Patients with multiple sclerosis (MS) lose the ability to keep the information in the visual working memory for a few seconds, found a new study published in the journal Multiple Sclerosis and Related Disorders. The accuracy of the working memory was significantly affected by progressive disease. 

These data suggest working memory dysfunction could be used as a biomarker of disease progression in the future, Mehdi Sanayei, MD, PhD, of the Isfahan University of Medical Sciences in Iran, and colleagues noted. Cognitive dysfunction commonly affects patients with MS, especially those with secondary progressive disease, they added.

It is unknown whether cognitive impairment is associated with the progressive nature of the disease in secondary progressive MS (SPMS) or is linked to other clinical factors, the investigators noted.

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In the present study, the researchers compared the working memory of 65 patients with SPMS, 69 patients with relapsing MS, and 77 healthy controls. They also analyzed the potential effect of age, disease duration, and disability on working memory.

To do this, they used 2 working memory tasks with different sets of stimuli, including faces or checkerboards, and different instructions. In the first task, participants were asked to identify the same or different faces or checkerboards, while in the second, they were asked “which 1 is the same.”

The results showed that working memory accuracy was significantly more impaired in SPMS patients than in patients with relapsing MS. Accuracy was worse in both groups of patients compared to healthy controls. The same thing was found using both tasks.

Accuracy was also affected by age and overall cognitive function but not by disease duration and disability, which only affected accuracy in working memory with the checkerboard task.

“Future studies are needed to reveal underlying mechanisms of working memory dysfunction in SPMS,” the researchers concluded.


Pourmohammadi A, Motahharynia A, Shaygannejad V, et al. Working memory dysfunction differs between secondary progressive and relapsing multiple sclerosis: effects of clinical phenotype, age, disease duration, and disability. Mult Scler Relat Disord. Published online November 12, 2022. doi:10.1016/j.msard.2022.104411