Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder and is characterized by recurrent episodes of complete or partial

obstruction Obstruction may refer to: Places * Obstruction Island, in Washington state * Obstruction Islands, east of New Guinea Medicine * Obstructive jaundice * Obstructive sleep apnea * Airway obstruction, a respiratory problem ** Recurrent airway o ...

of the upper airway leading to reduced or absent breathing during

sleep Sleep is a sedentary state of mind and body. It is characterized by altered consciousness, relatively inhibited sensory activity, reduced muscle activity and reduced interactions with surroundings. It is distinguished from wakefulness by a de ...

. These episodes are termed " apneas" with complete or near-complete cessation of breathing, or "

hypopnea Hypopnea is overly shallow breathing or an abnormally low respiratory rate. Hypopnea is defined by some to be less severe than apnea (the complete cessation of breathing), while other researchers have discovered hypopnea to have a "similar if not ...

s" when the reduction in breathing is partial. In either case, a fall in blood oxygen saturation, a disruption in sleep, or both may result. A high frequency of apneas or hypopneas during sleep may interfere with restorative sleep, whichin combination with disturbances in blood oxygenationis thought to contribute to negative consequences to health and quality of life. The terms obstructive sleep apnea syndrome (OSAS) or obstructive sleep apnea–hypopnea syndrome (OSAHS) may be used to refer to OSA when it is associated with symptoms during the daytime (e.g. excessive daytime sleepiness, decreased cognitive function). Most individuals with OSA are unaware of disturbances in breathing while sleeping, even after awakening. A bed partner or family member may observe an individual

snoring Snoring is the vibration of respiratory structures and the resulting sound due to obstructed air movement during breathing while sleeping. The sound may be soft or loud and unpleasant. Snoring during sleep may be a sign, or first alarm, of ob ...

or appear to stop breathing, gasp, or choke while sleeping. Individuals who live or sleep alone are often unaware of the condition. Symptoms may be present for years or even decades without identification, during which time the individual may become conditioned to the daytime sleepiness, headaches and fatigue associated with significant levels of sleep disturbance. Obstructive sleep apnea has been associated with neurocognitive morbidity, as well as a link between snoring and neurocognitive disorders.

Classification

In the third edition of the

International Classification of Sleep Disorders The International Classification of Sleep Disorders (ICSD) is "a primary diagnostic, epidemiological and coding resource for clinicians and researchers in the field of sleep and sleep medicine". The ICSD was produced by the American Academy of Slee ...

(ICSD-3), obstructive sleep apnea is classified amongst the sleep-related breathing disorders and is divided in two categories, namely adult OSA and pediatric OSA. Obstructive sleep apnea is differentiated from

central sleep apnea Central sleep apnea (CSA) or central sleep apnea syndrome (CSAS) is a sleep-related disorder in which the effort to breathe is diminished or absent, typically for 10 to 30 seconds either intermittently or in cycles, and is usually associated w ...

(CSA), which is characterized by episodes of reduction or cessation in breathing attributable to decreased effort, rather than upper airway obstruction. The respiratory effort must then be assessed in order to correctly classify the apnea as obstructive given the specificity of the diaphragmatic activity in this condition: the inspiratory effort is continued or increased through the entire episode of absent airflow. When

s are present alongside apneas, the term obstructive sleep apnea-hypopnea is used and when it is associated with daytime sleepiness and other daytime symptoms, it is called obstructive sleep apnea-hypopnea syndrome. To be categorized as obstructive, the hypopnea must meet one or more of the following symptoms: (1)

during the event, (2) increased oronasal flow flattening, or (3) thoraco-abdominal paradoxical respiration during the event. If none of them are present during the event, then it is categorized as central hypopnea.

Signs and symptoms

Common symptoms of OSA syndrome include unexplained daytime sleepiness, restless sleep, and loud

(with periods of silence followed by gasps). Less common symptoms are morning

headaches Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches. Headaches can occur as a result ...

;

insomnia Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, ...

; trouble concentrating; mood changes such as

irritability Irritability (also called as crankiness) is the excitatory ability that living organisms have to respond to changes in their environment. The term is used for both the physiological reaction to stimuli and for the pathological, abnormal or excessi ...

anxiety Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...

, and depression; forgetfulness; increased heart rate or blood pressure; decreased sex drive; unexplained weight gain; increased urinary frequency or

nocturia Nocturia is defined by the International Continence Society (ICS) as “the complaint that the individual has to wake at night one or more times for voiding (''i.e. to urinate'').” The term is derived from Latin ''nox, night'', and Greek '' �α ...

; frequent heartburn or

gastroesophageal reflux Gastroesophageal reflux disease (GERD) or gastro-oesophageal reflux disease (GORD) is one of the upper gastrointestinal chronic diseases where stomach content persistently and regularly flows up into the esophagus, resulting in symptoms and/ ...

; and heavy night sweats. Many people experience episodes of OSA for only a short period. This can be the result of an upper respiratory infection that causes nasal congestion, along with swelling of the throat, or

tonsillitis Tonsillitis is inflammation of the tonsils in the upper part of the throat. It can be acute or chronic. Acute tonsillitis typically has a rapid onset. Symptoms may include sore throat, fever, enlargement of the tonsils, trouble swallowing, and en ...

that temporarily produces very enlarged tonsils. The Epstein-Barr virus, for example, is known to be able to dramatically increase the size of lymphoid tissue during acute infection, and OSA is fairly common in acute cases of severe

infectious mononucleosis Infectious mononucleosis (IM, mono), also known as glandular fever, is an infection usually caused by the Epstein–Barr virus (EBV). Most people are infected by the virus as children, when the disease produces few or no symptoms. In young adult ...

. Temporary spells of OSA syndrome may also occur in individuals who are under the influence of a drug (such as alcohol) that may relax their body tone excessively and interfere with normal arousal from sleep mechanisms.

Adults

The hallmark symptom of OSA syndrome in adults is

excessive daytime sleepiness Excessive daytime sleepiness (EDS) is characterized by persistent sleepiness and often a general lack of energy, even during the day after apparently adequate or even prolonged nighttime sleep. EDS can be considered as a broad condition encompass ...

. Typically, an adult or adolescent with severe long-standing OSA will fall asleep for very brief periods in the course of usual daytime activities if given an opportunity to sit or rest. This behavior may be quite dramatic, sometimes occurring during conversations with others at social gatherings. The hypoxia (absence of oxygen supply) related to OSA may cause changes in the neurons of the

hippocampus The hippocampus (via Latin from Greek , ' seahorse') is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, ...

and the right frontal cortex. Research using neuro-imaging revealed evidence of hippocampal atrophy in people with OSA. They found that OSA can cause problems in mentally manipulating non-verbal information, in

executive functions In cognitive science and neuropsychology, executive functions (collectively referred to as executive function and cognitive control) are a set of cognitive processes that are necessary for the cognitive control of behavior: selecting and suc ...

and

working memory Working memory is a cognitive system with a limited capacity that can hold information temporarily. It is important for reasoning and the guidance of decision-making and behavior. Working memory is often used synonymously with short-term memory, ...

. This repeated brain hypoxia is also considered to be a cause of Alzheimer's disease. Diagnosis of obstructive sleep apnea is significantly more common among people in relationships, who are alerted to their condition by being informed by their sleeping partner since individuals with obstructive sleep apnea are often unaware of the condition. There is a stigma associated with loud snoring, and it is not considered a feminine trait. Consequently, females are less likely to be told by their partners that they snore, or to admit it to themselves or doctors. Furthermore, CPAP (Continuous Positive Airway Pressure) machines are also perceived negatively by females, and less likely to be utilized to their full extent in this group.

Children

Although this so-called "hypersomnolence" (excessive sleepiness) may also occur in children, it is not at all typical of young children with sleep apnea. Toddlers and young children with severe OSA instead ordinarily behave as if "over-tired" or "

hyperactive Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by excessive amounts of inattention, hyperactivity, and impulsivity that are pervasive, impairing in multiple contexts, and otherwise age-inappr ...

"; and usually appear to have behavioral problems like irritability, and a deficit in attention. Adults and children with very severe OSA also differ in typical body ''habitus''. Adults are generally heavy, with particularly short and heavy necks. Young children, on the other hand, are generally not only thin but may have "

failure to thrive Failure to thrive (FTT), also known as weight faltering or faltering growth, indicates insufficient weight gain or absence of appropriate physical growth in children. FTT is usually defined in terms of weight, and can be evaluated either by a low ...

", where growth is reduced. Poor growth occurs for two reasons: the work of breathing is intense enough that calories are burned at high rates even at rest, and the nose and throat are so obstructed that eating is both tasteless and physically uncomfortable. OSA in children, unlike adults, is often caused by obstructive

tonsil The tonsils are a set of lymphoid organs facing into the aerodigestive tract, which is known as Waldeyer's tonsillar ring and consists of the adenoid tonsil, two tubal tonsils, two palatine tonsils, and the lingual tonsils. These organs play ...

s and

adenoid In anatomy, the adenoid, also known as the pharyngeal tonsil or nasopharyngeal tonsil, is the superior-most of the tonsils. It is a mass of lymphatic tissue located behind the nasal cavity, in the roof of the nasopharynx, where the nose blends ...

s and may sometimes be cured with

tonsillectomy Tonsillectomy is a list of surgical procedures, surgical procedure in which both palatine tonsils are fully removed from the back of the throat. The procedure is mainly performed for recurrent tonsillitis, throat infections and obstructive sleep ...

and

adenoidectomy Adenoidectomy is the surgical removal of the adenoid for reasons which include impaired breathing through the nose, chronic infections, or recurrent earaches. The effectiveness of removing the adenoids in children to improve recurrent nasal sympto ...

