Electroencephalography of the brain: indications and contraindications, methodology. Deciphering the EEG of the brain What does the EEG mean in medicine

When a baby is worried about a frequent headache, the pediatrician sends him for a consultation with a pediatric neurologist. Finding out the cause of the pain is not easy, but now there are harmless, reliable and informative methods of examining even the smallest children.

Electroencephalography and echoencephaloscopy are prescribed by specialists for deviations in speech, mental, and motor development. These research methods make it possible to identify many other disorders in the work of the central nervous system.

EEG allows you to study brain activity and give an accurate assessment of the development of the child

What is an EEG, and what are the indications for prescribing the procedure for children?

If disorders of the central nervous system (CNS) are suspected, different diagnostic methods are used, especially EEG and ECHO EG, which are prescribed to a child of any age:

Electroencephalography (EEG) is a safe and informative method for diagnosing disorders in the central nervous system. An EEG records electrical impulses in different areas of the brain. The result is written on paper as a set of lines, which are analyzed by a specialist.
The second reliable method for studying the work of the central nervous system is echoencephalography (ECHO EG). Unlike EEG, echoencephalography uses ultrasonic waves to diagnose. They go inside the brain, return and are fixed by an electrical device.

The neurophysiologist makes a conclusion after the EEG and ECHO EG on the functioning of the central nervous system based on the presence or absence of certain waves, the degree of their consistency. The specialist will determine the area of the lesion and assess the current state of health of the baby, see the degree of damage and evaluate the effectiveness of the prescribed treatment.

This method is used at any age - even in newborn babies. The EEG is highly sensitive and shows even the smallest changes in the cerebral cortex. In addition, an encephalogram is an affordable and fast diagnostic method, which is very important when examining young children. An EEG is also done on people who are unconscious or in a coma.

The direction of the child on the EEG of the brain is prescribed by a pediatrician or a pediatric neurologist. Electroencephalography is prescribed in the presence of the following conditions:

epilepsy - to assess the degree of damage;
sleep disorders, in particular - sleepwalking;
inflammatory diseases of the central nervous system (meningitis);
pathology of newborns (hydrocephalus);
cerebral palsy;
autism, mental retardation, speech development (we recommend reading:);
stuttering and enuresis;
suspected neoplasm in the brain;
head injury;
frequent headaches with loss of consciousness;
behavioral changes: irritability, irascibility, tearfulness, hyperactivity, aggressiveness, weakness, poor memory;
after surgery in the CNS.

EEG of the brain is prescribed for various diseases and emotionally unstable behavior of the child

Contraindications for the study

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There are no contraindications to the electroencephalogram. It can be carried out by absolutely anyone, regardless of age and health status. It has no restrictions on the frequency of use, as it is completely safe.
During the study, the specialist will pay attention to the integrity of the skin. Electrodes should not be attached to open wounds, rashes or fresh stitches after surgery.
Preparing the child for the procedure
To obtain a reliable and informative result, the child must be prepared for the examination:
if he is aggressive, on the eve of the procedure he is given sedatives;
before the study, you should inform the doctor about what medicines (for example, anticonvulsants) the baby is taking, because they can distort the data;
do not feed foods that affect the nervous system (coffee, tea, energy drinks, chocolate);
before the study, it is recommended to wash your hair, do not apply varnishes, mousses, hair foams to your hair, there should not be dreadlocks and braids;
you need to remove all jewelry: earrings, hairpins, piercings;
feed the baby 2 hours before the procedure - in a hungry person, the concentration of sugar in the blood drops, which also distorts the results;

A couple of hours before the procedure, the child needs to eat: EEG results taken on an empty stomach may be slightly distorted
EEG for babies is best done during sleep;
older kids take toys, books with them to distract him during the procedure;
children should be psychologically prepared for the procedure, told how long it takes, because they will have to spend a long time in a calm, almost motionless state.

