue condition than in the baseline condition, whereas there was no significant effect of auditory cue on these measures. Neither cue had any significant effect on the timing of key events in gait initiation. Conclusions: Transverse line visual cues enable people with Parkinson's disease to begin walking with longer steps, greater push-off force and higher velocity. Auditory cues that others have shown to improve aspects of gait in people with Parkinson's disease do not appear to have any systematic effect on the first two steps of gait initiation.