Upper Airway Resistance Syndrome (UARS)

 Upper Airway Resistance Syndrome (UARS) is a common and under-diagnosed condition that can affect any age group. Patients with UARS do not have the apnea events of an OSA patient and therefore do not usually meet the criteria of OSA and may be  left untreated. It often begins as mild snoring with no sleep disruption. It should be noted however many patients with UARS do not demonstrate snoring. Some have an increase in respiratory effort only due to anatomical restrictions in the upper airway such as deviated septums, large turbinates, or congenitally narrow nasal passages. A common characteristic of people with UARS is that they share a small neck (and small windpipe). If there is resistance in breathing in the upper airway, as the diaphragm contracts downward, the air cannot enter the lungs fast enough generating a negative pressure in the airway. If the wind pipe is narrow, it can collapse blocking the airway.

The symptoms vary by age group but the end result is often the same: excessive daytime sleepiness, difficulty falling asleep and non-refreshing sleep. It is different than sleep apnea but can lead to the development of sleep deprivation over time (which has many pathological similarities to OSA). Some researchers feel that UARS is part of a spectrum of disorders that ranges from snoring to sleep apnea (with UARS somewhere in the middle). Other researchers feel it is a separate entity completely. UARS does not result in the characteristic apnea events or cessation of breathing seen in OSA, but rather the sleep deprivation caused by frequent arousals due to recurrent collapsing of the trachea (airway). It is now known that with OSA is associated with local neurological impairment which is responsible for the hypopneas and apneas seen in this disease. In contrast, UARS has an intact neurological system and the ability to respond to even minor changes in the upper airway dimension and resistance airflow.

There are significant differences between UARS and OSA and most researchers feel that they present two completely separate disorders with different pathogenesis. The Following table compares the two and their differences:

What differentiates UARS is that it is often associated with pain symptoms, in all age groups. Children suffering from migraine syndrome usually have UARS (or sleep-related-related bruxism) superimposed that is missed in the diagnosis. Pain is unusual in healthy children and the onset of chronic pain should immediately alert the parent to this condition. The can effect a child both physically and mentally and can affect the child for life.


Infants with UARS present with noisy breathing, and disturbed night time sleep. They tend to wake often and sleep restlessly. Grinding of the teeth (sleep-related bruxism) is common while sleeping.


Toddlers and preschool children present with snoring all the way up to sleep apnea (the full spectrum). There is secondary growth impairment, neurocognitive deficits (learning and memory), and in rare cases, cardiovascular problems. Tooth grinding while sleeping is very common in this group as well.  Bed-wetting , sleep walking and sleep talking are also common. Night terrors (it is terrifying to a child to not be able to breath!) are often seen, as well as head banging while falling asleep. Sometimes tooth grinding is so loud it can be heard rooms away (all of these symptoms are classified by the American Academy of Sleep Medicine as separate sleep disorders).


These children have similar symptoms to preschoolers except we start to see pain symptoms and headaches appear in this subgroup of UARS. Tooth grinding is common leading to sore jaw muscles, which can cause headaches, neck and back pain. These recurrent headaches are often misinterpreted as migraine syndrome and treated accordingly. Different than OSA, this group is not usually hyperactive from sleep deprivation. They do show poor hand to eye coordination, impaired learning and memory, and are more prone to dizziness and fainting. They tend to be smaller children and underweight. If they gain weight they can convert to OSA easily. If the bruxism is severe, the patient will lose height in their teeth increasing their overbite while retruding (pulling back) the mandible (further obstructing the upper airway).


Adolescents with UARS have similar symptoms to younger children: difficulty falling and staying asleep, difficulty with memory and learning, difficulty with sports (due to decreased stamina, fatigue, poor reaction times), and poor posture (slouching, rolled shoulders, support head with hand when sitting). Tooth grinding is almost always present in this group as are orthodontic malocclusions due to abnormal tongue positioning at rest and narrowing of the palate from chronic mouth breathing. Adolescents with UARS are more likely to undertake risky behaviors due to impaired decision making from sleep deprivation. They are much more likely to get involved in motor vehicle accidents, even more so than in Sleep Apnea. Reaction times are impaired in this group comparable to being over the legal blood alcohol limit. They almost all have a malocclusion or crooked or crowded teeth due to the chronic mouth breathing and resulting poor posture associated with mouth breathing. Bruxism is very common in this group and TMJ involvement can be seen in some. Pain in the TMJ on opening or when biting is common. When the lower jaw is pushed back, it can cause a compression of the TMJ and inflammation of the nerves and blood vessels at the back of the TMJ. This causes pain in the area as well as into the ear (as a chronic earache) or the sinuses over the upper molars (maxillary sinuses). Chronic Myofascial Pain is often seen in this group with the accompanying classic referred pain and headaches. Headaches tend to be worse upon waking, due to poor sleep and sleep-related bruxism.

