Encephalography of the brain. EEG – encephalogram of the brain, in what cases it is prescribed, what it shows. Rhythms of brain activity

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The activity of the brain, the state of its anatomical structures, the presence of pathologies are studied and recorded using various methods– electroencephalography, rheoencephalography, computed tomography, etc. A huge role in identifying various abnormalities in the functioning of brain structures belongs to the methods of studying it. electrical activity, in particular electroencephalography.

Electroencephalogram of the brain - definition and essence of the method

The functional activity of the human brain depends on the activity of the median structures - reticular formation And forebrain , which determine the rhythm, general structure and dynamics of the electroencephalogram. A large number of connections of the reticular formation and forebrain with other structures and the cortex determine the symmetry of the EEG, and its relative “sameness” for the entire brain.

An EEG is taken to determine brain activity during various lesions central nervous system, for example, with neuroinfections (poliomyelitis, etc.), meningitis, encephalitis, etc. Based on the EEG results, it is possible to assess the degree of brain damage due to various reasons, and clarify the specific location that was damaged.

The EEG is taken according to a standard protocol, which takes into account recordings in a state of wakefulness or sleep (infants), with special tests. Routine tests for EEG are:
1. Photostimulation (exposure to flashes of bright light on closed eyes).
2. Opening and closing eyes.
3. Hyperventilation (rare and deep breathing within 3 – 5 minutes).

These tests are performed on all adults and children when taking an EEG, regardless of age and pathology. In addition, additional tests may be used when taking an EEG, for example:

• clenching your fingers into a fist;
• sleep deprivation test;
• stay in the dark for 40 minutes;
• monitoring the entire period of night sleep;
• taking medications;
• performing psychological tests.

What does an electroencephalogram show?

Today, the electroencephalogram is widely used in the practice of neurologists, since this method allows for the diagnosis of epilepsy, vascular, inflammatory and degenerative brain lesions. In addition, EEG helps to determine the specific location of tumors, cysts and traumatic injuries brain structures.

An electroencephalogram with irritation of the patient by light or sound makes it possible to distinguish true visual and hearing impairments from hysterical ones, or their simulation. EEG is used in intensive care units for dynamic monitoring of the condition of patients in a coma. The disappearance of signs of electrical activity of the brain on the EEG is a sign of human death.

Where and how to do it?

Electroencephalograms for children under 14 years of age are taken only in specialized children's hospitals where pediatricians work. That is, you need to go to the children's hospital, find the neurology department and ask when the EEG is taken. Psychiatric clinics, as a rule, do not take EEGs for young children.

In addition, private medical centers specializing in diagnostics and treatment neurological pathology, also provide EEG services for both children and adults. You can contact a multidisciplinary private clinic, where there are neurologists who will take an EEG and decipher the recording.

An electroencephalogram should be taken only after a full night's rest, in the absence of stressful situations and psychomotor agitation. Two days before the EEG is taken, it is necessary to exclude alcoholic drinks, sleeping pills, sedatives And anticonvulsants, tranquilizers and caffeine.

Electroencephalogram for children: how the procedure is performed

To record an EEG, a cap is placed on the baby's head, under which the doctor places electrodes. The skin under the electrodes is wetted with water or gel. Two inactive electrodes are placed on the ears. Then, using alligator clips, the electrodes are connected to the wires connected to the device - the encephalograph. Because the electric currents are very small, then an amplifier is always necessary, otherwise brain activity will simply be impossible to register. It is the small current strength that is the key to the absolute safety and harmlessness of EEG, even for infants.

To begin the examination, the child's head should be placed flat. Anterior tilt should not be allowed as this may cause artifacts that will be misinterpreted. EEGs are taken for infants during sleep, which occurs after feeding. Wash your child's hair before taking the EEG. Do not feed the baby before leaving the house; this is done immediately before the test so that the baby eats and falls asleep - after all, it is at this time that the EEG is taken. To do this, prepare formula or express breast milk into a bottle that you use in the hospital. Up to 3 years of age, EEG is taken only in a state of sleep. Children over 3 years old can stay awake, but to keep your baby calm, take a toy, book, or anything else that will distract the child. The child should be calm during the EEG.

Typically, the EEG is recorded as a background curve, and tests with opening and closing the eyes, hyperventilation (slow and deep breathing), and photostimulation are also performed. These tests are part of the EEG protocol, and are performed on absolutely everyone - both adults and children. Sometimes they ask you to clench your fingers into a fist and listen various sounds etc. Opening the eyes allows us to assess the activity of inhibition processes, and closing them allows us to assess the activity of excitation. Hyperventilation can be carried out in children after 3 years of age in the form of a game - for example, asking the child to inflate a balloon. Such rare and deep inhalations and exhalations last for 2–3 minutes. This test allows you to diagnose latent epilepsy, inflammation of the structures and membranes of the brain, tumors, dysfunction, fatigue and stress. Photostimulation is carried out with the eyes closed and the light blinking. The test allows you to assess the degree of delay in the child’s mental, physical, speech and mental development, as well as the presence of foci of epileptic activity.

