Cervical and ocular vestibular-evoked myogenic potentials in acute vestibular neuritis

To clarify the origin and afferent pathways of short-latency ocular vestibular-evoked myogenic potential (oVEMP) in response to air-conducted sound (ACS), we evaluated cervical (cVEMP) and ocular VEMPs in patients with vestibular neuritis (VN).

In response to air-conducted tone burst, the oVEMP and cVEMP were measured in 60 healthy controls and in 41 patients with acute VN. The VN selectively involved the superior vestibular nerve (superior VN) in 30 patients, affected the inferior vestibular nerve only (inferior VN) in three and damaged both superior and inferior vestibular nerve branches in eight.

All 30 patients with superior VN presented normal cVEMPs, indicating preservation of the saccular receptors and their afferents in the inferior vestibular nerve. However, the oVEMP was abnormal in all patients with superior VN. By contrast, the patients with inferior VN showed normal oVEMP and abnormal cVEMP.

These dissociations in the abnormalities of cVEMP and oVEMP in patients with VN selectively involving the superior or inferior vestibular nerve suggest that the origin of the vestibular nerve afferents of oVEMP differ from those of cVEMP.

The oVEMP in response to ACS may be mediated by the superior vestibular nerve, probably due to an activation of the utricular receptors.