Study documents negative effect of warmer weather on cognitive performance in multiple sclerosis

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Mar 14, 2012

Kessler Foundation scientists have shown for the first time that outdoor temperature significantly affects cognitive functioning in multiple sclerosis (MS). Although it is recognized that disease activity increases during warmer months, this is the first study to document that cognition also fluctuates. During warmer outdoor temperatures patients with multiple sclerosis performed worse on tasks involving processing speed and memory. An estimated 50% to 65% of people with multiple sclersosis experience problems with thinking, learning, and remembering that can be disabling.

“Warmer outdoor temperature is associated with worse cognitive status in MS,” was published online ahead of print by Neurology. An accompanying editorial, “MS and heat: The smoke and the fire,” discusses the study’s contributions to understanding multiple sclerosis. According to the results, cognitive performance may be a more sensitive indicator of subclinical disease activity than traditional assessments.

In the study, which spanned the calendar year, 40 individuals with multiple sclerosis and 40 people without multiple sclerosis underwent cognitive assessment of memory and processing speed. People with multiple sclerosis scored 70% higher on cooler days; no association was found for individuals without multiple sclerosis. Funding was provided by the National MS Society and the NIH.

According to Victoria M Leavitt PhD, research scientist, and the study’s principal investigator, these findings have implications for patients, clinicians, and researchers. “This information is relevant to making life decisions and choosing therapies and evaluating their effects,” said Dr Leavitt. “Outdoor temperatures may be an important consideration when designing and conducting clinical trials, many of which span 6 months.” For example, taking baseline measurements during warmer months could inflate positive findings. The study’s co-investigators are James F Sumowski PhD, Research Scientist, Nancy Chiaravalloti PhD, Director of Neuropsychology & Neuroscience Research, and John DeLuca PhD, VP for Research.

Source: News Release
Kessler Foundation
March 13, 2012