The Effect of Subthreshold Vibration on Lateral Reactive Balance

Abstract

Previous research has indicated that subthreshold vibratory noise improves standing balance control in a diverse range of populations (i.e., young adults, older adults, and persons with diabetic neuropathy). However, there is limited literature examining whether these effects extend to reactive balance contexts. Therefore, the primary purpose of this study was aimed at determining whether vibratory noise input changes postural responses to unexpected ML perturbations. The secondary purpose was to replicate improvements in standing balance control that have been previously reported. Twenty-five participants (10 male and 15 females) were recruited for this study. In all trials, participants stood quietly with each foot on top of a rubber pad embedded with vibrating tactors, with their eyes closed and wearing headphones. The vibrating tactors were positioned such that it would stimulate the skin of the first and fifth metatarsal heads, as well as the heel. During the surface translation trials, participants were instructed to recover their balance in response to unexpected leftward and rightward support surface translations. During the standing trials, participants were asked to stand quietly. Reactive balance control was quantified using kinematic and spatiotemporal measures of the stepping response whereas static balance control was quantified using center of pressure measures. Results indicated that there were no discernable effects of vibration in reactive or static balance control measures. These findings suggest that the application of vibratory noise to the foot sole does not affect reactive or standing balance measures in younger adults. To identify the efficacy of vibratory noise in reactive balance, replication using older and clinical populations should be examined to determine if beneficial effects are confined to individuals that display worsened balance from decreased somatosensation