Visuoperceptual impairment in multiple sclerosis patients diagnosed with neuropsychological tasks

A comprehensive set of 31 binocular neuropsychological tasks assessing a se ries of spatial and non-spatial visuoperceptual abilities was used to study visuoperceptual impairment in a representative group of 49 MS-clinic patie nts exhibiting neither diagnosed ophthalmological afflictions nor major psy chiatric diagnoses. Among these patients, true frequency rate of visuoperce ptual impairment, ie. of subjects failing four or more tasks, was estimated at 26%. The pattern of visuoperceptual impairment was non-uniform, non-sel ective, restricted and idiosyncratic. Only four tasks yielded significant r ates of impairment They concerned colour discrimination, the perception of the Muller-Lyer illusion and object recognition in two separate conditions. Each of the four factors identified by factor analysis had an important re presentative (with factor loading > 0.35) among these four tasks. Failures on these tasks correlated poorly. Together, the four tasks satisfactorily p redicted visuoperceptual impairment as defined by the comprehensive set of tasks (sensitivity 86.7%; specificity 81.3%), but with regard to on unconta minated criterion, their aggregate sensitivity and specificity was only 75 and 56% respectively Visuoperceptual neuropsychological task performance re lated significantly but weekly to cognitive status, physical disability and to pyramidal, cerebellar and brain stem neurological signs, and did not co rrelate with other clinical neurological signs, disease duration, type of M S, a history of optic neuritis, depression or medication status.