Electroencephalogram rhythms

The human EEG contains alpha, beta, delta and theta rhythms, which have various characteristics and reflect certain types brain activity.

Alpha rhythm has a frequency of 8 – 14 Hz, reflects a state of rest and is recorded in a person who is in a state of wakefulness, but with eyes closed. This rhythm Normally regular, maximum intensity is recorded in the area of ​​the back of the head and crown. The alpha rhythm ceases to be detected when any motor stimuli appear.

Beta rhythm has a frequency of 13 – 30 Hz, but reflects the state of anxiety, restlessness, depression and the use of sedative medications. The beta rhythm is recorded with maximum intensity over the frontal lobes of the brain.

Theta rhythm has a frequency of 4–7 Hz and an amplitude of 25–35 μV, reflecting the state of natural sleep. This rhythm is a normal component of the adult EEG. And in children this type of rhythm on the EEG predominates.

Delta rhythm has a frequency of 0.5 - 3 Hz, it reflects the state of natural sleep. It can also be recorded in a limited amount during wakefulness, a maximum of 15% of all EEG rhythms. The amplitude of the delta rhythm is normally low - up to 40 μV. If there is an excess of amplitude above 40 μV, and this rhythm is recorded for more than 15% of the time, then it is classified as pathological. Such a pathological delta rhythm indicates a dysfunction of the brain, and it appears precisely over the area where pathological changes develop. The appearance of a delta rhythm in all parts of the brain indicates the development of damage to the structures of the central nervous system, which is caused by liver dysfunction, and is proportional to the severity of the disturbance of consciousness.

Electroencephalogram results

Such a conclusion must reflect the main characteristics of the EEG, and includes three mandatory parts:
1. Description of the activity and typical affiliation of EEG waves (for example: “The alpha rhythm is recorded over both hemispheres. The average amplitude is 57 μV on the left and 59 μV on the right. The dominant frequency is 8.7 Hz. The alpha rhythm dominates in the occipital leads.”).
2. Conclusion according to the description of the EEG and its interpretation (for example: “Signs of irritation of the cortex and midline structures of the brain. Asymmetries between the hemispheres of the brain and paroxysmal activity not found").
3. Determination of Compliance clinical symptoms with EEG results (for example: “Objective changes in the functional activity of the brain were recorded, corresponding to manifestations of epilepsy”).

Decoding the electroencephalogram

Decoding the electroencephalogram involves interpreting the conclusion. Let's consider the basic concepts that the doctor reflects in the conclusion, and their clinical significance(that is, what these or those parameters can indicate).

Alpha - rhythm

• constant recording of alpha rhythm in frontal parts brain;
• interhemispheric asymmetry above 30%;
• violation of sinusoidal waves;
• paroxysmal or arc-shaped rhythm;
• unstable frequency;
• amplitude less than 20 μV or more than 90 μV;
• rhythm index less than 50%.

High frequency and instability of the alpha rhythm indicate traumatic brain damage, for example, after a concussion or traumatic brain injury.

Disorganization of the alpha rhythm or its complete absence speaks of acquired dementia.

About delayed psycho-motor development in children they say:

• alpha rhythm disorganization;
• increased synchrony and amplitude;
• moving the focus of activity from the back of the head and crown;
• weak short activation reaction;
• excessive response to hyperventilation.

Excitable psychopathy is manifested by a slowdown in the frequency of the alpha rhythm against the background of normal synchrony.

Inhibitory psychopathy is manifested by EEG desynchronization, low frequency and alpha rhythm index.

Increased synchronization of the alpha rhythm in all parts of the brain, a short activation reaction - the first type of neuroses.

Weak expression of the alpha rhythm, weak activation reactions, paroxysmal activity - the third type of neuroses.

Beta rhythm

• paroxysmal discharges;
• low frequency, distributed over the convexital surface of the brain;
• asymmetry between hemispheres in amplitude (above 50%);
• sinusoidal type of beta rhythm;
• amplitude more than 7 μV.

Short spindles in the beta rhythm indicate encephalitis. The more severe the inflammation of the brain, the greater the frequency, duration and amplitude of such spindles. Observed in a third of patients with herpes encephalitis.

Beta waves with a frequency of 16 - 18 Hz and high amplitude (30 - 40 μV) in the anterior and central departments brain - signs of delayed psychomotor development of a child.

EEG desynchronization, in which the beta rhythm predominates in all parts of the brain, is the second type of neurosis.

Theta rhythm and delta rhythm

In children and young people under 21 years of age, the electroencephalogram may reveal diffuse theta and delta rhythms, paroxysmal discharges and epileptoid activity, which are normal variants and do not indicate pathological changes in brain structures.

