Sex differences in cognitive impairment in multiple sclerosis

Multiple sclerosis (MS) is twice as prevalent in females as in males, but the possibility of sex differences in the cognitive sequellae of the disease has not been considered. In this study male patients with MS performed more poorly than female patients on tests of verbal and nonverbal memory, visuospatial construction, and on the Mini Mental State Exam (MMSE) and the Wisconsin Card Sorting Test (WCST). The groups of male and female patients were similar in age, education, and on several measures of neurologic and emotional disturbance. Among normals there are no sex differences on the NMSE and WCST. Sex differences on the memory and visuospatial construction tests were larger in magnitude for the patients than for normal controls, implying that male patients are somehow especially vulnerable to cognitive deficits. Reanalysis of existing databases could clarify questions about the existence and source of cognitive sex differences in MS.