The study is not carried out for acute diseases (for example, SARS). When repeating the EEG, you need to take with you the results of the previous study.
EEG stages
The standard EEG procedure for a child includes several stages:
Taking data of brain activity at rest. The newborn baby will have an EEG done while sleeping.
Test with opening and closing of the eyes, recording of brain activity during the transition from a calm state to a state of activity.
Test with hyperventilation - the baby inhales and exhales on command. This stage helps to detect latent epilepsy and neoplasms.
Photostimulation. Mental and speech development is assessed, the presence of epilepsy is detected (see also:). This procedure looks like repeated flashes of light, the baby keeps his eyes closed.

The duration of the procedure is determined by the neurophysiologist, as a rule, it does not exceed half an hour.
The entire study lasts approximately 30 minutes. If necessary, the doctor may perform more tests. The patient is in a supine or sitting position. Babies up to a year are in the arms of their mother or on the changing table.
Electrodes are connected to the patient's head, a special mesh helmet is put on. Children attach 12 sensors to the surface of the head. Electrodes record electrical potentials between two sensors.
Patients with epilepsy have certain oscillatory waves that characterize epileptiform activity. It is better to register it during the period of pathological activity - during an epileptic seizure. The method is of great value in diagnosis; for its implementation, an epileptic seizure is provoked by special stimuli.
Interpretation of results in children
As a rule, the results can be collected the next day. It will not work to analyze the results of the electroencephalogram on your own, because a transcript with drawn curved lines of brain activity or a computer file is issued.
Only an experienced specialist can interpret them. He will evaluate the frequency, amplitude, rhythm of the curves, their jumps at certain moments.
The diagnosis will be made by a neurologist observing the baby, based on the decoding of the encephalogram and the symptoms that became the basis for referral for examination.
EEG norms
Depending on the age of the baby, the indicators of the norm differ. The EEG will show the deviations of the brain rhythms of a particular person from the average, normal. At the end, parents will find the following information:
Alpha rhythm. It reflects a state of rest, it is fixed in wakefulness with eyes closed. It ceases to be registered by devices when a stimulus appears. Failures in the alpha rhythm indicate the development of a tumor or cyst, a stroke or a mental disorder. Brain injury is characterized by a high frequency, with neurosis, a weak rhythm and paroxysmal activity appear.
Beta rhythm. Registered with anxiety, anxiety, depression. Failures of the beta rhythm indicate a concussion (we recommend reading:). Some of its indicators indicate encephalitis.
Theta rhythm. Registered in a state of natural sleep. The theta rhythm in a state of activity indicates the presence of pathology in the area of the brain where it is found. If it appears in all areas of the brain, then there is a significant lesion of the central nervous system. Normally, it should be no more than 15%. Violation of the theta and delta rhythms is collectively detected with mental retardation, psychopathy, and dementia. Paroxysmal theta and delta waves in the waking state indicate pathology of the deep parts of the brain. Paroxysmal activity in the central parts of the brain indicates acquired dementia.
BEA. The indicator of bioelectrical activity of the brain is normally rhythmic, it is synchronous. Its failure appears in the presence of convulsive syndrome and epilepsy. According to this indicator, migraine and headaches are diagnosed. If the EEG decoding refers to diffuse changes, this indicates a predisposition to epilepsy (we recommend reading:). Moderate dysrhythmia is not a serious disorder and requires only symptomatic treatment.
M-ECHO. Based on it, the displacement of the brain regions is estimated. Normally, a deviation of about 1 mm is allowed. If this indicator is higher, then the incorrect location of the brain regions is fixed.

There are a lot of EEG indicators, a competent specialist is engaged in their decoding. The qualifications and experience of the doctor is very important. So, for example, epileptiform changes on the EEG can occur with eye movement, vascular pulsation, changes in breathing, swallowing, and for other reasons. In 10% of epileptics, epileptiform discharges may not be recorded. All these nuances should be taken into account when preparing EEG findings.
Possible violations and their causes
EEG is very effective in detecting brain tumors. It helps to pinpoint their exact location. This method is used to diagnose injuries, inflammatory diseases, hydrocephalus and other conditions.
The main disorders and diseases investigated using EEG:
Meningoencephalitis. In this disease, an inflammatory process occurs in the brain. The cause of encephalitis is the ingestion of pathogens (viruses or bacteria). As a rule, there is a high temperature, nausea, vomiting, severe headaches.
Dropsy (hydrocephalus) (we recommend reading:). This is a common congenital pathology in which fluid accumulates in the cranial cavity. It develops as a result of birth trauma, inflammation of the central nervous system.
Epilepsy. It is characterized by convulsions and loss of consciousness. The cause of epileptic seizures in a baby can be alcohol abuse by the mother during pregnancy, heredity, birth trauma, and infectious diseases.
Neoplasms in the brain. Manifested by loss of consciousness, headaches, impaired hearing, vision and coordination (disorganization in space). The reasons for the appearance of tumors are unclear, experts believe that this is heredity, ionizing radiation, trauma and infectious diseases.

