Visiting the SDC for an overnight sleep study must be a new experience to you. Spending one night in the SDC is not like spending a night in the hospital. You may be under the impression that the bedroom you are going to sleep in is full of equipment, monitors and a medical person who will be watching you the whole night. That is far from truth.

You should look at it like spending one night in a hotel or in a relative’s house. The room you are going to spend the night in is a specially furnitured room. It will have a special cupboard to keep your clothes and a private washroom with all accessories. You can control temperature and light to your convenience.

What is an Overnight Sleep Study?

Sleep is a complex process during which, many physiological and pathological processes occur. In order to understand your sleep and any problems with it, we need to monitor several physiological parameters during sleep. During the sleep study, the following parameters will be monitored; brain waves, muscle movements, breathing through your mouth and nose, snoring, heart rate and rhythm, leg movements, chest and abdominal wall movements, oxygen level in the blood and carbon dioxide output. To monitor those functions, we apply small metal discs to your head and skin using an adhesive. Flexible elastic belts will be put around your chest and abdomen to monitor your breathing. A small plastic tube (cannula) will be put close to your mouth and nose to monitor your breathing. Oxygen level in the blood will be measured via a clip in your index finger or your ear lobe. None of the above devices are painful and all are designed to be as comfortable as possible. The equipment and the technician will be in a room separate from your sleeping room. You will be able to roll over and sleep in any position you like as easily as you would at home.

During the study, patient’s privacy is completely assured. You will be able to call the technician via a microphone anytime during the study.

What am I Supposed to do before a sleep Study?

On the day of your sleep study:

• Avoid caffeine containing beverages (tea, coffee, Pepsi, coca cola, chocolate) after 2 PM.
• Avoid napping.
• Before coming to the sleep center, wash and dry your hair to make it easy to apply the  adhesives.
• Pack a small bag that contains things you may need overnight like medications,  toothpaste and brush, your nightclothes and a towel.
• If you have special needs, please advise the sleep center staff before hand to be able to help you.

What Will Happen When You Arrive at The Sleep Disorders Center?

You will be asked to come to the sleep disorders center between 8 and 9 PM. On arrival, the technician will meet you, show you your room and the equipment used in the study. After that, you can sit in the waiting room to watch TV, read or relax. Before your bedtime, the technician will apply the wires and electrodes required to monitor your sleep. The technician will wake you up around 7 AM. If you want to get up before that be sure to inform the sleep technician before your study.

If you have breathing problems during sleep, the technician may awaken you from sleep to use a device that delivers air under positive pressure. The machine is called CPAP machine. Air is applied through a soft mask that fits around your nose. Your physician usually discusses the possibility of using this machine with you in the clinic.

What Will Happen After The Sleep Study?

Analysis and interpretation of a sleep study is a complex process. A typical sleep study involves 800-1000 pages of data. Its analysis is time-consuming and labor-intensive. Therefore, the results of the sleep study will not be available immediately. Your sleep study will be reviewed and interpreted by your doctor (a sleep specialist with special training in sleep disorders). When you come for follow up your physician will discuss with you the results and the management plan. The results of the sleep study will not be given by the technician and usually cannot be discussed over the telephone.

Sometimes an additional sleep test called multiple sleep latency test (MSLT), is needed as a part of the overall sleep evaluation. For this test, you need to stay in the sleep center for most of the day following your overnight sleep study. If your condition necessitates this test, your doctor will discuss that with you in the clinic beforehand. The test is a series of short naps beginning the morning after your overnight study.

Ahmed BaHammam, FACP, FCCP
Professor of Medicine
Director, University Sleep Disorders Center
College of Medicine, King Saud University