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

OBJECTIVE

To characterise the changes in cervical (cVEMP) and ocular (oVEMP) vestibular evoked myogenic potentials to different stimuli in patients with vestibular neuritis (VN).

METHODS

cVEMPs 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).

RESULTS

AC 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).

CONCLUSIONS

AC 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.

SIGNIFICANCE: Lateral 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.