Ocular vestibular evoked myogenic potentials in response to air-conducted sound and bone-conducted vibration in vestibular schwannoma.

OBJECTIVE: To clarify the origin and pathways of ocular vestibular evoked myogenic potentials (oVEMPs) to air-conducted sound (ACS), we compared the results of oVEMPs with ACS, with oVEMPs with bone-conducted vibration (BCV), cervical VEMPs (cVEMPs) with ACS, and the caloric test in patients with unilateral vestibular schwannoma (VS). STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. PATIENTS: Forty-five patients with untreated unilateral VS. MAIN OUTCOME MEASURE: Each patient underwent vestibular tests, including oVEMPs to ACS, oVEMPs to BCV, cVEMPs to ACS, and caloric tests. The correlations among these tests were evaluated. RESULTS: Of the 45 patients recruited, 28 patients (63%) showed reduced or absent oVEMPs to ACS solely on the affected side. There were no significant differences in abnormal response ratios among oVEMPs to ACS, oVEMPs to BCV, cVEMPs to ACS, or the caloric test. The results of oVEMPs to ACS had a significant correlation with those of oVEMPs to BCV and the caloric test (p 0.05). CONCLUSION: These findings support the hypothesis that oVEMP in response to ACS are predominantly mediated by the superior vestibular nerve and probably reflect the function of the utricle.