A lot of the diseases studied using EEG are hereditary or arise due to birth injuries, therefore they are diagnosed in infancy.
Hemorrhage in the brain. The causes may be injuries, hypertension, atherosclerosis, blood diseases (anemia, leukemia) (we recommend reading:). The patient is disturbed by dizziness, headaches, inattention, slowness and a state of general lethargy. For minor injuries, the conclusion will indicate that there are diffuse changes of a moderate nature. At the initial stage of atherosclerosis, moderately pronounced diffuse changes in the bioelectrical activity of the brain (BEA) are observed.
Cerebral palsy. The central nervous system is affected and the baby's motor activity is disturbed. Among the causes are intrauterine pathology of the central nervous system, heredity, asphyxia, infectious diseases in the first months of life.
Sleepwalking, or somnambulism (we recommend reading:). It manifests itself in sleepwalking and dreaming. The reasons for it are unclear, but scientists believe that heredity, environmental influences, and medications play a big role.
Mental disorders in children: autism, mental retardation, mental retardation, attention deficit disorder. Provoke their hereditary predisposition, pathological changes in the brain, strong psycho-emotional shocks.
Stuttering. A speech defect appears due to the child's hereditary predisposition, perinatal brain damage, past infectious diseases, rickets, traumatic brain injuries, and mental shocks.

This is an incomplete list of childhood disorders when EEG comes to the rescue in diagnosis. This method will help the neurologist to make the correct diagnosis and prescribe effective therapy for the baby.
Cost of diagnostics
How much does an EEG and ECHO EG cost? The cost varies in different regions and places of the procedure. Usually the price of an EEG varies from 600 to 3500 rubles. Echoencephalography costs from 500 to 3000 rubles.
Private medical clinics charge a higher price tag for examinations, unlike municipal institutions. The cost depends on the level of comfort during the procedure, the qualifications of doctors and other factors.

An EKG is an electrocardiogram, a recording of the electrical signals from the heart. The fact that a potential difference arises in the heart during excitation was shown as early as 1856, in the era of Dubois-Reymond. An experiment proving this was set up by Kelliker and Muller exactly according to Galvani's prescription: a nerve leading to a frog's leg was placed on an isolated heart, and this "living voltmeter" responded with a shudder of the leg to each contraction of the heart.

With the advent of sensitive electrical measuring instruments, it became possible to capture the electrical signals of a beating heart by applying electrodes not directly to the heart muscle, but to the skin.

In 1887, for the first time, it was possible to register a human ECG in this way. This was done by the English scientist A. Waller using a capillary electrometer (The basis of this device was a thin capillary in which mercury bordered on sulfuric acid. When current was passed through such a capillary, the surface tension at the boundary liquids changed and the meniscus moved along the capillary.)

This device was inconvenient to use and the widespread use of electrocardiography began later, after the appearance in 1903 of a more advanced device - the Einthoven string galvanometer. (The operation of this device is based on the movement of a conductor with current in a magnetic field. The role of the conductor was played by a silver-plated quartz thread with a diameter of several micrometers, tightly stretched in a magnetic field. When current was passed through this string, it bent slightly. These deviations were observed using a microscope. The device had low inertia and made it possible to register fast electrical processes.)

After the appearance of this device in a number of laboratories, they began to study in detail the difference between the ECG of a healthy heart and a heart with various diseases. For these works, V. Einthoven received the Nobel Prize in 1924, and the Soviet scientist A.F. Samoilov, who did a lot for the development of electrocardiography, received the Lenin Prize in 1930. As a result of the next step in the development of technology (the advent of electronic amplifiers and recorders), electrocardiographs began to be used in every major hospital.

