Article

We compared postural stability with eyes open (EO) and with visual feedback (VFB)
in 15 elderly subjects with cognitive impairment (SwCI) and 17 controls. Postural
stability was evaluated using the center-of-pressure (COP) mean radius and
velocity, while postural strategies by the frequency and damping of the
difference between the COP and the center-of-mass (COM) signals. Performance in
the VFB trials was measured by the ratio of time spent by the COP inside the
target on the screen to the total trial duration. With EO, both groups
demonstrated similar postural stability and strategies. The time spent inside the
target during VFB was significantly higher in controls than in SwCI. The VFB did
not affect the mean radius in either group, nor velocity and frequency in SwCI,
however it increased the mean velocity and frequency in controls. Besides, the
VFB increased damping significantly more in the SwCI than in controls. These
findings indicate that controls adequately responded to the demands of VFB and
used efficient strategy of postural control. In contrast, the SwCI seemed to have
lost the natural capability to use augmented feedback demonstrating impaired sway
control and deficit of sensory integration. All these symptoms of posture control
disorders could be objectively identified by the COP mean velocity and the
COP-COM frequency and damping. Increased damping in controls during VFB task may
account for early signs of cognitive impairment that cannot be captured by
standard tests.
CI - Copyright (c) 2011 Elsevier B.V. All rights reserved.

Langue : ANGLAIS