What do disturbances of theta and delta rhythms on the EEG indicate?
Delta waves with high amplitude indicate the presence of a tumor.

Synchronous theta rhythm, delta waves in all parts of the brain, bursts of bilateral synchronous theta waves with high amplitude, paroxysms in the central parts of the brain - indicate acquired dementia.

The predominance of theta and delta waves on the EEG with maximum activity in the occipital region, flashes of bilateral synchronous waves, the number of which increases with hyperventilation, indicates a delay in the psychomotor development of the child.

A high index of theta activity in the central parts of the brain, bilateral synchronous theta activity with a frequency of 5 to 7 Hz, localized in the frontal or temporal regions of the brain indicate psychopathy.

Theta rhythms in the anterior parts of the brain as the main ones are an excitable type of psychopathy.

Paroxysms of theta and delta waves are the third type of neuroses.

The appearance of high-frequency rhythms (for example, beta-1, beta-2 and gamma) indicates irritation (irritation) of brain structures. This may be due to various disorders cerebral circulation, intracranial pressure, migraines, etc.

Bioelectric activity of the brain (BEA)

What are they talking about various disorders bioelectric activity of the brain?
Relatively rhythmic bioelectrical activity with foci of paroxysmal activity in any area of ​​the brain indicates the presence of some area in its tissue where excitation processes exceed inhibition. This type of EEG may indicate the presence of migraines and headaches.

Diffuse changes in the bioelectrical activity of the brain may be normal if no other abnormalities are detected. Thus, if the conclusion only writes about diffuse or moderate changes bioelectrical activity of the brain, without paroxysms, foci of pathological activity, or without a decrease in the threshold seizure activity, then this is a variant of the norm. In this case, the neurologist will prescribe symptomatic treatment and place the patient under observation. However, in combination with paroxysms or foci of pathological activity, they speak of the presence of epilepsy or a tendency to seizures. Reduced bioelectrical activity of the brain can be detected in depression.

Other indicators

Interhemispheric asymmetry May be functional impairment, that is, not evidence of pathology. In this case, it is necessary to undergo examination by a neurologist and a course of symptomatic therapy.

Diffuse disorganization of the alpha rhythm, activation of diencephalic-stem structures of the brain against the background of tests (hyperventilation, closing-opening of eyes, photostimulation) is the norm, if the patient has no complaints.

Center of pathological activity indicates increased excitability of this area, which indicates a tendency to seizures or the presence of epilepsy.

Irritation of various brain structures (cortex, middle sections, etc.) is most often associated with impaired cerebral circulation due to various reasons (for example, atherosclerosis, trauma, increased intracranial pressure, etc.).

Paroxysms They talk about increased excitation and decreased inhibition, which is often accompanied by migraines and simple headaches. In addition, there may be a tendency to develop epilepsy or the presence of this pathology if a person has had seizures in the past.

Reducing the threshold for seizure activity indicates a predisposition to seizures.

The following signs indicate the presence of increased excitability and a tendency to convulsions:

• changes in electrical potentials of the brain according to the residual-irritative type;
• enhanced synchronization;
• pathological activity of the midline structures of the brain;
• paroxysmal activity.

Irritation of the cerebral cortex along the convexial surface of the brain, increased activity of the median structures at rest and during tests can be observed after traumatic brain injuries, with a predominance of excitation over inhibition, as well as with organic pathology of brain tissue (for example, tumors, cysts, scars, etc.).

Epileptiform activity indicates the development of epilepsy and an increased tendency to seizures.

Increased tone of synchronizing structures and moderate dysrhythmia are not pronounced disorders or pathologies of the brain. In this case, resort to symptomatic treatment.

Signs of neurophysiological immaturity may indicate a delay in the child’s psychomotor development.

Pronounced changes in residual organic type with increasing disorganization against the background of tests, paroxysms in all parts of the brain - these signs usually accompany severe headaches, increased intracranial pressure, attention deficit hyperactivity disorder in children.

Disturbance of brain wave activity (appearance of beta activity in all parts of the brain, dysfunction of midline structures, theta waves) occurs after traumatic injuries, and can manifest itself as dizziness, loss of consciousness, etc.

Organic changes in brain structures in children are a consequence infectious diseases, such as cytomegalovirus or toxoplasmosis, or hypoxic disorders that arose during childbirth. Necessary comprehensive examination and treatment.

Regulatory cerebral changes are registered in hypertension.

The presence of active discharges in any part of the brain , which intensify with exercise, means that in response to physical stress a reaction may develop in the form of loss of consciousness, visual impairment, hearing loss, etc. The specific reaction to physical activity depends on the location of the source of active discharges. In this case physical activity must be limited to reasonable limits.

In case of brain tumors, the following are detected:

• the appearance of slow waves (theta and delta);
• bilateral synchronous disorders;
• epileptoid activity.

Desynchronization of rhythms, flattening of the EEG curve develops in cerebrovascular pathologies. A stroke is accompanied by the development of theta and delta rhythms. The degree of electroencephalogram abnormalities correlates with the severity of the pathology and the stage of its development.

