Cognitive reserve in multiple sclerosis: Protective effects of education.

BACKGROUND: Recent data suggest that cognitive reserve modulates the adverse effects of multiple sclerosis (MS) pathology on cognitive functioning; however, the protective effects of education in MS are still unclear. OBJECTIVE: To explore education as an indicator of cognitive reserve, while controlling for demographic, clinical and genetic features. METHODS: A total of 419 MS patients and 159 healthy comparison (HC) subjects underwent a comprehensive neuropsychological (NP) assessment, and answered the Hospital Anxiety and Depression Scale. Based on the HC data, MS patients' NP scores were adjusted for sex, age and education; and the estimated 5(th) percentile (or 95(th) percentile, when appropriate) was used to identify any deficits. Patients also performed the Mini-Mental State Examination (MMSE); and their human leucocyte antigen HLA-DRB1 and apolipoprotein E (ApoE) genotypes were investigated. RESULTS: Patients with higher education were less likely (p < 0.05) to have cognitive deficits than those with lower education, even when controlling for other covariates. Other significant predictors of cognitive deficit were: age, Expanded Disability Status Scale (EDSS), Multiple Sclerosis Severity Scale (MSSS), and a progressive course. No significant association was found with the HLA-DRB1*15:01 or ApoE ε4 alleles. CONCLUSIONS: These results provide support to the use of education as a proxy of cognitive reserve in MS and stress the need to take into account education when approaching cognition in MS.