What is a Polysomnography? Diagnostic Tool In Sleep Medicine

A polysomnograph is used as a diagnostic test used on patients who suffers from obstructive sleep apnea to record various factors in determining the extent of sleep disorder. Sensors are placed strategically on the patient to test the following:

* Airflow – this determines the amount of air moving into and out of the airways to determine the extent of sleep apnea occurrences.

* Brain electrical activity (EEG or Electroencephalogram) – this determines what stage of sleep the patient is in at any time during the test.

* EKG – this records the heart rate and rhythm during the test and determines if any of the sleep apnea is leading to heart arrhythmias.

* Eye (EOG or Electroocculogram) - this records the movements of the eye during the test.

* Jaw muscle movement (EMG or Electromyogram) – this records any waking periods or spastic movements or arousals during the test.

* Leg muscle movement (EMG or Electromyogram) – this records muscle movements during sleep.

* Oxygen saturation or Pulse oximeter – this measures the oxygen saturation on fingers and ear lobes.

* Respiratory effort or piezo crystal effort sensor in the chest and abdominal areas – this determines movements in the chest wall or abdominal areas during breathing.

This study of sleep determines if there are any abnormalities in any of the stages of sleep. The stages of sleep are:

* Awake

* Transition from wake to sleep

* Light sleep

* Transition into Rapid Eye Movement (REM) sleep

* Deep sleep

* REM sleep

With obstructive sleep apnea there is generally more than 50% decrease in airflow with some efforts to breathe lasting over ten seconds. Central sleep apnea is defined when there is no airflow along with the ten second effort to breathe. Mixed sleep apnea means you have both central sleep apnea as well as obstructive sleep apnea.
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