VISUAL PROCESSING AND PERCEPTION DEFICITS IN MULTIPLE SCLEROSIS PATIENTS: REVIEW

Abstract

Multiple sclerosis (MS) is a chronic immune-mediated demyelinating encephalopathy disorder that is likely to impair visual functioning. Although cognitive problems in MS, especially memory and processing speed deficiency, have been well-established, there is relatively little attention given to visual perceptual dysfunction. The new data show that visual impairment in MS is not limited to optic neuritis and includes the disruptions at the different levels of the visual processing hierarchy, which are both cortical and subcortical systems. The synthesis of the results of behavioral, neuropsychological, neuroimaging, and socioemotional studies investigating visual processing and perceptual deficits in MS patients shows that the psychophysical testing, neuropsychological tests, and functional and structural neuroimaging indicate the presence of visual discrimination, visuospatial perception, visual processing speed, and emotion recognition impairments. These deficits are observed partially regardless of the optic neuritis history and duration of the disease. Taken together, the literature implies that visual perceptual impairment in MS is a combination of decelerated neuronal conduction, restructured functional connections, and restructured network formation. Although it is a clinically relevant area, visual perception is still poorly evaluated in the standard MS care. A more intensive perceptual measure combination could enhance the diagnostic sensitivity and guide specific rehabilitation interventions.