Fatigue, or extreme tiredness and exhaustion, is one of the most common and disabling symptoms of multiple sclerosis (MS). A new study suggests that fatigue in people with MS may actually be a sign of an undiagnosed sleep disorder.

“Sleep problems may be a hidden epidemic in the MS population, separate from MS fatigue,” lead author Dr. Steven Brass said in a news release. He is co-medical director of the UC Davis Sleep Medicine Laboratory.

Multiple sclerosis is a crippling disease that affects the brain and spinal cord. It causes the body’s immune system to damage the protective covering that surrounds the nerves. This damage disrupts messages between the brain and other parts of the body. The cause of the disease is unknown.

The study involved almost 2,400 people diagnosed with MS. Each completed a survey about MS history and duration, medication use and detailed sleep history. More than half of the study group said it took them longer than a half hour to fall asleep at night. Nearly 11 percent reported taking medication to fall asleep.

Results show that 70 percent of the study group screened positive for at least one sleep disorder. Nearly 38 percent had symptoms of obstructive sleep apnea (OSA). OSA is a chronic disease that involves repetitive pauses in breathing during sleep. Almost 32 percent reported symptoms of moderate to severe insomnia. Insomnia occurs when you have trouble falling asleep, staying asleep or waking up too early. Around 37 percent had signs of restless legs syndrome (RLS). RLS is a sleep disorder that affects the nervous system and makes you have an overwhelming urge to move your legs.

Despite these common symptoms, most of the participants had not been diagnosed with a sleep disorder by a doctor. Just 4 percent of those with symptoms of OSA had been diagnosed by a doctor. Similar data were seen for the other sleep disorders as well.

“This work suggests that patients with MS may have sleep disorders requiring independent diagnosis and management,” said Brass.

Be sure that you never ignore an ongoing sleep problem. You don’t have to go through life feeling tired, exhausted and frustrated. Help is available. Talk to your doctor. Ask about setting up an appointment with a sleep specialist at an accredited sleep center.

The study is published in the September issue of the Journal of Clinical Sleep Medicine.