An increase in the number of mechanistic studies targeting the association between sound and balance has been observed in recent years, but their results appear equivocal.
A search of PubMed and the Cochrane Database of Systematic Reviews for English-language studies on auditory input and postural control published from database inception through October 31, 2019, yielded 28 articles for review. These articles included 18 (64%) studies of healthy adults, 1 (4%) of participants with Alzheimer disease, 2 (7%) of participants with congenital blindness, 3 (11%) of participants with vestibular loss, and 4 (14%) of participants with diverse levels of hearing loss. Studies varied by the type of audio stimuli (natural vs generated sounds), apparatus (speakers vs headphones), and movement of sounds (eg, stationary, rotational). Most balance measurements involved standing on the floor or foam with eyes open or closed during which sway amount or velocity was quantified. Stationary broadband sounds, including white or environmental noise, may improve balance, but the results regarding stationary pure tone were inconclusive. The implication of moving sounds varied by apparatus (typically destabilizing when headphones were used) and sensory loss (more destabilizing with vestibular or hearing loss but perhaps less with a unilateral cochlear implant).
Findings from this review suggest that stationary broadband noise can serve as an auditory anchor for balance primarily when projected via speakers and when the balance task is challenging. More research is needed that includes individuals with sensory loss and that tests paradigms using dynamic, ecologically valid sounds; clinicians should also consider auditory cues and the presence of hearing loss in balance and fall-risk assessments.