A study involving 187 children and adolescents with multiple sclerosis, plus 44 who experienced their first neurologic episode (clinically isolated syndrome) indicative of MS, has found that 35% of those with MS and 18% of those with clinically isolated syndrome were cognitively impaired. Cognitive assessment was done using a battery of 11 tests. The most common areas of impairment were fine motor coordination, visual-motor integration, and speeded information processing.
http://www.futurity.org/health-medicine/cognitive-problems-for-1-in-3-kids-with-ms/