Comorbid intracranial vertebral artery asymmetry as a risk factor for severe vestibular neuronitis

Background: Our previous study had demonstrated that verterbral artery hypoplasia (VAH) contribute to ipsilateral vestibular dysfunction. The aim of this study was to test if VAH contributes to prognosis of vestibular neuronitis (VN) through presumed regional malperfusion. Methods: We performed a prospective magnetic resonance angiographic registry in patients with acute vestibular neuritis in which were then assigned to VAH (n = 29) and control group (n = 40). Vestibular function was determined by caloric irrigation, with the use of the vestibular paresis formula (to measure the extent of unilateral caloric paresis) within 3 days after the onset of symptoms and 12 months afterward. Results: The baseline vestibular paresis was higher (56.8 ± 15.9%) in the VAH VN subjects (n = 29), than in VN subjects without VAH (n = 40) (37.4 ± 17.7%) (p = 0.01). Analysis of variance showed a less percentage of the VAH group return to normal at 4th and 12th week visit. Conclusion: Our results suggested that comorbid VAH may predispose to severe VN at acute stage.