What Do Sleep Study Sensors Measure?

Sleep-study equipment can look complicated if you have never seen it before. Understanding what the sensors do can make the testing process feel less unfamiliar. Different studies use different combinations of sensors.

1. Brain activity

Electroencephalography (EEG) records electrical activity from the brain. In a comprehensive sleep study, it helps specialists identify sleep stages and when a person is asleep or awake.

2. Eye movements

Electro-oculography (EOG) records eye movements. These signals help identify different sleep stages, including periods associated with rapid eye movement.

3. Muscle activity

Electromyography (EMG) measures electrical activity in selected muscles. Depending on the study, it can help assess muscle activity during sleep.

4. Breathing and airflow

Sensors can record airflow and breathing effort. These measurements may help identify pauses or reductions in breathing during sleep.

5. Blood oxygen levels

A pulse oximeter, usually placed on a finger, estimates blood oxygen saturation. Oxygen measurements help clinicians assess whether breathing disturbances are associated with oxygen changes.

6. Heart activity

An ECG channel may record the heart's electrical activity during a comprehensive study, providing information about heart rate and rhythm during the recording.

Does every sleep study measure all these signals?

No. The signals recorded depend on the type of test and the clinical question. A home sleep apnea test usually records fewer signals than full polysomnography. Results need to be interpreted by a qualified professional.

Learn about testing options

Explore testing options offered by Srivari Healthcare in Chennai: available sleep-testing options.

Which equipment records what?

In clinical practice, systems such as the Sonata polysomnography system record brain, eye, muscle and heart signals alongside breathing, while a Scala polygraphy device focuses on breathing, oxygen and heart rate. Read more about sleep study equipment.

Related reading

• What Happens During an Overnight Sleep Study?

Think you may have sleep apnea?

A sleep study is how doctors confirm sleep apnea. Read how a sleep apnea test in Chennai works, or how you can do a home sleep study in your own bed. Your doctor decides which test suits you.

This article is educational and does not replace individual medical advice. Please speak to a qualified doctor about your own symptoms and results.