Complex sleep apnea is described by Mayo Clinic researchers

Reported by Susan Aldridge, PhD, medical journalist

A new type of sleep apnea, which is not responsive to conventional treatment, has now been discovered.
Sleep apnea is a disorder marked by a cessation of breathing many times in the night because of an obstruction of the airways. Research has found that sleep apnea is linked to heart disease. But it can normally be treated by a continuous airway pressure (CPAP) machine, which can open up the airways again. Now Mayo Clinic researchers have found that some patients don't benefit from this approach and may be suffering from a previously unknown form of sleep apnea.

They have looked at a group of 224 patients referred to the Mayo sleep clinic and found that 15 per cent have what they call complex sleep apnea, which is not relieved by CPAP. Males have a higher tendency to complex sleep apnea. One characteristic was not waking so much after initially falling asleep, a common complaint in 'ordinary' sleep apnea. The condition can be diagnosed by looking at sleep patterns in the sleep lab. The lack of response to conventional treatment for sleep apnea is a concern, but research into finding an effective way of treating the complex form of the condition is underway.

Source
Sleep September 2006