Why Are Sleep Studies Done?
Sleep studies are used to rule out or diagnose disorders such as:
- Sleep apnea and other sleep-related breathing disorders
- Nocturnal seizures
- Rapid eye movement (REM) sleep behavior disorder
- Sleep-related movement disorders such as periodic limb movement disorder
Polysomnography results may also help doctors determine if someone has restless legs syndrome. Though polysomnography is not generally used for circadian rhythm sleep-wake disorders, the results may highlight discrepancies indicative of abnormal sleep rhythms. Similarly, doctors may order polysomnography to assist in the diagnosis of sleep bruxism (teeth grinding) or parasomnias like sleepwalking, even if a sleep study is not technically required in these cases.
For people with sleep apnea, polysomnography can be performed while wearing a positive airway pressure (PAP) device. These devices supply pressurized airflow to keep the airway open, and the test is performed in order to determine the best pressure for each individual.
What To Expect During a Sleep Study
Full sleep studies typically take place in labs that resemble hotel rooms, with regular beds to help you relax and feel comfortable. You generally arrive at the sleep center about two hours before your usual bedtime, and sleep there overnight (or during the day, if you are a night shift worker).
Before you go to bed, a technician attaches the electrodes, breathing belt, airflow sensors, and pulse oximeter. While you sleep, technicians monitor your heart rate and breathing patterns. The sensors are not painful, although you may experience slight irritation that should disappear once the study ends. The PSG might also be recorded so a specialist can visually analyze your movements. Most sleep studies last for approximately the same time as a normal night of sleep.
If your doctor believes that you have moderate to severe obstructive sleep apnea, you may be able to perform a sleep study at home. In-home testing involves fewer sensors, so it is not appropriate for diagnosing other sleep disorders or medical conditions. Although the test can be carried out at home, the results must still be interpreted by a sleep specialist before a diagnosis is made.
What If I Can’t Sleep During a Sleep Study?
Sleep specialists understand that many people have difficulty falling asleep on the first night in a sleep laboratory. If you are concerned about falling asleep during your sleep study, talk to your doctor or a technician beforehand. They may have recommendations to help you relax for sleep.
If possible, avoid drinking caffeine or alcohol before the study begins. You should also avoid taking sleep medication, unless you have cleared it first with your doctor.
What Sleep Study Results May Mean
In addition to physiological data such as heart rate and breathing effort, polysomnography provides information about how long it takes you to fall asleep, the time spent in each sleep stage, total sleep time, and nighttime awakenings. After the sleep study, a specialist reviews the results to see if they indicate an underlying sleep disorder.
For example, if you regularly stopped breathing in your sleep, they may diagnose you with sleep apnea. If they detect excessive leg movements during sleep, they may consider a diagnosis of periodic limb movement disorder. For people who display physical movements or talking during dreams, the sleep specialist may identify a case of rapid eye movement (REM) sleep behavior disorder.
Depending on the findings, your healthcare provider may work with you to develop a treatment plan or refer you to another specialist for more testing.
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