An interesting article in a recent sleep medicine journal describes a rare condition where women moan intensely while sleeping. Contrary to what you may have been thinking, these women were not moaning due to either pain or erotic dreams. These seven women sought treatment at Stanford's sleep clinic due to a condition which has been coined catathrenia. They were all embarrassed by their condition, as well as having family members who were alarmed by the strange noises. Catathrenia has been classified in the parasomnia category, which are disturbances that occur during sleep-wake transitions, in contrast to sleep-breathing problems such as obstructive sleep apnea. This condition is typically seen in younger, premenopausal women, who are relatively thin.
When these women underwent an overnight sleep study, none were found to have obstructive sleep apnea. However, they all had in common the typical feature of multiple breathing pauses with arousals, leading to inefficient sleep. All these women also had in common smaller jaw sizes and a history of dental extractions for crowding or orthodontic problems. Many also complained of chronic fatigue symptoms as well.
This article caught my attention because of the nature of the cure for this condition. All the women were essentially cured with treatment that's normally given for people with obstructive sleep apnea. Yet, they didn't have obstructive sleep apnea. What they really had was upper airway resistance syndrome (UARS). As I've described at length in other articles, UARS is a variation/precursor to obstructive sleep apnea, where people have narrowed upper airway anatomy that causes brief obstructions and breathing pauses that are not severe enough to be called obstructive sleep apnea.
To receive a diagnosis of obstructive sleep apnea, you have to stop breathing completely or partially for 10 seconds or more, at least 5 times every hour while you sleep. But if you stop breathing 15 times every hour, but wake up after 2-3 seconds each, then your apnea score is 0 and you're told you don't have obstructive sleep apnea. These UARS patients are constantly tired and suffer from various other chronic conditions such as recurrent sinus pain or infections, low blood pressure, cold hands or feet, various gastrointestinal symptoms, anxiety/depression, and almost invariably, prefer not to sleep on their backs.
The lead author of this article (Dr. Guilleminault at Standford University) was the first to describe UARS as well. In his original UARS paper, he treated these constantly tired people with CPAP, or continuous positive airway pressure. This is a device that delivers gentle air pressure through the nose, thereby keeping their breathing passageways open. For the most part, they all did well, but in the long term, they could not continue sleeping with masks and hoses attached to their faces. Most UARS patients, due to heightened sensitivities, are unable to tolerate this device.
In this current study describing catathrenia, many of the patients tried CPAP as well, which worked, but they all refused to use it continuously. Most of the patients subsequently underwent various surgical procedures of the throat, and were reported as being "cured."
It's amazing how often I find studies that link common and uncommon medical conditions to sleep-breathing disorders. Knowing that sleep-breathing disorders (obstructive sleep apnea or upper airway resistance syndrome) may be linked to depression, anxiety, cold hands, migraines, irritable bowel syndrome, chronic fatigue syndrome, polycystic ovarian syndrome, obesity, ADHD, TMJ, diabetes, high blood pressure, high cholesterol, heart disease, heart attack and stroke, could a breathing problem during sleep be the common link? I've even seen multiple articles linking obstructive sleep apnea to epilepsy and cluster headaches. In my forthcoming book, Sleep, Interrupted, I propose that the this may be a possibility. It may be a bit of a stretch to say a definite yes, but I'm confident that in 10 to 15 years, the answer to the above question will be more clear. This just goes to show that what we generally take for granted my have an alternate explanation.