Prism adaptation improves representational neglect.

Previous work has shown that various symptoms of unilateral neglect, including the pathological shift of the subjective midline to the right, may be improved by a short adaptation period to a prismatic shift of the visual field to the right. We report here, in two neglect patients the improvement of imagery neglect after prism exposure. Despite a strong neglect observed for mental images, as well as for conventional tests, the mental evocation of left-sided information from an internal image of the map of France was fully recovered following prism adaptation to the right. This improvement could not be explained by the alteration of visuomotor responses induced by the prism adaptation. Therefore, prism adaptation may act not only on sensory-motor levels but also on a higher cognitive level of mental space representation and/or exploration.