Theta and delta waves in all parts of the brain; in some areas, beta rhythms are formed during injury (for example, with a concussion, loss of consciousness, bruise, hematoma). The appearance of epileptoid activity against the background of brain injury can lead to the development of epilepsy in the future.

Significant slowing of alpha rhythm may accompany parkinsonism. Fixation of theta and delta waves in the frontal and anterior temporal parts of the brain, which have different rhythms, low frequencies and high amplitudes, is possible in Alzheimer's disease

EEG of the brain is a non-invasive method of studying an organ in order to identify areas of increased convulsive readiness in its cortex. This diagnostic method allows you to identify pathological changes in adults and children that can affect functionality. individual areas hemispheres.

Electroencephalography (EEG) - research functional state brain by recording its bioelectrical activity. An electroencephalograph is used to carry out the procedure, followed by computer processing of the data.

The result of an EEG is an electroencephalogram - a graphic recording of brain rhythms in the form of curved lines.

What does it show?

This study shows:

• rhythms of electrical activity of the brain, their characteristics;
• the presence or absence of foci of increased convulsive readiness and their localization;
• consequences of brain surgery or stroke;
• tumor processes in the brain and their impact on functional activity;
• efficiency drug treatment for epilepsy.

Advantages

The main advantages of the EEG method in medicine:

• high accuracy and efficiency;
• no need for complex preparation;
• not only diagnoses diseases, but also helps to distinguish true disorders from simulations or hysteria;
• allows for research to be carried out when the patient is in serious condition or in a coma;
• is safe and painless for patients of different ages;
• the procedure is inexpensive, equipment is available in almost all hospitals;
• detects abnormalities in brain function early stages, before the appearance of clinical symptoms.

Flaws

The study also has disadvantages:

1. High sensitivity of the device to movements and tremor caused by psycho-emotional stress patient, causes interference, which may complicate diagnosis.
2. You must remain calm and still throughout the entire examination.
3. Particular difficulties arise with children, since it is difficult for young patients to explain the importance of the procedure.

Main indications for use

An encephalogram is performed in the following cases:

• complaints of insomnia, problems falling asleep, waking up at night;
• frequent dizziness, fainting;
• severe causeless headaches;
• epileptic seizures;
• psychopathy, psychosis, nervous breakdowns;
• poisoning with neurotoxic substances (lead, mercury, manganese, pesticides, carbon monoxide and others);
• infectious and viral diseases, affecting the brain(encephalitis, meningitis);
• suspicion of a tumor;
• comatose state of the patient;
• speech delay or mental development in children;
• head and neck injuries;
• all types of strokes;
• diseases of the endocrine system;
• study of the sleep-wake cycle;
• before, after and during surgical interventions on the brain.

Contraindications for EEG

There are no absolute contraindications for EEG of the brain, however, you can undergo the procedure on another day if you have:

• open head injuries;
• postoperative wounds;
• colds or ARVI, flu.

Caution should be exercised in studies in patients with acute mental disorders, as well as violent patients. Exercise tests (sounds, flashing lights), and even the very sight of a cap with electrodes can trigger an attack. If the benefit of the study outweighs the possible risk, then EEG is performed on such patients with preliminary drug sedation in the presence of an anesthesiologist.

Types of research methods

Several EEG research methods are used:

• routine;
• with deprivation;
• long;
• night.

Depending on the duration and purpose, computer encephalography is divided into types:

1. Electroencephalogram of the brain - used on primary stages examinations. Both background activity and stress tests (hyperventilation, sharp sounds, flashes of light).
2. EEG monitoring is a long-term recording of brain activity. Used when it is necessary to cover all possible physiological conditions Central nervous system (sleep, wakefulness, mental work, emotions).
3. Rheoencephalography is a study of cerebral vessels. Diagnostics is based on recording a changing value electrical resistance tissues when a weak current is passed through them high frequency. Gives information about tone and elasticity vascular wall, the value of pulse blood filling.

Routine method

The routine method consists of short-term (approximately 15 minutes) recording of brain biopotentials. This is necessary to examine and evaluate the dominant rhythms, the presence of pathological potentials and paroxysmal activity.

Functional tests are also carried out, during which the reaction to:

• opening - closing of eyes;
• clenching a fist;
• hyperventilation - forced breathing;
• photostimulation - blinking LEDs with eyes closed;
• sharp sounds.

The video shows an EEG with functional tests. Filmed by the channel “Clinic Doctor SAN”.

Encephalography with deprivation

Deprivation encephalography is performed with complete or partial sleep deprivation. Determines epileptic activity in situations that did not arise during provocative tests.

The patient either does not sleep all night or wakes up 2-3 hours earlier than usual. A routine EEG will be performed no earlier than 24 hours after the initial awakening.

