What is a Polysomnography?

 These symptoms and disorders may include:

• Loud nighttime snoring
• Daytime sleepiness
• Insomnia
• Narcolepsy
• Obstructive sleep apnea
• Restless leg syndrome
• REM behavior disorder (movements during dreaming)

Polysomnography is considered the “gold standard” for diagnosing obstructive sleep apnea or OSA. OSA is a common but under-diagnosed condition in which breathing ceases temporarily during sleep, up to hundreds of times per night, resulting in lowered blood oxygen levels.
How it Works
Polysomnography is performed at a sleep lab or sleep center by trained sleep specialists. Patients sleep in beds at the center, at their usual bedtime, in a comfortable bedroom. They are monitored both visually and electronically. The test is done at night in order to study normal sleep patterns.
Electrodes are placed on the chin, scalp, and outer edges of the eyes, and monitors are placed on the body to record heart rate and breathing. The sleep specialists directly watch patients while they sleep and record changes in position, breathing and heart rate. Episodes of apnea, or cessations in breathing, are also recorded. A video camera records position changes throughout the night. In addition, airflow through the nose and mouth, blood pressure, and blood oxygen levels are monitored.
The electrodes send signals indicating the two states of sleep, Rapid Eye Movement (REM) sleep and Non-rapid eye movement (NREM) sleep. REM sleep is associated with dreaming, and NREM has four different stages that the electrodes can detect. Normally, REM and NREM sleep alternate approximately every 90 minutes during the night. That means most people have four to five cycles of REM and NREM each night.
People with a normal sleep patterns will show normal brain waves and muscle movements during sleep, and no significant breathing difficulties. Abnormal results can lead to diagnosis of a sleep disorder. Reduced airflow through the nose and mouth, along with a fall in blood oxygen levels, may indicate sleep apnea.
Sleep disorders are associated with serious complications and effective treatment is available, so polysomnography is a highly useful tool for people who suspect they have sleep apnea or another sleeping problem.