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.