Article

While walking, one often has to suppress and adjust a planned step in order to
avoid a fall. Given that steps are preprogrammed this requires some form of motor
inhibition. Motor inhibition is commonly tested in hand function and only
recently attempts have been made to evaluate inhibition in the lower limbs,
during step initiation. As adequate motor inhibition might play a role in
avoiding falls a test to assess response inhibition during walking would be
valuable. We developed a task in which subjects walked on a treadmill by stepping
on projected patches of light, which could suddenly change color forcing the
subjects to avoid it by shortening or lengthening their steps. The difficulty
level was manipulated in 4 conditions by changing the distance available to
respond. We hypothesized that larger demands on motor inhibition during walking
would produce more failures and tested the performance of young adults (n=12) in
order to establish the protocol for use in older adults. The failure rate on the
walking test was analyzed. Reducing the available response distance by 150 mm
from the easiest condition resulted in a significant increase in failure rates
from 15.6% to 65.1%. Therefore, results indicate this novel test can be used to
assess the level of motor inhibition during walking. Additionally, in comparison
to previous literature on obstacle avoidance, our experiment shows that changing
a precise aiming movement is considerably more challenging than changing the same
movement executed automatically.
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Langue : ANGLAIS