Literature Review

How Does Cognitive Demand Affect Mobility in MS?

Performing a cognitive task may slow walking among patients with multiple sclerosis and limited mobility.


Patients with multiple sclerosis (MS) with an Expanded Disability Status Scale (EDSS) score between 4 and 6 have significantly slower times on the Timed Up and Go (TUG) test with the addition of a simple cognitive task, according to research published in the July–August issue of International Journal of MS Care. This reduction in performance “might have implications for a person’s more complex everyday activities,” the researchers said.

Patients with MS may develop cognitive impairment (eg, reduced processing speed or working memory), but standard cognitive assessments overlook how cognitive function affects mobility. To assess how the addition of a cognitive task affects mobility in patients with MS, George H. Kraft, MD, Emeritus Alvord Professor of MS Research at the University of Washington in Seattle, and colleagues conducted a study that included 52 adults with MS and 57 healthy controls. Participants had a mean age of about 47, and most were women.

George H. Kraft, MD

The participants completed three versions of the TUG test: the standard test, the test plus reciting the alphabet, and the test plus subtracting from a number by threes. Times to complete the tests were compared between controls and three groups of participants with MS—those with an EDSS score of 0–3.5 (n = 26), those with an EDSS score of 4.0–5.5 (n = 11), and those with an EDSS score of 6 (n = 15).

Overall mean times for the four groups were 8.0, 8.2, 11.1, and 11.6 seconds, respectively. Controls did not differ from people with MS without mobility problems (ie, those with an EDSS score of 0–3.5), but did differ from the other two groups.

“Individuals with MS and no mobility problems have ... very little increase in time due to the addition of cognitive tasks to the TUG test. The two more severe groups perform similarly to each other, with a steeper increase in time to perform the test when the cognitive demand increases,” the researchers said. “Although we cannot automatically generalize the results to more complex everyday activities, such as walking or driving a car while talking on a cell phone, the reduction in performance is an important issue that should be discussed with the patient and his or her caregiver.”

Jake Remaly

Suggested Reading

Ciol MA, Matsuda PN, Khurana SR, et al. Effect of cognitive demand on functional mobility in ambulatory individuals with multiple sclerosis. Int J MS Care. 2017;19(4):217-224.

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