Impairments of attention in individuals with multiple sclerosis

To investigate the status of attention in multiple sclerosis (MS) we administered tests of focused and divided attention to 39 MS patients and 18 age- and education-matched control subjects. In addition, a test of vigilance and a test of automatic information processing was administered. MS patients performed as well as controls on the automatic processing task and on most measures of focused and divided attention when accuracy but not speed was the dependent variable. By contrast, the MS patients performed significantly worse than controls on the more effortful measures of attention, especially those that engaged working memory or emphasized speeded responding. These results indicate that deficits of attention in MS patients are most likely to be evident on tasks which require concentrated cognitive effort.