Prism adaptation in the rehabilitation of patients with visuo-spatial cognitive disorders.

PURPOSE OF REVIEW The traditional focus of neurorehabilitaion has been on the patients' attention on their deficit, such that they should become aware of their problems and gain intentional control of compensatory strategies (descending approach). We review prism adaptation as one of the approaches that emphasize ascending rather than descending strategies to the rehabilitation of visuo-spatial disorders. The clinical outcome of prism adaptation highlights the need for a theoretical reconsideration of some previous stances to neurological rehabilitation. RECENT FINDINGS Recent years have given rise to a growing body of experimental studies showing that the descending strategy is not always optimal, especially when higher-level cognition is affected by the patients' condition. Ascending approaches have, for example, used visuo-manual adaptation for the rehabilitation of visuo-spatial deficits. A simple task of pointing to visual targets while wearing prismatic goggles can produce remarkable improvements of various aspects of unilateral neglect. SUMMARY The neural mechanisms underpinning visuo-manual plasticity can be viewed as a powerful rehabilitation tool that produces straightforward effects not only on visual and motor parameters, but on visuo-spatial, attentional and higher cognitive neurological functions. The use of prism adaptation therapy in neglect and other visuo-spatial disorders has just started to reveal its potential, both at a practical and theoretical level.