. This problem can also be caused by excessive weight in children. In this case, the symptoms are more like the symptoms adults feel such as restlessness, exhaustion, etc. If adenotonsillar hypertrophy remains the most common cause of OSA in children,

obesity Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's ...

can also play a role in the pathophysiology of upper airway obstruction during sleep which can lead to OSA, making obese children more likely to develop the condition. The recent epidemic increase of obesity prevalence has thus contributed to changes in the prevalence and in the characteristics of pediatric OSA, the severity of OSA being proportional to the degree of obesity. Obesity leads to the narrowing of upper airway structure due to fatty infiltration and fat deposits in the anterior neck region and cervical structures. Alongside with the additional weight loading on the

respiratory system The respiratory system (also respiratory apparatus, ventilatory system) is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies ...

, it increases the risk of pharyngeal collapsibility while reducing the intrathoracic volume and diaphragm excursion. Moreover, excessive daytime sleepiness resulting from sleep fragmentation can decrease physical activity and thus lead to weight gain (by sedentary habits or increased food intake to overcome

somnolence Somnolence (alternatively sleepiness or drowsiness) is a state of strong desire for sleep, or sleeping for unusually long periods (compare hypersomnia). It has distinct meanings and causes. It can refer to the usual state preceding falling asleep ...

). The obesity-related obstruction of upper airway structure has led some authors to distinguish between two types of OSA in children: type I is associated with marked lymphadenoid

hypertrophy Hypertrophy is the increase in the volume of an organ or tissue due to the enlargement of its component cells. It is distinguished from hyperplasia, in which the cells remain approximately the same size but increase in number.Updated by Linda J. ...

without obesity and type II is first associated with obesity and with milder upper airway lymphadenoid hyperplasia. The two types of OSA in children can results in different morbidities and consequences. Studies have shown that weight loss in obese adolescents can reduce

sleep apnea Sleep apnea, also spelled sleep apnoea, is a sleep disorder in which pauses in breathing or periods of shallow breathing during sleep occur more often than normal. Each pause can last for a few seconds to a few minutes and they happen many tim ...

and thus the symptoms of OSA.

Pathophysiology

The transition from wakefulness to sleep (either REM sleep or NREM sleep) is associated with a reduction in upper-airway muscle tone. During REM sleep, muscle tone of the throat and neck, as well as that of the vast majority of skeletal muscles, are almost completely relaxed. This allows the tongue and soft palate/oropharynx to relax, reducing airway patency and potentially impeding or completely obstructing the flow of air into the lungs during inspiration, resulting in reduced respiratory ventilation. If reductions in ventilation are associated with sufficiently low blood-oxygen levels or with sufficiently high breathing efforts against an obstructed airway, neurological mechanisms may trigger a sudden interruption of sleep, called a neurological arousal. This arousal can cause an individual to gasp for air and awaken. These arousals rarely result in complete awakening but can have a significant negative effect on the restorative quality of sleep. In significant cases of OSA, one consequence is sleep deprivation resulting from the repetitive disruption and recovery of sleep activity. This sleep interruption in Stage 3 (also called

slow-wave sleep Slow-wave sleep (SWS), often referred to as deep sleep, consists of stage three of non-rapid eye movement sleep. It usually lasts between 70 and 90 minutes and takes place during the first hours of the night. Initially, SWS consisted of both St ...

), and in REM sleep, can interfere with normal growth patterns,

healing With physical trauma or disease suffered by an organism, healing involves the repairing of damaged tissue(s), organs and the biological system as a whole and resumption of (normal) functioning. Medicine includes the process by which the cells ...

and

immune response An immune response is a reaction which occurs within an organism for the purpose of defending against foreign invaders. These invaders include a wide variety of different microorganisms including viruses, bacteria, parasites, and fungi which could ...

, especially in children and young adults. The fundamental cause of OSA is a blocked upper airway, usually behind the tongue and epiglottis, whereby the otherwise patent airway, in an erect and awake patient, collapses when the patient is lying on his or her back and loses muscle tone upon entering deep sleep. At the beginning of sleep, a patient is in light sleep and there is no tone loss of throat muscles. Airflow is laminar and soundless. As the upper airway collapse progresses, the obstruction becomes increasingly apparent by the initiation of noisy breathing as air turbulence increases, followed by gradually louder

as a

Venturi effect The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section (or choke) of a pipe. The Venturi effect is named after its discoverer, the 18th century Italian physicist, Giovanni Battista ...

forms through the ever-narrowing air passage. The patient's blood-oxygen saturation gradually falls until cessation of sleep noises, signifying total airway obstruction of airflow, which may last for several minutes. Eventually, the patient must at least partially awaken from deep sleep into light sleep, automatically regaining general muscle tone. This switch from deep to light to deep sleep can be recorded using ECT monitors. In light sleep, muscle tone is near normal, the airway spontaneously opens, normal noiseless breathing resumes and blood-oxygen saturation rises. Eventually, the patient reenters deep sleep, upper airway tone is again lost, the patient enters the various levels of noisy breathing and the airway blockage returns. The cycle of muscle-tone loss and restoration coinciding with periods of deep and light sleep repeats throughout the patient's period of sleep. The number of apnoea and hypopnoea episodes during any given hour is counted and given a score. If a patient has an average of five or more episodes per hour, mild OSA may be confirmed. An average of 30 or more episodes per hour indicates severe OSA.

Pathophysiological models

The causes of spontaneous upper-airway blockage are strongly debated by clinical professionals. The areas of thought are divided mostly into three medical groups. Some

pulmonologists Pulmonology (, , from Latin ''pulmō, -ōnis'' "lung" and the Greek suffix "study of"), pneumology (, built on Greek πνεύμων "lung") or pneumonology () is a medical specialty that deals with diseases involving the respiratory tract. ...

and

neurologists Neurology (from el, νεῦρον (neûron), "string, nerve" and the suffix -logia, "study of") is the branch of medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the brain, the spinal c ...

believe the risk factors to be: * Advanced age, although OSA occurs in neonates, as with Pierre Robin syndrome, and in all age groups of people. * Brain injury (temporary or permanent), although this does not account for the 99% of OSA patients who have normal brains and normal lives. * Decreased muscle tone caused by drugs or alcohol, or caused by neurological disorders. This also would not account for the majority of people with OSA. * Long-term snoring, which is postulated to potentially induce local nerve lesions in the soft tissues of the

pharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its st ...

. Snoring may produce traumatic vibrations that may give rise to nerve injuries in the upper airway muscles, further contributing to OSA. * Increased soft tissue around the airway, often resulting from obesity, though not seen in all patients with OSA. Some otorhinolaryngologists believe the risk factors to be structural features that give rise to a narrowed airway, such as enlarged

tonsils The tonsils are a set of lymphoid organs facing into the aerodigestive tract, which is known as Waldeyer's tonsillar ring and consists of the adenoid tonsil, two tubal tonsils, two palatine tonsils, and the lingual tonsils. These organs play a ...

, an enlarged posterior tongue or fat deposits in the neck. Further factors leading to OSA can be impaired nasal breathing, floppy soft palate or a collapsible

epiglottis The epiglottis is a leaf-shaped flap in the throat that prevents food and water from entering the trachea and the lungs. It stays open during breathing, allowing air into the larynx. During swallowing, it closes to prevent aspiration of food in ...

. Some oral and maxillofacial surgeons believe the risk factors to be a number of primary forms of

mandibular hypoplasia Micrognathism is a condition where the jaw is undersized. It is also sometimes called mandibular hypoplasia. It is common in infants, but is usually self-corrected during growth, due to the jaws' increasing in size. It may be a cause of abnorma ...

, which offers a primary anatomical basis to the development of OSA through

glossoptosis Glossoptosis is a medical condition and abnormality which involves the downward displacement or retraction of the tongue. It may cause non-fusion of the hard palate, causing cleft palate. It is one of the features of Pierre Robin sequence and Down ...

. Some maxillofacial surgeons who offer orthognathic surgery for treatment of OSA believe that their treatments offer superior guarantees of cure of OSA.

Risk factors

Obesity

It is well known that children, adolescents or adults with OSA are often

obese Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's we ...

. Obese people show an increase in neck fat tissue which potentiate respiratory obstruction during sleep. However, people of all ages and sex with normal body mass indices (BMIs) can also demonstrate OSA – and these people do not have significant measures of subdermal or intra neck fat as shown on

DEXA Dual-energy X-ray absorptiometry (DXA, or DEXA) is a means of measuring bone mineral density (BMD) using spectral imaging. Two X-ray beams, with different energy levels, are aimed at the patient's bones. When soft tissue absorption is subtracted ...

scans. It is speculated that they may have increased muscle mass, or alternatively have a tendency to decreased muscle tone potentiating airway collapse during sleep. However, loss of muscle tone is a key feature of deep sleep anyway, and whilst obesity seems a common association, it is not an invariable state of OSA. Sleeping supine (on one's back) is also represented as a risk factor for OSA. Clearly, gravity and loss of tongue and throat tone as a person enters deep sleep are clear and obvious factors contributing to OSA developing. But this explanation is also confounded by the presence of neck obesity. Use of CPAP definitively primarily expands a collapsed upper airway, allowing for nasal breathing – and positive use of CPAP would prove that airway collapse is the cause of OSA. Throat lesions, particularly enlarged tonsils, are well recognized as aggravators of OSA, and removal may provide full or partial or semi-permanent relief from OSA, which also indicates that enlarged tonsils may play a role in the pathogenesis of OSA.

