A review of the basic research into the cervical and ocular vestibular evoked myogenic potentials.

Abstract

In humans, intense air- and bone-conducted sound has been reported to evoke cervical vestibular evoked myogenic potentials (cVEMP) on the sternocleidomastoid muscle. In addition, these stimuli can evoke ocular vestibular evoked myogenic potentials (oVEMP) on the extraocular muscles. In this study, basic studies into the cVEMP and oVEMP were reviewed. First, the sensitivity of primary vestibular afferents in the internal auditory meatus was investigated. These studies suggested that irregular primary otoliths afferent from both utricular and saccular maculae might respond to both air- and bone-conducted sound. Second, the differences between utricle and saccule-activated neural circuitry in both vestibulo-ocular reflex (VOR) and vestibulocollic reflex (VCR) systems were evaluated. These studies described that utricular afferents have a strong projection to the VOR system, whereas the saccular afferents have a strong projection to the VCR system. Third, identifying the appropriate animal models for both cVEMP and oVEMP was also important to resolve the questions about the neural pathways underlying these responses.