Article

Augmented visual feedback (VF) may offer benefits similar to those of rhythmic
external cues in alleviating some mobility-related difficulties in individuals
with Parkinson's disease (PD). However, due to an impaired ability to reweigh
sensory information under changing circumstances, subjects with PD may be rather
vulnerable to incongruity of visual information. In the present study, we
investigated whether VF is indeed effective in improving motor functioning in a
weight-shifting task during upright stance, and whether subjects with PD are
affected more by incongruent VF than healthy controls. Participants performed
sideways swaying motions based on tracking of real-time and delayed VF - the
first providing congruent, and hence more accurate, visual information than the
latter. We analyzed center-of-pressure signals patterns for 28 individuals with
PD and 16 healthy, age- and gender-matched controls by estimating task accuracy,
movement pattern variability, and normalized movement amplitude. For conditions
without feedback and with real-time feedback, subjects with PD performed lateral
swaying motions with greater error (F(1, 42)=12.065, p=.001) and with more
variable movement patterns than healthy controls (F(1, 24)=113.086, p<.001).
Error change scores revealed that patients with PD were nevertheless still able
to use VF to improve tracking performance (t(24)=-2.366, p=.026). However,
whereas controls were able to adapt to a certain amount of visual incongruity,
patients with PD were not. Instead, movement amplitude was significantly reduced
in this group (F(1.448, 60.820)
=17.639, p<.001). By reducing movement amplitude,
subjects with PD appear to resort to a 'conservative' strategy to minimize
performance breakdown.
CI - Copyright (c) 2016 Elsevier B.V. All rights reserved.

Langue : ANGLAIS