Age

Old age is often accompanied by muscular and neurological loss of muscle tone of the upper airway. Decreased muscle tone is also temporarily caused by chemical depressants; alcoholic drinks and sedative medications being the most common. Permanent premature muscular tonal loss in the upper airway may be precipitated by

traumatic brain injury A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity (ranging from mild traumatic brain injury TBI/concussionto severe traumatic br ...

neuromuscular disorders A neuromuscular disease is any disease affecting the peripheral nervous system (PNS), the neuromuscular junction, or skeletal muscle, all of which are components of the motor unit. Damage to any of these structures can cause muscle atrophy and ...

, or poor adherence to chemical and or speech therapy treatments.

Muscle tone

Individuals with decreased muscle tone and increased soft tissue around the airway, and structural features that give rise to a narrowed airway are at high risk for OSA. Men, in which the anatomy is typified by increased mass in the torso and neck, are at increased risk of developing sleep apnea, especially through middle age and later. Typically, women experience this condition less frequently and to a lesser degree than do men, owing partially to physiology, but possibly also to differential levels of progesterone. Prevalence in

post-menopausal Menopause, also known as the climacteric, is the time in women's lives when menstrual periods stop permanently, and they are no longer able to bear children. Menopause usually occurs between the age of 47 and 54. Medical professionals often ...

women approaches that of men in the same age range. Women are at greater risk for developing OSA during

pregnancy Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occur ...

Medication and lifestyle

Lifestyle factors such as smoking may also increase the chances of developing OSA as the chemical irritants in smoke tend to inflame the soft tissue of the upper airway and promote fluid retention, both of which can result in narrowing of the upper airway. Cigarettes may also have an impact due to a decline of blood nicotine levels, which alters sleep stability. Smokers thus show a higher risk to develop OSA, but the effect of cigarettes on increased OSA is reversible with the cessation of smoking. Children exposed to cigarette smoke may also develop OSA as the lymphadenoid tissue will proliferate excessively in contact with the irritants. An individual may also experience or exacerbate OSA with the consumption of alcohol, sedatives, or any other medication that increases sleepiness as most of these drugs are also muscle relaxants. Allergic rhinitis and asthma have also been shown to be implicated in the increased prevalence of adenotonsillar hypertrophy and OSA.

Genetic

OSA also appears to have a genetic component; those with a family history of it are more likely to develop it themselves.

Craniofacial syndromes

Of substantial recent interest is the idea that there is a general human tendency towards developing short lower jaws (

neoteny Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compa ...

) is a major cause of OSA through a combined condition called

. The posterior “normal” tongue is displaced backwards by a smaller “abnormal” anterior tongue and lower jaw. In much the same way, a narrow upper jaw will also contribute to OSA due to its relation to airway volume. A more narrow upper jaw results in more narrow nasal passages and a more narrow throat, this also appears to be why so many OSA patients experience nasal congestion especially while lying down. Maxillofacial surgeons see many effects of small lower jaws, including crowded teeth, malocclusions, as well as OSA – all of which are treatable by surgical operations that increase and normalise jaw size. Operations such as custom BIMAX, GenioPaully, and IMDO (in adolescence) offer a valid medical option that replaces all traditional forms of OSA treatment – including CPAP, Mandibular Advancement Splints,

and UPPP. There are patterns of unusual facial features that occur in recognizable syndromes. Some of these craniofacial syndromes are genetic, others are from unknown causes. In many craniofacial syndromes, the features that are unusual involve the nose, mouth, and jaw, or resting muscle tone, and put the individual at risk for OSA syndrome.

Down syndrome Down syndrome or Down's syndrome, also known as trisomy 21, is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. It is usually associated with physical growth delays, mild to moderate intellectual dis ...

is one such syndrome. In this

chromosomal A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...

abnormality, several features combine to make the presence of obstructive sleep apnea more likely. The specific features of Down syndrome that predispose to obstructive sleep apnea include relatively low muscle tone, narrow

nasopharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its struct ...

, and large tongue. Obesity and enlarged tonsils and adenoids, conditions that occur commonly in the western population, are much more likely to be obstructive in a person with these features than without them. Obstructive sleep apnea does occur even more frequently in people with Down syndrome than in the general population. A little over 50% of all people with Down syndrome experience obstructive sleep apnea, and some physicians advocate routine testing of this group. In other craniofacial syndromes, the abnormal feature may actually improve the airway, but its correction may put the person at risk for obstructive sleep apnea ''after'' surgery when it is modified.

Cleft palate A cleft lip contains an opening in the upper lip that may extend into the nose. The opening may be on one side, both sides, or in the middle. A cleft palate occurs when the palate (the roof of the mouth) contains an opening into the nose. The ...

syndromes are such an example. During the newborn period, all humans are obligate nasal breathers. The palate is both the roof of the mouth and the floor of the nose. Having an open palate may make feeding difficult, but generally, does not interfere with breathing, in fact, if the nose is very obstructed, then an open palate may relieve breathing. There are a number of clefting syndromes in which the open palate is not the only abnormal feature; additionally, there is a narrow nasal passage – which may not be obvious. In such individuals, closure of the cleft palate – whether by surgery or by a temporary oral appliance – can cause the onset of obstruction. Skeletal advancement in an effort to physically increase the pharyngeal airspace is often an option for craniofacial patients with upper airway obstruction and small lower jaws (

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

s). These syndromes include

Treacher Collins syndrome Treacher Collins syndrome (TCS) is a genetic disorder characterized by deformities of the ears, eyes, cheekbones, and chin. The degree to which a person is affected, however, may vary from mild to severe. Complications may include breathing prob ...

and

Pierre Robin sequence Pierre Robin sequence (; abbreviated PRS) is a congenital defect observed in humans which is characterized by facial abnormalities. The three main features are micrognathia (abnormally small mandible), which causes glossoptosis (downwardly displ ...

. Mandibular advancement surgery is one of the modifications needed to improve the airway, others may include reduction of the tongue,

or modified uvulopalatoplasty.

Post-operative complication

OSA can also occur as a serious post-operative complication that seems to be most frequently associated with

pharyngeal flap surgery Pharyngeal flap surgery is a procedure to correct the airflow during speech. The procedure is common among people with cleft palate and some types of dysarthria. Pharyngeal flap procedures Posterior pharyngeal flap surgery is the most commonly us ...

as compared to other procedures for the treatment of

velopharyngeal inadequacy Velopharyngeal inadequacy is a malfunction of a velopharyngeal mechanism which is responsible for directing the transmission of sound energy and air pressure in both the oral cavity and the nasal cavity. When this mechanism is impaired in some way, ...

(VPI). In OSA, recurrent interruptions of

respiration Respiration may refer to: Biology * Cellular respiration, the process in which nutrients are converted into useful energy in a cell ** Anaerobic respiration, cellular respiration without oxygen ** Maintenance respiration, the amount of cellul ...

during sleep are associated with temporary

airway obstruction Airway obstruction is a blockage of respiration in the airway that hinders the free flow of air. It can be broadly classified into being either in the upper airway (UPA) or lower airway (LOA). Airway obstruction is a life-threatening condition ...

. Following pharyngeal flap surgery, depending on size and position, the flap itself may have an " obturator" or obstructive effect within the

during sleep, blocking ports of airflow and hindering effective

.Pugh, M.B. et al. (2000). Apnea. ''Stedman's Medical Dictionary (27th ed.)'' Retrieved June 18, 2006 from STAT!Ref Online Medical Library database. There have been documented instances of severe airway obstruction, and reports of post-operative OSA continues to increase as healthcare professionals (i.e. physicians, speech language pathologists) become more educated about this possible dangerous condition. Subsequently, in clinical practice, concerns of OSA have matched or exceeded interest in speech outcomes following pharyngeal flap surgery. The surgical treatment for velopalatal insufficiency may cause obstructive sleep apnea syndrome. When velopalatal insufficiency is present, air leaks into the nasopharynx even when the soft palate should close off the nose. A simple test for this condition can be made by placing a tiny mirror on the nose, and asking the subject to say "P". This p sound, a plosive, is normally produced with the nasal airway closes off – all air comes out of the pursed lips, none from the nose. If it is impossible to say the sound without fogging a nasal mirror, there is an air leak – reasonable evidence of poor palatal closure. Speech is often unclear due to inability to pronounce certain sounds. One of the surgical treatments for velopalatal insufficiency involves tailoring the tissue from the back of the throat and using it to purposefully cause partial obstruction of the opening of the

. This may actually ''cause'' OSA syndrome in susceptible individuals, particularly in the days following surgery, when swelling occurs (see below: Special Situation: Anesthesia and Surgery). Finally, patients with OSA are at an increased risk of many perioperative complications when they are present for surgery, even if the planned procedure is not on the head and neck. Guidelines intended to reduce the risk of perioperative complications have been published.

