Hearing provides cues for the maintenance of balance
Reviewed by Victor Osei-Lah

It is well known that balance relies on the integration of vestibular, visual and proprioceptive cues. However not much mention or attention has been given to the importance of auditory cues for balance maintenance. The authors set up experiments to test ‘the influence of hearing on balance by systematically manipulating the amount of spatial auditory, visual and proprioceptive cues available to human subjects and measuring their ability to maintain an upright stance’. They recruited 18 subjects with a wide age range (9 years to 78 years), 12 of whom had no balance problems. The rest had balance symptoms from unilateral peripheral vestibular deficit (n=2), Pendred syndrome (n=1), meningitis (n=1), gentamicin vestibulotoxicity (n=1) and BPPV with balance disturbance between episodes (n=1). All subjects had hearing threshold averages better than 30dB (0.5-2kHz) and when necessary hearing aids were issued. Standing on a stable or unstable balance platform, the degree of sway was computed for each subject in the light, in the dark (blindfolded) with and without auditory cues from five speakers located around the subjects. The most unfavourable scenario was sway in the sound off, light off situation. The authors found that external sound stimuli provided significant improvement in postural stability by demonstrating that the auditory cues combined with other cues provided useful information about body orientation. ‘The benefit each subject received from sound inputs was inversely related to the degree of imbalance without sound and was minimal when visual cues were also present’. In summary, the sense of sway decreased significantly from 7.0cm/sec in silence to 4.7cm/sec with the addition of external sound. Furthermore, the addition of sound led to the reduction of sway by 41%. ‘The amount of improvement due to sound was 54 percent of the amount of improvement observed in postural sway when visual cues only were provided to subjects standing in silence.’ This is a reminder that when dealing with patients with multisensory imbalance and falls, aural rehabilitation for hearing loss should not be ignored. It is no accident that the auditory and vestibular systems are co-located.

Auditory contributions to maintaining balance.
Stevens MN, Barbour DL, Gronski MP, Hullar TE.
JOURNAL OF VESTIBULAR RESEARCH
2016;26(5-6):433-8.