Augmentation of ocular vestibular-evoked myogenic potentials via bone-conducted vibration stimuli in Ménière disease.

OBJECTIVE: The asymmetry ratio of ocular vestibular-evoked myogenic potential (oVEMP) >40% is interpreted as augmented or reduced response depending on whether the nI-pI amplitude of the lesion ear is larger or smaller than that of the opposite ear, respectively. This study compared unilateral Ménière disease patients with augmented oVEMPs vs reduced oVEMPs to elucidate the mechanism of augmented oVEMP.

STUDY DESIGN: Case series with chart review.

SETTING: University hospital.

METHODS: Forty patients with unilateral definite Ménière disease were enrolled in this study, including 20 patients with augmented oVEMPs and another 20 patients with reduced oVEMPs in the hydropic side. All patients underwent audiometry, caloric test, and oVEMP and cervical VEMP (cVEMP) tests via bone-conducted vibration stimuli. Then, the oVEMP and cVEMP test results were compared with the stage of Ménière disease, respectively.

RESULTS: The augmented group had earlier nI and pI latencies and larger nI-pI amplitude of oVEMPs compared with the reduced group. Caloric test also revealed a significant difference in abnormal responses between the augmented and reduced groups. However, both groups did not differ significantly in the abnormal percentage of cVEMP test results. A significant trend to decline in the prevalence of augmented oVEMPs was noted from stages I to III-IV but not in that of abnormal cVEMPs.

CONCLUSION: The augmented oVEMPs have earlier latencies and larger amplitudes compared with the reduced oVEMPs, indicating that a relatively larger population of intact utricular afferents is activated during the early stage of Ménière disease.