Improving left hemispatial neglect using virtual reality

Background: In hemispatial neglect, space can be dissociated on the basis of "near" peripersonal vs "far" extrapersonal space. The clinical manifestations of neglect can be modified by having patients use a tool to explore "far" extrapersonal space. An explanation for this is that the use of a stick produced an extension of body space resulting in a remapping of "far" space as "near" space. Objectives: To determine whether the remapping of space can be generalized to the amelioration of the "affected" vs the "nonaffected" space, rather than being confined to the selective amelioration of "far" vs "near" neglect; and to determine whether tool use is a necessary condition for the remapping of space. Methods: Using virtual reality, the authors asked six hemispatial neglect patients to reach and grasp a real object while simultaneously observing the grasping of a virtual object located within a virtual environment by a virtual hand. The virtual hand was commanded in real time by their real hand. Results: After a period of adaptation, hemispatial neglect patients coded the visual stimuli within the neglected space in an identical fashion as those presented within the preserved portions of space. Conclusions: It is possible to re-create links between the affected and the nonaffected space. Wielding a tool is not a necessary condition in reopening neglected space.