Sleep Study (Polysomnography)


This diagnostic test is a study of the body and the brain waves during sleep. It is performed to identify sleep disorders. A sleep study can identify problems such as sleep apnea, narcolepsy, limb movement disorders and behavior disorders. A sleep study can also help a doctor determine the best course of treatment for a person who has a sleep disorder. The study may be performed at a hospital or a sleep center.


In preparation for a sleep study, the patient may be asked to avoid certain foods, drinks or activities that can disrupt the normal sleep cycle. At the sleep lab, sensors are placed on the patient's head, face, chest and legs. The sensors are attached to the surface of the skin. They are connected by wires to a computer. Technicians will leave the room to allow the patient to fall asleep. The patient may be monitored with a video camera and a microphone.

The Study

During the study, the monitoring equipment will measure and record several different types of data. The sensors will monitor the patient's brain activity, eye movements and heart rate. They will record the patient's breathing patterns, including the patient's oxygen level and respiratory effort. They will also measure the patient's muscle tone, position, body movements and the sounds the person makes during sleep. Most people do not sleep as well during a sleep study as they do at home, but a full night's sleep is not needed to provide the necessary data.


When the sleep study is complete, the sensors are detached and the patient is allowed to go home. The results of the study will be analyzed by a doctor, who will determine the proper course of treatment.