Cognitive level and rate of change in relapsing and progressive multiple sclerosis: a single-center retrospective...

Although secondary and primary progressive multiple sclerosis (MS) are associated with poorer cross-sectional cognition than relapsing MS, whether decline is faster remains uncertain. We examined associations of phenotype with cognitive performance and annual change.

In this single-center retrospective study, 37 patients with MS underwent serial assessment using the Symbol Digit Modalities Test (SDMT), Japanese version of the Montreal Cognitive Assessment (MoCA-J), and Frontal Assessment Battery (FAB) (161 observations; 144 for SDMT). Phenotype at the first assessment was retained throughout follow-up. Linear mixed-effects models included random intercepts and slopes and were adjusted for baseline age, sex, education, and Expanded Disability Status Scale (EDSS) score; time was mean-centered.

At baseline, 26 patients had relapsing and 11 had progressive disease. Mean follow-up was 4.2 years. The progressive group scored lower than the relapsing group: SDMT, -14.18 points (95% confidence interval [CI]: -25.00, -3.35); MoCA-J, -3.25 (-5.65, -0.85); FAB, -1.80 (-3.18, -0.43). Phenotype-by-time interactions were non-significant (SDMT: -0.87 points per year [95% CI: -2.03, 0.29]; MoCA-J: -0.24 [-0.54, 0.06]; FAB: -0.14 [-0.35, 0.08]).

Progressive MS was associated with lower cognitive performance after adjustment for baseline EDSS score, without evidence of different rates of change. Lower MoCA-J and FAB scores in progressive MS have rarely been documented in Japanese patients. Larger cohorts with longer follow-up are needed to determine whether rates differ.