Unperturbed and perturbed gait variability is increased in bilateral vestibulopathy compared with age- and...

Bilateral vestibulopathy (BVP) leads to gait and balance deficits, particularly markedly increased gait variability. However, the independent effects of age and BVP on gait variability and how mechanical perturbations affect these relationships are unclear. We tested the hypotheses that people with BVP would demonstrate increased gait variability compared with age- and sex-matched healthy participants and that these differences would increase further when walking with mediolateral perturbations. Forty-two people with BVP and 42 healthy age- and sex-matched adults walked at 0.6 m/s, 0.8 m/s, and 1.0 m/s on a treadmill (Computer Assisted Rehabilitation Environment; Motek) without and with two levels of pseudorandom mediolateral platform sway perturbations. The coefficients of variation (CoV) for step time, step length, double support time, and step width were calculated. The data were analyzed using marginal linear regression with an unstructured covariance matrix. Significant group × speed interaction effects were found for the CoV of all parameters (P < 0.01) with higher CoV in BVP versus healthy controls. Significant effects of the perturbation were found, with perturbations causing increased CoV of step time, double support time, and step width (P < 0.05), yet no significant group × perturbation interaction was found. Our findings confirm increased gait variability in people with BVP, independent of age and sex differences, consolidating previous findings in nonmatched groups. Mediolateral sway perturbations caused increased gait variability, but this increase was not significantly larger in the participants with BVP.NEW & NOTEWORTHY Using a strictly age- and sex-matched design, we show that bilateral vestibulopathy independently increases gait variability across walking speeds, particularly at slower speeds. Although prior findings from simpler balance tasks suggest heightened sensitivity to (sensory) perturbations in vestibulopathy, mediolateral perturbations during walking, while significantly increasing gait variability, did not disproportionately affect patients. These findings refine our understanding of vestibular contributions to gait variability and highlight how findings in non-gait-based tasks may not translate to gait.