Baseline age, disability, whole brain volume (WBV), and T2 lesion volume were significant predictors of long-term worsening information processing speed (IPS) in patients with multiple sclerosis (MS), according to study results published in Multiple Sclerosis Journal — Experimental, Translational and Clinical.

This study included 76 Norwegian patients diagnosed with MS from 1998 to 2000. All participants underwent neurologic examination, 1.5 T magnetic resonance imaging (MRI) of the brain, and clinical assessments at baseline. These assessments were performed again at 5 years and 10 years. Study researchers also assessed physical disability at each visit using the Expanded Disability Status Scale (EDSS). In addition, they calculated global and tissue-specific volumes at each visit. Using the Symbol Digit Modalities Test (SDMT), they measured changes in IPS.

Approximately 49% (n=37) of patients were considered cognitively impaired at baseline. Among participants available for assessment, at the 5- and 10-year follow up the rates of cognitive impairment fluctuated to 47% and 37%, respectively.

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At the 5-year follow up, factors predictive of worsening SDMT in the multivariable analysis include baseline age (β, -1.8; -4.5-0.9; P =.20), EDSS (β, -1.8; 95% CI, -3.9-0.3; P =.084), SDMT (β, -0.20; 95% CI, -0.40 to -0.01; P =.043), WBV (β, 0.042; 95% CI, 0.009-0.076; P =.015), and T2 lesion volume (β, -0.35; 95% CI, -0.55 to -0.16; P =.001). The study researchers noted that these predictive variables explained 30.2% of the variance of SDMT.

Baseline predictors of change in SDMT during the studied 10 years included age (β, –3.0; 95% CI, -6.4-0.4; P =.083), EDSS (β, 1.7; 95% CI, -0.7-4.0; P =.16), grey matter volume (β, 0.08; 95% CI, 0.02-0.13; P =.007), and T1 lesion volume (β, -1.1; 95% CI, -1.5 to -0.7; P <.001), which explained 39.4% of the variance of change in SDMT.

Limitations of this study included the relatively small size of the cohort as well as the high dropout rate over the 10-year period.

Using these identified predictors, the study researchers concluded that “identifying patients at higher risk of developing cognitive difficulties could help clinicians initiate proper follow-up” and aid treatment decisions.

Disclosure: This clinical trial was supported by Novartis. Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


Jacobsen C, Zivadinov R, Myhr KM, et al. Brain atrophy and clinical characteristics predicting SDMT performance in multiple sclerosis: A 10-year follow-up study. Mult Scler J Exp Transl Clin. Published online February 8, 2021. doi:10.1177/2055217321992394