Memory impairment in multiple sclerosis.

We compared the performance of 50 multiple sclerosis (MS) patients and 35 normal controls on a variety of memory tasks to determine the nature and severity of memory deficits in the MS patients and the proportion of patients affected. We also determined the relationship between memory and other cognitive functions, demographic factors, disease characteristics, depression, and psychoactive medication. We found significant differences between patients and controls on almost all memory tests. Patterns of learning, effects of interference, and improvement with cuing were similar for both groups. Thirty percent of patients showed severe memory impairment, 30% were moderately impaired, and 40% were mildly or not impaired. Memory dysfunction was related to impairment of other cognitive functions, lower socioeconomic status, chronic progressive type of MS, and use of antianxiety medication, but not to severity of disability, duration of MS symptoms or depression.