Sleep apnea is a breathing problem that keeps sufferers -- and their bedmates -- from getting a proper night's rest. Until now, there were only two kinds.
The most common kind is obstructive sleep apnea. That's when throat muscles relax and flesh in the throat can block the airway. There's also central sleep apnea. That's when the brain gives mixed-up signals to the muscles that control breathing.
Some people suffer both problems, find Timothy I. Morgenthaler, MD, and colleagues at the Mayo Clinic Sleep Disorders Center. They're calling this "complex sleep apnea."
The finding stems from the observation that the standard treatment for obstructive sleep apnea fails some patients. The treatment is a continuous airway pressure or CPAP machine. It uses air forced through a mask to keep a person's airway open during sleep.
"All of us in our sleep labs have observed for years that there are patients who appear to have obstructive sleep apnea, but the CPAP doesn't make them all that much better -- they still have moderate to severe sleep apnea even with our best treatment," Morgenthaler says, in a news release.
Complex Apnea: Men More Vulnerable
The Mayo researchers reviewed the records of 223 consecutive sleep clinic patients. They also looked at the records of 20 consecutive patients with central sleep apnea.
They found that 15% of sleep apnea patients have complex apnea, 84% have obstructive apnea, and 0.4% have central sleep apnea.
Obstructive sleep apnea strikes more men than women. But complex sleep apnea is much more of a male problem -- 81% of Mayo's complex apnea patients were men.
Unfortunately, the best treatment for complex sleep apnea isn't yet known.
The Mayo study appears in the September issue of the journal Sleep.
SOURCES: Morgenthaler, T.I. Sleep, September 2006; paper received in advance of publication. News release, Mayo Clinic.
By Daniel DeNoon
Reviewed by Louise Chang