Improving cognition in MS: Time to start prescribing exercise?
By Andrew D. Bowser
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Exercising the mind through cognitive rehabilitation is now a recommended intervention for the many individuals with multiple sclerosis (MS) who experience difficulties with memory, thinking, and other brain functions. Could exercising the body be too far behind?
In their 2018 recommendations for cognitive screening and management, the National MS Society said their updated review of the literature on cognitive rehabilitation had identified specific tools that can be considered as “practice standard” for use by rehabilitation specialists. The guidelines didn’t go as far as supporting exercise as an intervention to improve cognitive function, instead citing an emerging “potential benefit” attributable to certain exercise strategies.
That emphasis on cognitive rehabilitation was appropriate, experts say, now that there are close to 100 studies which, taken together, provide strong evidence that cognitive rehabilitation is effective in people with MS who have cognitive dysfunction.
Nonetheless, exercise training is emerging as a promising approach for improving cognition in MS, with a growing body of literature to support it, and a few randomized, controlled clinical trials underway, according to researcher Brian M. Sandroff, PhD.
A growing body of evidence
In a review of the medical literature between 2004 and 2015 by Dr. Sandroff and colleagues, there were just nine exercise training studies looking at cognitive outcomes in people with MS. Things have changed since then. In a report just recently published in Nature Reviews Neurology, Dr. Sandroff and coauthors identified 21 studies – for an increase of approximately 233% over the ensuing 4 years.
Dr. Brian M. Sandroff
“It’s about 15 years behind the cognitive rehabilitation literature, but starting to grow exponentially in terms of number of studies,” said Dr. Sandroff, assistant professor in the department of physical therapy at the University of Alabama at Birmingham. “And the methodology is getting better and better, which is starting to support general exercise-related benefits on different cognitive domains.”
People with MS who suffer from cognitive dysfunction need not wait for the results of randomized clinical trials to enjoy the benefits of exercise, according to researcher John DeLuca, PhD.
“It’s time that clinicians understand that persons with MS who have cognitive problems need treatment,” said Dr. DeLuca, who is senior vice president for research at the Kessler Foundation and professor in the department of physical medicine and rehabilitation at New Jersey Medical School, Newark.
Toward that end, the evidence for the benefit of cognitive rehabilitation is now very strong, and the evidence for exercise is preliminary but good, said Dr. DeLuca, who was first author on the Nature Reviews Neurology manuscript. “There’s nothing wrong with prescribing an exercise regimen, working with a physical therapist, going to the gym, taking walks on a regular basis – it really won’t hurt to prescribe increasing their mobility.”
Exercise and lifestyle physical activity recommendations from the National MS Society, published in April 2020, say that in general, health care providers should endorse and promote the benefits and safety of exercise and lifestyle physical activity for every person with MS.
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More data on the way
However, in order to consider exercise a “treatment” specifically for cognitive dysfunction, it would be necessary to specifically study exercise interventions specifically in MS patients who have cognitive impairment at baseline. Dr. Sandroff and Dr. DeLuca said they are only aware of two studies to date that fulfill that criteria, including a single-blinded, randomized, controlled trial published July 2020 in Multiple Sclerosis and Related Disorders. In that study, MS patients assigned to receive aerobic and Pilates training three sessions per week for 8 weeks had improvements in cognitive function versus controls, along with improvements in mood and quality of life after exercise, the investigators wrote in their published report.
More data are on the way. Dr. Sandroff is the principal investigator on two randomized trials prospectively enrolling large, representative samples of cognitively impaired individuals with MS. One of the studies, looking at the effect of exercise training on learning and memory outcomes, will include an estimated 40 participants and is expected to be completed by November 2021. The other will evaluate the effect of exercise training on cognition and brain function in an estimated 88 participants, with an estimated study completion date of September 2023.
The time is now
While results are pending, the time is now to address cognitive impairment in MS patients in clinical practice, according to experts. Drug treatment trials have turned in mixed results, so there’s an insufficient base of evidence to recommend treatment, according to the researchers. But exercise can be beneficial, as Dr. DeLuca noted, adding that cognitive rehabilitation has strong enough evidence that neurologists should be prescribing it now. “It’s really time that we provide the care that persons with MS who have cognitive problems deserve,” he said.