Article

With neuropsychological rehabilitation approaches neglect patients
can learn to compensate for the reduced awareness of the contralesional hemispace
that is often observed after right brain damage. Here, we report contralesional
"cross-over" deviations in line bisection that are hypothesized to be a result of
focusing on the contralesional hemispace while the intact hemispace is
"neglected". We investigate whether this unexpected pattern of deviation is
related to defects in the visual field, motor intention/hypokinesia deficits or
deficits in working memory. METHODS: Neglect patients with and without homonymous
field defects were screened for contralesional cross-over deviations in line
bisection of long lines. During line bisection eye movements were recorded in two
conditions with and without requiring hand movements in order to search for
directional hypokinesia. Visual fields were tested with near-threshold perimetry
and with supra-threshold campimetry. RESULTS: Of 53 chronic neglect patients only
8 showed cross-over in line bisection. Evidence for directional hypokinesia was
found in only one patient. Patients with cross-over focused more often to the
left than to the right of the objective line midpoint. Patients with and without
visual field defects did not differ in the extent of cross-over deviations.
Cross-over deviation and inconsistent stimulus detection in left hemispace were
correlated irrespective of the presence of a visual field deficit. Larger
cross-over deviations were associated with poorer verbal working memory span, and
disorganized patterns of eye movement were related to reduced visuo-spatial
working memory capacity. CONCLUSION: Increasing awareness of the disorder and the
use of compensatory strategies may have led to a cross-over shift of visual
search dominance towards the neglected side resulting in an exploration deficit
of the ipsilesional side.

Langue : ANGLAIS