Thalamic Atrophy Moderates Ties Between Fitness, Cognition: Study
The research boosts benefits of aerobic exercise training for MS patients
In people with multiple sclerosis (MS) who show atrophy in a brain region called the thalamus, aerobic fitness is strongly correlated with standardized assessments of cognition and walking ability.
However, these associations are not seen for MS patients who don’t have atrophy in the thalamus, according to a new study.
“This study suggests that aerobic exercise training has the potential to restore function in individuals with thalamic atrophy, who are clearly at risk for progressive physical and cognitive decline,” Brian Sandroff, PhD, senior research scientist at the Kessler Foundation and co-author of the study, said in a foundation press release.
The study, “Thalamic atrophy moderates associations among aerobic fitness, cognitive processing speed, and walking endurance in persons with multiple sclerosis,” was published in the Journal of Neurology.
In MS, inflammation causes damage to the central nervous system (the brain and spinal cord), which can cause symptoms such as cognitive difficulties, impaired coordination, and muscle spasms.
Some studies suggest that physical exercise can help protect nerve cells and improve outcomes for people with MS, but there is much still unknown about how exercise affects processes in MS.
Researchers at the Kessler Foundation sought to determine if aerobic fitness had a distinct impact in people with and without atrophy in the thalamus, an egg-shaped brain region that plays a central role in processing sensory information and regulating movement.
Loss of brain tissue in this region is a biomarker of neurodegeneration and is associated with faster physical and cognitive function declines.
The study included 44 people with MS, all of whom were able to walk. The participants completed the Symbol Digit Modalities Test (SDMT) — a standardized assessment of cognitive ability — as well as the six-minute walk test (6MWD), which assesses walking ability.
They also underwent a standardized assessment of aerobic exercise capacity called VO2 peak, which assesses how much oxygen is able to be utilized during vigorous exercise.
MRI scans were used to view the patients’ brains.
Most MS patients show an increased rate of brain atrophy — the gradual loss of brain tissue over time — but this does not necessarily affect all brain regions equally. Based on the MRI data, the scientists identified those patients with atrophy in the thalamus and then used statistical tests to look for associations between the variables.
Results showed that, among patients with thalamic atrophy, there were significant correlations between aerobic capacity and cognitive function, and between aerobic fitness and walking ability. In other words, patients who had better aerobic fitness tended to have better cognitive and walking abilities.
In patients without thalamic atrophy, however, these associations were weaker and did not reach statistical significance.
“This study provides initial evidence of strong, selective associations among aerobic fitness, cognitive processing speed, and walking endurance in persons with TA [thalamic atrophy],” the researchers concluded. “Such data support TA as a moderator of the association among aerobic fitness, cognitive processing speed, and walking endurance in persons with MS.”
Sandroff said “randomized controlled trials of aerobic exercise training” in those with thalamic atrophy was needed to look at the effect on outcomes.
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