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Full Polysomnography Test

Diagnostic Polysomnography (PSG) – Level 1 Sleep Study

Polysomnography is an evaluation performed as part of a sleep study. Polysomnography is a painless and safe sleep test. It usually takes place in a hospital or private clinic. It is also possible to consider a test at home.


If you have already been prescribed a polysomnography in a sleep lab by your doctor, please contact us to find out how we can perform this test.


Why do a polysomnography test?

This sleep test allows to identify different parameters such as: 

  • respiratory arrests (sleep apnea)
  • hypopneas that cause oxygen deprivation or short brain awakenings
  • high resistance of the upper airways 

Polysomnography can also identify other sleep disorders such as: 

  • narcolepsy
  • restless legs syndrome 
  • excessive snoring
  • insomnia 

How a polysomnography test is performed?

Polysomnography is an evaluation most often performed at night. The patient is placed in a room so that he can be monitored during his sleep phase. 

Electrodes are placed on the patient’s head, face, torso, legs and arms.


During the test, the respiratory therapist will monitor many body functions including:

  • Brain waves (EEG)
  • Eye movements (EOG)
  • Chin muscle tone (CEMG)
  • Breathing patterns
  • Snoring or any other noise emitted during sleep
  • Heart rate and blood pressure
  • Blood oxygen levels
  • Body position

Muscle activity or skeletal muscle activation (EMG). Frequent leg movements could be an indication of periodic limb movement disorder.


It is also recommended not to consume alcohol or coffee at least 24 hours before the evaluation.


Polysomnography test results 

A single polysomnography is sufficient to assess the patient’s sleep and detect any underlying sleep disorders. 


Polysomnography measures :

  • the different sleep cycles 
  • muscle movements 
  • the frequency of apneas during the night
  • the frequency of hypopnea 

Dorma specialists determine an index of sleep apnea or hypopnea measured during the sleep cycle. An index equal to 5 or less is considered normal.


If the score is greater than 5, the patient is subject to sleep apnea:

  • between 5 and 15, sleep apnea is considered mild. 
  • between 15 and 30, sleep apnea is considered moderate. 
  • greater than 30, sleep apnea is considered severe.

What to do after a polysomnography test? 

Depending on the results, we will offer you a second appointment to discuss the different treatment options together.


Full polysomnography tests are not indicated for everyone. Alternatives include, home respiratory polygraphy. The latter affords you the comfort of performing the test at home.


Ask your doctor or book an appointment now to learn more about the various alternatives to polysomnography.

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