Consequences

There are 3 levels of consequences: physiologic, intermediate and clinical. The physiologic consequences contain hypoxia, sleep fragmentation, autonomic nervous system dysregulation or hyperoxia. The intermediate results regroup inflammation, pulmonary vasoconstriction, general metabolic dysfunction, oxidation of proteins and lipids or increased adiposity. The clinical repercussions are composed by pulmonary hypertension, accidents, obesity, diabetes, different heart diseases or hypertension.

In children

Obstructive sleep apnea is the most common Sleep-Disordered Breathing (SDB) and affects up to 11% of children born at term – it is even more common (3 to 6 times more) in children born pre-term. As a SDB, OSA in children can lead to several adverse consequences, also in the long-term with consequences lasting into adulthood. The implications of OSA in children are complex and cover a large scope of consequences: when it is left untreated, OSA can lead to morbidity affecting many different domains of life (organs, body systems, behavioral disturbance, depression, decreased

quality of life Quality of life (QOL) is defined by the World Health Organization as "an individual's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards ...

, etc.). Therefore, nocturnal symptoms indicating the presence of OSA (e.g.

, gasping, restless sleep and excessive energy used to breathe during sleep) are associated with daytime symptoms such as concentration and learning difficulties and irritability, neurocognitive development impairment, decreased school performance and behavioral difficulties. For example, SDB such as OSA contributes to hyperactive behavior that can lead to the diagnosis and treatment of

attention deficit hyperactivity disorder Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by excessive amounts of inattention, hyperactivity, and impulsivity that are pervasive, impairing in multiple contexts, and otherwise age-inap ...

(ADHD). However, once the SDB is treated, the hyperactive behavior can improve, and the treatment can be stopped.

Obesity Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's ...

also has an impact on the consequences of OSA and lead to different manifestations or severity. Studies have shown that, contrary to adults, children with obstructive sleep-disordered breathing are able to maintain cerebral oxygenation. However, the condition still has effects on the brain and can lead to adverse neurocognitive and behavioral sequelae. It is particularly concerning as those consequences happen while the brain is still developing. The degree to which the sleep is disturbed and fragmented has been significantly linked to the severity of the consequences, the latter having the possibility to decrease once the sleep is improved. It is more the disruption of sleep processes than the total amount of sleep the child experience that generates the adverse consequences on the child's daytime functioning; it contributes to the hyperactivity for example. Children with OSA may experience learning and memory deficits and OSA has also been linked to lowered childhood IQ scores.

Neurocognitive and behavioral consequences

Nocturnal sleep fragmentation has been linked to neurocognitive impairments, therefore, the identification of SDB such as OSA is crucial in children, those impairments having the possibility to be reversible with the appropriate treatment for the sleep disorder. The neurocognitive and behavioral dysfunctions commonly present in children with OSA include the following: hyperactivity, impulsivity, aggressive behaviors, low social and communication abilities and reduced adaptive skills. Children with OSA commonly show cognitive deficits, resulting in attention and

concentration In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: '' mass concentration'', ''molar concentration'', '' number concentration'', ...

difficulties, as well as lower academic performance and IQ. Poor academic performances have been linked to OSA and suggested to result from cortical and sympathetic arousals and

hypoxemia Hypoxemia is an abnormally low level of oxygen in the blood. More specifically, it is oxygen deficiency in arterial blood. Hypoxemia has many causes, and often causes hypoxia as the blood is not supplying enough oxygen to the tissues of the bod ...

which affects

memory consolidation Memory consolidation is a category of processes that stabilize a memory trace after its initial acquisition. A memory trace is a change in the nervous system caused by memorizing something. Consolidation is distinguished into two specific processe ...

. A study with Indian children affected by OSA has shown poor school grades, including mathematics, science, language and physical education. This study allowed to see the overall impact of OSA on learning abilities associated with language or numeracy skills, and physical development. It has been suggested that the deficits in academic performance related to OSA could be mediated through reduced

or language skills, those domains contributing highly to learning abilities and behavior. The deficits in school performance can nevertheless be improved if adenotonsillectomy is performed on children to treat the OSA. It is thus crucial to identify the OSA for children with school difficulties; many cases remaining unnoticed. As studies have shown that learning skills and behaviors can be improved if the OSA is treated, the neurocognitive and behavioral deficits are thus at least partly reversible. This reversible dimension has been postulated to be negatively correlated to the duration of the symptoms, which would mean that the longer the OSA is left untreated, the less reversible are the consequences.

Somatic and metabolic consequences

Similarly to adults, OSA in children is linked to a higher risk for cardiovascular morbidities, due to increased sympathetic activity and impaired cardiac autonomic control. Amongst the cardiovascular dysfunctions resulting from OSA, we can find systemic hypertension and blood pressure dysregulation (elevated blood pressure, or variability of the blood pressure for example). The variability of the blood pressure has been shown to be correlated with the severity of the symptoms such as the frequency of the apnea and

. Pulmonary hypertension is also common amongst the cardiovascular problems resulting from OSA. Children with obstructive sleep-disordered breathing also show a faster heart rate during wakefulness and during sleep. In adult patients, OSA has been shown to be associated with insulin resistance. In children, metabolic consequences of OSA are complicated to assess as they can also be associated to

puberty Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a bo ...

and

(if present). However, when OSA is associated with obesity, the interaction of the two conditions can lead to metabolic disturbances such as insulin resistance and altered lipidemia,

liver disease Liver disease, or hepatic disease, is any of many diseases of the liver. If long-lasting it is termed chronic liver disease. Although the diseases differ in detail, liver diseases often have features in common. Signs and symptoms Some of the si ...

, abdominal adiposity and metabolic syndrome. Obesity interact with those effects.

Nocturnal enuresis

Children with OSA also show a higher risk for

nocturnal enuresis Nocturnal enuresis, also informally called bedwetting, is involuntary urination while asleep after the age at which bladder control usually begins. Bedwetting in children and adults can result in emotional stress. Complications can include urina ...

and it is hypothesized to be caused by an excessive production of

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellular ...

, impaired performance of the

bladder The urinary bladder, or simply bladder, is a hollow organ in humans and other vertebrates that stores urine from the kidneys before disposal by urination. In humans the bladder is a distensible organ that sits on the pelvic floor. Urine enters ...

and

urethra The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra c ...

or an inability to suppress the nocturnal bladder contraction, due to a failure to arouse. The risk for nocturnal enuresis increases with the severity of the sleep-disordered breathing: the more respiratory events per hour of sleep, the higher is the risk for nocturnal enuresis. Obesity may also play a role as it is associated with OSA and with nocturnal

diuresis Diuresis () is increased urination (polyuria) or, in the related word senses more often intended, the physiological process that produces such an increase or the administration of medications to encourage that process. It involves extra urine pr ...

(due to unhealthy diet). The interaction between OSA and obesity might thus result in nocturnal enuresis. Considering the high prevalence of nocturnal enuresis amongst children with sleep-disordered breathing, it is important to consider the latter in the differential diagnosis of nocturnal enuresis as the treatment of the sleep disorder might have a favourable therapeutic effect on the enuresis. For example, an adenotonsillectomy performed to reduce OSA has a positive impact on nocturnal enuresis. A study has shown that this surgery has 60–75% chance to resolve the nocturnal enuresis completely, and 80–85% chance to reduce its symptoms alongside others symptoms of OSA.

Other consequences

Contrary to adults,

(EDS) is not the most commonly reported symptoms in children with OSA. However, using objective questionnaires, it is possible to notice that the frequency of EDS in children is higher than what is reported by the parents or caretakers (40–50%). And the risk for EDS is even increased when OSA is associated with

. Due to all the consequences and symptoms it generates, OSA in children lead to a significant decrease in the

, the decrease being even higher when obesity is present. The quality of life can however be improved with the treatment of OSA. SBD have also been linked to a higher rate of

internalizing disorder An internalizing disorder ( or internalising disorder) is one type of emotional and behavioral disorder, along with externalizing disorders, and low incidence disorders. People who have an internalizing disorder will keep their problems to themse ...

s such as

and depression. Indeed, depressive symptoms have shown to be higher in children with OSA, especially in males. Once again, the severity of depressive symptoms is positively correlated with the severity of the SBD. It also interacts with obesity as obese children have higher risk to show depressive symptoms and obesity can cause OSA. The link can also go the other way around with the depression inducing obesity (due to

overeating Overeating occurs when an individual consumes more calories in relation to the energy that is expended via physical activity or expelled via excretion, leading to weight gain and often obesity. Overeating is the defining characteristic of bing ...

) which worsens the OSA. Adenotonsillectomy can decrease the intensity of the depressive symptoms. Other consequences of a disturbed sleep in children with OSA comprise

anhedonia Anhedonia is a diverse array of deficits in hedonic function, including reduced motivation or ability to experience pleasure. While earlier definitions emphasized the inability to experience pleasure, anhedonia is currently used by researchers t ...

increased fatigue and decreased interest in daily activities, which in turn can affect the child's social relationships.

