The Effect Of Vibratory Noise Input On Postural Responses To An Unexpected Loss Of Balance

Abstract

Vibratory noise input applied to the foot sole has been shown to improve static balance control across various populations (i.e., younger adults, older adults, individuals with diabetic neuropathy etc.). However, there is little research on whether vibratory noise improves reactive balance control. This is concerning because falls typically occur when an individual is unable to quickly recover from a loss to their balance. Therefore, the purpose of this thesis was to examine whether vibratory noise input affects postural responses following an unexpected surface translation. A secondary aim was to examine the effects of vibration on static balance performance to replicate previous findings. Eighteen adults (10 females and 8 males) completed six quiet standing trials and 28 surface translation trials. For all trials, participants stood barefoot, while blindfolded and wearing headphones. Three vibrating elements were placed directly underneath each foot (i.e., one each at the first metatarsal, fifth metatarsal and at the heel). For each standing trial, participants were instructed to stand quietly. For each surface translation trial, participants were instructed to recover their balance without stepping in response to a unexpected surface translation. Participants were unaware of which trials did or did not have vibration applied to the foot soles. Static and reactive balance control were quantified using various kinematic, kinetic and electromyography (EMG) measures, while the ability to recover balance was quantified through the measurement of EMG and body kinematics. Results indicated that vibratory noise input did not influence most measures of static and reactive balance control. This suggests that the application of vibratory noise input to the foot soles is not beneficial in younger adults. Future studies should replicate this study with clinical populations to determine whether the benefits of vibratory noise input are limited to individuals with worsened balance ability.