The overnight sleep study is used to evaluate patients when they are sleeping. This laboratory test is extremely valuable for diagnosing and treating many sleep disorders, including neurologic disorders, movement disorders and breathing disorders at night. Sleep studies (also called polysomnography) are fully covered by the Ontario Health Insurance Plan.

Patients come to the laboratory at 8:30 p.m. on the appointed day. There they meet with a sleep technologist, who will explain and perform the study. They are led to their assigned room, where they should complete questionnaires and prepare for sleep (wash face, brush teeth, change into sleep clothes, etc.).

For studying the quality of sleep, electrodes are applied to the scalp, sides of the head and under the chin, chest and leg. This lets us measure brain waves, heart rate, and eye movements. A sensor is placed by the nose and mouth for measurement of airflow. Belts are placed around the rib cage and abdomen for measurement of breathing movements. A clip is placed on a finger for measurement of blood oxygen levels. Other measurements may be done as required. There are no needles and no pain. The electrodes are connected to a box by the bedside for relaying the signals to a control room. In addition, all patients are videotaped while asleep.

In the control room, the technologist monitors the patient's sleep and general condition. Any problems with the study may be easily dealt with. Patients may easily call the technologist if there is a problem as well by simply flicking a switch next to their bed.  Patients generally get out from the study around 6:30 to 7 in the morning. However, if an earlier wake-up is needed, the patient just needs to let the technologist know.

Once the sleep study is completed, it is scored by a registered technologist and sent to a sleep physician for interpretation. The report is then sent to the physician who ordered the sleep study and appropriate follow-up is arranged, if requested.  The entire process takes only 2-3 weeks or less.

Sleep studies are generally easy to tolerate, comfortable for patients, and give the sleep physician the information he/she needs to accurately diagnose and treat the sleep disorder.