People with multiple sclerosis often complain that they experience both mental and physical fatigue. A new study published in the October 10 issue of Neurology, the scientific journal of the American Academy of Neurology, helps 1 why.
The study showed that MS patients lose cognitive ability after repeated testing, while healthy people improved while taking the same tests. The study involved 45 individuals with MS and 14 control participants who were given tests which measured memory, conceptual planning, attention span and verbal communication. While the control participants improved following repeated testing, the MS participants performed worse. For example, following two rounds of mathematical tests, the MS patients had slower reaction times than the control group. The MS patients also reported feeling more depressed and more physically and mentally fatigued than did the control participants.
According to neurologist Lauren Krupp, MD, of the State University of New York at Stony Brook, the study is significant because it could increase understanding of the disease. "These findings on the mental fatigue experienced by MS patients during the course of a day should be of interest to teachers, employers, family members and others who regularly interact with MS sufferers," she said.
While the causes of physical fatigue in MS have been identified, researchers still aren't sure why MS patients suffer from mental fatigue. However, Krupp said, cognitive activity may be affected by problems with major organs or the blood system. "For example, fluctuations in supply or metabolism of glucose, the primary fuel for the brain, may have some impact on declines in cognitive performance,"