Long-term EEG recording

Long-term recording of parameters during sleep is often performed after deprivation EEG, since sleep is a powerful activator for the detection of epiactivity.

Only when performing a sleep EEG can it be carried out differential diagnosis epilepsy with cognitive impairment. Therefore, this type of examination is prescribed if the doctor suspects that changes in the brain occur while the patient is sleeping.

Night EEG

Night EEG recording occurs in a hospital setting as follows:

• begins a few hours before bedtime;
• covers the period of falling asleep and the entire night's sleep;
• ends after natural awakening.

If necessary, additionally:

• video monitoring;
• electrooculography (EOG);
• recording of a cardiogram (ECG);
• electromyograms (EMG);
• spirography.

How to prepare for research

Basic rules of preparation:

1. The day before, you need to thoroughly wash your hair with shampoo. Do not use styling products (varnishes, foams). Hair should be down.
2. Remove earrings, hairpins and all metal objects.
3. Before the examination, discuss with your doctor the use of medications (sleeping pills, tranquilizers, anticonvulsants, etc.). Some may need to be temporarily cancelled. If this is not possible, be sure to warn the specialist who will conduct the EEG so that he takes these circumstances into account when deciphering the results.
4. Avoid alcohol, caffeine-containing and energy drinks(coffee, tea, Pepsi). Do not consume chocolate and cocoa. The same applies to foods and medications with a sedative effect.
5. 2 hours before the procedure you need to eat, but not in excess.
6. It is advisable not to smoke on this day or at least 2-3 hours before the test.
7. Remain calm before and during the procedure. Avoid stress the day before.
8. Get a good night's sleep (except in deprivation studies).

Methodology

The EEG technique is as follows:

1. Electrodes are connected to the electroencephalograph, which are placed in the form of a cap on the surface of the subject’s head. Standard scheme provides for the installation of 21 electrodes. These sensors are designed to capture potential differences between electrodes in different leads and transmit information about them to the main equipment (device, computer) for automatic processing and analysis. They record at a certain frequency - 5–10 pulses per second.
2. The encephalograph processes the received signals, amplifies them and records them on paper in the form of a broken line, very reminiscent of an ECG. During recording, the patient is asked not to move and lie with his eyes closed.
3. After performing a resting EEG, stress tests to assess the brain's response to stress.
4. A neurologist or neurophysiologist must interpret the results and issue a conclusion.

The study is carried out in a specially equipped room, protected from noise and light.

How long does the procedure take?

The EEG time depends on the type of study:

Stages

Algorithm for conducting routine EEG:

1. The patient sits on a chair or lies on the couch, relaxes, and closes his eyes.
2. Electrodes are applied to the head. Places of contact with the skin are lubricated with gel or isotonic solution.
3. After turning on, the device begins to read information and transmit it to the monitor in the form of a graph. This records background activity.
4. Carrying out functional tests necessary to assess the brain’s response to stressful situations.
5. Completion of the procedure. The electrodes are removed, the doctor makes a description and prints out the results.

EEG monitoring

EEG monitoring is carried out to record and recognize brain activity during an epileptic attack.

The patient is hospitalized in a hospital for several days, and all anticonvulsants are discontinued for provocation. Monitoring is carried out with parallel audio and video recording for a day or more.

The method is more effective than conventional EEG for localizing areas of increased seizure activity, as well as for prescribing and monitoring the effectiveness of drug therapy.

Features of the procedure in children

For children under one year of age during sleep: the duration of the procedure is adjusted according to the regime.

Before the study:

• wash your hair with shampoo;
• fed;
• go to bed on schedule.

After one year, the child can be examined while awake. The parents’ task is to psychologically prepare the baby, talk about the procedure and its importance. You can come up with a game of astronauts or superheroes so that the child adapts faster.

EEG is performed for children without stress tests.

What do EEG results show and their interpretation?

The interpretation of the electroencephalogram shows many types of waves in one or more diagrams. Each of them has its own characteristics and will display a certain type of activity.

Decoding the EEG graph

The EEG can be deciphered based on the following parameters:

1. Alpha wave - will show the functioning of the brain in a state of inactive wakefulness. Depression of the α rhythm is caused by anxiety, fear, and activation of autonomic nervous activity.
2. Beta wave - wakefulness mode, active mental work. IN in good condition poorly expressed.
3. Theta wave - natural sleep and falling asleep. An increase in the theta rhythm is observed during prolonged psycho-emotional stress, mental disorders, twilight states characteristic of some neurological diseases, asthenic syndrome, concussion.
4. Delta wave - phase deep sleep. As is the case with the theta rhythm, its appearance during wakefulness indicates neurological disorders.

When describing the EEG, the following are taken into account:

• patient's age;
• general condition (tremor, visual impairment, weakness in the limbs);
• taking medications, anticonvulsant therapy;
• date of last attack;
• symmetry of rhythm amplitudes in different hemispheres;
• rhythm frequency;
• presence or absence of paroxysm;
• synchronicity of rhythms.

