Sleep apnoea - or 'apnea', the American spelling - is a common, well-known set of medical dysfunctions that have been identified for decades. Until the 1970s, however, they were not considered a serious disorder. That has changed.
Apnoea is Greek for ‘without breath’, and refers to periods during the night when a sleeper’s breathing stops. These periods occur in one of three modes:
Central Sleep Apnoea (CSA: where the mind fails to trigger the autonomic breathing reflex; the most benign form)
Obstructive Sleep Apnoea (OSA: where the failure to breathe is caused by a structural obstruction; the most dangerous form)
Mixed Sleep Apnoea (which is simply a mixture of the two).
Central Sleep Apnoea tends to be self-correcting, as the brain tends to detect the lowered oxygen level and rouses the autonomic breathing function before serious damage from oxygen deprivation is likely to occur. As Mixed Sleep Apnoea is normally only a serious problem because of the Obstructive component, only Obstructive Sleep Apnoea (the most commonly diagnosed and medically serious form), its causes, symptoms, and treatments, will be further discussed here.
Sleep researchers divide sleep into 5 general levels, 1 through 4 and REM (Rapid Eye Movement, or dream state). A normal pattern will start with higher levels 1 and 2, then progress through deeper levels 3 and 4. The progression will not always be linear however. Sounds, movements of bed partners, etcetera, can rouse sleepers from those lower levels without ever bringing them completely out of sleep.
After the lower levels have been achieved, short periods of REM are experienced, gradually lengthening as they happen through the night. Breathing tends to be deep and regular, especially during the deeper stages. Some variation is common during REM, apparently depending on the content of the dreams.
Toward morning, there is generally a longish (10 to 20 minute) period of REM that is the one most likely to result in a dream one might remember on awakening.
One clinical definition of an adult apnoea is 'a ten second cessation of breathing', and a child apnoea as 'the equivalent of two-and-a-half missed breaths'.
The periods and frequencies of apnoea are individual to the patient. They may run from a few ‘episodes’ a night, to hundreds; their duration may last from seconds to more than a minute. The dangers of apnoea are oxygen deprivation and, because of it, a rapid increase in heart rate as the body attempts to speed the suddenly inadequate oxygen supply through the body.
The rapid heart rate is not initially a health concern; but, repeated multiple times a night, over years and decades, the heart become enlarged and ‘worn out’; putting the patient at a constantly increasing risk of heart failure.
Apnoea sufferers often exhibit extreme daytime drowsiness and 'instant napping' abilities, caused by their 'sleep deprivation'. This is not considered 'good sleep' and only marginally makes up for the lost nightime rest. The nap attacks can be easily mistaken for narcolepsy - a disorder that causes people to, suddenly and without warning, enter sleep mode, often under times of stress.
In some rarer cases, the sufferer may not experience extreme daytime drowsiness, as the brain compensates for the sleep-time distress by shortening the time needed to get to sleep, enter deep sleep, and by moving massive blocks of REM up to the beginning of the night. The result is a shortened sleep pattern that counters some of the problems with sleep deprivation, but does little to protect the heart from the inevitable periods rapid heart function.
Symptoms and Detection
For most apnoea sufferers, their first indication that they may have a problem will likely come from family members or bed partners. Obstructive Sleep Apnoea sufferers are often heavy snorers, often referred to as wall-shakers or similar appellation.
Bed partners are the most likely to notice that actual apnoea is occurring.
Symptoms to be aware of include daytime drowsiness and nap attacks (the ability to nearly instantly fall into deep sleep): falling asleep at the wheel of a car or at a desk, lessened ability to concentrate and think clearly, general fatigue, falling asleep in front of the television or while reading.
It is the absence of sufficient REM (dreams) that contributes most to the drowsiness felt during the day. So an additional symptom is the continued lack of dreams remembered on waking. If you consistently have 'dreamless' sleep, you may be suffering from apnoea.
