Novel method for recording vestibular evoked myogenic potential: minimally invasive recording on neck extensor muscles.

Abstract

Vestibular evoked myogenic potential (VEMP) has been used to test vestibulocollic reflex. However, VEMP is not stable on elderly patients because of their weak muscular strength. In this study, we tried to record VEMP on median neck extensor muscles with weak muscular contraction We recorded VEMP from normal subjects and patients by novel and conventional methods. Thirty-one normal subjects and 56 patients with vertigo or hearing loss were tested in a seated or prone position without muscular tension. The different electrodes were placed on the median surface at the palpable bottom of the occipital bone. Our response showed a clear negative peak at 13 ms on normal subjects, with reversed polarity compared with VEMP on the sternocleidomastoid muscle. This potential is defined as VEMP caused by the proper latencies, dependency of the strength on sound stimulation, and independence of hearing ability. In the cases of acoustic neurinoma, onset latencies were prolonged or nonexistent. The responses on neck extensor muscles could not be recorded on some elderly patients. This new method of recording VEMP is less invasive and suitable for elderly patients.