In adults

While there are some similarities between adults and children, OSA does not have the same consequences in both populations. Examples of similarities are the

– which is the most common complaint in both pediatric OSA and OSA in adults – variability of blood pressure and cardiovascular morbidities. A major difference is the

(EDS) which is commonly reported in adult OSA, while it is not very common in pediatric OSA. Nevertheless, OSA in adults also implies a large scope of adverse and serious consequences, the latter leading to higher mortality amongst OSA patients. Those consequences are even worsened by common morbidities such as

Neurocognitive consequences

Similarly to children, OSA affects

cognitive functions Cognitive skills, also called cognitive functions, cognitive abilities or cognitive capacities, are brain-based skills which are needed in acquisition of knowledge, manipulation of information and reasoning. They have more to do with the mechanisms ...

in adults.

Meta-analysis A meta-analysis is a statistical analysis that combines the results of multiple scientific studies. Meta-analyses can be performed when there are multiple scientific studies addressing the same question, with each individual study reporting me ...

have shown that the most common cognitive impairments happen in the domains of attention, verbal and visual delayed

long-term memory Long-term memory (LTM) is the stage of the Atkinson–Shiffrin memory model in which informative knowledge is held indefinitely. It is defined in contrast to short-term and working memory, which persist for only about 18 to 30 seconds. Long- ...

, visuospatial/constructional abilities and

, such as mental flexibility. The executive functioning – mainly dominated by the

prefrontal cortex In mammalian brain anatomy, the prefrontal cortex (PFC) covers the front part of the frontal lobe of the cerebral cortex. The PFC contains the Brodmann areas BA8, BA9, BA10, BA11, BA12, BA13, BA14, BA24, BA25, BA32, BA44, BA45, BA46 ...

– being significantly impaired in patients with OSA, it is believed that the prefrontal region and its connectivity are affected by sleep disorders. Regarding memory deficits,

verbal memory Verbal memory is a term used in cognitive psychology which refers to memory of words and other abstractions involving language. Verbal encoding Verbal encoding refers to the interpretation of verbal stimuli. Verbal encoding appears to be strongly ...

is significantly impaired as patients show difficulties in recalling verbal information immediately as well as with a delay. While meta-analysis have shown no deficits in retention of information for patients with OSA, those impairment in verbal memory may be linked to problems in encoding information. This deficit in encoding of information is also noticed in visuo-spatial memory; however, the

visual memory Visual memory describes the relationship between perceptual processing and the encoding, storage and retrieval of the resulting neural representations. Visual memory occurs over a broad time range spanning from eye movements to years in order ...

seems to be intact in OSA patients. The cognitive impairments have been suggested to be resulting from sleep fragmentation and sleep deprivation, as well as the excessive daytime sleepiness associated with them. More precisely, attention and memory deficits seem to result from sleep fragmentation, while deficits in global cognitive function (executive function, psychomotor function, language abilities) are more related to hypoxia or hypercarbia which accompanies the obstructive events during sleep. However, no consistent correlation has been found between the degree of cognitive impairment and the severity of the sleep disturbance or hypoxia. These impairments may improve with an effective treatment for OSA, such as

continuous positive airway pressure Continuous positive airway pressure (CPAP) is a form of positive airway pressure (PAP) ventilation in which a constant level of pressure greater than atmospheric pressure is continuously applied to the upper respiratory tract of a person. The ...

(CPAP) therapy. Driving a motor vehicle is an example of a complex task that relies on driver's cognitive abilities, such as attention, reaction time and vigilance. Very brief moments of inattention called microsleep events could be an indicator for daytime vigilance impairment, although these may not be present in all drivers with obstructive sleep apnea.

Behavioral consequences

The

hyperactivity Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterised by excessive amounts of inattention, hyperactivity, and impulsivity that are pervasive, impairing in multiple contexts, and otherwise age-inappr ...

and difficulties in

emotional regulation Emotional self-regulation or emotion regulation is the ability to respond to the ongoing demands of experience with the range of emotions in a manner that is socially tolerable and sufficiently flexible to permit spontaneous reactions as well as ...

found in pediatric patients (children) are not reported in adults. OSA in adults is nevertheless associated with personality changes and

automatic behavior Automatic behavior, from the Greek ''automatos'' or self-acting, is the spontaneous production of often purposeless verbal or motor behavior without conscious self-control or self-censorship. This condition can be observed in a variety of context ...

. The biggest impact of OSA is the excessive daytime sleepiness (EDS), reported in approximately 30% of OSA patients. EDS can be caused by the disturbance of sleep quality, the insufficient sleep duration or the sleep fragmentation and it is responsible for further complications as it may lead to

depressive symptoms Depression is a mental state of low Mood (psychology), mood and aversion to activity, which affects more than 280 million people of all ages (about 3.5% of the global population). Classified medically as a mental disorder, mental and Abnor ...

, impairments of social life and decreased effectiveness at work. Studies have shown that those consequences of EDS can be improved following a CPAP treatment.

Physiological and metabolic consequences

OSA in adults is associated with a higher risk for cardiovascular morbidities,

diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ...

, hypertension, coronary artery disease and stroke – OSA might have a role in the etiology of these conditions. Those conditions may lead to increased mortality that an appropriate treatment for OSA may reduce. OSA is often linked with hypertension as it induces an increase in sympathetic activity that can lead to the elevation of blood pressure. The OSA-related

hypercapnia Hypercapnia (from the Greek ''hyper'' = "above" or "too much" and ''kapnos'' = "smoke"), also known as hypercarbia and CO2 retention, is a condition of abnormally elevated carbon dioxide (CO2) levels in the blood. Carbon dioxide is a gaseous pro ...

has been suggested to be related to this development of hypertension. Treating the OSA may prevent the development of hypertension. The relationship between OSA and excess body weight is complex as obesity is more prevalent amongst OSA patients but can also be a

risk factor In epidemiology, a risk factor or determinant is a variable associated with an increased risk of disease or infection. Due to a lack of harmonization across disciplines, determinant, in its more widely accepted scientific meaning, is often ...

for the development of OSA – it accounts for 58% of adult cases. Thus, both OSA and obesity (when present) may work synergistically and lead to

hyperlipidemia Hyperlipidemia is abnormally elevated levels of any or all lipids (fats, cholesterol, or triglycerides) or lipoproteins in the blood. citing: and The term ''hyperlipidemia'' refers to the laboratory finding itself and is also used as an umbre ...

, diabetes, insulin resistance and other symptoms of the metabolic syndrome. The metabolic syndrome itself is often associated with OSA: 74–85% of OSA patients are diagnosed with it. CPAP therapy can lead to an improvement of some of the cardiovascular component of the metabolic syndrome while

weight loss Weight loss, in the context of medicine, health, or physical fitness, refers to a reduction of the total body mass, by a mean loss of fluid, body fat ( adipose tissue), or lean mass (namely bone mineral deposits, muscle, tendon, and other co ...

is also recommended for its positive effects on OSA consequences and metabolic dysfunctions. An intervention comprising exercise and diet is thus effective for the treatment of OSA as it positively impacts the severity of both obesity symptoms and OSA symptoms. Individuals with Type 2 diabetes are often co-diagnosed with OSA, where Type 2 diabetes prevalence rates range between 15% to 30% within the OSA population. The relationship between OSA and Type 2 diabetes could possibly be explained by the fact that OSA-characteristic fragmented sleep and irregular hypoxemia leads to the dysregulated metabolism of glucose in the blood. In particular, many polysomnography studies showed that OSA left untreated worsens glycemic control in individuals with Type 2 diabetes. However, it is possible that the relationship between OSA and Type 2 diabetes is bidirectional since diabetes-related nerve dysfunction may affect the respiratory system and induce breathing disturbances during sleep.

Psychological consequences

Sleep is of major importance for psychological and emotional health. As it is greatly impaired in OSA, this condition is associated with

mood disorder A mood disorder, also known as an affective disorder, is any of a group of conditions of mental and behavioral disorder where a disturbance in the person's mood is the main underlying feature. The classification is in the '' Diagnostic and St ...

s and several psychological outcomes, especially depression and

. Therefore,

psychological disorders A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitti ...

are commonly observed in OSA patients who show a higher

prevalence In epidemiology, prevalence is the proportion of a particular population found to be affected by a medical condition (typically a disease or a risk factor such as smoking or seatbelt use) at a specific time. It is derived by comparing the number o ...

psychological distress Mental distress or psychological distress encompasses the symptoms and experiences of a person's internal life that are commonly held to be troubling, confusing or out of the ordinary. Mental distress can potentially lead to a change of behavior, a ...

, mostly due to the impaired sleep quality and structure and the repeated episodes of hypoxia. The presence of psychological disorders may also worsen the sleep disorders which implies that the psychopathology may either be a

factor Factor, a Latin word meaning "who/which acts", may refer to: Commerce * Factor (agent), a person who acts for, notably a mercantile and colonial agent * Factor (Scotland), a person or firm managing a Scottish estate * Factors of production, suc ...

or a consequence of the OSA. The adverse consequences of OSA such as cardiovascular comorbidities and metabolic disturbances also play a role on the development of mental disorders, and patients with chronic condition have also been reported to have higher risk to experience depression. In OSA patients with psychiatric disorders, it is crucial to treat the OSA as it may reduce the psychiatric symptoms. Some cases of OSA are caused by

nasal obstruction Nasal congestion is the blockage of nasal breathing usually due to membranes lining the nose becoming swollen from inflamed blood vessels. Background In about 85% of cases, nasal congestion leads to mouth breathing rather than nasal breathin ...

which has also been related to psychological problems due to an altered

ratio In mathematics, a ratio shows how many times one number contains another. For example, if there are eight oranges and six lemons in a bowl of fruit, then the ratio of oranges to lemons is eight to six (that is, 8:6, which is equivalent to the ...