 ADULTS: 18 +

In adults, the symptoms are not like sleep apnea (see charts above). An untreated adult with this has a reaction time that is slowed (comparable to being impaired with alcohol). Some studies have shown that patients with UARS have worse psychomotor performance than those with untreated sleep apnea. In severe cases, the cardiovascular morbidity is similar to sleep apnea (enlarged right ventricle of the heart and increased blood pressure resistant to treatment). Untreated UARS is similar or in some cases even worse than untreated sleep apnea for the risk of falling asleep while driving a car or operating machinery and being injured. Type 2 diabetes and under active thyroid are also common in this group. The other hallmark of UARS is chronic pain. It has been linked to Fibromyalgia (up to 40% of FM patients suffer from UARS), Chronic Myofascial Pain (more than 35% suffer from this), and most, if not all, adults with UARS are grinders and often present with sensitive, broken teeth.


The causes of UARS are only starting to be understood. The leading cause of UARS in all age groups is enlarged tonsil and adenoid tissue blocking or partially blocking the airway, usually resulting from allergies. The resulting allergic rhinitis (plugged nose due to allergies) can cause craniofacial anomalies (distortions in the face such as deviated septum, facial asymmetries affecting the airway, narrow high palates, large tongues, long soft palates), neuromuscular diseases (causing collapse of the soft tissue of the upper airway and blockages). Children who are obese are at higher risk of developing both UARS and OSA. As the BMI index increases, UARS can quickly appear and rapidly convert into Sleep Apnea due to fat deposits in the back of the throat. In severe obesity in children, CPAP therapy is the only course of treatment and new pediatric CPAP machines and masks are available when indicated. In adults, narrow tracheas and nasal passages can result in  restrictions in airflow and cause this disease.


Normal posture of the breathing system is not seen with UARS. This affects the head posture, neck posture, and spinal posture. The following photos and table outline some of the changes that occur due to mouth breathing and UARS. It affects directly on the dental development, with narrowing of the upper jaw and crowding of the upper teeth, as well as changes on their skeletal posture characterized by forward rolling of the shoulders and slouching posture. The tongue assumes an abnormal horizontal or low posture placing abnormal pressure on the teeth and the resulting crowding seen with this group.

Tongue Posture Abnormalities


Postural Changes with Mouth Breathing


Diagnosis of UARS is not always as easy as with sleep apnea. Overnight polysomnographs do not always pick this up. There is a specialized sensor that can be inserted through the nose back into the trachea called a PES probe . If the trachea collapses, this sensor will detect it confirming the diagnosis. This has been considered the gold standard for diagnosis of UARS.

Pes Probe the “Gold Standard”

There are now newer techniques available that can accurately measure pressure changes through the nose or even changes in breathing patterns using nasal cannulas,  making diagnosis much more comfortable and easier/safer to administer.

UARS testing with Nasal Cannula


It should be remembered that even small decreases or increases in airflow can have profound consequences. In some cases, nasal strips placed over the nose can increase the airflow enough (Nozovent is one currently available) to prevent collapsing of the nostrils while sleeping. This is inexpensive and patients can try this in the comfort of their own home as a “first step”.  A simple test one can do is to plug one nostril with a finger, close the mouth tight and take a deep breath. If the open nostril collapses and breathing is difficult, then these strips may be an option to try. If not, then the problem could be deeper.

Some patients are treatable simply by changing their sleep posture. Sleeping on one’s side can decrease resistance in the upper airway in some people whereas sleeping on the back increases resistance. Their are special aids that can be used that prevent sleeping on the back. There are special cushions available that strap the the back preventing back sleeping. If you have chronic muscle and back pain, be sure to place a pillow between your legs for comfort when sleeping on your side. The chronic pain syndromes associated with UARS are recognized as a sleep disorder in their own right and can affect sleep.

Treatment of allergic inflammation of the nasal passageways can provide relief to those poor patients who seem to be allergic to everything. The use of OTC (over the counter) antihistamines can often provide relief for this group. ENT’s and allergists often prescribe nasal steriods which are very effective at reducing swelling in the nasal passages.

It should be noted that the average person sleeps about 1/3 of their lifetime. If your posture while sleeping is poor, you will suffer! Using a proper support pillow is important. Many manufacturers of pillows now offer them in different densities and thicknesses. For OSA and UARS, a side sleeper pillow should be used. It is firm and holds the head level with the spine while sleeping. It also discourages back sleeping. These are readily available in department stores and are inexpensive. If you suffer from allergies, your pillow and bedding could be contributing. Dust mites are a fact of life, they live in everyone’s house. They feed on dead skin that  falls off of us and they release droppings (waste). These droppings are very allergenic to most people and, considering your face is right in the pillow for 7 or 8 hours, can cause some significant allergies. Over time, your pillow begins to fill up with these droppings and when your pillow is about 6 months old, up to 1/3 of its weight can be dust mite droppings! Change your pillow every 3 months and consider putting it into a sealed allergy cover and duct tape the end shut. You can also buy allergy bags for your mattresses that you slide the mattress, zip closed and duct tape to seal.  While you are at it, remove all the trinkets, fuzzy decorative objects, picture frames etc that collect dust. They are not called DUST MITES without a reason. and excess dust will promote them, aggravating your sinuses and allergies. We tend to clutter our bedrooms and this only contributes to the problem.