Coherence analysis is used to assess the synchrony of the functional activity of brain regions. One of its main advantages is its independence from the amplitude of oscillations of signals from different areas of the brain. This makes it possible to show and evaluate the participation of different areas of the cortex in the performance of certain brain functions.

Electroencephalography is a painless procedure in which the doctor records the electrical activity of the patient's brain using electrodes attached to the scalp.

Every person's brain constantly creates electrical impulses, even during sleep.

This complex brain activity is displayed as several wavy lines on EEG.

Electroencephalography is one of the main diagnostic tests for epilepsy. EEG also plays a very important role in the diagnosis of a number of neurological diseases.

Why is electroencephalography done?

An EEG can confirm, rule out, or provide additional information, necessary for doctors for such diseases:

. Epilepsy and other seizure disorders.
. Traumatic brain injury.
. Brain tumors.
. Encephalitis is inflammation of the brain.
. Encephalopathy of various origins.
. Memory impairment.
. Sleep disorders.
. Stroke.

EEG cannot measure intellectual abilities patient or diagnose mental illness. An EEG may be used to confirm brain death or coma.

Risks associated with the procedure

How should you prepare for electroencephalography?

To prepare for an EEG you should:

Wash your hair the night before the procedure, but do not use any conditioners, creams or hair fixatives.
. Avoid drinking caffeinated drinks for at least six hours before the test.
. Tell your doctor about all medications you are taking that affect the nervous system and, if necessary, stop taking them temporarily.

If you are going to have an EEG done while you are sleeping, your doctor may ask you to sleep less than usual (or not sleep at all) before the test. If you have trouble falling asleep during the procedure, you may be given a sedative.

What happens during the procedure?

In American hospitals, before the procedure, the technician marks with a special pencil those areas of the head to which the electrodes will be attached. These points can be lubricated with a special cream that improves the recording quality.

The technician then applies metal discs (electrodes) to your scalp using a special adhesive. The electrodes are connected by wires to a machine that amplifies the brain's electrical signals and allows them to be recorded as a graph.

In some cases, a kind of elastic “cap” is used, to which electrodes are attached in the right places - this avoids installing electrodes directly on the skin. Once the electrodes are placed, the EEG procedure takes 30 to 60 minutes.

Before the procedure, you need to relax, take a comfortable position and close your eyes. At various points, the technician may ask you to open your eyes, do a simple mental calculation, read text, look at a picture, breathe deeply (hyperventilate), or look at flashes of light.

Your doctor may suggest a video EEG, which will require you to go to the hospital. This is a long-term synchronous recording of EEG, video and audio information. During the test, all movements of your body are recorded on video in parallel with a recording of your electroencephalogram (for example, during an epileptic seizure). This way, the doctor will be able to determine the location in your brain of the lesion that started the attack.

What to do after the procedure?

If you had to enter sedative, then after the EEG you will need to rest for a while. The effect of the drug does not wear off immediately, so after the procedure you should not drive or leave the hospital without an accompanying person.

Electroencephalography results

Your doctor will schedule an appointment to discuss the test results with you. If possible, take a family member or friend with you. You may have difficulty understanding and remembering all the information your doctor explains about results, diagnosis, and treatment.

Write down all the questions you want to ask your doctor in advance. Don't be afraid to ask if you don't understand something during the consultation. Patients often ask the doctor the following questions after an EEG:

What should I do given my results?
. What tests and procedures await me in the future?
. Could something have affected the results of my analysis?
. Do I need to have another EEG and when?

Konstantin Mokanov

To date, electroencephalography- one of the most common and accessible methods for diagnosing changes occurring in the brain. This test of the nervous system evaluates the electrical activity of the brain. During the procedure, locations of brain damage are identified, convulsive readiness, electrical activity. Special preparation for the study is not needed, it has no contraindications and does not cause discomfort.

Indications for electroencephalography

There are certain conditions in which a person definitely needs to see a doctor to have an EEG performed. These include seizures involuntary movements, unusual sensations, inexplicable behavior, fainting. One of the common reasons similar conditions is epilepsy.

Also this study must be carried out after traumatic brain injury. Using this technique, it is possible to determine the location of damage and assess the degree of complexity of brain changes.

So, the established indications for performing electroencephalography include the following conditions:

1. . This procedure allows you to identify areas of the brain that are responsible for triggering seizures. It makes it possible to evaluate the effectiveness medicines, make a decision regarding cessation of drug therapy, assess the severity of brain dysfunction during the non-attack period.
2. Convulsive seizures of unknown etiology.
3. Fainting states.
4. Suspicion of . Electroencephalography allows you to determine the need for additional research.
5. paroxysmal nature.
6. . The study makes it possible to assess the extent of brain damage and the effectiveness of its recovery. Repeated procedures allow you to determine the rate at which symptoms of brain dysfunction disappear.
7. Condition after brain surgery.
8. Inflammatory processes in the central nervous system - cerebral arachnoiditis,.
9. Delayed psychological or speech development unknown etiology.
10. Perinatal disorder of the nervous system.
11. Endocrine pathologies.
12. Behavioral disorders of paroxysmal nature.

