Article

Gait instability is a common problem following stroke, as evidenced by increases
in fall risk and fear of falling. However, the mechanism underlying gait
instability is currently unclear. We recently found that young, healthy humans
use a consistent gait stabilization strategy of actively controlling their
mediolateral foot placement based on the concurrent mechanical state of the
stance limb. In the present work, we tested whether people with stroke (n = 16)
and age-matched controls (n = 19) used this neuromechanical strategy.
Specifically, we used multiple linear regressions to test whether (1) swing phase
gluteus medius (GM) activity was influenced by the simultaneous state of the
stance limb and (2) mediolateral foot placement location was influenced by swing
phase GM activity and the mechanical state of the swing limb at the start of the
step. We found that both age-matched controls and people with stroke classified
as having a low fall risk (Dynamic Gait Index [DGI] score >19) essentially used
the stabilization strategy previously described in young controls. In contrast,
this strategy was disrupted for people with stroke classified as higher fall risk
(DGI </=19), particularly for steps taken with the paretic limb. These results
suggest that a reduced ability to appropriately control foot placement may
contribute to poststroke instability.

Langue : ANGLAIS