A sleep study, also called polysomnography (PSG), is a diagnostic test to evaluate a person’s sleep patterns, breathing, and physical movements during sleep.

Sleep studies are conducted by medical professionals in sleep labs or at home, and the results are used to diagnose sleep disorders and develop treatment plans.

Types of Sleep Studies

There are two main types of sleep studies: in-lab PSG and home sleep apnea testing (HSAT).

In-Lab PSG

An in-lab PSG is performed in a sleep lab or clinic where you stay overnight.

During the study, a sleep technologist will attach electrodes to your scalp, face, chest, and legs to monitor brain waves, muscle activity, heart rate, breathing, and oxygen levels during sleep. The test measures different aspects of sleep, including the amount and quality of sleep, the duration of each sleep stage, and the presence of sleep-disordered breathing like snoring, apneas, or hypopneas.

Home Sleep Apnea Testing (HSAT)

HSAT is a type of sleep study done at home using a portable device that measures your breathing and oxygen levels during sleep.

The device is similar to a pulse oximeter and is worn on your wrist or finger, while a nasal cannula or a small sensor attached to the chest measures airflow. HSAT is designed for people who have a high risk of having obstructive sleep apnea, a common sleep disorder characterized by repeated episodes of breathing cessation during sleep.

The test is simple to use, and there is no need to stay overnight at the lab. However, HSAT has some limitations and may miss some sleep disorders that cannot be detected outside a sleep lab.

Who Needs a Sleep Study?

A sleep study may be recommended by your doctor if you suspect you have a sleep disorder or if you exhibit signs and symptoms of poor sleep quality, including:.

Loud snoring
Insomnia or difficulty falling asleep
Excessive daytime sleepiness or fatigue
Gasping or choking during sleep
Restless sleep or frequent awakenings
Headaches in the morning
Shortness of breath or chest pain during sleep
Bedwetting as an adult

Common Sleep Disorders Diagnosed with a Sleep Study

A sleep study can diagnose various sleep disorders, including:.

Obstructive Sleep Apnea (OSA): A common disorder that causes breathing to repeatedly stop and start during sleep, resulting in lower oxygen levels in the blood, disrupted sleep, and other health problems like high blood pressure, heart disease, stroke, and diabetes.
Central Sleep Apnea (CSA): A type of sleep apnea that is less common than OSA and involves a lack of respiratory effort during sleep, leading to a decreased or absent airflow.
Narcolepsy: A disorder characterized by excessive daytime sleepiness, sudden attacks of sleep, and recurring episodes of loss of muscle tone (cataplexy).
Rapid Eye Movement (REM) Sleep Behavior Disorder (RBD): A disorder that involves acting out vivid, intense, and violent dreams during REM sleep, often causing injury to the person or their bed partner.
Parasomnias: A group of sleep disorders that involve abnormal behaviors, movements, emotions, perceptions, or dreams during sleep, such as sleepwalking, talking, eating, or night terrors.

How to Prepare for a Sleep Study

If your doctor recommends a sleep study, you need to prepare for it properly to get accurate results. Here are some tips:.

Follow your regular sleep routine and sleep schedule for at least two weeks before the study.
Avoid caffeine, alcohol, and nicotine for at least four hours before the study.
Take your usual medications, unless your doctor instructed you otherwise.
Do not nap on the day of the study.
Wash your hair and avoid using hair products, as this can interfere with the electrodes’ attachment.
Bring comfortable sleepwear, toiletries, and any medications you need.

What Happens During a Sleep Study?

The specifics of the sleep study procedure depend on whether you are having an in-lab PSG or HSAT.

In-Lab PSG

If you are having an in-lab PSG, you will be asked to arrive at the sleep lab or clinic a few hours before your bedtime. A sleep technologist will greet you and explain the procedure to you.

The technologist will then attach the electrodes to your scalp, face, chest, legs, and finger, and a belt around your waist to monitor your breathing. The wires are colored and labeled, so they do not get confused.

After the electrodes are attached, you will be allowed to relax and watch TV, read or engage in other quiet activities to help you fall asleep naturally.

The technologist will observe you through a camera monitor and can communicate with you through an intercom. The appropriate location of the wires and electrodes will make it easier for you to move and be comfortable while you are sleeping once you get used to them.

The next morning, the technologist will remove the electrodes, and you can go home or follow your regular daily routine, unless told otherwise by your doctor.

Home Sleep Apnea Testing

If you are having HSAT, you will pick up the device from the sleep center or have it mailed to you. You will receive instructions on how to attach the sensors and wear the device while sleeping.

You will need to press a button to start the device when you are ready to sleep and reset it when you wake up. After the test is complete, you will return the device to the sleep center, where the results will be analyzed by a doctor and interpreted to you.

What Happens After the Sleep Study?

After your sleep study, your doctor will review the results and determine if you have a sleep disorder and how severe it is.

If you have a sleep disorder, your doctor will recommend appropriate treatments based on your test results, medical history, and physical exam.

Treatment options may include:.

Continuous Positive Airway Pressure (CPAP) therapy: A common treatment for sleep apnea that involves wearing a mask over the nose or mouth that delivers air pressure to keep the airway open during sleep.
Oral appliances: Devices that are worn in the mouth to treat snoring and mild-to-moderate obstructive sleep apnea by keeping the airway open.
Behavioral therapy: Techniques to improve sleep hygiene, reduce stress, and promote healthy sleep habits.
Medications: Drugs to treat specific sleep disorders, such as narcolepsy, insomnia, and RBD.
Surgery: Procedures to remove excess tissue in the throat, tongue, or tonsils that may be obstructing the airway during sleep.

Conclusion

A sleep study is a diagnostic test used to evaluate your sleep patterns, breathing, and physical movements during sleep. It can diagnose various sleep disorders and help develop appropriate treatment plans.

If you are experiencing symptoms of a sleep disorder, talk to your doctor about the benefits of a sleep study and how it can help you sleep better.