Study finds better physical ability is tied to higher cognition in MS
Performance correlated with cognition only in adults with more disability
Having better physical performance is associated with higher cognitive function in people with multiple sclerosis (MS), particularly among those with more disability, a study finds.
Disability levels, in turn, correlate negatively with cognition and physical performance, with patients with moderate disability having worse scores on assessments than those with milder disability. The study, “Correlation of Cognition With Disability and Physical Performance in Patients With Relapsing-Remitting MS,” was published in the Journal of Central Nervous System Disease.
Cognitive impairment, particularly problems with memory and processing capacity, is a common issue with MS, and has a significant impact on a patient’s quality of life and their ability to perform daily activities.
However, “cognition is still not routinely assessed in MS patients,” wrote the study’s researchers. And, while some evidence suggests exercise can improve cognition in MS, “a full understanding of the association between cognitive performance and physical disability is still lacking, especially at different levels of patients’ disability.”
Tie between cognition, physical performance, and disability
Here, researchers in Finland conducted an observational study (NCT04115930) with 41 adults with relapsing-remitting MS (RRMS) to assess the relationship between cognition, physical performance, and disability in MS. The patients, 40 of whom were assessed for disability using the Expanded Disability Status Scale (EDSS), were divided into an EDSS-low group (scores up to 2.5, indicating no to mild disability) and an EDSS-high group (scores ranging between 3 and 5.5, indicating moderate to severe disability. A control group of 20 healthy volunteers was also included.
The participants were assessed for disability using a composite measure called the MS Functional Composite (MSFC), which assesses walking function with a timed 25-foot walk, arm and hand dexterity with the nine-hole peg test, and cognitive function with the Paced Auditory Serial Addition Test (PASAT-3).
As expected, MSFC scores were significantly lower in the MS patients than the controls, and the EDSS-high group had worse scores on this composite measure than the EDSS-low group. Similar observations were made for the PASAT-3 test alone.
The researchers then examined how two other measures of cognition and physical performance correlated with MSFC. Cognition was assessed with Symbol Digit Modality Test (SDMT), which measures cognitive processing speed, and physical function was assessed with the 6-minute walk test, a test of endurance that measures the distance a person can walk in six minutes.
Again, scores in these two measures were worse for patients, and those with low EDSS scores performed significantly better than those with high scores.
Cognition, as assessed with the SDMT, significantly correlated with MSFC scores when all the patients were examined. Physical function also significantly correlated with both disability measures, the EDSS and MSFC, in the whole RRMS group. No correlations were observed when the EDSS-low and EDSS-high groups were examined individually.
Physical activity, in turn, only correlated significantly with cognition in the EDSS-high group, meaning that, among people with higher disability levels, a better physical performance is associated with better cognition. No significant associations were seen in the EDSS-low group or in the whole group of patients.
“This study found a clear association between disability and cognition, and physical performance in RRMS patients,” the researchers wrote. “The MSFC and the SDMT complement each other well in assessing patients’ disability and cognition in clinical use.”
About the Author
