A-69 Baseline Predictors of Longitudinal SDMT Performance in Individuals with Multiple Sclerosis

Abstract

Abstract Objective More than half of persons with MS (PwMS) experience cognitive difficulties during the course of their illness. However, not everyone develops cognitive problems suggesting a role for important moderating factors. The object of the current study was to identify baseline predictors of cognitive trajectories in PwMS. Methods 680 PwMS completed the Symbol Digit Modalities Test (SDMT) and a battery of patient-reported outcome (PRO) measures as part their participation in The Comprehensive Longitudinal Investigation of Multiple Sclerosis at Brigham and Women’s Hospital (CLIMB). Each participant had at least 2 SDMT measurements as well as demographic (age, sex), clinical (EDSS, disease duration, course type), and PRO (fatigue, depression, and quality of life) data. Participants had a concurrent brain MRI scan at the time of the baseline SDMT measurement; intracranial cavity (ICC) was calculated for each participant as a proxy of brain reserve. The association between each baseline measure and the longitudinal change in the SDMT over the course of the follow-up period was calculated using a linear mixed effects model. Results Increased baseline age (95% CI: −0.29, −0.06; p = 0.002), increased baseline EDSS (95% CI: −0.24, −0.01; p = 0.037), and decreased baseline ICC (95% CI: 0.02, 0.25; p = 0.023) were each associated with a greater decline in the SDMT score longitudinally. Although most PRO measures were cross-sectionally correlated with SDMT performance, none were associated with longitudinal change. Discussion Older individuals and those with more clinical disability are likely to experience declines in SDMT performance over time. Individuals with high baseline brain reserve tend to have more favorable SDMT trajectories.