Sleep Studies

What is a sleep study?

A sleep study (medical term - polysomnogram or PSG) is where a number of bodily functions are monitored while you are asleep. A sleep study will often entail an EEG (electroencephalogram) to monitor brain waves, an EOG (electroocculogram) to monitor eye movements and an ECG (electrocardiogram) to monitor heart activity.

Other tests may monitor airflow through the nose and mouth, blood oxygen content and any sound or movement, such as snoring or involuntary limb movements.

What are sleep studies used for?

Sleep studies are useful in the diagnosis of conditions relating to sleeping problems, for example when someone is having problems breathing while sleeping (which may indicate sleep apnoea) or where someone is having difficulty getting to sleep, or waking frequently. A sleep study is also useful for monitoring heart activity while the person is asleep.

Where are sleep studies conducted?

Sleep studies can either be done at a hospital or 'sleep lab' or clinic, where you stay overnight, or they can be conducted at home with a portable sleep monitor. A portable sleep monitor may provide your doctor or specialist with all the information needed, however, if you have heart disease (or are suspected of having heart disease) or have lung disease, an overnight sleep study at a hospital or sleep clinic is required.

What happens during a sleep study?

A medical technician attaches electrodes (which are embedded in small patches) which are attached to the skin on your head, chest and legs before you go to sleep at the hospital or sleep clinic, or before you go home if doing the test at home. You then go to sleep as normal and have the device removed by the medical technician.

How do I prepare for a sleep study?

In general there is very little that needs to be done to prepare for a sleep study, however you should avoid drinking any alcohol before the test and avoid any drinks with caffeine (eg tea, coffee, some soft drinks) after midday on the day you are have the sleep study.