The effect of different types of mastoid vibration on vertical ground reaction force during walking in vision-available and vision-deprived environments.

Abstract

Mastoid vibration (MV) is a non-invasive way to induce vestibular illusions. However, the influence of MV on gait kinetics during different visual conditions has not been well-established. The purpose of this study was to examine the influence of different types of MV (bilateral vs unilateral) on vertical ground reaction force (vGRF) during walking under both vision-available (VA) and vision-deprived (VD) conditions. Twenty healthy adults walked at their preferred speed on a pressure-sensor treadmill and vGRF characteristics (peak forces, impulses, loading/unloading rates, and variability) were recorded under VA and VD conditions, with and without MV. Vision deprivation increased magnitude and variability of most vGRF variables, suggesting more cautious gait. Bilateral MV (but not unilateral MV) significantly increased the components of vGRF and their variabilities in push-off phase, likely as part of a consistent "press forward" motor response to the vestibular illusion. These results show that MV systematically modulates kinetics, particularly when applied bilaterally and with no visual input. This interaction between vestibular and visual afferents in these young adults may lay a foundation and should be considered in the clinical assessment of gait patterns (GRF profiles) in the future, particularly when using pressure sensor embedded treadmills.