If you live in some areas of Canada or  areas like Arizona, dry air can be a problem for airways as at certain times of the year. Room humidity should ideally be around 40-45%. This reduces evaporation from the body and helps dry skin and nasal irritation. A room humidifier can significantly help but you must clean them regularly to prevent mold growing inside (this is another problem in itself!). In Canada, the average house in winter be as low as 26-28% humidity due to the cold weather!

Removal of large tonsils and adenoids is the standard treatment for UARS in pediatric patients, school age children and adolescents. Expansion of the upper jaw in children with narrow palates can help significantly (the nose floor is the roof of the mouth). Around age 8 ½, removable or cemented expansion appliances can be effectively used to widen the upper jaw which gives the tongue more room and helps reduce mouth breathing. If allergies are a factor, daily use of antihistamines can help. Sometimes steroid nasal sprays can open up blocked passageways. Allergy shots by an allergist can desensitize an allergic patient effectively. Early treatment is preferable due to the impaired memory,  growth and learning seen in these children. Bagging the pillow and beds in children with dust mite allergies is essential!

 Orthodontic treatment can be used in the early permanent dentition stage (11-12).  The use of braces with a  cemented (or removable) ALF appliance (Advanced Light Force) can treat this effectively. Often, however, the mouth breathing persists as it is “normal” for the child to mouth breath now and the loss of muscle tone in their lip muscles prevents a good lip seal at rest.  Their education can suffer as well, due to poor concentration and impaired memory. In severe pediatric cases, pediatric CPAP masks are now available for the use of CPAP/NPAP machines while sleeping for ages 3 and up. Sleep apnea appliances are not indicated for this age group as they can alter their facial growth resulting in a prominent lower jaw. The youngest age shown safe for mandibular advancement appliances such as the Luco Hybrid OSA Appliance is 18 as most or all of the facial development is believed to be completed at this age. It is important that the patient’s dental age is used as opposed to their chronological age for this determination. Some children mature slower and treatment may need to be delayed until facial developments is completed And some may be treated earlier. 18 year olds with Class III bites (small upper jaw to lower jaw ratio) May experience a significant bite shift where the lower teeth are ahead of the upper with all mandibular advancement appliances.

Expansion appliances in children work not only at making room for the teeth, but also increase the width of the nasal passages. This is a necessary treatment and is best completed in the mixed dentition stage around 8 1/2 to 9. Maxillary Expansion (click for animation). Expansion of the upper jaw occurs with the pivot point above the nose resulting in a widening of the nasal passage. It is not as much as the palate due to the  location of the center of rotation but still does give a bit more room for air to flow. When a patient has a narrow palate, this almost always results in a reduction of nasal airflow. In adolescents, braces may be combined with an expansion appliance attached  (such as the A.L.F).

 In young adults (18+), appliances that advance the jaw and tongue forward can effectively treat most forms of UARS (such as the Luco Hybrid OSA Appliance).  If there are persistent large tonsils and adenoids, they are often removed to assist nasal breathing. Other patients require the use of a CPAP/NPAP (forced air device) as in Obstructive Sleep Apnea as there is just too much obstruction and not enough airway. Surgery to reduce the size of large turbinates in the nose can increase airflow. These cases must be assessed by a sleep specialist who determines the best course of treatment. It is imperative that patients with UARS strive to keep their weight as close to normal as possible to prevent progressing into sleep apnea.

If you suspect that your child may have UARS, we recommend obtained a referral through your family doctor to an ENT or Respirologist for assessment as young as possible. The earlier the child is treated, the earlier normal growth and development will begin and continue for the duration of the child’s growth. Costly orthodontics can be minimized with early intervention and expansion appliances can significantly help when used in younger children.  With the effects on behavior, memory formation and learning, treatment or lack of treatment can affect the child for life. Poor grades don’t get them into college. Abstinence from sports can lead to weight gain, weak bone structure, weak postural muscles, and chronic muscle/headache pain often lasted for life. Reliance on pain medications for chronic pain can result in experimentation with other drugs  and alcohol (risky behaviors) and injury to organs and the brain can occur if mixed with other drugs or alcohol.

If you are an adult with Fibromyalgia, Chronic Myofascial Pain, TMD (jaw pain), ADHD, or insomnia, you should look into being tested for UARS as a large percentage of patients with these disorders have UARS which may be triggering the symptoms. Sleep deprivation lowers the pain threshold. By improving your sleep, you will be raising your pain threshold lessening the severity of your pain symptoms and allowing the treatment(s) you may be receiving for this to work much more effectively.

Next: Sleep-Related Bruxism