News Release

Kessler Foundation researchers link task length with cognitive fatigue in MS

Findings have implications for study design in cognitive MS research

Peer-Reviewed Publication

Kessler Foundation

Joshua Sandry, Kessler Foundation

image: Dr. Sandry is a postdoctoral fellow in Neuropsychology & Neuroscience Research at Kessler Foundation. His fellowship is funded by a grant from the National Multiple Sclerosis Society. view more 

Credit: Kessler Foundation

West Orange, NJ. January 21, 2015. Kessler Foundation researchers have authored a new article that provides insight into the factors that contribute to cognitive fatigue in individuals with multiple sclerosis (MS). The article, "Subjective cognitive fatigue in MS depends on task length," was epublished ahead of print on October 27 in Frontiers in Neurology (doi: The authors are Joshua Sandry, PhD, Helen Genova, PhD, Ekaterina Dobryakova, PhD, John DeLuca, PhD, and Glenn Wylie, DPhil, of Kessler Foundation. This study was supported by the National MS Society and the New Jersey Commission for Brain Injury Research.

Cognitive fatigue, which is common in MS, has subjective and objective manifestations. Treatment for fatigue is hindered by the lack of understanding of contributing factors. This study examined how the variables of processing speed, working memory, time on task and cognitive load influence cognitive fatigue in 32 individuals with MS and 24 controls. The investigators found that subjective and objective fatigue were independent of one another, and that subjective cognitive fatigue increased as time on task increased. This increase in cognitive fatigue was greater in the MS group. No relationship was found between cognitive fatigue and the other cognitive variables.

"In our study, task length was the factor associated with subjective cognitive fatigue," said Dr. Sandry, lead author, "which supports the hypothesis of Temporal Fatigue. This finding should be considered when designing cognitive studies in MS populations." Dr. Sandry noted, "More research is needed to look at these parameters in people with different types of MS, different levels of cognitive impairment and in more advanced stages."


Grant support: NMSS RG 4232A1/1 (Helen M. Genova); New Jersey Commission for Brain Injury Research 10-3216-BIR-E-0 (Glenn Wylie); NMSS) Postdoctoral Fellowship Grant MB0024 (Joshua Sandry).

About MS Research at Kessler Foundation

Kessler Foundation's cognitive rehabilitation research in MS is funded by grants from the National Institutes of Health, National MS Society, NJ Commission of Brain Injury Research, Consortium of MS Centers, Biogen Idec, Hearst Foundation, the International Progressive MS Alliance, and Kessler Foundation. Under the leadership of John DeLuca, PhD, senior VP for Research & Training, and Nancy Chiaravalloti, PhD, director of Neuropsychology & Neuroscience Research, scientists have made important contributions to the knowledge of cognitive decline in MS. Clinical studies span new learning, memory, executive function, attention and processing speed, emotional processing, employment and cognitive fatigue. Research tools include innovative applications of neuroimaging, mobile devices, and virtual reality. Among recent findings are the benefits of cognitive reserve and aerobic exercise; correlation between cognitive performance and outdoor temperatures; efficacy of short-term cognitive rehabilitation using modified story technique; factors related to risk for unemployment, and the correlation between memory improvement and cerebral activation on fMRI. Foundation research scientists have faculty appointments at Rutgers New Jersey Medical School. The opening of the Rocco Ortenzio Neuroimaging Center at Kessler Foundation has greatly expanded the Foundation's capability for neuroscience research in MS and other neurological conditions.

About Kessler Foundation

Kessler Foundation, 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. Kessler Foundation leads the nation in funding innovative programs that expand opportunities for employment for people with disabilities. For more information, visit

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