Galvanic vestibular-evoked myogenic potentials in evaluating damaged sites of vestibular neuritis

To test the possibility of pure otolithic organ deficits and validate the histopathological evidence of retrovestibular neural impairment in vestibular neuritis (VN), the authors adopted a topographic survey combining cervical vestibular-evoked myogenic potential (cVEMP) and ocular vestibular-evoked myogenic potential (oVEMP) using various stimulation modes and caloric tests.

Forty patients with VN were enrolled in this study. All patients underwent pure tone audiometry, acoustic cVEMP, galvanic cVEMP, vibratory oVEMP, galvanic oVEMP, and caloric tests. Different combinations of vestibular tests were further compared and analyzed.

According to vestibular test results in affected VN ears, the proportion (10%) of pure saccular dysfunction was significantly less than that (52.5%) of saccular nerve deficit. The proportion (2.5%) of pure utricular dysfunction was significantly less than that (37.5%) of utricular nerve deficit. The percentage (82.5%) of VN involving the ampullar vestibulo-ocular reflex (VOR) pathway was significantly higher than that (40%) involving the utriculo-ocular reflex (UOR) pathway. The superior, inferior, and total VN percentages were 37.5%, 17.5%, and 45%, respectively. The proportion of inferior VN was significantly less than that of VN involving the superior vestibular nerve.

There were significantly fewer cases of pure otolithic organ dysfunction than vestibular nerve involvement in VN patients. The damage to the ampullar VOR pathway was more significant than that to the UOR pathway, and both pathways might be independent of each other. In addition, the incidence of isolated inferior VN was significantly less than that of VN involving the superior vestibular nerve.

Level 3.