Recovery and rehabilitation of visual cortical dysfunction.

Damage to the human cerebral cortex can result in a number of distinct visual perceptual impairments, including visual field defects, impaired eye movements, visual agnosia, visuospatial disorders, impaired binocular fusional convergence, achromatopsia, visual hallucinations and defective visuoperceptual discrimination. Such impairments are common following stroke, traumatic brain injury, and other forms of cortical dysfunction, and may have significant implications for the ability to participate in rehabilitation of nonvisual functions and performance of normal daily activities. We review these cortically-based visual impairments, with emphasis on the course of recovery and methods of rehabilitation. In addition, longitudinal data are presented on the recovery of impaired visuoperceptual discrimination in 25 patients with cortical damage caused by stroke. Although the majority of these patients experienced good recovery without specific intervention, approximately one-third were left with significant chronic impairments of visuoperceptual discrimination. Despite promising recent developments in the treatment of cortically-based visual defects, there remains considerable need for information on the natural course of recovery of such impairments, as well as development of empirically validated rehabilitation procedures.