Article

Several studies point to prism adaptation as an effective tool for the
rehabilitation of hemispatial neglect. However, some recent reports failed to
show a significant amelioration of neglect after prism adaptation as compared to
control treatments. This apparent contradiction might reflect important
differences in the procedures used for treatment. Here we compare the effects of
two treatments (performed for 10 sessions, over 2 weeks) in two groups of
patients, based either on a Terminal (TPA) or a Concurrent (CPA) prism adaptation
procedure. During TPA only the final part of the pointing movement is visible and
prism adaptation relies most strongly on a strategic recalibration of visuomotor
eye-hand coordinates. In contrast, during CPA the second half of the pointing
movement is visible, and thus adaptation mainly consists of a realignment of
proprioceptive coordinates. The present results show that both TPA and CPA
treatments induced a greater improvement of neglect as compared to a control
treatment of pointing without prisms. However, neglect amelioration was higher
for patients treated with TPA than for those treated with CPA. At the same time,
the TPA treatment induced a stronger deviation of eye movements toward the left,
neglected, field as compared to the CPA treatment. Interestingly, in TPA patients
the visuomotor and oculomotor effects of the treatment were directly related to
the patients' ability to compensate for the optical deviation induced by prism
during pointing (i.e., Error reduction effect). In summary, prism adaptation
seems particularly effective for the recovery of visuo-spatial neglect when
conducted with a procedure stressing a correction of visuomotor eye-hand
coordinates, i.e., with a TPA procedure. The present observations may help to
better understand the mechanisms underlying prism-induced recovery from neglect
and the procedural basis for some of the contradictory results obtained when
using this rehabilitative strategy.
CI - Copyright (c) 2011 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS