The Causes of Snoring and Obstructive Sleep Apnoea
During normal breathing, air is drawn through the nose and past soft tissues at the back of the throat. These tissues include the uvula, the soft palate and the tongue.
During waking hours, the airways are held open by the tone of the muscles around them. During sleep, these muscles relax. In some people, the soft tissues may relax too much (or collapse), leading to obstruction of the airways.
In an attempt to overcome the obstruction, the person breathes harder, using the chest wall muscles and diaphragm. But the harder the person tries to breathe, the more the walls of the airway collapse; this is similar to trying to suck through a straw which collapses as the effort to withdraw liquid is increased.
The obstruction may be partial (hypopnoea) or complete. If breathing is absent for more than 10 seconds, the condition is known as apnoea.
Oral appliance therapy uses a dental device fitted inside the moth to prevent the airways from collapsing during sleep. This is usually achieved by holding the jaw forward.
The Symptoms and Signs Of Obstructive Sleep Apnoea
People who have obstructive sleep apnoea almost always snore loudly and usually have a number of other symptoms, including the following:
- Choking or gasping during sleep - Tiredness on waking - Sore, dry throat on waking
- Morning headache - Excessive daytime sleepiness - Poor concentration
- Memory deterioration - Decreased sex drive or impotence
- Personality changes that may include irritability - Decrease in job performance - Anxiety or depression
Diagnosis and Assessment Of Obstructive Sleep Apnoea
Proper diagnosis of the cause of sleep apnoea is essential so that the most appropriate treatment can be offered. People with symptomatic snoring should be assessed in a sleep disorder clinic before any treatment starts.
As many different problems can cause symptoms, this assessment may involve specialists with expertise in a number of areas, including dentistry, respiratory medicine, ear-nose-throat surgery, neurology and speech pathology. Assessment in a sleep disorder clinic will often involve the monitoring of sleep patterns during an overnight stay.
Obstructive sleep apnoea can cause interruptions to breathing many times during the night, each episode lasting from 10 seconds to two minutes. A person is considered to have sleep apnoea if there are more than five partial or complete obstructions per hour of sleep.
Typically, the apnoea episode ends when the person wakes up briefly. Usually, the person has no awareness of these brief episodes at the time but finds that sleep is not refreshing.