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Polysomnogram

Used to Diagnose Various Sleep Disorders

image of male researcher during sleep study

For a PSG, you usually will stay overnight at a sleep center. This study records brain activity, eye movements, heart rate, and blood pressure. A PSG also records the amount of oxygen in your blood, air movement through your nose while you breathe, snoring, and chest movements. The chest movements show whether you're making an effort to breathe.

PSG results are used to help diagnose:

  • Sleep-related breathing disorders, such as sleep apnea
  • Sleep-related seizure disorders
  • Sleep-related movement disorders, such as periodic limb movement disorder
  • Sleep disorders that cause extreme daytime tiredness, such as narcolepsy (PSG and MSLT results will be reviewed together)

Polysomnogram Titration

Your doctor also may prescribe a PSG Titration to find the right setting for you on a "PAP" machine. In this test while you sleep , the technician will check the amount of oxygen in your blood and whether your airway stays open. He or she will adjust the flow of air through the mask to find the setting that's right for you.

CPAP, Bi level and ASV are PAP treatment options for sleep apnea that range from standard (CPAP) to advanced (ASV).

Sleep apnea is a common disorder in which you have one or more pauses in breathing or shallow breaths while you sleep. In obstructive sleep apnea, the airway collapses or becomes blocked during sleep. A "PAP" machine uses mild air pressure to keep your airway open while you sleep.


Split-Night Protocol Polysomnogram

If your doctor thinks that you have sleep apnea, he or she might schedule a split-night sleep study. During the first half of the night, your sleep is checked without a "PAP" machine. This will show whether you have sleep apnea and how severe it is.

If the PSG shows that you have sleep apnea, you'll use a CPAP machine during the second half of the split-night study. A technician will help you select a CPAP mask that fits and is comfortable.

Sometimes the entire study isn't done during the same night. Some people need to go back to the sleep center for the CPAP titration study.

Also, some people might need more than one PSG. For example, your doctor may recommend a followup PSG to:

  • Adjust your CPAP settings after weight loss or weight gain
  • Recheck your sleep if symptoms return despite treatment with CPAP
  • Find out how well surgery has worked to correct a sleep-related breathing disorder

Source: National Heart, Lung, and Blood Institute