Obstructive Sleep Apnoea, (OSA), is a condition where the upper airway collapses and prevents air from entering the lungs. It occurs only during periods of sleep and is caused by a lack of muscle tone in the upper part of the airway which leads to the ‘obstruction’ as the airway temporarily collapses.
These obstructions cause short periods where the sleeper is no longer breathing but are only classed as clinically significant if each bout lasts more than 10 seconds and there are more than 10 individual occurences in an hour. The reason that the periods of apnoea only last for a short time is thanks to the sleeper’s brain, which automatically wakes them up, a loud snort or snore usually accompanies this with normal breathing patterns resuming. During the day there is adequate muscle tone to keep the airway permanently open.
For those with OSA, the awakening periods occur frequently throughout the night and severely affect the quantity and quality of sleep achieved.
Do I Have OSA?Surprisingly it is most often the sufferer’s sleeping partner that notice the symptoms first, as they are woken by the loud snores.
Common symptoms reported by OSA patients include:
- Excessive daytime sleepiness, often associated with irritability and short temper.
Anxiety/depression in undiagnosed, long term sufferers. - Unexplained changes in mood and/or behaviour, such as forgetfulness.
Headaches upon waking. - Very loud, intense snoring which is often accompanied by pauses or gasps.
- Decreased interest in sex.
- Having some of these symptoms does not mean you necessarily have OSA, we all suffer from them periodically but for those with sleep apnoea they will exhibit the majority of these for a chronic period of time.
How is OSA diagnosed?Like most medical conditions the degree of the symptoms can range from mild to severe. Diagnosis of the condition will be identified by means of a sleep study carried out by a specialist, where a night is spent in a hospital sleep laboratory, where various equipment is used to monitor numerous physiological functions whilst you are asleep. Upon analysis of the results the specialist can then decide the best course of treatment.
A apnoea/hypopnoeic index, (AHI), is used to classify the severity of the OSA. The AHI calculates the number of apnoeic and hypopneic occurences per hour of sleep. Hypoponea is a reduction in the airflow, as opposed to a complete obstruction. If this index gives a value of more than 10, treatment and further study is required.
The investigation procedure is called polysomnography and includes observation of brain waves, airway muscle tone, airflow in the mouth and nose, heart rate and blood oxygen levels.
More recently home sleep studies have become popular and will replicate more reliably a ‘normal’ nights sleep in a familiar environment and more importantly in a comfortable bed.
OSA Treatment
Treatment depends on the severity of the condition. In mild to moderate cases mandibular advancement devices, (MAD), are used alongside a weight loss program, which together are frequently successful. Treatment for more severe case consists of MAD’s alongside CPAP technology. CPAP refers to continuous positive airway pressure machines, which deliver a continuous stream of air through a mask worn over the nose to keep the sleeper's airway permanently open.