Article

Patients with unilateral neglect tend to ignore sensory information from their
contralesional hemispace. Many symptoms of neglect can be reduced by exposing
patients to rightward-shifting prism goggles. It was noted that the effects on
neglect symptoms last for at least two hours. This seems surprising in light of
the fact that the after-effect of prism adaptation in healthy subjects lasts only
for a few trials. To account for this discrepancy Michel et al. (2003) referred
to anecdotal observations which suggested that neglect patients show little
awareness of prism-induced spatial errors. They argued that this lack of
awareness might interfere with more conscious attempts to compensate for the
prism goggles (called strategic control) and thereby enhance the effects of more
implicit corrective mechanisms (called spatial realignment) leading to more
pronounced and longer-lasting after-effects. We examined this hypothesis in a
group of neglect patients, patients with right-hemispheric lesions but no neglect
and a group of healthy age-matched controls. Our findings confirm that strategic
control mechanisms are impaired in neglect patients. However, their after-effects
seem neither reduced nor pathologically increased, thereby suggesting that the
two mechanisms of prism adaptation, namely strategic control and spatial
realignment are quite independent of each other. Furthermore we found that these
deficits are quite specific for neglect since other patients with
right-hemisphere lesions but no neglect are not impaired in this task. We discuss
the implications of our findings for our understanding of visual neglect, prism
adaptation and the perception and action model.
CI - Copyright (c) 2011. Published by Elsevier Ltd.

Langue : ANGLAIS