In addition, computer EEG allows you to make a diagnosis people who complain of the following symptoms:

1. Hypertension, fluctuations in blood pressure;
2. Neurotic disorders;
3. Vertebro-basilar insufficiency in the case of.

The main advantage of electroencephalography is the fact that there are no contraindications to its implementation. Besides, this procedure It is carried out quite quickly and does not cause discomfort.

Preparation for the procedure

Before the study, you need to wash and dry your hair. Wherein styling products cannot be used– varnishes, sprays, mousses. In addition, you need to undo your braids, remove hair clips, and do not put jewelry on your head. Sometimes the doctor asks you to reduce your sleep duration before performing the test. This is necessary so that a person can fall asleep during electroencephalography. In this case, the duration of sleep is reduced by an average of 3-4 hours. Use sedatives cannot because they may influence the results.

If the procedure is performed on a child, he should be prepared to use a special cap. This is usually done in game form– experts advise playing as astronauts or pilots.

Methodology

In adults

During the study, the patient usually sits in a chair or lies on a bed. At the same time, electrodes are attached to his head - this is done using a special cap-helmet. If there is a need for a long-term study, the electrodes are secured with special paste and glue. When recording, a person must sit or lie still - any movement creates interference, which complicate the decoding of the recording.

The photo shows the process of recording brain activity

During the procedure, tests with hyperventilation and photostimulation are almost always performed. During hyperventilation, the patient should take deep breaths for several minutes. Photostimulation involves exposure to bright light that is directed into the patient's eyes. Both tests make it possible to identify certain disorders that cannot be determined at rest. If necessary, electroencephalography is also performed during sleep. However, the study does not imply introduction into the body medications or exposure to electric current.

If electroencephalography is performed on a person with epilepsy, seizures can be seen on the recording. A specialist can even turn to the patient with a request to provoke an attack - this allows you to specify its origin, type, and assess the prospects for treatment.

During the procedure, video recording may be carried out - in in this case the study is called EEG video monitoring.

The duration of the procedure may vary - this indicator is influenced by the diagnosis, the patient’s condition, the presence of epileptic seizures and the capabilities of the laboratory. In most cases, the necessary information can be obtained within half an hour. But sometimes the doctor increases or decreases the duration of the recording.

In children

This procedure is prescribed to those children who have any developmental disabilities– motor, speech, mental. Even if the child does not have seizures, electroencephalography will reveal disorders in the functioning of the brain.

For children, this procedure is usually prescribed in the following cases:

• To determine the stages of brain development taking into account the age of the child.
• For a thorough study of epilepsy and monitoring the effectiveness of treatment.
• If the child has fainting, seizures, etc.
• In the presence of developmental delays or psycho-emotional disorders.
• When a child’s academic performance declines or a tendency toward inexplicable behavior occurs.
• If you have fears and nightmares.
• After traumatic brain injury.
• For cerebral blood flow disorders.

Of course, performing electroencephalography in young children has certain features. In particular, it can be quite difficult to prevent the child from moving during the procedure. It is recommended to hold him or distract him with toys. In any case, conducting electroencephalography in a child will have inevitable interference that will have to be put up with.

Where can I get tested?

In Moscow there are quite a few medical centers who are conducting this research:

1. Medical center "NIARMEDIC". The cost of the procedure is 2500 rubles. Address: Marshal Zhukov Ave., 38 bldg. 1
2. Medical center Dobromed". The cost of the procedure is 2700 rubles. Address: st. Lyapidevskogo, 14 building 1
3. Spectra Medical Center. The cost of the procedure is 1700 rubles. Address: st. Gerasima Kurina, 16.
4. Medical center "PENTA-CLINIC". The cost of the procedure is 2750 rubles. Address: Chistoprudny Boulevard, 12 bldg. 2.
5. Medical center "Clinic No. 1". The price of the procedure is 2100 rubles. Address: Khimki, st. Moskovskaya, 14

Video about electroencephalography:

Electroencephalography is one of the most accessible methods for studying the state of the brain. It allows you to assess a person’s condition with epilepsy, circulatory disorders in the brain, injuries, etc. In addition, this procedure has non-invasive nature, does not cause pain and does not harm health, so it can be performed even on children.

Electroencephalography (EEG) is a procedure that is performed to study the brain, checking its functions and electrical activity. This method helps to timely detect pathologies of the vessels of the main organ of the central nervous system, malignant and benign tumors, epilepsy. Today, EEG is considered one of the most accurate and proven methods for diagnosing a patient even in an unconscious state. The procedure itself does not have a negative impact on human health, which is why it is often prescribed to infants.

