Spatial Cues Provided by Sound Improve Postural Stabilization: Evidence of a Spatial Auditory Map?

Abstract

It has long been suggested that sound plays a role in the postural control process. Few studies however have explored sound and posture interactions. The present paper focuses on the specific impact of audition on posture, seeking to determine the attributes of sound that may be useful for postural purposes. We investigated the postural sway of young, healthy blindfolded subjects in two experiments involving different static auditory environments. In the first experiment, we compared effect on sway in a simple environment built from three static sound sources in two different rooms: a normal vs. an anechoic room. In the second experiment, the same auditory environment was enriched in various ways, including the ambisonics synthesis of a immersive environment, and subjects stood on two different surfaces: a foam vs. a normal surface. The results of both experiments suggest that the spatial cues provided by sound can be used to improve postural stability. The richer the auditory environment, the better this stabilization. We interpret these results by invoking the “spatial hearing map” theory: listeners build their own mental representation of their surrounding environment, which provides them with spatial landmarks that help them to better stabilize.

The contribution of cochlear implants to postural stability

“…The data presented here add to our growing understanding that spatial audition can give a measurable balance improvement in people with normal and impaired hearing . A group of 14 older, experienced bilateral hearing aid users were shown to remain stable for a longer period of time standing on a solid surface or on foam while wearing their hearing aids compared to without .…”

“…24 The data presented here add to our growing understanding that spatial audition can give a measurable balance improvement in people with normal and impaired hearing. [12][13][14] A group of 14 older, experienced bilateral hearing aid users were shown to remain stable for a longer period of time standing on a solid surface or on foam while wearing their hearing aids compared to without. 14 A more recent study, again investigating a population wearing hearing aids, used variability of the center of pressure as a main outcome measure and reported similar results.…”

“…9 Recent evidence has emerged showing that external auditory sources such as speaker arrays can contribute to maintaining balance, possibly by serving as fixed environmental reference points. [10][11][12][13] Notably, this effect has been seen in hearing aid users, whose postural control becomes worse when they are not wearing their hearing aids, reducing their access to environmental sounds. 14,15 The effect of auditory inputs provided by cochlear implants on postural stability has not yet been examined to a similar extent.…”

Surgical treatment of otosclerosis leading to changes in postural control and quality of life

“…Such results confirm previous experiences showing an increased positive effect of sound stimulation, especially when other sensory inputs, such as vision, are neglected. 34,39 To this end, it is worth noting that some authors have demonstrated an increase, or even the reappearance, of VEMPS signal in operated ears after stapedotomy. 40,41 Hypotheses involving saccular overstimulation, due to proximity to the stapes prosthesis, have been proposed, whereas other studies involving VEMPS found contrasting evidence.…”

“…From a physiological standpoint, it could be speculated that the restoration of efficient sound transmission may partially influence postural function, possibly providing subjects with additional information about the surrounding environment to better control body movements; sound may act as a spatial landmark helping integrating other sensory inputs, thus improving overall balance control. 33,34 In this light, it has been proposed that a sound-induced vestibular activation would evoke a vestibulo-postural reflex, influencing balance; 35,36 indeed, previous works highlighted various effects of sound on posture from increased oscillation on the mediolateral (x) plane 35 to reduced sway in the same axis 37 and beneficial effects on anteroposterior (y) oscillations. 38 In our study population, a reduction in postural sway was found in both x and y planes with eyes open as well as closed (Fig.…”