Decline of cognition in multiple sclerosis: dissociable deficits.

Three female patients (ages 32, 37 and 27 years) developed progressive deficits of cognition in stages of multiple sclerosis in which physical disability ratings were low. Neuropsychological examination revealed severe cognitive impairments in the first two patients. Cognitive functioning was essentially intact in the third patient, although her work pace was significantly slowed. CT scanning of the brain showed cortical atrophy as well as white matter lesions in patients 1 and 2, and multiple lesions and oedema of predominantly white matter in patient 3. The differences of cognitive dysfunction between the third and the first two patients may be related to involvement of different anatomical structures.