Video Head Impulse Test Results in Patients With a Vestibular Schwannoma-Sensitivity and Correlation With Other Vestibular System Function Tests, Hearing Acuity, and Tumor Size

Objective:No previous studies have investigated a vestibular function test battery combining the Video Head Impulse Test (VHIT), the caloric test, and the cervical vestibular evoked myogenic potential (cVEMP) test. The objective was to investigate the sensitivity of the three vestibular tests to the presence of a vestibular schwannomas (VS), and possible correlations between test results, hearing acuity, and tumor size.Study Design:Retrospective cohort study.Setting:University hospital.Patients:Fifty-nine patients with a unilateral VS.Intervention:Audio-vestibular tests; the VHIT, cVEMP, caloric irrigation, pure-tone audiometry, and speech discrimination.Main Outcome Measure:Findings, sensitivity, and correlations between VHIT saccades and gain; cVEMP potentials, unilateral caloric weakness; hearing acuity.Results:The sensitivity for VS was 80% for the VHIT, 93% for the caloric test, and 73% for the cVEMP test. VHIT gain and saccades were associated, and both had a positive correlation to caloric function. Medium-sized tumors demonstrated the highest gain asymmetry while larger tumors were associated with saccades. There was a weak correlation between vestibular findings and hearing acuity.Conclusion:The VHIT is sensitive to the occurrence of a VS, but less so than the caloric test, and vestibular function deteriorates to some extent with increasing tumor size. VHIT outcomes are positively correlated to caloric function, but only vaguely to cVEMP and hearing acuity. The combined vestibular function test battery reached a sensitivity of 97% to the occurrence of a VS and could thus potentially substitute MRI for tumor screening upon the diagnosis of an asymmetrical hearing loss.