Significance of Vestibular Evoked Myogenic Potentials in Peripheral Vestibulopathy

Kim, Hyun Young; Park, Kee Hyung; Kim, Hee Tae; Kim, Seung Hyun; Kim, Juhan; Kim, Myung Ho; Sung, Ki Bum

Abstract

BACKGROUND: Loud monaural clicks evoke myogenic potentials in the tonically contracting ipsilateral sternocleido-mastoid muscle. Clinical studies have suggested that these myogenic potentials are of vestibular origin, especially inferior vestibular nerve. Neurophysiological experimental studies also suggest that they are most likely to be of saccular origin. These potentials are called vestibular evoked myogenic potentials (VEMPs). Vestibular neuritis (VN) affects only part of the vestibular nerve trunk, usually the superior division (horizontal canal paresis) which may be detected by caloric test. But inferior vestibular nerve involvement in VN may not be detected by caloric test. So we compared the results of caloric test and VEMPs in patients with VN, in order to evaluate inferior vestibular nerve function.
METHODS
Twenty-one normal controls were selected to determine the normal data of VEMPs. Patients group was consisted of clinically suspected peripheral vertigo [vestibular neuritis 10, benign paroxysmal positional vertigo of the posterior semicircular canal (PSC-BPPV) 7, Meniere's disease 3]. Caloric test and VEMPs were performed in all subjects according to our protocol.
RESULTS
Normal VEMPs responses were found in all control groups. In all VN patients, caloric test was unilaterally abnormal and abnormal VEMPs was found in 4 of 10 VN patients. In patients with PSC-BPPV, abnormal caloric response was found in 2 of 7 patients but p13/n23 in VEMPs was present normally in all patients.
CONCLUSIONS
These results suggest that VEMPs could provide different information from the caloric test and could be helpful in evaluating inferior vestibular nerve involvement in patients with peripheral vestibulopathy. (J Korean Neurol Assoc 19(5):498~502, 2001)