What is the nature of the ECG?

When any nerve or muscle fiber is excited, current in some of its sections flows through the membrane into the fiber, while in others it flows out. In this case, the current necessarily flows through the external medium surrounding the fiber, and creates a potential difference in this medium. This makes it possible to register fiber excitation using extracellular electrodes without penetrating into the cell.

The heart is a fairly powerful muscle. Many fibers are synchronously excited in it, and a sufficiently strong current flows in the medium surrounding the heart, which even on the surface of the body creates a potential difference of the order of 1 mV.

In order to learn more about the state of the heart from an ECG, doctors record many curves between different points on the body. It takes a lot of experience to understand these curves. With the advent of computer technology, it became possible to largely automate the process of "reading" the ECG. The computer compares the patient's ECG with samples stored in its memory, and gives the doctor a suggested diagnosis (or several possible diagnoses).

Now there are many other new approaches to the analysis of the ECG. This one seems very interesting. According to those registered from many points of the body, and their change in time, it is possible to calculate how the wave of excitation moves through the heart and which parts of the heart have become unexcitable (for example, affected by a heart attack). These calculations are very laborious, but they became possible with the advent of computers.

This approach to ECG analysis was developed by L. I. Titomir, an employee of the Institute for Information Transmission Problems of the USSR Academy of Sciences. Instead of many curves that are difficult to understand, the computer draws on the screen the heart and the spread of excitation through its departments. You can directly see in which region of the heart the excitation is slower, which parts of the heart are not excited at all, etc.

The potentials of the heart were used in medicine not only for diagnostics, but also for the control of medical equipment. Imagine that a doctor needs to take x-rays of the heart at different phases of its cycle, i.e. at the moment of maximum contraction, maximum relaxation, etc. This is necessary for some diseases. But how to catch the moment of greatest contraction? You have to take many shots in the hope that one of them will fall into the right phase.

And so the Soviet scientists V, S. Gurfinkel, V. B., Malkin and M. L. Tsetlin decided to turn on the X-ray equipment from the ECG wave. This required a not very complex electronic device, which included shooting with a given delay relative to the ECG wave. The solution of the problem, ingenious in itself, is especially interesting because it was one of the first (now numerous) devices in which the natural potentials of the organism control one or another artificial device; this area of technology is called biofeedback.

The skeletal muscles of the body also generate potentials that can be registered from the surface of the skin. However, this requires more advanced equipment than for ECG registration. Separate muscle fibers usually work asynchronously, their signals, superimposed on each other, are partially compensated, and as a result, lower potentials are obtained than in the case of an ECG.

The electrical activity of skeletal muscle is called an electromyogram - EMG. For the first time, the potentials of human muscle fibers were discovered by listening to them with a telephone set by the Russian scientist N. E. Vvedensky back in 1882.

In 1907, the German scientist G. Pieper used a string galvanometer for their objective registration. However, this was a complex and time-consuming method. Only after the cathode oscilloscope and electronic equipment appeared in 1923 did electromyography begin to develop intensively. Now it is widely used in science, medicine, sports, as well as for biofeedback.

One of the first great applications of EMG biofeedback is the creation of prostheses for people who have lost an arm. Such prostheses were first created in our country.

What is an EEG?

This is an electroencephalogram, i.e., the electrical activity of the brain, potential fluctuations created by the work of brain neurons and recorded directly from the surface of the head. Nerve cells, like muscle fibers, do not work simultaneously: when some of them create a positive potential on the surface of the skin, others create a negative one. The mutual compensation of potentials here is even stronger than in the case of EMG. As a result, the EEG amplitude is about a hundred times smaller than the ECG, so their registration requires more sensitive equipment.

For the first time, EEG was recorded by the Russian scientist V. V. Pravdich-Nemsky on dogs using a string galvanometer. He administered curare to dogs so that stronger muscle currents would not interfere with the registration of brain currents.

In 1924, the German psychiatrist H. Berger began studying human EEG at the University of Jena. He described periodic oscillations of brain potentials with a frequency of about 10 Hz, which are called the alpha rhythm. He was the first to register the EEG of “a person during an epileptic seizure and came to the conclusion that Galvani was right in suggesting that during epilepsy a site appears in the nervous system, where the currents are especially strong (the cells there are continuously excited at a high frequency).

