Educational attainment and cognitive status in MS: Reading, writing, and economics.

Cognitive impairment is a prevalent and debilitating consequence of multiple sclerosis (MS; for review, Rocca et al. 1) for which we have no effective treatments. 2 The best approach to 'treatment' may be early intervention to prevent cognitive decline; however, a science and clinical practice of early intervention/pre-ventative medicine requires accurate identification of patients at greatest risk of future cognitive decline, which is currently quite difficult. Research presented within this issue may advance early identification of at-risk MS patients. Silva and colleagues 3 identify lower educational attainment as a risk factor for cog-nitive impairment in 419 Portuguese MS patients: cognitive impairment was more common among patients with lower (⩽ 9 years, 25% of patients impaired) versus higher (> 9 years, 15% of patients impaired) educational attainment. Findings were most pronounced for cognitive efficiency and memory: the cognitive domains most affected by MS. 1 By comparison , only 3% of 159 healthy controls were cogni-tively impaired. These results are consistent with a growing literature on cognitive reserve in MS (for review, Sumowski and Leavitt 4), which shows that MS patients with higher levels of education (e.g. Benedict et al. 5), intelligence (e.g. Sumowski et al. 6), and mentally-stimulating lifestyles (reading, writing, hobbies, e.g. Sumowski et al. 7) are at lower risk for cognitive decline/impairment. Silva and colleagues advance this literature by investigating reserve in a large cross-sectional sample representing about 80% of patients seen at an outpatient MS clinic. This may be the largest MS sample used in reserve research to date, which affords more confident generalization to the MS population. Also, use of educational attainment as a proxy of reserve has utility, as this demographic information is readily available to clinicians. On the one hand, it may not seem surprising that educational attainment predicts cognitive status. Importantly, however, Silva and colleagues adjusted cognitive performance for education before examining the link between educational attainment and risk for cognitive impairment. As such, the reported link between higher education and lower risk for cognitive impairment cannot be simply explained by higher premorbid cognitive function. Instead, patients with higher education performed closer to education-adjusted expectations, whereas patients with lower education performed worse than expected, which is consistent with the reserve hypothesis. Educational attainment is not normally distributed, but, rather, has a bimodal or multimodal distribution. The authors dichotomized educational attainment based on expectations within the Portuguese educational system (⩽ 9 years versus > 9 …