Closed-loop auditory feedback for the improvement of gait in patients with Parkinson's disease.

OBJECTIVE: To study the effects of closed-loop auditory feedback cues, corresponding to patient self-motion, on the walking abilities of patients with Parkinson's disease, in comparison to the effects of open-loop (metronome-like) auditory cues.

METHODS: Sixteen patients on their regular medication schedule participated. A device which translates patient steps into a clicking cue sounded by earphones provides auditory feedback for gait pattern correction. Walking speed and stride length are measured. Device-on performance is compared to device-off performance and to baseline performance, and short-term residual performance following 15 min rest is compared to baseline performance.

RESULTS: Device-on performance was found to represent, on average, 10.72%±19.53% improvement in walking speed and 6.77%±6.57% improvement in stride length with respect to device-off performance, and an average improvement of 12.37%±18.37% in walking speed and 4.30%±3.64% in stride length with respect to baseline performance, with 87.5% and 81.25% of the patients improving their walking speed and stride length, respectively. Average short-term residual performance showed 9.09%±6.34% improvement in walking speed and 6.52%±4.36% improvement in stride length, compared to baseline performance, with 85.71% of the patients improving in both walking speed and stride length.

CONCLUSIONS: Closed-loop auditory feedback improves walking speed and stride length in patients with Parkinson's disease. Improvement in walking speed is more pronounced than improvement in stride length. Yet, in contrast to previously studied open-loop auditory cues, training with closed-loop auditory feedback results in non-negligible on-line improvement in stride length. Moreover, in contrast to previously reported results of open-loop auditory cuing, training with closed-loop auditory feedback has residual effects, which suggest the examination of this approach in a comprehensive therapy program.