Auditory Stimuli Influence on Vestibulo-Ocular Reflex Gains.

OBJECTIVES

The extent and clinical relevance of direct auditory influences on the vestibulo-ocular reflex (VOR) remain uncertain. This study aims to characterize auditory effects on VOR gain using a video head impulse test (vHIT) protocol under controlled auditory stimulation.

DESIGN

Forty healthy adults completed standard vHIT in silence, then repeated it while 5 stimuli, 500 and 1000 Hz tone bursts, a 100 μsec click, continuous white noise, and a synthetic/da/ speech token, were presented monaurally through insert earphones at 60 dB SL (referenced to stimulus-frequency threshold for tone bursts or to pure-tone average for other stimuli) and at each participant's individualized vestibular evoked myogenic potential (VEMP) threshold (the higher of cervical VEMP or ocular VEMP thresholds). Linear mixed-effects models compared canal gains with silent baselines and examined ear-side effects.

RESULTS

Stimuli at 60 dB SL produced no VOR gain change. At VEMP threshold, tone bursts and white noise significantly reduced gain in the lateral and anterior canals, with a few small increases in the right anterior canal. Clicks had smaller effects, and speech produced only minimal change. Posterior-canal gains were essentially unchanged. Side-of-presentation effects were small and inconsistent, indicating no systematic lateralization.

CONCLUSIONS

High-intensity sound modulates human VOR gains mainly in the anterior and lateral canals, a pattern consistent with pathways served by the superior vestibular nerve, though the relative contributions of peripheral and central mechanisms remain to be determined. The auditory-vHIT protocol offers a proof-of-concept approach for probing auditory modulation of VOR responses that may, with further validation, contribute to the clinical evaluation of vestibular disorders.