Electroencephalography is a fast and effective method diagnosing the functioning of the main organ of the central nervous system. With its help you can find out the exact condition brain cells and their activity. The procedure does not take much time because it is carried out using the latest equipment.

The electroencephalogram is a curved line resulting from changes in the indicators of the main organ of the central nervous system. Using this diagnostic method, the activity of the cerebral cortex is determined. If a person is healthy, the picture is combined with nervous processes. In the presence of a serious disease of the main organ of the central nervous system, no harmony is achieved.

Why do you need to do an EEG?

Electroencephalography is performed if a brain disorder is suspected. In addition, this research method makes it possible to:

A doctor may prescribe electroencephalography in the following cases:

• concussion or TBI;
• previously conducted surgical interventions, affecting brain activity;
• cysts, tumors of the main organ of the central nervous system;
• convulsions;
• neurological problems: tremors of the limbs, loss of consciousness, loss of balance;
• hypertension;
• delayed speech development, mental retardation.

In addition, electroencephalography of the brain helps to identify diseases such as schizophrenia and epilepsy. Mental disorders can also be detected using this diagnostic method, which is why EEG is often prescribed to people who want to get a driver's license medical certificate, or those who apply for a permit to carry a weapon.

Methods for recording electroencephalography

Recording of bioelectrical signals of the brain is carried out in the following ways:

Electroencephalography performed during night sleep is called EEG monitoring. To properly conduct the study, the patient needs to stay for some time in a hospital setting and also pay for the use of additional equipment.

How to prepare for an EEG of the brain

There is no need to perform any special measures before performing electroencephalography.

From the moment the specialist issues a referral for the procedure, the patient must stop taking anticonvulsants.

Before carrying out this diagnostic method, you need to wash your hair without using styling products. Hair extensions, dreadlocks and braids should be removed or undone. Before starting the procedure, you need to remove all metal elements: rings, bracelets, chains, earrings.

If electroencephalography is performed on a child, parents should explain to him in advance that the procedure is safe and will not cause harm to health. Experts advise parents to take toys with them so that babies do not cry and are not afraid of unfamiliar surroundings.

In order for the study to be successful, the child must be calm. Adult patients need to remember that EEG is not performed on people who are suffering from acute respiratory infections or acute respiratory viral infections at the time of the procedure.

Methodology

During the EEG, a special cap is put on the patient's head, with which the electrodes will be secured. Children need 12 pieces, adults - 21.

EEG electrodes are metal devices with electrically conductive parts inside. Thin wires extend from these elements, connecting them to a device - an electroencephalograph. It amplifies the pulses received from the sensors, which it sends to the computer for further processing. The signals appear on a special monitor in the form of a curve of lines, from which a specialist can determine whether there are areas in the main organ of the central nervous system that are not working correctly.

Decoding EEG in an adult

Patients need to know how the results of the electroencephalogram are analyzed. An accurate diagnosis can only be made by a specialist based on certain signs present in the patient.

Below are several concepts that are taken into account after the doctor interprets the results:

1. Alpha rhythm. Normally, the rate is from 8 to 14 Hz. If a person is healthy, the amplitude between the hemispheres of the brain will fluctuate up to 100 μV. Among the signs vascular pathologies note the following: the difference in oscillations between the hemispheres is more than 30%, the frequency is unstable, the index does not go beyond 50%, the amplitude is below 20 or above 90 μV.
2. Beta rhythm. The indicator is determined in the frontal lobes of the main organ of the central nervous system. Both cerebral hemispheres show an asymmetric amplitude of 3 to 5 μV. In pathology, the difference between the hemispheres is more than 50%, the amplitude exceeds 7 μV, and a sinusoidal rhythm is noted.
3. Theta rhythm And delta rhythm. The indicators are recorded during sleep. If they appear during wakefulness, this may indicate dystrophic changes brain.
4. BEA– this is bioelectrical activity. If a person is healthy, his indicators will be rhythmic and synchronous. In a patient suffering from depression or seizures, BEA values ​​will be unstable.

EEG in childhood

For babies, electroencephalography is usually performed during sleep. This procedure helps to identify various disorders of the main organ of the central nervous system of a young patient. In addition, using EEG, you can check the maturation of brain cells in the first 12 months of a child’s life, as well as identify areas of the organ with pathological changes.

The doctor gives a referral for an EEG in the following cases:

• determining the correctness of the prescribed treatment for epilepsy, febrile seizures, various attacks and adjustments in medication dosage;
• prognosis of brain lesions and assessment of the current state of the main organ of the central nervous system;
• staging accurate diagnosis at ischemic damage nervous system or determining the severity of the disease;
• assessment of the presence of bioelectrical activity of the child’s brain in the first months of life.

It is important to remember that the EEG procedure for a baby is painless and completely safe.

Electroencephalography can reveal serious violations brain and successfully fight them. The earlier the pathology was detected, the greater the chances of full recovery patient.