Effects of acoustic stimuli used for vestibular evoked myogenic potential studies on the cochlear function.

OBJECTIVE: To study if acoustic stimuli used for vestibular evoked myogenic potential (VEMP) studies can damage the cochlea. STUDY DESIGN: Prospective diagnostic study. SETTING: Academic tertiary referral center. METHODS: In 30 young healthy adults aged between 20 and 35 years without any audiovestibular disorders, cVEMP studies were performed in a standard setting (tone burst, 500 Hz, 133 dB SPL, stimuli rate 200). Before and after acoustic stimulation for the cVEMP examination, the cochlear function was measured using pure tone audiometry and distortion product otoacoustic emissions (DPOAE). Additionally, the subjects were asked about ear symptoms. RESULTS: In all subjects, cVEMP could be recorded. Eight (27%) of them reported subjective hearing symptoms direct after the VEMP examination. All were again free of complaints on the next day. Hearing thresholds did not deteriorate in pure tone audiometry. DPOAE levels decreased on the exposed side in the high-frequency range (4,000-6,000 Hz). The subjects with subjective ear symptoms had a stronger level decrease. In a follow-up measurement 24 hours later, the DPOAE levels showed recovery. CONCLUSION: Acoustic stimuli used to elicit VEMP were found to have an adverse effect on the cochlear function. A clinically relevant hearing loss was not found in our study in healthy adults. Subjective auditory symptoms were reversible within 24 hours. Nevertheless, the stimulus levels and the number of repetitions should be kept as low as possible.