Three recent studies have been published focused on the cognitive side of multiple sclerosis (MS). Each study was published by researchers at Kessler Foundation (West Orange, N.J.) - studies that could eventually lead to cognitive therapies being approved for reimbursement by insurers.

Many know that physically, MS can cause muscle rigidity, pain and paralysis. Lesser known are the cognitive effects -- including fatigue, trouble with memory and speech.

One Kessler Foundation study, funded by the National MS Society, found that people with MS performed worse on processing speed and memory tasks during warmer outdoor temperatures versus during cooler outdoor temperatures.

The second study, also funded, in part, by the National MS Society, sheds light on cognitive fatigue in people with multiple sclerosis. Cognitive fatigue is fatigue resulting from mental work rather than from physical labor.

Meanwhile, the third study provides the first evidence for beneficial effects of aerobic exercise on brain and memory in people with MS.

The study connecting MS to outdoor weather is the first report of brain activation being associated with outdoor temperature in MS, said Victoria M. Leavitt, Ph.D., research scientist at Kessler Foundation and principal investigator for the study. It was released by Brain Imaging & Behavior.

Added James Sumowski, Ph.D, a research scientist on the study: "The significant effect of warmer weather on cognition should be considered when designing and conducting clinical trials on other cognitive elements of MS.

This information might assist clinicians in choosing clinical treatment, and help researchers develop effective strategies for coping with the negative effects of weather-related effects on cognition that impact independence, education, employment and activities of daily living, added Dr. Sumowski.

As for the cognitive fatigue study, the study used three approaches to examine the propensity of an individual to feel fatigued ("trait" fatigue), as well as the fatigue an individual feels in the moment ("state" fatigue).

This study is the first to use neuroimaging to investigate these two, separable aspects of fatigue. Increased access to neuroimaging testing equipment is a new benefit to researchers at Kessler Foundation, which is the only freestanding rehabilitation institution in the U.S. with a research dedicated imaging center.

Kessler Foundation's Neuroimaging Center, which opened earlier this year, is designed to accelerate the pace of research discoveries for individuals with physical and cognitive disabilities -- in areas such as multiple sclerosis, spinal cord injury and stroke.

The cognitive fatigue study is being published on Nov. 1 in PlosOne.

The study investigated the neural correlates of cognitive fatigue in MS utilizing neuroimaging approaches. such as:

  • functional magnetic resonance imaging (fMRI), which allows researchers to look at where in the brain activation is associated with a task or an experience
  • diffusion tensor imaging (DTI), which allows researchers to look at the health of the brain's white matter; and
  • voxel-based morphometry (VBM), which allows researchers to investigate structural changes in the brain.

"We looked specifically at the relationship between individuals 'self-reported fatigue and objective measures of cognitive fatigue using state-of-the-art neuroimaging," explained Helen Genova, Ph.D, research scientist in Neuropsychology & Neuroscience Research at Kessler Foundation.

"The importance of this work lies in the fact that it demonstrates that the subjective feeling of fatigue can be related to brain activation in specific brain regions," Genova added. "This provides us with an objective measure of fatigue, which will have incalculable value as we begin to test interventions designed to alleviate fatigue."

As for the study on the effects of aerobic exercise on the brain and memory for people with MS, the study's participants were two MS patients with memory deficits who were randomized to non-aerobic (stretching) and aerobic (stationary cycling) conditions. Aerobic exercise resulted in a 16.5 percent increase in hippocampal volume, a 53.7 percent increase in memory, and increased hippocampal resting-state functional connectivity. Non-aerobic exercise resulted in minimal change in hippocampal volume and no changes in memory or functional connectivity.

The study was published in Neurocase: The Neural Basis of Cognition. Dr. Leavitt served as primary author.

"Aerobic exercise may be the first effective treatment for MS patients with memory problems," noted Dr. Leavitt. "Moreover, aerobic exercise has the advantages of being readily available, low cost, self-administered, and lacking in side effects." No beneficial effects were seen with non-aerobic exercise.

Dr. Leavitt noted that the positive effects of aerobic exercise were specific to memory; other cognitive functions such as executive functioning and processing speed were unaffected. Kessler Foundation is a major nonprofit organization in the field of disability, is a global leader in rehabilitation research that seeks to improve cognition, mobility and long-term outcomes, including employment, for people with neurological disabilities caused by diseases and injuries of the brain and spinal cord. Addtionally, Kessler Foundation leads the nation in funding innovative programs that expand opportunities for employment for people with disabilities.