Vestibular neuritis has selective effects on air- and bone-conducted cervical and ocular vestibular evoked myogenic potentials

ObjectiveTo characterise the changes in cervical (cVEMP) and ocular (oVEMP) vestibular evoked myogenic potentials to different stimuli in patients with vestibular neuritis (VN).MethodscVEMPs and oVEMPs were recorded using air-conducted (AC; clicks and short tone bursts) and bone-conducted (BC; lateral impulses and taps) stimuli in VN patients (n = 23) and normals (n = 40).ResultsAC evoked cVEMPs revealed few abnormalities, significantly less than for AC evoked oVEMPs (cVEMP: 22% vs oVEMP: 68%, P < 0.001). Lateral impulses showed high rates of abnormalities (74% vs 70%, P > 0.05) for both reflexes. Although forehead taps produced low rates of abnormalities for both reflexes (33% vs 13%, P > 0.05), response amplitudes were smaller from the affected ear (P < 0.05).ConclusionsAC stimuli were associated with low abnormality rates of cVEMPs, consistent with sparing of inferior nerve function in VN, but frequent abnormalities of oVEMPs. The high rates of abnormalities shown for lateral impulses suggest a dependence on superior nerve (i.e. utricular) afferents for both oVEMPs and cVEMPs.SignificanceLateral impulses behave as expected for utricular function and AC cVEMPs for saccular function. The AC evoked oVEMP seems to depend on the integrity of the superior vestibular nerve, possibly due to saccular afferents travelling in it.

► In vestibular neuritis, cVEMPs and oVEMPs evoked by short accelerations were both often abnormal. ► These findings are consistent with the acceleration responses depending upon the utricle. ► In contrast, AC-evoked oVEMPs were often abnormal, but cVEMPs were mostly normal. ► The AC responses suggest that the fibres mediating the oVEMP lie in the superior part of the nerve. ► We suggest a role for saccular fibres in the superior nerve for AC evoked oVEMPs.