Bone-conducted vestibular evoked myogenic potentials in patients with congenital atresia of the external auditory canal

Abstract

Objective: The purpose of this study was to determine whether vestibular evoked myogenic potentials from the sternocleidomastoid muscle in response to bone-conducted clicks and short tone-bursts can be used to assess vestibular apparatus function in patients with conductive hearing problems, particularly bilateral external auditory canal atresia. Design: Evoked-potential responses to bone-conducted auditory stimuli were recorded from the sternocleidomastoid muscle of 15 patients (11 male and four female, aged 4–20 years) with congenital bilateral atresia of the external auditory canal, with or without the middle ear anomalies. Setting: This study was conducted in the outpatient clinic of the Tokyo University Hospital, Department of Otolaryngology, University of Tokyo. Intervention: Diagnostic. Outcome measures: Bone-conducted vestibular evoked myogenic potentials in response to clicks and short tone-bursts were recorded with surface electrodes over both sternocleidomastoids in each patient. Results: In all patients, bone-conducted clicks and short tone-bursts evoked larger biphasic responses from the sternocleidomastoid ipsilateral to the stimulated ear. Short tone-bursts evoked vestibular evoked myogenic potentials with higher amplitude and better waveform morphology than clicks at the same subjective intensity. Conclusion: Loud auditory stimuli delivered by bone conduction can evoke myogenic potentials from the sternocleidomastoid. This method is a noninvasive, rapid, and convenient test for investigating the vestibular system function in patients with bilateral external auditory canal atresia, with or without the middle ear anomalies.