Unperturbed and perturbed gait variability is increased in bilateral vestibulopathy compared to age-sex-matched healthy participants

Abstract
Background: 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.
Research Question: 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.
Significance: 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.