Since it was a question of very weak potentials recorded by a little-known doctor, Berger's results did not attract attention for a long time; he himself published them only 5 years after the discovery. And only after they were confirmed in 1930 by the famous English scientists Adrian and Matthews, they were "... stamped with academic approval," according to G. Walter, an English scientist who studied the clinical aspects of EEG in Gall's laboratory. In this laboratory, methods were developed that made it possible to determine the location of a tumor or hemorrhage in the brain by EEG, just as they had previously learned to determine the location of a heart attack in the heart by ECG.

In the future, in addition to the alpha rhythm, other brain rhythms were discovered, in particular, rhythms associated with different types of sleep. There are many projects for biofeedback using EEG. For example, if the driver's EEG is recorded all the time, then with the help of a computer it is possible to determine the moment when he begins to doze off and wake him up. Unfortunately, all such projects are still difficult to implement, since the EEG amplitude is very small.

In addition to EEG - oscillations of the brain potential in the absence of special effects, there is another form of brain potentials - evoked potentials (EPs).

Evoked potentials are electrical reactions that occur in response to a flash of light, sound, etc. Since many brain neurons respond almost simultaneously to a bright flash of light, evoked potentials usually have a much larger value than the EEG. It is no coincidence that they were discovered much earlier than the EEG (in 1875, by the Englishman Keton and, independently of him, in 1876 by the Russian researcher V. Ya. Danilevsky).

With the help of evoked potentials, interesting scientific problems can be solved. For example, after a flash of light, the response (EP) occurs first in the occipital region of the brain. From this we can conclude that it is in this region that signals about light arrive.

With electrical stimulation of the skin, evoked potentials arise in the dark region of the brain.

When the skin of the hand is irritated, they occur in one place, the skin of the leg in another. It is possible to map such responses, and this map shows that the surface of the skin gives a projection on the parietal region of the human cerebral cortex. Interestingly, some proportions are violated during this design, for example, the projection of the hand turns out to be disproportionately large. Yes, this is natural: the brain needs much more detailed information about the hand than, for example, about the back.

EEG (electroencephalography)- study of the electrical activity of the brain. When performing this study, a special silicone or fabric cap is put on the patient's head with electrodes attached to it, which record electrical activity at different points of the head. The results of changes in this activity are displayed on a computer screen or paper tape in the form of graphs, by which the doctor can determine the nature and nature of the patient's disorders.

When is electroencephalography needed?

First of all, if you suspect epilepsy. This disease is characterized by special EEG changes - the so-called epileptiform activity. Less specific are EEG changes in infections of the nervous system, brain injuries, and in some hereditary diseases.

Preparation for electroencephalography

On the eve of the study, it is recommended to wash (and, of course, dry) the head, do not use hair styling products, undo the braids, remove jewelry and hairpins from the head. In some cases, the attending physician may ask to limit sleep on the eve of the study, most often this is necessary so that the patient can fall asleep during the EEG. Sleep restriction means a significant reduction in its duration - by several hours (at least 3-4 hours). It is usually not recommended to administer sedatives before the study, as they change the EEG pattern.

Before performing an EEG, you can psychologically prepare a child by explaining to him in a playful way the need to put on an electrode cap. Traditionally, it is recommended to do this in the form of a game of pilots or astronauts.

It is worth taking it with you on a towel so that after the examination you can clear your head of traces of the electrode gel. Young children may need to be fed during recording.

How is an EEG performed?

The patient usually sits in a chair or lies on a bed during the examination. Electrodes are attached to the head with the help of special caps-helmets. If it is necessary to record for a long time, the electrodes can be fixed on the head with a special paste and fixed with a special glue (collodion). During the recording, the patient is advised to sit (or lie) still, because. movements cause interference on the EEG, making it difficult to “decipher”. It is impossible to prohibit small children from moving, so parents are given instructions on holding the child, diverting his attention with the help of toys. Of course, when recording EEGs in children, one has to put up with the inevitable interference.

