Polysomnography: the essence of the method, indications, contraindications, methods

Polysomnography is a method of studying the work of the human body during sleep, which allows to identify the cause of its violation. This is one of the most sparing methods of diagnosis: painless, and almost not felt by the patient, because during the study the patient is asleep. Can be carried out and children (from an early age), and pregnant and elderly patients. About what is a polysomnography, what are the indications and contraindications to this method of research, as well as on the methodology of its implementation and the necessary equipment and will be discussed in our article.

Indications for polysomnography

This study is indicated for patients who have had any sleep disorders. These are:

• narcolepsy;
• sleep paralysis;
• a superficial dream or frequent causeless awakenings;
• bruxism (gnashing of teeth in a dream);
• somnambulism (sleepwalking, sleeping);
• a twist;
• enuresis;
• nightmares;
• hypersomnia;
• obstructive sleep apnea syndrome (short-term respiratory sleep stops associated with the pathology of the upper respiratory tract);
• syndrome of central sleep apnea (respiratory arrest due to immaturity of the brain or inflammatory processes in the brain stem area);
• sleep disorders associated with epilepsy;
• increased motor activity during sleep (restless legs syndrome);
• arrhythmias during sleep;
• increased blood pressure in the night and morning hours;
• sleep disorders, as consequences of any severe somatic pathology (in diabetes mellitus, after a stroke or myocardial infarction, against a background of thyroid gland diseases, and so on);
• condition after a traumatic brain injury.

For patients of childhood, in addition to the diseases listed above, indications for polysomnography are:

• ADHD;
• poor ability to learn;
• Obsessive stereotypes when falling asleep and after awakening (for example, rocking in a crib or other, repeatedly repeated, monotonous movements);
• tics;
• stuttering;
• wince in a dream;
• neurotic disorders;
• encopresis (incontinence of feces) in preschool children and older;
• delay of physical, intellectual and / or speech development.

Are there any contraindications?

Since monitoring the body's work during sleep is not an invasive method of diagnosis, there are no absolute contraindications for its conduct. The study should be postponed for a while, if you have such diseases:

• acute respiratory viral infection;
• acute infectious diseases of a different nature;
• chronic diseases in the acute stage.

These conditions can affect the results of polysomnography, therefore, in order to avoid an unreliable result, it is not recommended to conduct a study in these periods.

The essence of the method

Polysomnography combines several methods of research conducted simultaneously. It includes:

• EEG (electroencephalography - 4 channels): a study of the electrical activity of the brain to determine its work in different phases of sleep;
• ECG (electrocardiography) in the 1 st lead: study of the heart - excitability, conductivity, contractility;
• electrooculography: control over the movements of the eyeballs;
• electromyography: the study of the muscle tone of the chin;
• determination of oronasal (respiratory) flow: carried out with the help of special devices, located in the region of the nostril or angle of the mouth, fixing the temperature of the inhaled and exhaled air;
• control of the respiratory movements of the chest and abdomen;
• control over the movements of the lower limbs;
• pulse oximetry: determination of the degree of saturation of blood with oxygen (saturation);
• determining the position of the patient's body.

Some of these points are investigated with the help of special sensors, and others - by video shooting (in the room where polysomnography is conducted, install a video camera, often with infrared illumination, which allows you to get an image even in conditions of total darkness).

What does polysomnography reveal?

During sleep, various pathological changes may occur in the body's work, which fixes the method of research described by us. In particular, they are:

• sleep apnea syndrome (stopping breathing during sleep);
• abrupt changes in blood pressure to a greater or lesser extent;
• arrhythmias;
• muscle spasms (determined, including, with bruxism);
• violations of blood circulation;
• violation of oxygen saturation of blood;
• disorders in the brain (sleep phases, their duration, possible deviations);
• movements in one or another part of the body (in particular, the lower limbs - with restless legs syndrome);
• drift or collapse.

Methodology of the study

Before going to bed, the patient is given special electrodes that record all the changes that occur in the body during sleep.

