Cognitive impairment in multiple sclerosis

Abstract

For a long time, cognitive impairment in multiple sclerosis patients has been considered less important than, for instance, physical disability. This is no longer true because of the crucial role that cognitive deficits play in the good day-to-day adjustment of patients. This review highlights recent progress made in this area. A special focus lies on studies investigating the neural correlates of cognitive impairment in multiple sclerosis patients as detectable by conventional, quantitative and functional magnetic resonance imaging. Measures of information-processing speed appear to be the most robust and sensitive markers of cognitive impairment in multiple sclerosis patients. Recent studies demonstrate that single, predominantly speed-related cognitive tests may be superior to extensive and time-consuming test batteries in screening overall cognitive decline. Quantitative magnetic-resonance-imaging findings suggest the extent of subtle tissue damage in normal-appearing white and grey matter to correlate best with the severity of cognitive impairment in multiple sclerosis patients. From neuropsychological test data, and findings from magnetic resonance imaging and functional magnetic resonance imaging it is evident that cognitive impairment in multiple sclerosis is not just the result of tissue destruction, but rather a balance between tissue destruction, tissue repair, and adaptive functional reorganization.