During recording, photostimulation and hyperventilation tests are almost always performed. Photostimulation is the effect of bright flashes of light directed into the eyes of the patient. Hyperventilation is possible in children who know how to follow instructions, tk. this test requires deep breathing for several minutes. Both of these tests help detect some EEG abnormalities that are not visible at rest. If necessary, you can record the EEG during sleep.

The study is painless and does not involve the introduction of drugs into the body or the passage of electricity through the body. However, for young children with an EEG, it may be uncomfortable to put on an EEG cap and try to limit freedom of movement during recording.

If a patient is being examined for epilepsy, seizures can sometimes be seen during the recording. The doctor may even ask to provoke an attack in order to clarify its type, origin and assess the possibilities of the upcoming treatment. In this case, a video recording can be performed, such a study is called EEG video monitoring.

The duration of the study may differ in different laboratories depending on the patient's diagnosis, his condition, the presence of epileptic seizures during the study, etc. It is often possible to obtain the necessary information in about half an hour, but the doctor or laboratory assistant can, if necessary, increase or decrease the recording time.

What is EEG video monitoring?

A long-term (usually many hours) recording of electroencephalography is called EEG monitoring. There is no exact time for this study, it is chosen by the attending physician and EEG laboratory staff, depending on the specific situation.

With simultaneous recording of the patient's behavior on a video camera, the study will be called EEG video monitoring (or video EEG monitoring, this is the same thing). EEG monitoring ordered if needed

to see the states that disturb the patient and clarify their nature
record a long EEG if a short standard record does not reveal specific changes
evaluate the EEG pattern during wakefulness and sleep.

Is it always necessary to sleep during EEG monitoring?

No, sometimes being awake is enough if during the study an unequivocal answer to the question of the attending physician is received. For example, if the patient's parents are worried about specific unusual conditions in the child during wakefulness (for example, tics) and these were recorded during monitoring, then sleep is often not needed.

On the other hand, states that the patient and his family do not know about can be found in a dream, so a competent neurologist should explain the details of the monitoring to the patient and the EEG doctor in advance.

Which EEG monitoring is better - daytime or nighttime?

The default night monitoring is “better” because it lasts longer and usually contains a sleep record. In the daytime, not everyone manages to fall asleep, and the duration of the daytime recording is usually 2-4-6 hours (depending on the laboratory). You can also navigate by complaints - if some events occur strictly at night, then a night recording is needed to detect them. But it must be remembered that many hours of EEG in an isolated room is tiring for the patient, especially for a child. Many issues can be resolved in the course of a relatively short recording and not torment the patient with senseless pastime in a locked office. In addition, night EEG video monitoring costs much more than daytime monitoring, and it is almost impossible to do it free of charge (under a compulsory medical insurance policy) on an outpatient basis. Thus, if daily monitoring is enough to answer the question of the attending physician, then you can try to save your nerves, time and money. But if the doctor needs a strictly night recording, then it will be necessary to perform it.

What does the EEG result look like?

The EEG result is issued in the form of printouts of the obtained graphs with the conclusion of a specialist about the presence and nature of violations. Sometimes the result is written to a CD, especially if you need to save the EEG video monitoring data. All EEG results must be carried with you at all consultations with neurologists, and it is “graphs”, and not just conclusions. It is better to store printouts in hard folders, you do not need to fold and fold them.

The resulting conclusion must be shown to the attending physician. It must be remembered that the EEG result is not yet a diagnosis, but only part of the overall picture, according to which the attending physician will make an impression of the patient. Sometimes an “abnormal” EEG can be recorded in a healthy person, while in a patient, on the contrary, there may be no changes. The attending physician or, in difficult situations, the council should decipher the received data and “translate” them into a generally accessible language.

Electroencephalogram (EEG) refers to the functional methods of studying the brain. EEG recording is a recording of neuronal activity when electrodes are applied to various parts of the head during wakefulness, active mental or physical stress. The method is absolutely harmless and painless.

An electroencephalographic study is performed for adults and children. The EEG procedure reveals the functional activity of the reticular formation, hemispheres, subcortical nuclei, nerve fibers of the forebrain. An encephalogram of the brain allows you to determine the degree of damage to a certain area of \u200b\u200bthe brain in neurological and mental disorders.

