What does a sleep study do?
A sleep study is an overnight recording used to collect information about what happens in your body while you sleep. The most comprehensive type is called polysomnography (PSG). Depending on the type of study, recorded signals can include brain activity, eye and muscle movements, breathing, respiratory effort, blood oxygen levels and heart activity.
These signals help a qualified healthcare professional evaluate sleep and breathing patterns. A sleep study does not diagnose a condition by itself; the recording needs to be reviewed and interpreted in the context of the patient's symptoms and clinical assessment.
Why might a doctor recommend a sleep study?
A doctor may consider sleep testing when symptoms or clinical findings suggest a sleep disorder. For obstructive sleep apnoea, common warning signs include frequent loud snoring, breathing that repeatedly starts and stops, gasping during sleep and excessive daytime sleepiness. Other symptoms can include morning headaches, dry mouth, tiredness and difficulty concentrating.
The appropriate test depends on the individual. The American Academy of Sleep Medicine states that polysomnography is the standard diagnostic test for adults when obstructive sleep apnoea is suspected after a comprehensive sleep evaluation, while certain home testing approaches may be appropriate for selected uncomplicated adults.
What happens during polysomnography?
Before the recording begins, sensors are positioned to collect the signals required for the particular study. During comprehensive PSG, these may include:
- EEG to record brain activity used in sleep staging.
- EOG to record eye movements.
- EMG to record muscle activity.
- Airflow and chest/abdominal effort to evaluate breathing.
- Pulse oximetry to record blood oxygen saturation.
- ECG or heart-rate monitoring.
The exact setup varies according to the study type and clinical requirements. OYASUMI provides Level I and Level II comprehensive PSG services; you can read the practical differences on our Sleep Studies page.
Can a sleep study be performed at home?
Some sleep recordings can be performed outside a sleep laboratory using portable equipment. However, not every patient or clinical situation is suitable for the same type of home testing. The required study should be determined through an appropriate clinical pathway rather than chosen only for convenience.
What happens after the recording?
After the study, the recorded signals are reviewed and scored. The report can then be interpreted as part of the clinical evaluation. A result should be considered together with your symptoms, medical history and the reason the study was requested.
Preparing for a sleep study
Preparation instructions can vary with the equipment and study. Follow the instructions given for your specific appointment. If you are unsure about medicines, caffeine, skin or hair products, or anything that may affect the recording, ask the healthcare team before changing your normal routine or medication.
Not sure where to start?
If you have sleep-related symptoms but are not sure what they mean, our short adult questionnaire can help you organise your concerns before speaking with a doctor. It is a screening and educational tool, not a diagnosis.