Ocular vestibular evoked myogenic potential to air conducted sound stimulation and video head impulse test in acute vestibular neuritis.

BACKGROUND: Air-conducted (ACS) cervical VEMP (cVEMP) reflect both saccular and inferior vestibular nerve function. Ocular VEMP (oVEMP) to air and bone-conducted vibration (BCV) are critically discussed, whether they reflect predominantly utricular and superior vestibular nerve function. The video head impulse test (vHIT) accurately detects changes in the high frequency range (5-7 Hz) of the vestibular ocular reflex (VOR) in all 3 planes and can be used to assess semicircular canals (SCC) impairment.

OBJECTIVES: To evaluate oVEMP and cVEMP in response to 500 Hz ACS stimulation and to compare these with vHIT results in acute unilateral vestibular neuritis (VN) to classify the probable involvement of SCC and otolith organs.

MATERIALS AND METHODS: Patients with VN were studied. ACS oVEMP and ACS cVEMP (100 dB nHL 500 Hz tone burst stimulation) were recorded. The vHIT for the 3 SCC were performed simultaneously.

RESULTS: ACS oVEMP and ACS cVEMP in combination with vHIT allows the differentiation of 4 types of VN: entire VN (EVN), superior VN (SVN), inferior VN (IVN), and ampullary VN (AVN). Lesions of EVN, SVN, and IVN may be either complete or partial.

CONCLUSION: ACS oVEMP and ACS cVEMP to 500 Hz stimulation together with the vHIT allows a better differentiation of receptor involvement in VN. Results suggest a different origin of AC oVEMP and AC cVEMP to 500 Hz in complete SVN and IVN. Partial SVN and IVN may indicate a role of saccular fibers in oVEMP.