1- To describe the prevalence of CI and cognitive profile of the PwMS cohort. 2- To compare the cognitive performance of PwMS in relation to Expanded Disability Status Scale (EDSS) and MS duration.

Cognitive impairment (CI) is a common symptom of multiple sclerosis, with a negative effect on patients' daily lives.

Cross-sectional study. Measuring instruments: Clinical and cognitive variables were assessed (EDSS, Fatigue severity scale, Beck Depression Inventory, BICAMS battery, PASAT, verbal fluency, 7/24 test). CI was defined as impairment in ≥ 2 cognitive domains. Parametric and non-parametric statistics were used, p< 0.05 was considered significant.

323 PwMS were recruited. Mean age: 40.71±12.89 years; mean education: 13.43±4.2 years; mean EDSS: 2.05±1.94 (median 2.5 IQR8) and stratified EDSS was 0-3:61.7%; 3.5-8:38.3%; mean MS duration: 8.51±8.29 years; female 62.8%; relapsing-remitting MS (RRMS) 91.6%. Objectives:1)The prevalence of CI at inclusion study was 47.5%. The most affected cognitive domains were: attention and processing speed followed by verbal memory, verbal fluency and visual memory. 2)Patients with EDSS between 3.5-8 presented worse cognitive performance (p<0.05). The PwMS duration >20 years presented worse cognitive performance compared to those of ≤5 years (p<0.05). The group of >20 years presented worse performance than those of 6-10 years (p<0.05). In a multivariable logistic regression model, EDSS was an independent risk factor to reach CI when adjusted for potential confounders (adjusted Odds Ratio (OR) 1.43, 95% confidence interval (CI) 1.09-1.87, p=0.01).

The prevalence of IC in our cohort was similar to previous reports. Disability (EDSS) was an independent predictor of CI