Sleep stages affect severity of sleep apnoea
Recent findings from a sleep study have uncovered why the severity of obstructive sleep apnoea changes throughout the night.
Obstructive sleep apnoea (OSA) is a common disorder that affects more than 1 million Australians. It is diagnosed when a person stops breathing more than five times per hour.
OSA occurs when a person’s airway is too narrow or the size or shape of their airway causes it to close during sleep. Other causes, which are being investigated by NeuRA, include waking too easily during sleep or poor functioning of the muscles around the throat.
Previous studies indicate that upper airway collapsibility doesn’t change with sleep stage. However, a new study by Dr Jayne Carberry has identified that muscular activity and airway collapsibility are sleep stage dependent.
The study found that the upper airway is more collapsible in lighter sleep and REM sleep compared to deeper slow wave sleep. These changes may be due to changes in the genioglossus muscle, which runs from the chin to the tongue and enables us to stick out our tongues.
This new information will change the way in which airway collapsibility is measured and used in future studies and will improve our understanding of how to better treat OSA.
Current treatment includes the sufferer wearing a mask over the nose that constantly blows air into the airways to prevent them from collapsing. This therapy (which was invented by an Australian) is called a Continuous Positive Airway Pressure (CPAP) and benefits millions of people worldwide. However around half the people who try it are unable to tolerate it. Studies such as the most recent one from Dr Carberry will lead to new, more tolerable therapies for people with OSA.