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

and

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...

brain cells Brain cells make up the functional tissue of the brain. The rest of the brain tissue is structural or connective called the stroma which includes blood vessels. The two main types of cells in the brain are neurons, also known as nerve cells, an ...

. Nasal obstruction can thus aggravate the psychological health of OSA patients. Nasal surgery for those patients might decrease the OSA severity and improve the psychological symptoms.

Other consequences

Untreated OSA also leads to a decreased quality of life, difficulties in

social functioning A social skill is any competence facilitating interaction and communication with others where social rules and relations are created, communicated, and changed in verbal and nonverbal ways. The process of learning these skills is called socia ...

, occupational problems and

accidents An accident is an unintended, normally unwanted event that was not directly caused by humans. The term ''accident'' implies that nobody should be blamed, but the event may have been caused by unrecognized or unaddressed risks. Most researche ...

and a greatly increased rate of vehicle accidents. Those serious outcomes of OSA are mostly related to the excessive daytime sleepiness resulting from the sleep fragmentation and highlight the need to provide the patients with appropriate treatment. Effective treatment majorly improves those adverse consequences, including quality of life. OSA patients also frequently report

pain disorder Pain disorder is chronic pain experienced by a patient in one or more areas, and is thought to be caused by psychological stress. The pain is often so severe that it disables the patient from proper functioning. Duration may be as short as a few d ...

s such as headache or fibromyalgia, OSA patients showing an increased pain intensity alongside a decreased

pain tolerance Pain tolerance is the maximum level of pain that a person is able to tolerate. Pain tolerance is distinct from pain threshold (the point at which pain begins to be felt).

Diagnosis

In a systematic review of published evidence, the

United States Preventive Services Task Force The United States Preventive Services Task Force (USPSTF) is "an independent panel of experts in primary care and prevention that systematically reviews the evidence of effectiveness and develops recommendations for clinical preventive services". ...

in 2017 concluded that there was uncertainty about the accuracy or clinical utility of all potential screening tools for OSA, and recommended that current evidence is insufficient to assess the balance of benefits and harms of screening for OSA in asymptomatic adults. The diagnosis of OSA syndrome is made when the patient shows recurrent episodes of partial or complete collapse of the upper airway during sleep resulting in apneas or hypopneas, respectively. Criteria defining an apnea or a hypopnea vary. The American Academy of Sleep Medicine (AASM) defines an apnea as a reduction in airflow of ≥ 90% lasting at least 10 seconds. A hypopnea is defined as a reduction in airflow of ≥ 30% lasting at least 10 seconds and associated with a ≥ 4% decrease in pulse oxygenation, or as a ≥ 30% reduction in airflow lasting at least 10 seconds and associated either with a ≥ 3% decrease in pulse oxygenation or with an arousal. To define the severity of the condition, the Apnea-Hypopnea Index (AHI) or the Respiratory Disturbance Index (RDI) are used. While the AHI measures the mean number of apneas and hypopneas per hour of sleep, the RDI adds to this measure the respiratory effort-related arousals (RERAs). The OSA syndrome is thus diagnosed if the AHI is > 5 episodes per hour and results in daytime sleepiness and fatigue or when the RDI is ≥ 15 independently of the symptoms. According to the American Association of Sleep Medicine, daytime sleepiness is determined as mild, moderate and severe depending on its impact on social life. Daytime sleepiness can be assessed with the Epworth Sleepiness Scale (ESS), a self-reported questionnaire on the propensity to fall asleep or doze off during daytime. Screening tools for OSA itself comprise the STOP questionnaire, the Berlin questionnaire and the STOP-BANG questionnaire which has been reported as being a very powerful tool to detect OSA.

Criteria

According to the

, there are 4 types of criteria. The first one concerns sleep – excessive sleepiness, nonrestorative sleep, fatigue or insomnia symptoms. The second and third criteria are about respiration – waking with breath holding, gasping, or choking; snoring, breathing interruptions or both during sleep. The last criterion revolved around medical issues as hypertension, coronary artery disease, stroke, heart failure, atrial fibrillation, type 2 diabetes mellitus, mood disorder or cognitive impairment. Two levels of severity are distinguished, the first one is determined by a polysomnography or home sleep apnea test demonstrating 5 or more predominantly obstructive respiratory events per hour of sleep and the higher levels are determined by 15 or more events. If the events are present less than 5 times per hour, no obstructive sleep apnea is diagnosed. A considerable night-to-night variability further complicates diagnosis of OSA. In unclear cases, multiple testing might be required to achieve an accurate diagnosis.

Polysomnography

Nighttime in-laboratory Level 1 polysomnography (PSG) is the gold standard test for diagnosis. Patients are monitored with EEG leads,

pulse oximetry Pulse oximetry is a noninvasive method for monitoring a person's oxygen saturation. Peripheral oxygen saturation (SpO2) readings are typically within 2% accuracy (within 4% accuracy in 95% of cases) of the more accurate (and invasive) reading o ...

, temperature and pressure sensors to detect nasal and oral airflow, respiratory impedance plethysmography or similar resistance belts around the chest and abdomen to detect motion, an ECG lead, and EMG sensors to detect muscle contraction in the chin, chest, and legs. A hypopnea can be based on one of two criteria. It can either be a reduction in airflow of at least 30% for more than 10 seconds associated with at least 4% oxygen desaturation or a reduction in airflow of at least 30% for more than 10 seconds associated with at least 3% oxygen desaturation or an arousal from sleep on EEG. An "event" can be either an apnea, characterized by complete cessation of airflow for at least 10 seconds, or a

in which airflow decreases by 50 percent for 10 seconds or decreases by 30 percent if there is an associated decrease in the oxygen saturation or an arousal from sleep. To grade the severity of sleep apnea, the number of events per hour is reported as the apnea-hypopnea index (AHI). An AHI of less than 5 is considered normal. An AHI of 5–15 is mild; 15–30 is moderate, and more than 30 events per hour characterizes severe sleep apnea.

Home oximetry

In patients who are at high likelihood of having OSA, a

randomized controlled trial A randomized controlled trial (or randomized control trial; RCT) is a form of scientific experiment used to control factors not under direct experimental control. Examples of RCTs are clinical trials that compare the effects of drugs, surgical te ...

found that home

oximetry Pulse oximetry is a noninvasive method for monitoring a person's oxygen saturation. Peripheral oxygen saturation (SpO2) readings are typically within 2% accuracy (within 4% accuracy in 95% of cases) of the more accurate (and invasive) reading o ...

(a non-invasive method of monitoring blood oxygenation) may be adequate and easier to obtain than formal polysomnography. High probability patients were identified by an

Epworth Sleepiness Scale The Epworth Sleepiness Scale (ESS) is a scale intended to measure daytime sleepiness that is measured by use of a very short questionnaire. This can be helpful in diagnosing sleep disorders. It was introduced in 1991 by Dr Murray Johns of Epwor ...

(ESS) score of 10 or greater and a Sleep Apnea Clinical Score (SACS) of 15 or greater. Home oximetry, however, does not measure apneic events or respiratory event-related arousals and thus does not produce an AHI value.

Treatment

The treatment of OSAS depends upon the level of obstruction, if the obstruction is at nose or epiglottis a surgery could be required depending on the condition. Numerous treatment options are used in obstructive sleep apnea.Friedman: Sleep Apnea and Snoring, 1st ed. 2008 Avoiding alcohol and smoking is recommended, as is avoiding medications that relax the central nervous system (for example, sedatives and muscle relaxants).

Weight loss Weight loss, in the context of medicine, health, or physical fitness, refers to a reduction of the total body mass, by a mean loss of fluid, body fat ( adipose tissue), or lean mass (namely bone mineral deposits, muscle, tendon, and other co ...

is recommended in those who are overweight.

Continuous positive airway pressure Continuous positive airway pressure (CPAP) is a form of positive airway pressure (PAP) ventilation in which a constant level of pressure greater than atmospheric pressure is continuously applied to the upper respiratory tract of a person. The ...

(CPAP) and mandibular advancement devices are often used and found to be equally effective. Physical training, even without weight loss, improves sleep apnea. There is insufficient evidence to support widespread use of medications. In selected patients, e.g. with tonsillar hyperplasia tonsillectomy is recommended. In patients failing CPAP and oral appliances, surgical treatment with conservative uvulopalatopharyngoplasty (UPPP) as salvage surgery is recommended. Randomized controlled studies of the efficacy of UPPP are published, showing effect on nocturnal respiration and excessive daytime sleepiness, and a systematic Meta-analysis.

Physical intervention

The most widely used current therapeutic intervention is ''positive airway pressure'' whereby a breathing machine pumps a controlled stream of air through a mask worn over the nose, mouth, or both. The additional pressure holds open the relaxed muscles. There are several variants: * Continuous positive airway pressure (CPAP) is effective for both moderate and severe disease. It is the most common treatment for obstructive sleep apnea. *

Variable positive airway pressure Positive airway pressure (PAP) is a mode of respiratory ventilation used in the treatment of sleep apnea. PAP ventilation is also commonly used for those who are critically ill in hospital with respiratory failure, in newborn infants (neonates), ...