The procedure can be carried out in a hospital or at home in a patient. In the first case, a room specially designated for polysomnography is required, in which there is a comfortable bed with the ability to adjust the angle of inclination of the head and foot end for maximum comfort of each individual patient. In addition to the bed in the room, there may be other furniture elements for the convenience of the patient, as well as a bed for his attendant (without him to do during the study of the child, especially the younger age).

The patient comes to the department in the evening, just before bedtime. Numerous electrodes are applied to his skin in order to register all the parameters mentioned above (brain activity, heart function, etc.) - as a rule, this takes about 30-40 minutes. Sensors are installed in such a way as to cause the patient as little as possible discomfort and not interfere with his healthy sleep.

After applying the electrodes, the patient falls asleep. The entire period of sleep, the device records changes in the body and transfers this data to a computer located in the next room. In addition, the entire night running a video camera, which sends an image to the same computer.

In the morning, the electrodes are removed and the patient goes home. Within 1-2 days the results of the study are deciphered, after which they invite the patient to a consultation or send him the result in electronic form.

Polysomnography can be performed at home. Usually, research at home is assigned to people who can not sleep outside the home, or especially emotional, sensitive to changing the situation, children.

Polysomnographic systems: types, advantages and disadvantages

As mentioned above, a sleep study can be conducted in a hospital setting or at home using a fixed or mobile polysomnography system, respectively.

Stationary system

It is not necessarily necessary to be large and cumbersome: modern devices are very compact, approaching in size to mobile.

The main difference between the two types of polysomnography is that when carrying out a stationary study, the data coming from the device on the computer are available to the constant supervision of medical personnel: he can evaluate them in a mode, so to speak, real-time. In case the doctor finds, for example, a sleeping sensor, he can immediately come to the ward and set it in place.

The advantages of stationary polysomnography are as follows:

• high information value of the method and absolute accuracy of diagnosis of many conditions that change the quality of sleep;
• differential diagnosis of sleep disorders;
• the ability to eliminate recording artifacts at any time and continuously monitor the quality of incoming signals to the computer.

Disadvantages of the method:

• expensive equipment;
• the need for a separate area for research;
• the need for constant presence during the study of personnel, that is, his nightly watch.

Mobile system

By the number of channels, modern mobile polysomnographic systems are not inferior to stationary ones. However, this research is carried out in a comfortable for the patient conditions - at home (and this is an obvious plus for many) or in the ward of any department. Throughout the night, data is stored in the memory of the mobile device, and after waking up the subject, they are copied to the computer. The study of sleep at home does not provide for the presence of a doctor near you and does not require the allocation of special rooms for this purpose.

However, there are also disadvantages in it:

• there is no possibility of video surveillance (except that the patient will arrange it for himself on his own);
• there is no possibility of correction of signal disturbances, for example, in the case of electrode disconnection - if this happens, one of the indicators of the study is not informative.

Do you need preparation for polysomnography?

As with any other, the study of sleep should be properly prepared:

• for 1-2 days before polysomnography it is not recommended to watch movies that excite the nervous system and play computer games;
• during the day before the test, do not drink tea, coffee, alcohol (alcohol-containing foods, for example, sweets, also do not use), Coca-Cola and other energy or tonic drinks; Do not take medications that affect the nervous system;
• take a shower, prepare a clean, sleep-comfortable clothes;
• Lack of supper;
• Do not apply cream, do not use perfume;
• wipe the varnish from the thumb of the left hand, short-cut the nail (to connect the pulse oximeter);
• You can take your favorite pillow, if any, and your child - your favorite toy for sleeping;
• do not forget your passport, personal hygiene items and clean, replaceable shoes.

Polysomnography is the "gold standard" of diagnosis in doubt, which allows you to establish an exact diagnosis after a single procedure - the cause of sleep disorders.

Union of Pediatricians of Russia, video on "Polysomnography: preparation for research. Tips for parents »:

Polysomnography: preparation for the study. Councils to parents - the Union of pediatricians of Russia.

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Carrying out a polysomnographic study:

Polysomnography

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