What happens in the sleep laboratory?

To diagnose a sleep disorder clearly, comprehensively, and reliably, patients must be examined in a sleep laboratory. This examination method is also called polysomnography. It is used when preliminary examinations have yielded no or inconclusive results, to confirm the diagnosis, or to test treatment options.

A detailed medical history is usually taken before polysomnography. All relevant data regarding the current health status are documented in the process. This also includes the outpatient collection of sleep medicine-relevant data using polygraphy.

An examination in the sleep laboratory may be necessary not only at night but also during the day. For example, in cases of severe daytime sleepiness, a meaningful assessment of the severity can be obtained.

Prior to the examination, the treating doctor should be informed about any medication use or other special circumstances, as these can also affect sleep or the sleep study.

After the examination or the evaluation of the results, the next steps are discussed with the patient. If necessary, further examinations may be required, or a therapy may be recommended.

Polygraphy.

Polygraphy follows a detailed medical history. It is carried out when a sleep-related breathing disorder is suspected and includes the measurement of various bodily functions. The goal is to confirm, refute, or further narrow down the suspicion. Additionally, suitable treatment options can sometimes already be determined.

Polygraphy takes place at the patient’s home and is conducted during the night. Patients receive a portable device and are instructed on how to use it. The examination is painless and allows almost unrestricted movement with the device during the night. One should try to sleep as they normally do, so that the results reflect the most realistic picture possible. Values such as blood oxygen levels, breathing, and body position are recorded during the examination. A chest strap with the device and an abdominal strap are attached to the body before you go to sleep. The device should be positioned approximately in the middle and at chest height. Next, the oxygen sensor is placed on the finger, and finally, the nasal cannula is fitted. All cables must be connected to the device for the recording.

After the diagnostic night at home with the polygraph device, it is simply returned to the treating doctor. There, the measurement results are carefully evaluated and the next steps are discussed.

Polysomnography.

Polysomnography is an advanced overnight examination that complements polygraphy to confirm the diagnosis of a sleep disorder. This examination is usually conducted in a sleep laboratory. Before going to bed, electrodes and sensors are attached to patients. These record breathing events such as apneas. Additionally, EEG measurements are performed to determine sleep quality and blood oxygen saturation. Leg movements and other parameters are also recorded. The collected data are then analyzed. After one to two nights, a diagnosis can be confirmed or ruled out, and appropriate therapy can be started.

If sleep apnea is diagnosed, patients often spend an additional night in the sleep laboratory using the new sleep breathing therapy device to check the settings made and the success of the therapy.

In order to obtain meaningful polysomnography results, the day of the examination should be as ordinary as possible. However, behavior – especially the consumption of stimulants and intoxicants – should be discussed with the treating sleep medicine specialist in advance. They may recommend avoiding coffee, tea, cola, or other beverages containing caffeine or other stimulants from around 2:00 PM onwards.

Regular medication intake and the next steps should also be discussed in advance. Medications should not be discontinued independently and should be brought along for the night of the examination. For the evaluation, it is helpful to present a recent ECG, a recent lung function test, and, if applicable, the questionnaire previously received from the sleep laboratory, duly completed. Ask your sleep laboratory which documents are required for the examination.

You can take some simple preparations yourself to make sure the polysomnography runs smoothly: The skin should be as free of oils as possible to ensure the electrodes adhere well to the body. Hair spray, gel, oil, or similar products should be avoided. Creams should either not be used or applied sparingly. Nail polish should not be worn due to the measurement of blood oxygen levels. A clean shave under the chin is also ideal. This improves the adhesion of the electrodes but is not mandatory, of course.

The suitcase is packed with everything needed for the evening, the night itself, and the morning. Loose-fitting sleepwear makes it easier to attach the electrodes to the torso and legs. In addition to clothing, a towel, toothbrush, etc., you can also pack something to read or keep yourself occupied in case you have to wait. The information on what to consider or bring with you will be given to you during preparation from the sleep laboratory. The procedure can vary from one laboratory to another, so that we can only give recommendations here.