Cognitive impairment at the onset of multiple sclerosis: relationship to lesion location.

The impact of lesion location on cognitive functioning was assessed in a group of 97 patients with a clinically isolated syndrome. Using the Brief Repeatable Battery, we evidenced that 24% of patients showed at least one abnormal test, 20% at least two and 15% at least three. Verbal learning performances were inversely associated with presence of lesions in Broca's area, in the right frontal lobe and in the splenium while spatial learning performances were inversely correlated to the presence of lesions in the deep white matter. No associations were evidenced between lesion location and performance of tasks exploring attention and executive functions.