Multiple Sclerosis (MS) is a disorder in which the body's immune system attacks and destroys myelin, a membrane that covers axons in the brain and spinal cord. Myelin serves both to protect axons and to speed the conduction of electrical impulses along nerve fibers. The destruction of myelin results in scarring and loss of nerve cells and can lead to a whole host of symptoms for MS patients, including paralysis, depression, loss of memory, fatigue and problems with vision, balance, bladder and bowel control. However, because it is a disease that progresses slowly, MS can be very mild for some patients and many people with MS are able to lead full and active lives.
According to the National Institute of Neurological Disorders and Stroke at the National Institutes of Health, MS is more common in women than men and is more than twice as likely to affect whites as other races. Also, the prevalence of MS among people in the more northerly climate zone is five times higher than for people in the tropics. The cause of MS is unknown but environmental, viral and genetic causes may play a role. MS is not fatal or contagious, although severe symptoms may lead to a shortened or decreased quality of life for some people.
Fatigue, one of the most common symptoms of MS, can be profoundly disabling. The cause of fatigue in MS is not well understood but some researchers believe that the degree of fatigue felt by MS patients is an indication of how far along the disease has progressed. However, a recent study conducted by researchers from Pennsylvania State University found that depression and sleep disturbance were stronger predictors of fatigue in MS patients than disease severity. Specifically, the results of this study showed that all three contribute to fatigue in MS, but that sleep disturbance is the biggest contributor.
MS is also associated with a number of sleep disorders. According to a study led by W. Elon Fleming, MD, at the Sleep Disorders Center at Island Hospital in Anacortes, Washington, the most common sleep disorders in MS patients are