A polysomnography sleep study is a test that helps doctors understand how a person sleeps and identify potential sleep disorders. It monitors different body functions during sleep, such as breathing, heart rate, brain activity, oxygen levels and movement.

This information helps healthcare providers determine if sleep interruptions may be affecting health and daily life. Sleep studies can also benefit overall health by finding ways to improve sleeping quality, increase daytime alertness and improve quality of life.

 Types of Sleep Studies

• Polysomnography (PSG) – Conducted overnight at a sleep center, this test records brain waves, breathing, oxygen levels, heart rate, and body movements to assess sleep disorders such as sleep apnea, restless legs syndrome, and narcolepsy.
• Home Sleep Apnea Test (HSAT) – A portable test used at home to detect obstructive sleep apnea by measuring breathing patterns, airflow, and oxygen levels. It provides less data than an in-lab study and is not suitable for diagnosing other sleep disorders.
• Multiple Sleep Latency Test (MSLT) – A daytime test that measures how quickly a person falls asleep and enters REM sleep. It helps diagnose narcolepsy and excessive daytime sleepiness.
• CPAP Titration Study – Conducted in a sleep lab, this test determines the correct air pressure settings for a continuous positive airway pressure (CPAP) machine, which is used to treat sleep apnea.
• Split-Night Sleep Study – A combination test that starts with polysomnography in the first half of the night. If sleep apnea is detected, the second half is used to adjust CPAP settings.
• Maintenance of Wakefulness Test (MWT) – Measures how well a person can stay awake in a quiet setting. This test is often used for individuals in safety-sensitive jobs or those experiencing excessive sleepiness.
  

How Does a Sleep Study Work?

A sleep study is a noninvasive test that tracks how the body functions during sleep. It is used to help diagnose sleep disorders by monitoring breathing, brain activity, heart rate, oxygen levels and movement. Depending on the situation, sleep studies can be done in a sleep center, hospital or sometimes at home with a portable device.

What To Expect at a Sleep Center

If the study is done at a sleep center, it usually begins in the evening. A private, comfortable room, like a hotel room, is provided. A sleep technologist will place small, painless sensors on the scalp, chest, arms, legs and near the eyes. These sensors are connected to a computer that records important body functions while the person sleeps. A small clip may also be placed on the finger or ear to measure oxygen levels.

The sleep environment is designed to be as normal as possible. A low-light video camera may be used to observe sleep patterns. If assistance is needed during the night, a technologist is available. Most people sleep well enough for doctors to collect the information they need. 

Home Sleep Testing

For some individuals, a home sleep study test may be an option. This is a simpler version of a sleep study that primarily focuses on breathing patterns, heart rate and oxygen levels. A healthcare provider will give instructions on how to attach the sensors and use the device. After the study, the device is returned for analysis. 

After the Sleep Study

In the morning, the sensors are removed, and the information is sent to a doctor for review. This process may take some time, as specialists carefully analyze the data to determine if there are any sleep-related issues. A follow-up visit is usually scheduled to discuss the results and possible next steps.

What Can a Sleep Study Diagnose?

Here are common conditions diagnosed through a sleep study:

• Sleep Apnea – A condition where breathing repeatedly stops and starts during sleep. It may cause snoring, choking or gasping for air and excessive daytime sleepiness.
• Insomnia – Trouble falling asleep or staying asleep, which may lead to daytime fatigue and difficulty concentrating.
• Restless Legs Syndrome (RLS) – A condition that causes an irresistible urge to move the legs, often accompanied by uncomfortable sensations.
• Narcolepsy – A neurological disorder that affects the brain’s ability to control sleep-wake cycles, leading to excessive daytime sleepiness and sudden sleep episodes.
• Periodic Limb Movement Disorder (PLMD) – Involuntary leg or arm movements that happen during sleep, sometimes causing frequent awakenings.
• Parasomnias—Unusual behaviors during sleep, such as sleepwalking, sleep talking or REM sleep behavior disorder, in which people physically act out dreams.
  

When To Get a Sleep Study

A sleep study may be recommended if sleep problems are affecting daily life, causing excessive tiredness or leading to other health concerns. Sleep disorders can develop gradually or suddenly and recognizing the signs early can help in finding the right solution. A doctor might suggest a sleep study if someone experiences:

• Loud, frequent snoring
• Daytime sleepiness
• Trouble falling or staying asleep
• Unusual movements during sleep
• Morning headaches or dry mouth
• Frequent nighttime awakenings
• Difficulty concentrating or memory issues
  

Who Performs Sleep Studies?

Sleep studies involve several healthcare professionals who specialize in monitoring, diagnosing and managing sleep disorders.

• Sleep Technologists – These trained professionals conduct sleep study in a sleep center, hospital or clinic. They attach sensors to the patient, monitor sleep patterns using specialized sleep study equipment and ensure that all data is recorded properly. They do not diagnose conditions but collect the information that doctors use for analysis.
• Sleep Physicians (Doctors) – Physicians with expertise in sleep study medicine analyze the data from the sleep study to diagnose sleep disorders. They may recommend treatment options, such as CPAP therapy, oral appliances or lifestyle modifications. Sleep physicians can come from different medical backgrounds, including pulmonology, neurology and otolaryngology.
• Pulmonologists – Lung and respiratory specialists assess breathing-related sleep disorders, such as obstructive sleep apnea. They help manage conditions affecting airflow and oxygen levels during sleep.
• Neurologists – These doctors focus on neurological sleep disorders, such as restless legs syndrome, narcolepsy or sleep-related movement disorders. They evaluate how brain activity during sleep may contribute to symptoms.
• Otolaryngologists (ENT Doctors) – Ear, nose and throat providers evaluate structural airway issues that may contribute to snoring or sleep apnea. They may recommend surgical or non-surgical interventions to improve breathing during sleep.
• Primary Care Physicians – General practitioners often recognize sleep-related symptoms and refer patients to a sleep specialist for further evaluation. They may also help manage contributing factors such as obesity, high blood pressure or diabetes.
• Dentists (Sleep Dentistry Providers) – Some dentists specialize in sleep medicine and fit patients with oral appliances designed to prevent airway obstruction. These devices are often used as an alternative to CPAP therapy for mild to moderate sleep apnea.
• Home Sleep Test Providers – For some patients, a home sleep study may be recommended. These providers supply the necessary equipment and instructions for conducting the home polysomnography sleep test. They collect the recorded data and send it to a sleep specialist for review. 

Find a Sleep Study Doctor

Sleep studies are conducted by many different types of providers, including pulmonologists, neurologists and sleep medicine doctors. If you're in San Antonio, TX, Baptist Medical Network offers sleep study services to help diagnose and manage sleep disorders. Consult your doctor to determine if a sleep study is needed and to find a qualified provider.