Does cognitive reserve apply to multiple sclerosis?

Cognitive reserve (CR) is the degree of spare cognitive capacity available to protect against the effects of disease or trauma to the brain.¹ Individuals with more CR are theorized to be less likely to show cognitive changes associated with neurologic change. CR has mostly been studied in Alzheimer disease (AD); there is significant support for CR buffering the effects of AD. A seminal study found significant postmortem evidence for AD pathology in the brains of 10 elderly individuals whose brains were larger than average and who had not shown any clinical signs of AD while living.²

In this issue of Neurology®, Sumowski and colleagues³ studied CR in patients with multiple sclerosis (MS), making a central contribution. The authors tested 44 patients with MS using a task of memory and learning known as the Selective Reminding Test. The authors chose to examine memory, because memory deficits are often the most commonly reported cognitive problems in MS.⁴ Importantly, although neuroimaging indices (e.g., brain atrophy) can partially explain lower performance on such tasks, such indices can only account for about 10%–15% of variance. The authors reason that …