Quick answer. A sleep study (polysomnography) records what happens in your body while you sleep to diagnose sleep disorders such as obstructive sleep apnoea, narcolepsy and abnormal movements. Painless sensors record brain waves, eye movements, muscle activity, breathing, airflow, heart rhythm, oxygen levels and snoring. In Singapore it can be done in a hospital sleep lab (in-lab polysomnography) or, for selected cases, as a home sleep test using a portable device. Public hospital sleep centres – including at SGH, NUH and NNI – offer these tests, usually after a doctor’s referral. A specialist interprets the results to guide diagnosis and treatment such as CPAP. No needles are involved.
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A sleep study, or polysomnography, is the main test used to investigate sleep problems. It continuously records signals from your brain and body while you sleep, allowing a sleep physician to see how well you breathe, how your sleep is structured, and whether abnormal events such as pauses in breathing or limb movements are occurring.
In Singapore, sleep studies are carried out at hospital sleep centres and, for suitable patients, at home using portable devices. This guide explains why and when a sleep study is done, the difference between in-lab and home tests, what to expect on the night, what the test measures, and how results are interpreted.
At a glance
| Aspect | In-lab polysomnography | Home sleep test |
|---|---|---|
| Where | Overnight in a hospital sleep laboratory | In your own bed at home |
| What it measures | Comprehensive: brain waves, breathing, oxygen, heart, limb movements, video | Mainly breathing-related signals (e.g. airflow, oxygen, pulse) |
| Best for | Complex cases, narcolepsy (with MSLT), CPAP titration, uncertain diagnoses | Suspected moderate-to-severe obstructive sleep apnoea in suitable patients |
| Supervision | Monitored by a sleep technician | Self-applied; reviewed afterwards |
| Comfort | Unfamiliar environment, many sensors | Familiar surroundings, fewer sensors |
What is a sleep study?
Polysomnography is a non-invasive overnight test that records multiple body signals as you sleep. Small sensors are attached to your scalp, face, chest, abdomen, finger and legs using stickers, tape or soft belts – no needles are involved. The recordings let a sleep physician assess your sleep stages, breathing and any abnormal events. A related daytime test, the Multiple Sleep Latency Test (MSLT), uses scheduled naps to investigate excessive sleepiness and is used to diagnose narcolepsy.
Why and when a sleep study is done
Your doctor may recommend a sleep study if you have symptoms suggesting a sleep disorder, including:
- Suspected obstructive sleep apnoea – loud snoring, witnessed pauses in breathing, choking or gasping at night, and daytime sleepiness.
- Suspected narcolepsy or unexplained excessive daytime sleepiness – usually requiring overnight study plus an MSLT.
- Abnormal movements or behaviours in sleep – such as periodic limb movements or parasomnias.
- Assessing or fine-tuning treatment – for example, a CPAP titration study to set the right pressure for sleep apnoea.
A study is also useful when the diagnosis is unclear or symptoms persist despite treatment.
In-lab versus home sleep test
In-lab polysomnography is the most comprehensive option. You spend a night in a hospital sleep lab where a technician applies the sensors and monitors the recording. It captures the widest range of signals and is preferred for complex cases, narcolepsy assessment (with MSLT), CPAP titration, and when other conditions need to be excluded.
Home sleep tests use a smaller portable device that you apply yourself at home. They focus mainly on breathing-related signals and are suitable for selected patients with a high likelihood of moderate-to-severe obstructive sleep apnoea, or for those who cannot or prefer not to stay overnight in hospital. Some Singapore sleep centres use wrist-worn devices with a finger probe for this purpose. Your doctor decides which test is appropriate; a normal or inconclusive home test may still need to be followed by an in-lab study.
What to expect on the night
For an in-lab study, you usually arrive in the evening and are shown to a private room. A trained sleep technician attaches the sensors, which takes time but is painless. You then sleep as normally as you can; the technician monitors the recording, and video may be used. Tips that help:
- Follow any pre-test instructions – for example, avoiding caffeine, alcohol and daytime naps, and bringing your usual medications and sleepwear.
- Bring a list of your medicines, as some can affect the results.
- Don’t worry if you feel you slept less than usual; enough data is usually still captured.
For a home test, staff will show you how to fit the device, and you sleep in your own bed before returning the equipment.
What it measures and interpreting results
A full polysomnography typically records:
- Brain waves (EEG) and eye movements – to map sleep stages.
- Muscle activity and limb movements – to detect periodic limb movements and parasomnias.
- Airflow and breathing effort – to detect apnoeas and hypopnoeas.
- Blood oxygen levels and heart rhythm.
- Snoring and body position.
A sleep physician reviews all of this and calculates measures such as the apnoea-hypopnoea index (AHI), which grades sleep apnoea severity. Results are explained to you along with a diagnosis and treatment plan, which may include CPAP, lifestyle changes, or further tests. Always discuss your report with your doctor rather than interpreting numbers alone.
Where to have a sleep study in Singapore
Sleep studies are available at public hospital sleep centres and private providers. Public options include the SGH Sleep Centre (a large multidisciplinary sleep unit), the NUH Sleep Centre, sleep services at the National Neuroscience Institute (NNI) for neurology-related sleep disorders, and other restructured hospitals such as NTFGH. Most require a referral from a doctor. Costs vary depending on the hospital, whether the study is in-lab or at home, subsidy status and any additional tests, so check with the provider; subsidies may apply at public hospitals.
Related guides
- Best Respiratory & Lung Clinics in Singapore — our editorial shortlist
- Restless legs syndrome
- Narcolepsy
- Shift work & jet lag
Sources
- SGH – Sleep Centre (polysomnography, MSLT, WatchPAT home study)
- NUH – Sleep Centre Services (in-lab and home sleep study, MSLT)
- SingHealth – Sleep Disorders: Conditions & Treatments
- HealthXchange (SingHealth) – Home sleep study explained
Related conditions & guides
Related conditions and guides you may find useful:
- Insomnia Treatment in Singapore
- Obstructive Sleep Apnoea and CPAP in Singapore
- Snoring & Obstructive Sleep Apnoea (OSA) Treatment in Singapore
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