What is an Overnight Sleep Study?
A sleep study (polysomnogram), charts your brain waves, heart beat, and breathing as you sleep. It also records your eye and leg movements as well as muscle tension. Sensors are placed on your head, face, chest and legs sending tiny electrical signals to a computer.
It is a painless process which uses sensors to record a patient’s sleeping patterns. Many people are concerned that they will be unable to sleep when the sensors are hooked up to them. Usually however, patients are able to fall asleep fairly easily and do stay asleep most of the time.
The signals show when you are asleep and awake during the night. The brain-wave and eye-movement detectors show stage of sleep you are in. The breathing monitors show the number of times you stop breathing. They can also detect low air flow and changes in oxygen level.
The leg sensors show both minor twitches and major movements that occur during the night. A sensor will also be placed on your finger to note changes in the level of oxygen in your blood.
What should I bring to my sleep study?
If you're coming to the Sleep Center for an overnight study, we suggest you pack as if you were visiting a hotel. The Sleep Center provides shampoo, soap, a blow dryer and towels. Because you will be monitored by a technician and a video camera, we require our patients to wear sleepwear during the study.
In order to feel more comfortable, you are encouraged to bring your own pillow to the sleep center. Some patients also like to bring a book or magazine to read before going to sleep.
What to Expect at the Sleep Center:
When you arrive at the clinic, we'll give you a tour and orientation. You'll meet the technician who will be present during your study and you'll see the bedrooms, which we have tried to make as home-like as possible. After your orientation, we will set you up with the sleep study equipment and then you'll go to sleep.
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 central control room. In addition, all patients are videotaped while asleep.
In the central control room, the technologist monitors the patient’s sleep and general condition. Any problems with the study may be easily dealt with. Patients may call the technologist if there is a problem as well.
For some patients who have sleep apnea, the effects of continuous positive airway pressure (CPAP) are evaluated. Usually these are patients who have had a previous sleep study to diagnose the condition. During the CPAP study, everything is done as is for a diagnostic study. In addition, a mask is fit around the nose or around the nose and mouth. During sleep, we attempt to find a pressure level that holds the airway open and lets the patient get a good night’s sleep.
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.
If the sleep study takes place on a weeknight, most people get up the next day at whatever their preferred time is, and you can shower and go to work as usual. Most people don't experience much interference with their sleep. However, some people may experience poor sleep and may want to plan on taking the following day off.
Once the sleep study is completed, it is scored by a scoring technologist and sent to a sleep specialist for interpretation. This entire process takes 7–10 days. The interpretation is sent to the physician who ordered the sleep study and appropriate follow-up is arranged.
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.
How do I get the results?
Once your diagnostic study has been scored, your referring doctor will receive a copy of the results and you will receive a phone call from the sleep center advising you of the results. Your referring doctor may also want to review the results with you.
For those patients who are diagnosed with sleep apnea, three to six weeks after the CPAP study they will have an appointment with the center’s Sleep Specialist. At that time, the Sleep Specialist will go over the results of their studies, answer any questions the patient may have, and evaluate current symptomology to ensure no additional treatment is needed.