Left spatial hemineglect: An unmanageable explosion of dissociations? no

Abstract

The term “spatial hemineglect” refers to the defective ability of patients with unilateral cerebral lesions (more frequently in the right hemisphere) to explore the side of space contralateral to the lesion, and to report stimuli presented in this portion of space. The differential diagnosis of hemineglect from global disorders of space exploration and perception is based on the presence of a contra-ipsilateral gradient, whereby performance is comparatively preserved in the ipsilateral side (right in right brain-damaged patients). In the more widely used diagnostic tasks, such as target cancellation and line bisection, patients can use the unaffected ipsilesional arm and are free to move their head and eyes, to compensate for associated visual half-field deficits. A defective performance in these tasks, therefore, cannot be attributed to primary sensory or motor deficits, which may occur in the absence of spatial hemineglect (see Bisiach & Vallar, 1988).