Additional symptoms may include high blood pressure and other cardiovascular disease, memory problems, weight gain, impotency, and headaches.
Strangely, as the apnoea-induced stress on the body makes sleeping an uncomfortable act, one can find that they sleep less than a healthy seven or eight hours a night, perhaps as little as two or three. They may even unconsciously develop sleep avoidance tendencies, probably because of a subconscious awareness of the distress that the body feels during the apnoea episodes.
The most common cause of the obstruction, or blockage, is soft tissue at the rear of the throat. There are patients for whom the tongue is a problem, or inadequate muscle tension of the tongue and throat muscles.
Weight can be a substantial part of an apnoea problem. OSA is more common among the obese, especially men over forty; but is not dependent on any of these statistical factors. Even normal weight children have been known to be afflicted.
There may be accompanying problems with the nasal passages, swollen turbinates (scroll-like, membrane-covered, bony plates on the wall of the nasal cavity) and/or chronic congestion.
A severely deviated septum can contribute to the effects of any other obstructions.
Some instances of 'cot-death', or 'crib-death', are thought to be the result of infant sleep apnoea.
To be properly diagnosed, one must visit a sleep clinic, or sleep lab equipped hospital. One common method is a two night (nights only) stay at the site.
The first night, the body is wired up with skin surface sensors (brainwave, eyelid, oxygen, leg muscle, chest expansion, and others) and allowed to attempt a normal eight hour sleep. The goal is to measure the frequencies and lengths of any periods of apnoea.
The second night the procedure is repeated, but with the addition of a CPAP (Continuous Positive Air Pressure) or Bi-PAP (Bi-directional Positive Air Pressure) device aiding the patient’s breathing.
If during the first night the patient displays a severe apnoea problem, the device may be brought immediately into play. After any testing, the readouts are studied for breathing, muscle activity, heart rates, sleep patterns, etc. These readings are correlated to provide a clear picture of any potential sleep problems, and should point to areas of potential treatment.
Treatments and Surgeries
Some patients gain moderately or substantially from Treatments or Surgeries which may include any combination of -
Weight Loss: If the symptoms developed after a weight gain, this may be all that is necessary to reduce the apnoeas to a non-threatening level.
Allergy Treatment: If the apnoeas are largely congestion related, caused by allergies to foods or environment, changes in diet or environment may be of value.
Soft tissue: removal of soft tissue at the back of the throat, the palate, or a portion of the tongue.
Neck muscle: surgical tightening of muscles that are too relaxed to aid in keeping the air passages open during sleep.
Septoplasty: normalisation of the breathing passages by correcting a Deviated Septum.
Improvement in the neck muscles ability to keep passages open have also been realised in patients undergoing therapy such as the throat muscle exercise that results from singing or taking up wind instruments.
Nasal: Somnoplasty (reduction of the turbinates through cauterisation), or Radio-Somnoplasty, reducing the turbinates by ‘cooking’ them from the inside with an inserted needle-antenna and radio waves).
Here too, exercise can be a benefit. Most people have a tendency to take shallow breaths, utilising less than 25% of their lung capacity. Deep breathing exercises can help retrain the body to expect deeper breaths, and better oxygenate the blood.
Non-Surgical treatment may be through use of a CPAP (Continuous Positive Air Pressure); or Bi-PAP (Bi-directional Positive Air Pressure) device aiding the patient’s breathing; or even combining oxygen with one of the other two.
The intents of the treatments are two-fold; the first is to stop the apnoeas from occurring, the second (nearly as vital to sleep health) is to return the patient to a normal seven or eight-hour sleep pattern.
This can be a serious disorder. Prolonged, untreated OSA can lead to a reduced quality of life, and an early death. Persons who have been given reason to suspect that they might have OSA should be checked. No one should need suffer from this potentially debilitating and dangerous dilemma; and nobody should put others at risk by driving if they may be a danger to themselves, their passengers, or their fellow travellers.