How an electroencephalogram (EEG) is performed

During the examination, the patient should be in a position convenient for him (sitting or lying down).

The procedure cannot be performed if:

The patient is in an agitated state;
During this period, course treatment with sedatives is carried out;
The patient is hungry.

During the procedure, a special cap is put on the subject's head, to which electrodes are connected. The most convenient in operation are bridge electrodes attached to the surface of the head with the help of a small thickening made of a fine porous sponge (cotton wool). Outside, the electrodes are covered with a special cloth. Before the procedure, all sensors are immersed in a saturated saline solution for 15–20 minutes. The electrodes in contact with the skin surface form a closed electrical network. All vibration measurements from different areas are transmitted to the device. Deciphering the graphic indicators by a specialist gives a conclusion about the state of the brain.

If a long-term electroencephalographic study is necessary, the electrodes are attached to the scalp using a special gel. During the session, you can not move, so as not to create unnecessary interference that complicates decoding. Repeated procedure is performed no earlier than 10 days later.

Research objectives

Indications for carrying out are:

EEG techniques

In practice, four main methods are used:

A routine technique is used to diagnose paroxysmal conditions. During the study, a short-term recording of biocurrents is performed.

Testing applied:

photostimulation (exposure to a beam of bright light directed at the closed eyes of the subject);
hyperventilation (performing by the patient for 3-5 minutes of deep breaths);
opening and closing eyes.

Routine testing reveals abnormalities that cannot be registered at rest.

In the event that the routine technique is not informative, an EEG of the brain with deprivation (forced sleep deprivation) is performed. To this end, the patient is intentionally not allowed to sleep. Before a deprivation session, sedatives and tranquilizers are excluded.

Long-term EEG recording (during daytime sleep) is performed with suspicion of changes in brain function during sleep.

The EEG is most informative during nocturnal sleep. Before going to bed, the wakefulness zone is marked, and then all biocurrents are recorded from this area during falling asleep, night sleep and awakening. If necessary, connect additional sensors with video recording.

Contraindications for EEG

The procedure is safe and harmless. A limitation on the study is the presence of a fresh bleeding wound on the head or freshly applied stitches.

EEG preparation

In order for the procedure to be successful, you need to prepare.

To do this, perform the following procedures:

Encephalography of the brain is carried out in the morning, after sleep;
In order to eliminate errors in diagnosis, it is necessary to refuse to take drugs that affect the functioning of the brain. Anticonvulsants, in agreement with the attending physician, are not taken 3 days in advance;
On the evening before the study, it is recommended to wash your hair. Dry your hair without using chemical styling products;
There should be no wounds or abrasions on the scalp;
Before the examination, the patient needs to remove all metal jewelry from himself;
If an electroencephalographic study is performed on a child, the patient must be convinced of the painlessness and safety of the procedure.

Features of the EEG for children

In childhood, using the EEG of the brain, it is possible to assess the functional state, to identify the presence of pathological changes and epileptiform activity of brain structures against the background of sleep without the use of drugs.

An encephalogram of the brain in childhood is performed in the following cases:

During the study, the child must be in a calm state (sitting in a chair). A special hat is put on the head, with a large number of wires connected to it. Before the procedure, the nurse or doctor first establishes contact with the child, enthusiastically engaging in an interesting game with him, while simultaneously performing the steps to install the electrodes.

Benefits of an electroencephalogram

Currently, the EEG technique of the brain has been replaced by other studies: MRI, computed tomography, ultrasound of the brachiocephalic vessels.

EEG Benefits:

Availability and safety of the study.
Rapidity. The procedure takes 15-20 minutes.
This is an informative method for examining patients with epilepsy. EEG of the brain - the possibility of differential diagnosis in determining the nature of the attack (epileptic or not epileptic).
Deciphering graphic indicators is a way to control the therapeutic effect of prescribed drugs, the ability to establish the primary focus of the disease.
The patient's admission to driving vehicles when passing a medical certificate for the traffic police depends on the results of the study. This is the most reliable way to detect hidden craniocerebral injuries.

The EEG of the brain shows violations of the brain, so if necessary, you should not refuse to carry out this procedure.