(VPAP) (also known as bilevel (BiPAP or BPAP)) uses an electronic circuit to monitor the patient's breathing and provides two different pressures, a higher one during inhalation and a lower pressure during

exhalation Exhalation (or expiration) is the flow of the breath out of an organism. In animals, it is the movement of air from the lungs out of the airways, to the external environment during breathing. This happens due to elastic properties of the lungs, ...

. This system is more expensive and is sometimes used with patients who have other coexisting respiratory problems or who find breathing out against an increased pressure to be uncomfortable or disruptive to their sleep. *

Nasal EPAP Nasal expiratory positive airway pressure (Nasal EPAP) is a treatment for obstructive sleep apnea (OSA) and snoring. Contemporary EPAP devices have two small valves that allow air to be drawn in through each nostril, but not exhaled; the valves ...

, which is a bandage-like device placed over the nostrils that utilizes a person's own breathing to create positive airway pressure to prevent obstructed breathing. * Automatic positive airway pressure, also known as "Auto CPAP", incorporates pressure sensors and monitors the person's breathing. Review in: * A 5% reduction in weight among those with moderate to severe OSA may decrease symptoms similarly to CPAP. Encouraging people with moderate to severe OSA to use CPAP devices can be challenging as their use often requires a behavioural change in sleeping habits. 8% of people who use CPAP devices stop using them after the first night, and 50% of people with moderate to severe OSA stop using their devices in the first year. Educational initiatives and supportive interventions to help improve compliance with CPAP therapy have been shown to improve the length of time people who need CPAP therapy use their devices. ''Oral appliances'' or splints are often preferred but may not be as effective as CPAP. This device is a mouthguard similar to those used in sports to protect the teeth. It is designed to hold the lower jaw slightly down and forward relative to the natural, relaxed position. This position holds the tongue farther away from the back of the airway and may be enough to relieve apnea or improve breathing. Many people benefit from sleeping at a ''30-degree elevation'' of the upper body or higher, as if in a

recliner A recliner is an armchair or sofa that reclines when the occupant lowers the chair's back and raises its front. It has a backrest that can be tilted back, and often a footrest that may be extended by means of a lever on the side of the chair, ...

. Doing so helps prevent the gravitational collapse of the airway. Sleeping on a side as opposed to sleeping on the back is also recommended. Some studies have suggested that ''playing a

wind instrument A wind instrument is a musical instrument that contains some type of resonator (usually a tube) in which a column of air is set into vibration by the player blowing into (or over) a mouthpiece set at or near the end of the resonator. The pitc ...

'' may reduce snoring and apnea incidents. This may be especially true of double reed instruments.

Rapid Palatal Expansion

In children, orthodontic treatment to expand the volume of the nasal airway, such as nonsurgical Rapid

Palatal expansion A palatal expander is a device in the field of orthodontics which is used to widen the upper jaw (maxilla) so that the bottom and upper teeth will fit together better. This is a common orthodontic procedure. Although the use of an expander is mo ...

is common. Since the palatal suture is fused in adults, regular RPE using tooth-borne expanders cannot be performed. Mini-implant assisted rapid palatal expansion (MARPE) has been recently developed as a non-surgical option for the transverse expansion of the maxilla in adults. This method increases the volume of the nasal cavity and nasopharynx, leading to increased airflow and reduced respiratory arousals during sleep. Changes are permanent with minimal complications.

Surgery

Surgical treatments to modify airway anatomy, known as

sleep surgery Sleep surgery is a surgery performed to treat sleep disordered breathing. Sleep disordered breathing is a spectrum of disorders that includes snoring, upper airway resistance syndrome, and obstructive sleep apnea. These surgeries are performed by ...

, are varied and must be tailored to the specific airway obstruction needs of a patient. Surgery is not considered a first line treatment for obstructive sleep apnea in adults. There are prospective, randomized, comparative clinical trials, and also a systematic Meta-analysis, showing evidence that conservative

uvulopalatopharyngoplasty Uvulopalatopharyngoplasty (also known by the abbreviations UPPP and UP3) is a surgical procedure or sleep surgery used to remove tissue and/or remodel tissue in the throat. This could be because of sleep issues. Tissues which may typically be remov ...

(UPPP) with or without

is effective in selected patients failing conservative treatment. For those with obstructive sleep apnea unable or unwilling to comply with first line treatment, the surgical intervention has to be adapted to an individual's specific anatomy and physiology, personal preference and disease severity. Uvulopalatopharyngoplasty with or without is the most common surgery for patients with obstructive sleep apnea. Studies have shown that treatment effect of tonsillectomy increases with tonsil size. However, there is little randomized clinical trial evidence for other types of

. There are a number of different operations that may be performed including: *

Septoplasty Septoplasty �sɛp.toˌplæ.sti(Etymology: L, saeptum, septum; Gk, πλάσσειν plassein – to shape), or alternatively submucous septal resection and septal reconstruction, is a corrective surgical procedure done to straighten a deviated ...

is a corrective surgical procedure for

Nasal septum deviation Nasal septum deviation is a physical disorder of the nose, involving a displacement of the nasal septum. Some displacement is common, affecting 80% of people, mostly without their knowledge. Signs and symptoms The nasal septum is the bone and ...

in which the

nasal septum The nasal septum () separates the left and right airways of the nasal cavity, dividing the two nostrils. It is depressed by the depressor septi nasi muscle. Structure The fleshy external end of the nasal septum is called the columella or co ...

is straightened. *

Tonsillectomy Tonsillectomy is a list of surgical procedures, surgical procedure in which both palatine tonsils are fully removed from the back of the throat. The procedure is mainly performed for recurrent tonsillitis, throat infections and obstructive sleep ...

in an attempt to increase the size of the airway. * Removal or reduction of parts of the

soft palate The soft palate (also known as the velum, palatal velum, or muscular palate) is, in mammals, the soft tissue constituting the back of the roof of the mouth. The soft palate is part of the palate of the mouth; the other part is the hard palate. ...

and some or all of the

uvula The palatine uvula, usually referred to as simply the uvula, is a conic projection from the back edge of the middle of the soft palate, composed of connective tissue containing a number of racemose glands, and some muscular fibers. It also conta ...

, such as

(UPPP) or laser-assisted uvulopalatoplasty (''LAUP''). Modern variants of this procedure sometimes use

radiofrequency Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upper ...

waves to heat and remove tissue. *

Turbinectomy A turbinectomy or turbinoplasty (preserving the mucosal layer) is a surgical procedure, that removes tissue, and sometimes bone, of the turbinates in the nasal passage, particularly the inferior nasal concha. The procedure is usually performed t ...

is a surgical procedure in which all or some of the

turbinate In anatomy, a nasal concha (), plural conchae (), also called a nasal turbinate or turbinal, is a long, narrow, curled shelf of bone that protrudes into the breathing passage of the nose in humans and various animals. The conchae are shaped lik ...

bones are removed to relieve

. * Reduction of the tongue base, either with laser excision or

radiofrequency ablation Radiofrequency ablation (RFA), also called fulguration, is a medical procedure in which part of the electrical conduction system of the heart, tumor or other dysfunctional tissue is ablated using the heat generated from medium frequency alternati ...

. * Genioglossus advancement, in which a small portion of the lower jaw that attaches to the tongue is moved forward, to pull the tongue away from the back of the airway. *

Hyoid suspension Hyoid suspension, also known as hyoid myotomy and suspension or hyoid advancement, is a surgical procedure or sleep surgery in which the hyoid bone and its muscle attachments to the tongue and airway are pulled forward with the aim of increasing ai ...

, in which the hyoid bone in the neck, another attachment point for tongue muscles, is pulled forward in front of the larynx. * Maxillomandibular advancement In the morbidly obese, a major loss of weight (such as what occurs after bariatric surgery) can sometimes cure the condition. OSA in children is often due to enlarged tonsils and adenoids because the lymphoid tissue grows fast during young age. Surgical removal of enlarged tonsils (tonsillectomy) and the adenoid (adenoidectomy) are currently first line treatment among children with OSA. The operation is a common procedure but in the most extreme cases, children with severe OSA requires special precautions before, surgery (see "Surgery and obstructive sleep apnea syndrome" below). In some countries, a milder surgical procedure called tonsillotomy is used to remove the protruding tonsillar tissue, a method associated with less pain and lower risk of postoperative hemorrhage.

Neurostimulation

For patients who cannot use a continuous positive airway pressure device, the U.S. Food and Drug Administration in 2014 granted pre-market approval for an upper airway stimulation system that senses respiration and delivers mild electrical stimulation to the

hypoglossal nerve The hypoglossal nerve, also known as the twelfth cranial nerve, cranial nerve XII, or simply CN XII, is a cranial nerve that innervates all the extrinsic and intrinsic muscles of the tongue except for the palatoglossus, which is innervated by ...

in order to increase muscle tone at the back of the tongue so it will not collapse over the airway. The device includes a handheld patient controller to allow it to be switched on before sleep and is powered by an implantable pulse generator, similar to one used for cardiac rhythm management. Approval for this active implantable

neuromodulation Neuromodulation is the physiological process by which a given neuron uses one or more chemicals to regulate diverse populations of neurons. Neuromodulators typically bind to metabotropic, G-protein coupled receptors (GPCRs) to initiate a second ...

device was preceded by a clinical trial whose results were published in the ''

New England Journal of Medicine ''The New England Journal of Medicine'' (''NEJM'') is a weekly medical journal published by the Massachusetts Medical Society. It is among the most prestigious peer-reviewed medical journals as well as the oldest continuously published one. His ...

