Recovery of vestibulo-ocular reflex in vestibular neuronitis depending on severity of vestibulo-ocular reflex damage

Objective: The aim of this study is to evaluate clinical symptoms and recovery of vestibule-ocular reflex (VOR) in patients with vestibular neuronitis (VN) in dependence on severity of VOR damage according to video head impulse test (vHIT).

Methods: 45 patients with VN and superior or both superior and inferior vestibular nerves involvement were recruited and horizontal gain was measured with vHIT. According to gain asymmetry the patients were divided in three groups: 11 patients with 8-19% gain asymmetry, 10 patients with 20-39% gain asymmetry and 24 patients with more than 40% gain asymmetry.

Results: Coexisting chronic heart and endocrinological diseases could contribute to greater damage of VOR in VN. In patients with less gain asymmetry the full recovery of gain on the affected side was more often. When gain asymmetry was more than 40%, only 10% of patients demonstrated full recovery of gain in 8-12 months. Dynamic visual acuity (DVA) could normalize in patients with clinically significant gain asymmetry. DVA stays decreased more often in patients with in the most gain asymmetry even after vestibular rehabilitation. Benign paroxysmal positional vertigo appeared in 8.9% of patients with VN and had no correlation with VOR asymmetry. Steroid treatment didn't show significant impact on VOR recovery in patients with VN.