Sleep Apnea Syndrome: How to test it

Sleep Apnea Syndrome refers to transient cessation of respiration during sleep. There is a sleep test, called polysomnography that is usually done to diagnose sleep apnea. Polysomnography is a study of sleep cycles and behavior, usually done all night long in a sleep center, which involves observing a person at sleep while continuously charting brain waves, muscle activity, breathing, eye movements, and heart rhythms.

There are two kinds of polysomnograms:

• Overnight polysomnography test: It involves monitoring brain waves, muscle tension, eye movement, respiration, oxygen level in the blood and audio monitoring. (for snoring, gasping, etc.)
• Home monitoring test: A Sleep Technologist hooks the patient up to all the electrodes and instructs him on how to record his sleep with a computerized polysomnograph that he takes home and returns in the morning. These are painless tests that are usually covered by insurance.

Polysomnography tracks a variety of processes in the body.

• Special sensors placed on the head show brain wave patterns which can be used to determine what stages of sleep or wakefulness a person is in.
• Electrodes are used to track muscular movement or tension.
• Breathing monitors on the nose, mouth, or chest can tell when breathing stops, airflow is low, or oxygen levels change.
• Heart rate and rhythms are also continuously monitored.
• Blood oxygen level & blood pressure is ceaselessly.

This study allows doctors to track the different stages of sleep, called nonrapid eye movement (NREM) sleep and rapid eye movement (REM) sleep, which is associated with dreaming. The test can track other characteristics of your sleep, such as the number of times you awaken. It can also evaluate any abnormal sleeping behaviors, such as sleepwalking, nightmares, or periodic limb movement disorder. In addition, the study can evaluate various other sleeping disorders which include trouble falling or staying asleep (insomnia), breathing that stops during sleep (apnea), or a problem with falling asleep suddenly during the day (narcolepsy).

Testing procedure: In usual Sleep testing protocols, the patient arrives in the evening and is given time to become comfortable in a room where he sleeps alone. A technologist attaches electrodes to his head, legs, and chest. Signals from these sensors travel through wires to a computer where they show what stages of sleep or wakefulness he in. Other monitors are placed around the chest, near the nose and mouth, and on finger. The patient will be able to read or relax until bedtime. Although he will be able to move and turn over during sleep, the technologist may ask the patient to try sleeping in a certain position for a part of the night. Technologist will also observe the patient by video during the night in case sensors come loose or need to be removed for patient to go to the bathroom.