Vestibular Evoked Myogenic Potential Generated by 500 Hz Tone Burst in Unilateral Peripheral Vestibulopathy

ABSTRACT

BACKGROUND AND OBJECTIVES:Vestibular evoked myogenic potential (VEMP) has become a valuable diagnostic tool evaluating the integrity of sacculocollic reflex and has been done using click sound in most previous clinical trials. This study aims to investigate VEMP responses generated by 500 Hz tone burst in unilateral peripheral vestibulopathy and compare the response with caloric test and subjective visual vertical (SVV). MATERIALS AND METHOD:Clinical records of 37 patients (18 men and 19 women, aged 14-80 years) with unilateral peripheral vestibulopathy were reviewed. Diagnoses were Meniere's disease (n=13), vestibular schwannoma (n=4) and acute peripheral unilateral vestibulopathy (n=20). They underwent 500Hz tone burst VEMP, caloric test and SVV test. Thirteen healthy volunteers (26 ears, 8 men and 5 women, 25~41 years) with normal hearing were enrolled as control group. RESULTS:VEMP response was present in every control ear using 500 Hz tone burst stimuli. In Meniere's disease, VEMPs were positive in 57% (4/7) of patients with abnormal caloric response group and 83% (5/6) with normal caloric response. In acute peripheral vestibulopathy, VEMPs were positive in 47% (9/19) of patients with abnormal caloric response, 0% (0/1) with normal caloric response. The average of CP (canal paresis) in positive VEMP group was 62.4% and that in negative VEMP group was 48.2% (P>0.05). CONCLUSION:Reliable and reproducible test results can be obtained using 500 Hz tone burst stimuli. VEMP results were not in concordance with other vestibular tests, which reflects the dynamic process of dizziness and variable extent of pathology in each case.