''.

Radiofrequency ablation

Radiofrequency ablation Radiofrequency ablation (RFA), also called fulguration, is a medical procedure in which part of the electrical conduction system of the heart, tumor or other dysfunctional tissue is ablated using the heat generated from medium frequency alternati ...

(RFA), which is conceptually analogous in some ways to surgery, uses low frequency (300 kHz to 1 MHz) radio wave energy to target tissue, causing

coagulative necrosis Coagulative necrosis is a type of accidental cell death typically caused by ischemia or infarction. In coagulative necrosis, the architectures of dead tissue are preserved for at least a couple of days. It is believed that the injury denatures stru ...

. RFA achieves its effects at 40 °C to 70 °C unlike other electrosurgical devices which require 400 °C to 600 °C for efficacy. Subsequent evaluations of safety and efficacy have led to the recognition of RFA by the American Academy of Otolaryngology as a somnoplasty treatment option in selected situations for mild to moderate OSA, but the evidence was judged insufficient for routine adoption by the American College of Physicians. RFA has some potential advantages in carefully selected

medical Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care practic ...

settings, such as intolerance to the CPAP device. For example, when adherence is defined as greater than four hours of nightly use, 46% to 83% of patients with obstructive sleep apnea are non-adherent with CPAP for a variety of reasons, including discomfort while sleeping. RFA is usually performed in an

outpatient A patient is any recipient of health care services that are performed by healthcare professionals. The patient is most often ill or injured and in need of treatment by a physician, nurse, optometrist, dentist, veterinarian, or other health care ...

setting, using either

local anesthetic A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general a ...

s or conscious sedation anesthesia, the procedure itself typically lasting under 3 minutes. The targeted tissue, such as tongue or palate, is usually approached through the mouth without the need for incisions, although occasionally the target is approached through the neck using assisted imaging. If the tongue is being targeted, this can be done from either

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal c ...

ventral Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

side. Complications include

ulceration An ulcer is a discontinuity or break in a bodily membrane that impedes normal function of the affected organ. According to Robbins's pathology, "ulcer is the breach of the continuity of skin, epithelium or mucous membrane caused by sloughing o ...

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dis ...

, nerve weakness or numbness and swelling. These complications occur in less than 1% of procedures.

Medications

Evidence is insufficient to support the use of medications to treat obstructive sleep apnea. This includes the use of fluoxetine,

paroxetine Paroxetine, sold under the brand names Paxil and Seroxat among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It is used to treat major depressive disorder, obsessive-compulsive disorder, panic disorder ...

acetazolamide Acetazolamide, sold under the trade name Diamox among others, is a medication used to treat glaucoma, epilepsy, altitude sickness, periodic paralysis, idiopathic intracranial hypertension (raised brain pressure of unclear cause), urine alkal ...

, and

tryptophan Tryptophan (symbol Trp or W) is an α-amino acid that is used in the biosynthesis of proteins. Tryptophan contains an α-amino group, an α-carboxylic acid group, and a side chain indole, making it a polar molecule with a non-polar aromatic ...

among others. Recent studies are trying to investigate cannabinoids as a treatment for OSA, especially dronabinol which is a synthetic form of THC (delta-9-tetrahydrocannabinol). Cannabis is known to influence sleep, for example it can reduce sleep onset latency, however, results are not consistent. Studies about dronabinol have shown positive impact on the OSA, as they observed a reduced AHI (Apnea-Hypopnea Index) and an increased self-reported sleepiness (the objective sleepiness being unaffected). However, more evidence are needed as many effects of those substances remain unknown, especially the effects of a long-term intake. The effect on sleepiness and weight gain are particularly of concern. Because of uncertainty about its effects and a lack of consistent evidence, the American Academy of Sleep Medicine does not approve the use of medical cannabis for the treatment of OSA.

Oral appliances / functional orthopedic appliances

Evidence to support oral appliances/functional orthopedic appliances in children is insufficient with very low evidence of effect. However, the oral appliances/functional orthopedic appliances may be considered in specified cases as an auxiliary in the treatment of children who have craniofacial anomalies which are risk factors of apnea.

Prognosis

Stroke and other cardiovascular diseases are related to OSA, and those under the age of 70 have an increased risk of early death. Persons with sleep apnea have a 30% higher risk of

heart attack A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ma ...

or death than those unaffected. In severe and prolonged cases, increased in pulmonary pressures are transmitted to the right side of the heart. This can result in a severe form of congestive heart failure known as ''

cor pulmonale Pulmonary heart disease, also known as cor pulmonale, is the enlargement and failure of the right ventricle of the heart as a response to increased vascular resistance (such as from pulmonic stenosis) or high blood pressure in the lungs. Chroni ...

''. Diastolic function of the heart also becomes affected. Elevated arterial pressure (i.e., hypertension) can be a consequence of OSA syndrome. When hypertension is caused by OSA, it is distinctive in that, unlike most cases (so-called

essential hypertension Essential hypertension (also called primary hypertension, or idiopathic hypertension) is the form of hypertension that by definition has no identifiable secondary cause. It is the most common type affecting 85% of those with high blood pressure. T ...

), the readings do ''not'' drop significantly when the individual is sleeping (non-dipper) or even increase (inverted dipper). Without treatment, the sleep deprivation and lack of oxygen caused by sleep apnea increases health risks such as cardiovascular disease, aortic disease (e.g. aortic aneurysm), high blood pressure, stroke,

clinical depression Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Intro ...

, weight gain,

, and even death. OSA is associated with cognitive impairment, including deficits in inductive and deductive reasoning, attention, vigilance, learning, executive functions, and episodic and working memory. OSA is associated with increased risk for developing

mild cognitive impairment Mild cognitive impairment (MCI) is a neurocognitive disorder which involves cognitive impairments beyond those expected based on an individual's age and education but which are not significant enough to interfere with instrumental activities o ...

and dementia, and has been associated with neuroanatomical changes (reductions in volumes of the hippocampus, and gray matter volume of the frontal and parietal lobes) which can however be at least in part reversed with CPAP treatment.

Epidemiology

Until the 1990s, little was known regarding the frequency of OSA. A recent meta-analysis of 24 epidemiological studies on the

of OSA in the general population aged 18 and older revealed that for ≥ 5 apnea events per hour, OSA prevalence ranged from 9% to 38%, specifically ranging from 13% to 33% in men and 6% to 19% in women, while in the population aged 65 and older, OSA prevalence was as high as 84%, including 90% in men and 78% in women. Nevertheless, for ≥ 15 apnea events per hour, OSA prevalence ranged from 6% to 17%, and almost 49% prevalence in the older population aged 65 and older. Moreover, a higher BMI is also linked to a higher prevalence of OSA, where a 10% increase in body weight led to a 6-fold risk of OSA in obese men and women. However, OSA is underdiagnosed as it is not always accompanied by daytime sleepiness which can leave the sleep-disordered breathing unnoticed. The prevalence of OSA with daytime sleepiness is thus estimated to affect 3% to 7% of men and 2% to 5% of women, and the disease is common in both developed and developing countries. OSA prevalence increases with age and is most commonly diagnosed in individuals over 65 years old, with estimations ranging from 22.1% to 83.6%. The prevalence has drastically increased the past decades mainly explained by the obesity epidemic currently observed. Men are more affected by OSA than women, but the phenomenology differs between both genders. Snoring and witnessed apnea are more frequent among men but insomnia for example is more frequent among women. The OSA frequency increase with age for the women. The mortality is higher for women. Some studies report that it is more frequent among the Hispanic and African American population than among the white population. If studied carefully in a sleep lab by polysomnography (formal "sleep study"), it is believed that approximately 1 in 5 American adults would have at least mild OSA.

Research

Neurostimulation Neurostimulation is the purposeful modulation of the nervous system's activity using invasive (e.g. microelectrodes) or non-invasive means (e.g. transcranial magnetic stimulation or transcranial electric stimulation, tES, such as tDCS or trans ...

is currently being studied as a method of treatment; an implanted hypoglossal nerve stimulation system received European CE Mark (Conformité Européenne) approval in March 2012. Also being studied are exercises of the muscles around the mouth and

throat In vertebrate anatomy, the throat is the front part of the neck, internally positioned in front of the vertebrae. It contains the pharynx and larynx. An important section of it is the epiglottis, separating the esophagus from the trachea (windpip ...

through activities such as playing the didgeridoo.

References

{{Sleep Sleep disorders

Classification

Signs and symptoms

Adults

Children

Pathophysiology

Pathophysiological models

Risk factors

Obesity

Age

Muscle tone

Medication and lifestyle

Genetic

Craniofacial syndromes

Post-operative complication

Consequences

In children

Neurocognitive and behavioral consequences

Somatic and metabolic consequences

Nocturnal enuresis

Other consequences

In adults

Neurocognitive consequences

Behavioral consequences

Physiological and metabolic consequences

Psychological consequences

Other consequences

Diagnosis

Criteria

Polysomnography

Home oximetry

Treatment

Physical intervention

Rapid Palatal Expansion

Surgery

Neurostimulation

Radiofrequency ablation

Medications

Oral appliances / functional orthopedic appliances

Prognosis

Epidemiology

Research

See also

References