What is a sleep study?

Sleeping is something most of us take for granted until, for one reason or another, we cannot get a good night's sleep. There can be a wide range of causes for this; anxiety or stress may stop us sleeping, but there may also be a physical cause like snoring.

Sleep studies usually involve you either collecting a piece of equipment, wearing it for 1-2 nights and then returning it for downloading and analysis, or involve an overnight stay within a specialist sleep unit. They traditionally come in the form of either Overnight Oximetry, Portable Multi-Channel Monitoring or Polysomnography.

Overnight Oximetry

When you are referred to the hospital for tests you may have a simple screening test first which is called Overnight Oximetry. This test is usually done in your own home. You will be given a machine to take home which measures the level of oxygen in your blood and your heart rate. This needs to be worn when you go to sleep and will be used for one or two nights. You will then return this to the hospital where the information can be downloaded onto a computer and analysed by a trained healthcare scientist.

You will be asked to fill in some questionnaires about your sleepiness and the information gained from this and the overnight oximetry will be used to decide if you need to be treated for sleep apnoea or whether you may need further testing with a more detailed “sleep study”.

Portable Multichannel Monitoring

This is a more detailed sleep study which will monitor your breathing, heart rate and oxygen levels. This may still be done in your own home, or may involve an overnight stay in hospital.

A healthcare professional will show you how to use the equipment (if you are taking it home) or will fit it for you (if you are staying in hospital). There will be 2 bands which will fit around your tummy and chest to monitor the movements that are made when you breathe in and out. You will have a probe put onto your finger to measure your oxygen levels and pulse rate and you may also have an airflow sensor above your top lip. The equipment may be used for one or two nights and all the information obtained will be downloaded onto a computer and analysed by a trained healthcare professional.

All the information gathered from the tests and questionnaires will then be used to decide which treatment is best for you. If the information is still not adequate to make a diagnosis, you may be asked to perform a Polysomnography test.

Polysomnography

This sounds very complicated but is very similar to the portable multichannel monitoring. It is a test that is usually performed in hospital so will require you to have an overnight stay. You will be given all the information you need about what to bring with you when you receive your appointment and if you have any questions the healthcare professional will be happy to help.

The polysomnography test is the same as the portable multichannel monitoring with some extra equipment to monitor your leg movements and the quality and depth of your sleep. Electrodes will be stuck on (either with glue or using self-adhesive pads) to your legs and chest and also your temples, under your chin and scalp. There may also be a video recording of you when you are sleeping and sound recording to listen to any snoring.
As with the previous tests all the information gathered will be interpreted by a trained healthcare professional and a diagnosis can then be made. Once this has been completed we can then choose the correct treatment for you.