Comparison of vestibulo-ocular reflex instantaneous gain and velocity regression in differentiating the peripheral vestibular disorders

Background and Aim: Vestibuloocular reflex (VOR) gain is the central variable for estimating VOR function, and there are several algorithms to calculate gain. The current study aimed to investigate the ability of VOR instantaneous gain and velocity regression as a possible physiological biomarker for differentiating peripheral vestibular disorders of various etiologies. Methods: Video head impulse test (vHIT) was performed on 27 healthy volunteers (normal group) and 29 patients (pathologic group) including three types of peripheral vestibulopathies including unilateral Meniere s disease, unilateral superior vestibular neuritis, and bilateral vestibulopathy. Results: Analyses indicated that the mean VOR instantaneous gain at 40 ms, 60 ms, 80 ms, and velocity regression at 100 ms differred significantly within the normal and pathologic groups. Also, complete normative data for VOR at 40 ms, 60 ms, and 80 ms instantaneous gain has been provided for the vHIT. Conclusion: The findings of this study suggest that different vestibular pathologies have a distinct effect on cupular-endolymph function, which could be tracked by VOR dynamic changes.