Article

Visual tracking of the surrounding environment is an important daily task, often
executed simultaneously with the regulation of upright balance. Visual and
postural coordination may be affected by aging which is associated with a decline
in sensory and motor functions. The aim of the present study was to assess the
effects of aging on the control of saccadic and smooth pursuit eye movements when
standing on a moving surface. Nineteen young and 12 elderly subjects tracked a
visual target presented as unpredictable smooth pursuit or saccadic
displacements. Subjects were instructed to maintain gaze on target during quiet
stance with or without yaw surface rotations. Elderly subjects followed both
saccadic and pursuit targets with less accuracy than young subjects. Moreover,
elderly subjects responded with longer time lags during saccadic target shifts
and executed more catch-up saccades during smooth pursuits than younger subjects.
Standing on a moving surface induced larger target-gaze errors. Catch-up saccades
during pursuit occurred more frequently during surface perturbations. Our results
suggest that visual tracking abilities decline with age and that postural
challenge affects accuracy but not timing of gaze responses. Such declines
observed with aging may result from multiple but minor sensory and motor
deficits.
CI - Copyright (c) 2010 Elsevier B.V. All rights reserved.

Langue : ANGLAIS