What is a Polysomnography
It is a sleep study, where monitors you while you sleep or trying to sleep.
There are two states of sleep:
- Sleep with rapid eye movement (REM) or synchronized sleep
- Sleep without rapid movement (NREM) or sleep without synchronization
The rapid eye movement sleep is associated with dreaming. The muscles of the body, except your eyes and lungs, do not move during this stage of sleep.
The NREM sleep has four stages that can be detected by the waves of brain electrical activity (EEG).
The REM sleep alternates with NREM sleep approximately every 90 minutes. A person with normal sleep usually has 4 to 5 cycles of sleep and rapid eye movement overnight.
A sleep study measures the sleep cycles and stages by recording the following information:
- Air flow into and out of the lungs during breathing
- Oxygen levels in the blood
- Body position
- Brain waves (EEG)
- Effort and respiratory
- electrical muscle activity
- Eye movements
- Heart
The test is done to diagnose possible sleep disorders including obstructive sleep apnea (OSA), which is often suspected because of the following symptoms:
- Daytime sleepiness (falling asleep during the day)
- Loud snoring
- Periods of breath holding, followed by gasping or snorting
- Restless sleep
- Narcolepsy
- Disorder Periodic limb movement (frequent movements of the legs during sleep)
- Behavior disorder Rapid eye movement (a condition in which people "act out" their dreams physically)
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