Purpose: 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 is unclear. We tested the hypotheses that people with BVP would demonstrate increased gait variability compared to age-and sex-matched healthy participants and that these differences would increase further when walking with mediolateral perturbations.

Methods: Forty-two people with BVP and 42 healthy age- and sex-matched adults walked at 0.6m/s, 0.8m/s, and 1.0m/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 analysed using marginal linear regression with an unstructured covariance matrix.

Results: Significant group*speed interaction effects were found for the CoV of all parameters (P<0.01) with higher CoV in BVP vs. 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.

Conclusion: Our findings confirm increased gait variability in people with BVP, independent of age and sex differences, consolidating previous findings in non-matched groups. Mediolateral sway perturbations caused increased gait variability but this increase was not significantly larger in the participants with BVP.