Reading strengthens neural connections:

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The functioning of the brain and its condition, the presence of disorders can be recorded using special diagnostic methods that purposefully reveal various deviations in its work. The methods are mainly characterized by the study of the activity of the brain in its various states. These methods include:

electroencephalography, rheoencephalography,
Computed and magnetic resonance imaging;
Ultrasonic ;
Neurosonography;

There are still quite a number of different research methods, but our today's conversation will focus on such a highly effective and common method as electroencephalography (EEG). This method works on the principle of recording the activity of neurons in different areas of the brain, after which the result is displayed on paper using electrodes.

This procedure is carried out in order to assess the activity of the functioning of the brain in various pathologies or disorders of the central nervous system (meningitis, encephalitis, etc.). The method allows you to determine the localization of the lesion and assess the current state of the brain and the degree of its damage.

Also, the EEG is highly sensitive and reflects the slightest changes in the cerebral cortex, which has an advantage over other research methods.

Adults and children can be allowed to this procedure, due to the fact that this study of the cerebral cortex is absolutely safe and painless.

Today, it is increasingly used before obtaining a driver's license and a license to carry weapons. For medicinal purposes, it can be prescribed in the following cases:

After direct surgical intervention;
To identify cysts and tumor formations;
With open and closed head injuries, of varying severity;
Frequent headaches, dizziness
To confirm the development of epilepsy, cerebral palsy, SVD;
With the appearance of convulsive seizures, numbness of the limbs, fainting;
With hypertension;
With a delay in the development of mental indicators in a child and possible speech problems (etc.).
To assess the effectiveness of drug therapy;

Basically, the study of the brain using EEG is carried out by a neurologist, although a psychiatrist or neurophysiologist can also give a referral.

Before the procedure, the diagnostician must warn the subject about some rules that must be observed in order to conduct the procedure safely and obtain accurate results. To do this, follow these recommendations:

12 hours before the procedure, you should completely abandon foods and drinks stimulating the nervous system (caffeine, energy drinks);
Psycho-emotional arousal should be avoided before the procedure;
A few hours before the event, you should stop watching TV, playing computer games and listening to loud music;
Before the procedure, it is enough to wash your hair. All possible gels, varnishes, masks, etc. should be absent on the hair.
Consult a specialist if you are taking sedatives, anticonvulsants, or other drugs that affect the nervous system. Basically, these groups of drugs are canceled 3 days before the procedure.
The procedure is not carried out with ARVI, influenza.

If the diagnosis is carried out for a child, then the baby should be explained that the procedure is not dangerous and absolutely painless. Parents are advised to bring any toys and other things with them in order to somehow distract the child from the procedure. In order for the study to give accurate results, the baby must be calm both before the procedure and during it.

If the child is less than a year old, then the procedure is carried out in the hands of the mother.

Carrying out diagnostics

EEG is carried out in an office with isolation from possible external stimuli (sound, light). The patient takes a position, sitting or lying on the couch, after which a special cap is put on his head.

Sensors are connected to the cap, which are connected to the encephalograph. Pre-sensors are lubricated with gel for better conductivity. The diagnostic time depends on whether the patient will be additionally loaded, so the time can vary from 20 minutes to 2 hours.

EEG is carried out in stages and may include several additional functional loads. The initial stage is characterized by a standard study, the eyes are closed, after which functional tests are selected that can detect pathology or disorders.

It is possible to single out the standard course of the procedure, including functional loads:

The background curve is registered;
Opening and closing the eyes with some interval to study the state of the cerebral cortex in a calm and active state;
Phonostimulation. It is carried out with the help of external stimuli (sound, finger snaps, etc.);
Photostimulation. Assesses the psychomotor and speech state of the child, and also allows you to identify epilepsy. It is carried out using any light source, with the necessary intervals, for 20-30 minutes.
Hyperventilation. Allows, tumor formation or inflammation. It is carried out with the help of deep, rhythmic breathing.
Polysomnography. This additional load records EEG data directly when a person is sleeping.
Deprivation or refusal of sleep. In this case, the patient needs to give up sleep for one night or get up a few hours earlier. This load is connected in cases where the standard recording of biological potentials did not bring any results.