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.