Polysomnography, also called a sleep study, is a comprehensive test used to diagnose sleep disorders. Polysomnography records your brain waves, the oxygen level in your blood, heart rate and breathing, as well as eye and leg movements during the study.
Polysomnography may be done at a sleep disorders unit within a hospital or at a sleep center. While it’s typically performed at night, polysomnography is occasionally done during the day to accommodate shift workers who habitually sleep during the day.
In addition to helping diagnose sleep disorders, polysomnography may be used to help initiate or adjust your treatment plan if you’ve already been diagnosed with a sleep disorder. Sometimes you may be able to do the sleep study at home. Home sleep apnea testing uses a limited number of sensors to focus primarily on diagnosing obstructive sleep apnea.
Why do I need a Sleep Study?
A doctor can use a polysomnography to diagnose sleep disorders.
It often evaluates for symptoms of sleep apnea, a disorder in which breathing constantly stops and restarts during sleep. The symptoms of sleep apnea include:
- sleepiness during the day despite having rested
- ongoing and loud snoring
- periods of holding your breath during sleep, which are followed by gasps for air
- frequent episodes of waking up in the night
- restless sleep
During the polysomnography, the technician will measure your:
- brain waves
- eye movements
- skeletal muscle activity
- heart rate and rhythm
- blood pressure
- blood oxygen level
- breathing patterns, including absence or pauses
- body position
- limb movement
- snoring and other noises
What do the results mean?
A sleep center doctor will review this data, your medical history, and your sleep history to make a diagnosis.
If your polysomnography results are abnormal, it may indicate the following sleep-related illnesses:
- sleep apnea or other breathing disorders
- seizure disorders
- periodic limb movement disorder or other movement disorders
- narcolepsy or other sources of unusual daytime fatigue