Cognitive impairment in multiple sclerosis: A longitudinal study
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文摘
Despite the large number of studies on congnitive dysfunction in Multiple Sclerosis (MS), the bulk of our information still comes mainly from cross-sectional surveys. This leaves unanswered crucial questions about the natural history of intellectual decline and its relationships with evolution of neurological impairment starting from the onset of the disease. Moreover, few authors have specifically considered the impact of cognitive dysfunction on a patient's everyday life, rather focusing on disease-related motor disabilities. Our survey is one of the first controlled, longitudinal studies conducted on a clinically homogeneous sample of early-onset MS patients. The cognitive performance of 50 MS subjects (mean disease duration 1.5 ± 1.6 years) and 70 healthy controls was assessed on an extensive neuropsychological battery at the inclusion in the study, and again after a 4-year period. On initial testing, MS patients performed significantly worse than controls on verbal memory and abstract reasoning tasks; these deficits remained stable on the retest, at which time linguistic disturbances on the Set and Token tests also emerged. There was a poor correlation between the extent of cognitive decline and clinical characteristics of the disease, so that during the follow-up period cognitive and neurological deficits appeared not to develop in parallel. Stepwise linear regression analysis showed that the degree of cognitive impairment on initial testing was an important independent predictor of the future handicap in work and social activities. These findings underline the role of cognitive dysfunction even in patients in an incipient phase of the disease with low-level neurological disabilities.