Article

Visual input is highly relevant for safely stepping over obstacles. In this
study, gaze-behaviour was investigated in elderly, middle-aged and young subjects
as they walked on a treadmill repeatedly stepping over obstacles, which
approached either on the right or left side. In between obstacle-steps, subjects
visually fixated a target N or F located two or four steps ahead on the floor,
respectively. An acoustic warning signal announced the obstacles, after which
subjects were free to look wherever they wanted. Gaze-movements were measured by
video-oculography. Four conditions with 20 obstacles were conducted (two with
target N, two with target F). In two conditions, high-precision stepping was
investigated by asking subjects to step with minimal foot-clearance over the
obstacles, while receiving acoustic feedback about their performance. In the
high-precision conditions, more subjects (target N: 70%, F: 81%) turned their
gaze on the obstacles and for a longer time than in unrestricted conditions. When
fixating on the near target N and unrestricted stepping over the obstacles,
significantly more elderly subjects (85%) turned their gaze on the obstacle
compared to middle-aged (17%) and young subjects (29%). The elderly turned their
gaze earlier and longer on the obstacle than middle-aged or young subjects. Our
results reveal a different gaze-behaviour strategy of elderly subjects suggesting
a greater dependency on visual inputs.
CI - Copyright (c) 2011 Elsevier B.V. All rights reserved.

Langue : ANGLAIS