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How Polysomnography is used to Diagnose Central Sleep Apnea

Wondered how polysomnography is used to diagnose central sleep apnea? Read on to find out.

Central sleep apnea is a dangerous medical condition where because of the malfunctioning of the region of the brain which controls breathing, a person will stop breathing multiple times within the span of a single night. This dangerous condition is extremely hard to diagnose since the symptoms of central sleep apnea match those of insomnia and unlike obstructive sleep apnea only a sleep study can be used to diagnose central sleep apnea.

To see the central sleep apnea connection first we look at SLEEP STUDY and SLEEP CYCLE

What is a Sleep Study?

How the results of a Sleep Study is used to Diagnose Central Sleep Apnea

Also known as Polysomnography, a sleep study is basically a test which will monitor different parameters while you sleep to diagnose any possible sleep disorders. This test which takes one complete night will usually be done in a hospital or a sleep centre. Things of your body which will be monitored are:

  • Your brain waves
  • Oxygen level present in your blood
  • Heart rate
  • Breathing
  • Movement of legs and arms

The above parameters will be used to monitor your sleep cycles when you sleep to find out if anything abnormal occurs.

What is the Sleep Cycle?

A single sleep cycle consists of passing through NREM and REM once. There are totally four stages of sleep. The first three together are classified under NREM sleep and the fourth stage is known as REM sleep. Every human being will pass through multiple sleep cycles consisting of REM and NREM sleep (it usually takes one and a half hours to move from REM to NREM). In a single night multiple cycles will be completed, the only difference between the cycles will be the time spent in REM which will increase after every cycle.

  1. NREM sleep: NREM or Non-Rapid Eye Movement sleep is the starting point of sleep in humans. When you go to bed, your brain will go into this mode of sleep. As the name suggests, in this stage your eyes will not move and your brain waves will also become slower than normal.
  2. REM sleep: Also known as Rapid Eye Movement sleep, within 90 minutes from the onset of NREM a person will enter the REM part of the sleep cycle. This phase of the sleep cycle is characterized by rapid movement of the eyes along with increased brain activity. This is the time when people dream.

The things a sleep specialist will look out for are apneas, arousals (a shift in brain activity), irregularities in heart beat, the position of the body, saturation level of oxygen in the body, and other irregularities in breathing. Along with the above information on both of the above phases; such as time spent in each phase and number of cycles per night, along with other information regarding the oxygen level in the blood and heart rate will be used together to diagnose different sleep disorders such as central sleep apnea.

Thus a sleep study or polysomnography is necessary to diagnose central sleep apnea.


  1. Can regular people read the polysomnography to discover about central sleep apnea or only doctor can do that?

  2. thanks for this central sleep apnea article