Influence of a rhythmic auditory stimulation on asymptomatic gait

The direct effects of a rhythmic auditory stimulation (RAS) on the gait of asymptomatic subjects are not clear. Previous studies only showed modifications in the gastrocnemius activity, inconsistent effects on temporal parameters, and no modification of spatial parameters. Furthermore, the influence of RAS on kinematics and kinetics has only been reported in pathological gait. The objective of this study was to perform a full comparison of gait characteristics in asymptomatic subjects at preferred and reduced walking speed between without and with RAS conditions. Spatiotemporal parameters, kinematics, kinetics and EMG signals datasets were collected for each condition. RAS conditions were obtained by asking subjects to walk on metronomic beats. 17 asymptomatic subjects were included in the study (12M/5W, 37.4±15.7years, 74.0±14.8kg, 1.77±0.09m). Comparisons between without and with RAS conditions were then performed using the Statistical Parametric Mapping method. For all combined subjects, the effect of RAS was limited whatever the walking speed. Meanwhile, global effects were observed for kinematics, kinetics and EMG at both spontaneous and reduced walking speed, which can only be explained by covariances (i.e., no effect on individual time-series). The use of RAS to impose a specific cadence matching the desired walking speed (e.g., to collect normative data) appears thus possible, as none parameters were modified individually. However, RAS should be used with caution taking into account covariances (i.e., muscle synergy or joint coordination patterns). This study has to be extended to a larger number of subjects to confirm these observations.