Mayo Clinic researchers discover new type of sleep apnea

The two previously known types of sleep apnea are obstructive sleep apnea and central sleep apnea. In obstructive sleep apnea, the more common form, the throat muscles relax and the airway is narrowed, momentarily cutting off breathing and resulting in noisy snoring. With central sleep apnea, the brain does not send proper signals to the muscles that control breathing.

The newly discovered type, complex sleep apnea, is a combination of both obstructive and central sleep apneas.

Patients with complex sleep apnea at first appear to have obstructive sleep apnea and stop breathing 20 to 30 times per hour each night. However, unlike typical obstructive sleep apnea patients, their breathing problem is not completely alleviated by a continuous airway pressure (CPAP) machine, which functions like a pneumatic splint to open a patient’s airway.

Instead, once the CPAP is applied to complex sleep apnea patients, the obstruction seems to dissipate, but they still do not breathe properly. Symptoms of central sleep apnea then appear and fragmented sleep results, due to frequent pauses in breathing.

The investigators found that complex sleep apnea comprised 15% of all sleep apnea patients, while 84% had obstructive sleep apnea and 0.4% had central sleep apnea. They also discovered that males have a higher tendency to have complex sleep apnea. The researchers said that this may be due to less stable respiratory control in males than females.

The complex sleep apnea patients had sleep and cardiovascular histories similar to the obstructive sleep apnea patients.

According to the Mayo Clinic researchers, no known factors influence risk for complex sleep apnea. An effective treatment has not been identified, but research continues to test breathing assistance machines to alleviate this condition’s symptoms.