Experimental assessment of gait with rhythmic auditory perturbations

To understand the impact of implicit auditory perturbations during gait, we used a pacing task that involves the proper timing and synchrony between heel strike and metronome beats. Five individuals performed two different types of tasks presented in the following order: 1) walk on a treadmill while listening to a steady metronome (non-perturbed condition), and 2) walk on a treadmill while listening to the metronome with rhythmic auditory alteration (perturbed condition). We examined the quality of synchronization between heel strike and the metronome beat, the non-synchronous period following perturbation, and the synchronization period. The subjects followed tightly the metronome beats even for changes of less than 10 msec. In addition, we recorded the electromyographic (EMG) activity of selected muscles of the leg and we found the same pattern for the onset and offset of EMG activity. These results indicate an entrainment between the gait cadence and the metronome rhythm in healthy adults and support new therapies to stimulate changes in rhythm and symmetry.