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Polysomnogram
 

 

A polysomnogram, or sleep study, is a test that uses several types of measurements to identify sleep stages and various sleep problems. The brain controls sleep and its different stages including drowsiness, light sleep, deep sleep and dream sleep. To determine the stage of sleep requires measuring different activities of the brain and body. These activities include brain waves (EEG), eye movements and muscle tone. A full sleep study will measure other parameters as well, including respiratory effort (chest and abdominal wall movements), cardiac rhythm (EKG), leg movements and oxygen saturation

Sleep studies also may be videotaped for later review of any abnormal body movements observed during the study.

We monitor the activities that occur during sleep by applying wires with small metal discs called electrodes to the head and skin. Flexible Velcro belts are placed around the chest and abdomen to measure breathing effort. The level of oxygen carried in the blood and heart rate are monitored by a clasp that fits on the index finger.  None of these devices are painful and all are designed to be as comfortable as possible. At most sleep lab centers, the surroundings (especially the bedrooms) are relaxing and comfortable, like a hotel room. The technical equipment and technicians will be in a room separate from the sleeping room, and the electrode wires will be gathered together so that rolling over and changing positions will be almost as easy as it would be at home.

The sleep study, its analysis and interpretation are part of a complex process. Many hours of work are required by specially trained professionals to process or "score" the large amount of data recorded during the study. A sleep specialist, with special knowledge of sleep and its disorders, then interprets this information. A typical sleep study involves more than 800 pages of data and is a time-consuming and labor-intensive process. Results may not be available immediately.

Sleep studies are useful for a number of purposes. They are conducted on patients who have a numerous complaints, the majority being excessive daytime sleepiness. Most sleep studies are done to diagnose sleep apnea. Sleep studies are rarely done for patients with insomnia because little useful information is obtained if a patient cannot fall asleep in the lab.  A sleep specialist will determine who should or should not have a sleep study.

Following a sleep study, our technicians carefully compile results of all evaluations and provide them to sleep specialists who evaluate them and make treatment recommendations. All information is forwarded promptly to the patient's own physician for follow-up and additional treatment.