Snoring is defined as noisy breathing during sleep that is caused by vibration of the soft palate in the pharynx (that portion of the upper passage which is located behind the tongue and soft palate in the upper third of the neck).
Anything which interferes with or obstructs the airway may cause snoring. It can also be due to a combination of relaxed soft tissues and narrowed passage; either due to congenital factors or the presence of obstructing masses.
In children, snoring is most likely caused by enlarged adenoids blocking the nasopharynx [the airway behind the nasal cavity] or enlarged tonsils blocking the oropharyngeal airway [the throat].
The most common cause of snoring in young adults is usually ingestion of alcohol prior to bedtime. Excessive relaxation and swelling of the oropharynx soft tissues are the cause of the narrowing of the airway.
When an individual ages, the amount of electrical signals sent by the brain to the muscles that control the opening of the airway during sleep tends to decrease, thus allowing the muscles to become more flaccid. When the muscles become flaccid, they flutter and vibrate during inhalation and produce snoring sounds.
Obesity and a large neck circumference may also contribute to snoring.
Depending upon the amount of air that passes through the airway and the speed with which the muscles of the throat and upper neck vibrate, the pitch and depth of the snoring sound can vary from as soft as a whisper to an extremely loud raucous sound. Generally speaking, the narrower the airway, i.e. the greater the obstruction, the greater is the effort required for inhalation and the louder the snoring. However, absence of snoring may indicate complete obstruction with no airflow.
Snoring in patients who do not have sleep apnea is called “Simple or Nonapneic snoring". Snoring in these patients usually produces no symptoms, with the exception of the adverse effect their snoring may have upon their bed partners.
Snoring is a sign that during sleep, the airway has become narrower than normal. In some snoring patients, the increased effort of breathing through this narrowed airway increases the work of breathing to such an extent that it fragments the sleep and disrupts the deep restorative Stage III and Stage IV sleep which is primarily responsible for the restoration of energy and daytime alertness.
These so called "Sleepy Snorers" have what is now known as the Upper Airway Resistance Syndrome [UARS]. For these individuals, snoring is associated with fatigue, daytime sleepiness, lack of concentration and often reduced work performance.
Simple Snoring, Upper Airway Resistance Syndrome and Sleep Apnea represent different degrees of narrowing of the upper airway during sleep.
In Simple Snoring the airway is only slightly narrowed and/or blocked. It remains patent and the only sign of narrowing is vibration [snoring]. In Upper Airway Resistance Syndrome, the narrowing of the airway is more pronounced. While it remains patent, the increased breathing effort through narrowed airway invariably fragments the sleep. In Obstructive Sleep Apnea, the airway completely collapses and blocks the movement of air.
Sleep apnea is an involuntary obstruction of breathing during sleep that causes a complete cessation of air flow to the lung. Each obstruction lasts for a minimum of 10 seconds and in some cases may last as long as two minutes. There are two types of sleep apneas, the obstructive types (when blockage of the pharynx is the cause) and central type, when the absence of brain signals for breathing is the cause of cessation of airflow.
Sleep apnea occurs in all age groups and ethnic groups and affects both sexes, although it occurs more commonly in males than in females.
Approximately 2 million Canadians suffer from significant sleep apnea
4% of middle-aged men have sleep apnea associated with daytime sleepiness.
2% of middle-aged women have sleep apnea associated with daytime sleepiness.
Obstructive sleep apnea is a serious, potentially life-threatening condition that is characterized by brief recurring interruptions of breathing during sleep. Sleep apnea occurs when the tongue and the muscles of the throat relax during sleep and temporarily block the airway entirely. Surprisingly, obstructive sleep apnea was not recognized until 1965.
During normal sleep, the muscles that control the tongue, the soft palate and the air passage in the upper part of the neck receive electrical signal from the brain and contract. Contraction of the muscles causes the airway to stay open. If the electrical activities from the brain decrease, then these muscles relax and the airway becomes narrower, thereby partially or completely blocking the air passage. Presence of enlarged tonsils, adenoid or a tumor in the nasopharynx or tongue base can contribute to further obstruction. Other anatomical factors such as small jaw, excessive fat in a short neck and narrow palatal arch are the common contributing factors as well.
For most individuals, sleep apnea appears to result from a failure of the brain to continue sending sufficient electrical signals to those muscles in the upper neck. Eventually, when the electrical activities diminish further or cease completely, the muscles are unable to hold the air passage open and collapse inwards, resulting in total blockage of the air passage during inhalation (breathing in). Because there is a complete obstruction, there is no air flow and consequently no sounds are heard during the apnea.
Sleep Apnea can be diagnosed via an overnight sleep study [polysomnogram].
A polysomnogram is a diagnostic test that records a variety of body functions during sleep, including the electrical activity of the brain, eye movement, muscle activity, heart rate, respiratory effort, air flow and blood oxygen levels. These parameters are used collectively to both diagnose sleep apnea and also to determine its severity.
The specific sleep apnea treatment prescribed is based upon each patient’s medical history, physical examination and the results of their overnight sleep study. A common treatment for obstructive sleep apnea is Continuous Positive Airway Pressure (CPAP). It should be noted that medication is generally not effective in the treatment of obstructive sleep apnea. Other treatment options include surgery to correct anatomical obstruction such as removal of a large tonsils and widening of an obstructing pharynx such as palatal surgery.
Continuous Positive Airway Pressure [CPAP] is the most common and most effective treatment for sleep apnea.
With CPAP, the patient wears a mask over the nose (or over the nose and mouth) during sleep and breathes air which is at a slightly greater pressure than the surrounding air. The air inside the patients' air passage is then maintained at a greater pressure than the air surrounding the body. This pressure differential pressurizes and holds open the air passage in the upper neck where the obstruction resulting from inadequate innervations of the muscles occur during sleep.
The pressure of the inhaled air is constantly monitored and adjusted during an overnight sleep study [a CPAP Titration Study] so that it is sufficiently high enough to prevent the throat from collapsing during sleep, which prevent the happening of "apnea".
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