Tired all the time: Could undiagnosed sleep problems be making MS patients' fatigue worse?

People with multiple sclerosis (MS) might assume that the fatigue they often feel just comes with the territory of their chronic neurological condition.

But a new University of Michigan study suggests that a large proportion of MS patients may have an undiagnosed sleep disorder that is also known to cause . And that disorder – obstructive – is a treatable condition.

In the latest issue of the Journal of Clinical Sleep Medicine, researchers from the U-M Health System's Sleep Disorders Center report the results of a study involving 195 patients of the U-M Multiple Sclerosis Center.

In all, 56 percent of the MS patients were found to be at increased risk for obstructive sleep apnea, based on a method of screening for the condition known as the STOP-Bang questionnaire. But most had never received a formal diagnosis of sleep apnea, and less than half of those who had been told they had sleep apnea were using the standard treatment for it.

The authors also found that patients who were more fatigued were more likely to also be at elevated risk for sleep apnea – even after taking into account other factors that might have contributed to feelings of fatigue, such as age, gender, body mass index (BMI), , depression, and other nighttime symptoms.

The research is based on patients' answers from a sleep questionnaire designed by the authors, and four validated instruments designed to assess daytime sleepiness, fatigue severity, insomnia severity and obstructive sleep apnea risk. Medical records also were accessed with patients' permission, to examine clinical characteristics that may predict fatigue or obstructive sleep apnea risk.

"We were particularly surprised by the difference between the proportion of patients who carried an established diagnosis of obstructive sleep apnea – 21 percent—and the proportion at risk for obstructive sleep apnea based on their STOP-Bang scores, which was 56 percent," says the study's lead author, Tiffany Braley, M.D., M.S. "These findings suggest that OSA may be a highly prevalent and yet under-recognized contributor to fatigue in persons with MS."

Braley, an assistant professor of Neurology and specialist at the U-M Medical School, conducted the study in collaboration with professors Ronald Chervin, M.D., M.S., and Benjamin Segal, M.D. Chervin is the Director of U-M Sleep Disorders Center, and Segal directs the U-M MS Center.

Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system that causes inflammation and damage of the brain and spinal cord. In addition to neurological disability, MS patients suffer from a number of chronic symptoms, the most common of which is fatigue. Fatigue is also one of the most disabling symptoms experienced by MS patients.

Braley cautions that the design of this new study does not allow for demonstration of cause and effect – that is, the researchers can't prove based on survey results that the patients felt more fatigued because they had a high score on a sleep apnea risk survey. But, she says, "the findings should prompt doctors who treat MS patients to consider sleep apnea as a possible contributor to their patients' fatigue, and recommend appropriate testing and treatment."

The standard treatment for , called continuous positive airway pressure, or CPAP, involves a machine and mask device that applies a stream of air to the upper airway to keep it open during sleep.

The patients in the study had an average age of 47 and had lived with MS for an average of 10 years. Two-thirds were female, consistent with the prevalence of MS in the U.S., and two-thirds were taking a medication to treat their MS. Three-quarters had the relapsing-remitting form of the disease.

More information: Reference: "Obstructive Sleep Apnea and Fatigue in Patients with Multiple Sclerosis," Journal of Clinical Sleep Medicine, dx.doi.org/10.5664/jcsm.3442

add to favorites email to friend print save as pdf

Related Stories

Sleep apnea common among stroke-related brainstem injuries

Feb 12, 2014

People whose brainstems are affected by their stroke have a significantly higher prevalence of sleep apnea than those who have stroke-related injury elsewhere in the brain, according to research presented at the American ...

Recommended for you

Sleep apnea linked to poor aerobic fitness

Nov 24, 2014

People with moderate to severe obstructive sleep apnea may have an intrinsic inability to burn high amounts of oxygen during strenuous aerobic exercise, according to a new study led by researchers at University ...

Sleep apnea may contribute to kidney disease progression

Nov 14, 2014

Sleep apnea may accelerate kidney function decline in diabetic patients with kidney disease, according to a study that will be presented at ASN Kidney Week 2014 November 11-16 at the Pennsylvania Convention Center in Philadelphia, ...

Surgery for sleep apnea improves asthma control

Nov 04, 2014

Surgical removal of the tonsils and adenoids in children suffering from sleep apnea is associated with decreased asthma severity, according to the first large study of the connection, published in the journal ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.