The influence of visual vertigo and vestibulopathy on oculomotor responses

Abstract

Objective: Dynamic visual inputs can cause visual vertigo (VV) in patients with vestibulopathy, leading to dizziness and falls. This study investigated the influence of VV on oculomotor responses. Methods: In this cross-sectional, single-blind study, with experimental and control groups, 8 individuals with vestibulopathy and VV, 10 with vestibulopathy and no VV, and 10 healthy controls participated. Oculomotor responses were examined with 2-dimensional video-oculography. Participants were exposed to dynamic visual inputs of vertical stripes sweeping across a screen at 20 deg/sec, while seated or in Romberg stance, with and without a fixed target. Responses were quantified by optokinetic nystagmus frequency (OKNf) and gain (OKNg). Results: Seated with no target, VV participants had higher OKNf than controls (37 ± 9 vs. 24 ± 9 peaks/sec; P< 0.05). In Romberg stance with no target, they had higher OKNf than controls (41 ± 9 vs. 28 ± 10 peaks/sec; P< 0.05). With a target, OKNf was higher in VV participants compared to controls (7 ± 7 vs. 1 μ 2 peaks/sec; P< 0.05). In Romberg with no target, OKNg was higher in the VV group (0.8 ± 0.1) compared to controls (0.6 ± 0.2; P=0.024). OKNf and OKNg did not differ according to VV status. Conclusions: VV participants had increased OKNf and OKNg compared to healthy participants. Visual dependency should be considered in vestibular rehabilitation.