Memory and learning problems often occur in multiple sclerosis, but bewilderingly, are only weakly associated with the severity of the disease. A study involving 44 people around the age of 45 who had MS for an average of 11 years has found that those with a mentally active lifestyle had good scores on the tests of learning and memory even if they had higher amounts of brain damage. The findings suggest that, as with Alzheimer’s disease, 'cognitive reserve' protects against cognitive impairment. Differences in cognitive reserve may explain why some people have memory problems early in the disease, while others do not develop memory problems until much later, if at all.
(2010). Intellectual enrichment lessens the effect of brain atrophy on learning and memory in multiple sclerosis.
Neurology. 74(24), 1942 - 1945.