Joint Contributions of Auditory, Proprioceptive and Visual Cues on Human Balance.

One's ability to maintain their center of mass within their base of support (i.e., balance) is believed to be the result of multisensory integration. Much of the research in this literature has focused on integration of visual, vestibular, and proprioceptive cues. However, several recent studies have found evidence that auditory cues can impact balance control metrics. In the present study, we sought to better characterize the impact of auditory cues on narrow stance balance task performance with different combinations of visual stimuli (virtual and real world) and support surfaces (firm and compliant). In line with past results, we found that reducing the reliability of proprioceptive cues and visual cues yielded consistent increases in center-of-pressure (CoP) sway metrics, indicating more imbalance. Masking ambient auditory cues with broadband noise led to less consistent findings; however, when effects were observed they were substantially smaller for auditory cues than for proprioceptive and visual cues - and in the opposite direction (i.e., masking ambient auditory cues with broadband noise reduced sway in some situations). Additionally, trials that used virtual and real-world visual stimuli did not differ unless participants were standing on a surface that disrupted proprioceptive cues; disruption of proprioception led to increased CoP sway metrics in the virtual visual condition. This is the first manuscript to report the effect size of different perturbations in this context, and the first to study the impact of acoustically complex environments on balance in comparison to visual and proprioceptive contributions. Future research is needed to better characterize the impact of different acoustic environments on balance.