Some people suffer from sleep disorders for which no exact cause can be diagnosed during normal medical examinations. In such cases, sufferers are sent to a sleep laboratory for polysomnography.
What is polysomnography?
Polysomnography is a comprehensive examination of all body functions during sleep. Polysomnography is the term used to describe a comprehensive examination of all body functions during sleep. It is usually performed as an inpatient in a sleep laboratory and records the depth, quality, and course of sleep. The following body functions are tested: Brain activity by EEG (electroencephalogram), heart rate by ECG (electrocardiogram), breathing patterns and breath sounds, eye movements, muscle tension, body posture and movements, body temperature and oxygen saturation in the blood. All of the examined values together result in a sleep profile that provides information about the cause of the sleep disorder.
Function, effect, and goals
Polysomnography is used whenever no correct cause for sleep disorders can be found by conventional examinations, but health is at risk if the sleep disorders are left untreated. Above all, it is indispensable in the case of sleep apnea syndrome, because affected persons snore and have breathing pauses during snoring, which lead to sleep not being restful, so that they suffer from daytime fatigue up to microsleep. This is particularly dangerous in road traffic and breathing pauses lead to cardiovascular problems in the long term. Other areas of application include.
- Epilepsy
- Nightmares
- Narcolepsy
- Panic attacks
- Psychogenic paralysis
- Pavor nocturnus (night terrors) in children.
- Restless Legs Syndrome (restless legs).
- Somnambulism (nocturnal sleepwalking)
To find the causes of these sleep disorders, polysomnography examines sleep in its various stages. During sleep, neurological characteristics and cardiovascular parameters are recorded and the behavior of patients during sleep is monitored by video cameras. Before an examination is performed in the sleep laboratory, a detailed history and physical examination must be performed to narrow down the possible cause of the sleep disorder. If a chest pressure measurement with esophageal probe is necessary, the patient must be informed about the risks beforehand. There are two forms of polysomnography. Minor polysomnography examines psychiatric disorders, epilepsies, and obstructive sleep apnea syndrome (OSAS). The following parameters are monitored and recorded:
- Brain waves
- Heart activity
- Blood oxygen saturation and heart rate by pulse oximetry]
- Eye movements
- Muscle activity (including the masseter muscle)
- Breath flow and breathing movements
A large polysomnography is performed if the sleep disorders do not improve even with treatment. Then additional parameters are recorded:
- Blood pressure
- Body temperature
- Erection
- Breathing pressure when using a respiratory mask
- Snoring sounds
- Monitoring by microphone
Most often, polysomnography is performed on two consecutive days and nights as an inpatient in the sleep laboratory. The patients are placed electrodes on the skin for the measurements in different parts of the body (head, corner of the eye, chin, chest, lower leg). The examination is monitored by staff throughout. After the examination, the findings are discussed with the patient and appropriate therapy is initiated. If the recordings are not sufficiently conclusive, the examination must be repeated if necessary.
Risks, side effects, and hazards
Because polysomnography is a painless, noninvasive examination method, complications do not usually occur. If side effects occur at all, they are usually skin reactions to the adhesive used to attach the electrodes to the skin. When measuring the pressure of the thorax with an esophageal probe, the insertion of the probe can be uncomfortable and cause more stress to patients. There is a small risk of injury to the nasopharynx and esophageal mucosa. However, they rarely occur.The room in which the examination is performed is similar to a hotel room. It is quiet and dark during the examination and recording. A video camera records all movements. Patients could behave normally during the time. New wireless technology makes it possible for them to move around freely and even go to a restroom without having to be disconnected from a night nurse. During the examination, someone is always there to talk to via microphone. On the day of the examination, patients should not sleep during the day and should not drink any caffeinated beverages after about 14. To ensure that the electrodes hold well on the head, hair should be freshly washed, but no hair spray, oil or gel should be used. For the night, you may bring anything that helps you sleep well, including your own pajamas. Since the sleep environment in the sleep laboratory is different from the usual environment at home, it is possible that you may not be able to fall asleep or sleep through the night so well in the sleep laboratory, but that does not matter for the results of the examination, the records are still meaningful. Newer mobile technology also allows an examination at home, which offers the advantage of a sleep recording under realistic conditions and can therefore be more meaningful than in the sleep laboratory. Following the examination, appropriate therapeutic measures are discussed with the patient, e.g., in the case of sleep apnea, a breathing mask is recommended during sleep to supply oxygen to prevent breathing cessations.
