Normal Sleep Cycle
Sleep consists of 2 distinct states - Non REM (Rapid Eye Movement) sleep and REM Sleep.
These alternate in 90 to 110 minute cycles with a normal sleep pattern of 4 to 5 cycles.
Non REM sleep accounts for 75% of sleep and has four sequential phases. Delta sleep is the final phase and is a deep sleep that is important for physical rest, restorative, and is characterized by large, slow delta waves in the brain. This delta sleep accounts for a greater proportion of total sleep time in children and decreases by age 50 to 60. By 60 it is almost absent.
REM sleep improves the ability to sustain attention when awake and improves learning. In its absence, recollection of newly learned material is impaired. A decrease in tone of the upper airway muscles during REM sleep predisposes individuals to obstructive sleep apnoeas.
Sleep Disordered Breathing
(Snoring, Upper Airway Resistance Syndrome, Obstructive Sleep Apnoea)
This is a result of an anatomical abnormality of either the oral airway or nasal passages. It is of non-psychological origin.
Oral airway problems include
- swollen adenoids and tonsil
- a small airway (anatomical as opposed to pathological in origin)
- malocclusion (bad bite)
- hormonal imbalances (such as menopause)
- sinus problems
In a person suffering from sleep disordered breathing, the AIRWAY COLLAPSES in on itself when the person breathes in and out, shutting of the airway either completely or partially. (very important concept in the treatment for these conditions)
There are 3 categories of sleep disordered breathing
- snoring (the mildest form)
- upper airway resistance syndrome
- obstructive sleep apnoea
Snoring is often a cry for help. Modern medicine practically ignored this nighttime distress signal until recently.
Snoring is a clear signal that an airway is blocked.
- Enlarged tonsils and adenoids easily block airways in children and in some adults.
- An overgrown small jaw can result in a small airway that is more easily blocked when the a sleeping jaw drops.
- compressed and crowded throat tissues can result in choking a sleeper hundreds of times a night
Habitual snoring often signals the presence of dangerous nighttime sleep disorders. Sleep disorders are known to be an independent risk factor for a number of diseases, including hypertension, cardiovascular disease, cerebrovascular disease (strokes) and diabetic insulin resistance.
Snoring alone is hard on the heart and brain. Research suggests that snorers have low night oxygen even if they do not have a sleep disorder. Snoring has been found to be a predictor of poor school performance. A study that compared childhood snoring at 2 to 6 years of age to school performance in middle school were more likely to have snored during early childhood. They were also more likely to require later tonsil and adenoid removal.
There are 2 major types of sleep apnoea
Obstructive Sleep Apnoea is a complete cessation of breathing during sleep for at least 10 seconds. During an episode of OSA, the entire upper airway is blocked causing airflow to stop. This disrupts sleep as a lack of oxygen results. The person awakens repeatedly as a result of making an effort to breathe in the presence of a lack of oxygen.
Central Sleep Apnoea is defined as a period of 10 seconds without airflow due to lack of stimulus form higher levels of the brain and the apnoea can be longer periods of time.
Mixed – Combination of the 2 above
Risk factors for sleep apnoea include obesity, increasing age, male gender, family history, alcohol, sedative use, smoking, hypertension, breathing disorders such as asthma, menopause, and anatomic abnormalities of the upper airway. A further risk factor is malocclusion (bad bite) and bruxism.
Initial evaluation is done using an Epsworth Sleepiness Scale.
Defintive diagnosis is made using an overnight sleep study called polysomnogram (PSG). The persons sleep is monitored and measured throughout the night. Sleep Disordered Breathing is further divided in problems of nasal origin and those with oral airway problems.
The 3 treatment options are
CPAP (gold standard of treatment) uses a device that forms a pneumatic splint and is placed over the person’s nose during sleep. It opens up the airway with positive pressure and has been found to be effective in moderate or severe OSA. However compliance is very poor. Its use is associated with laceration of the nose, rawness of the throat, bloating of the stomach, nasal congestion and ironically sleep deprivation.
Surgery is helpful where there is an anatomical obstruction such as enlarged tonsils and/or adenoids, an enlarged uvula or nasal anatomical problems. Surgery has ponly been found to be 30 – 50% effective
Oral Appliances (Mandibular Advancement Splints) are indicated for people with mild to moderate OSA who prefer them to CPAP (continuous positive airway pressure) therapy, or who do not respond to are not appropriate candidates for or who fail treatment attempts with CPAP.
Oral appliance therapy is non invasive, less obtrusive than CPAP, and effective in the treatment of milt to moderate cases of sleep disordered breathing. Oral appliances may be worn overnight, or during t he day or both, depending on individual person’s treatment. The oral appliances are used to achieve TMJ and mandibular repositioning or tongue retention or both.
Success rates have been found to be as high as 76%.
Oral appliances can sometimes cause mild discomfort and temporary minor shifts of your bite that are easily corrected by removing the appliance and by opening and closing the mouth a few times.
There are different types of oral appliances. Just like there are different shoe sizes for people, there are different appliances for sleep disordered breathing. Do not get stuck into thinking of a particular brand. Custom fabricated appliances include Silent Night, TAP, Silencer, Somnomed MAS, EMA I and II, OASYS, CPAP Pro, the tongue retaining Device and many more. There are specific benefits to each appliance and these mnust be matched to each patient’s specific needs.
EXAMPLE : The SomnoMed MAS:
- Permits full range of mouth opening/closing and complete jaw closure
- Minimises disruption to normal oral functions like speech, drinking and yawning
- Minimises impingement on the oral airway and the tongue space
- Enables the wearer to open the mouth, yet have the jaw remain forward at all times.
For additional information including published research about SomnoMed MAS, please visit www.somnomed.com.au