Natural history of cognitive dysfunction in multiple sclerosis: a 4-year longitudinal study

Despite the large number of studies on cognitive dysfunction in multiple sclerosis (MS) published over the last decade, the bulk of information still comes mainly from cross-national surveys. In the present study, the cognitive performance of 50 patients with early-onset MS was compared with that of 70 demographically matched healthy controls over a 4-year follow-up period. On initial testing, patients showed significant impairment on verbal memory and abstract reasoning tasks. On the second evaluation, linguistic disturbances on the set and token tests also emerged. Clinical characteristics of the disease at onset had a limited predictive power for the cognitive outcome; however, the extent of cognitive decline proved to be an independent predictor of handicap in work and social activities beyond the degree of neurological impairment.