Disruption of brain activity leads to neurological problems in the child. To identify the cause of unpleasant symptoms, the pediatrician prescribes instrumental diagnostic methods. The most informative is the EEG. The procedure is absolutely painless and safe even for newborns.

What is EEG

Neurons are the structural unit of the brain. Their task is to generate and transmit electrical impulses to the rest of the body's cells. The work of neurons forms the bioelectrical activity of the brain. EEG (electroencephalogram) is a diagnostic method that displays any functional changes in the functioning of the central nervous system and brain structures.

The development of EEG began in the late 30s of the 20th century. The method was constantly improved and became widespread in the 80s. Today, EEG is actively used in psychiatry and neurology to diagnose brain lesions.

Electrodes (sensitivity sensors) are placed on the patient's head. They detect minimal biological currents, bursts of brain activity and transmit information to an electroencephalograph. The device amplifies the potential of electrical impulses, processes the collected data and records them on paper in the form of a curved line.

What does an encephalogram show?

An EEG of the child’s head is carried out according to a standard protocol, tracking brain activity during activity, sleep, or when the body is exposed to irritants. An electroencephalogram answers the following questions:

• are there any disturbances in the functioning of the brain, their severity;
• whether the change in sleep and wakefulness occurs correctly;
• in what lobe are areas of increased activity located;
• whether the chosen treatment regimen is effective;
• Is the dosage of medications calculated correctly?

Why do EEGs for children?

The study is carried out to assess the state of health after loss of consciousness, traumatic brain injury (concussion, brain contusion). The doctor prescribes an encephalogram if the following indications or symptoms are present:

• attention disorder;
• frequent headaches;
• convulsions or seizures;
• suspicion of a tumor or hemorrhage in the brain;
• hot temper and irritability;
• a sharp increase or decrease in blood pressure;
• sleep disorders.

Indications for EEG monitoring

Long-term synchronous recording of brain activity in different states (rest, activity, sleep) is called EEG monitoring. Such an electroencephalogram is performed every few days or months for children who have been diagnosed with the following conditions or diseases:

• epilepsy;
• sleepwalking or insomnia;
• inflammatory diseases of the brain – meningoencephalitis, meningitis;
• rehabilitation period after surgery on the head;
• cerebral palsy - the presence of motor disorders that arose in the peripartum period;
• dropsy of the brain (hydrocephalus) – accumulation of excess fluid in the head;
• enuresis – urinary incontinence;
• autism is a painful mental condition when a child does not tolerate contact with others;
• stuttering;
• delayed mental or physical development;
• memory impairment.

Preparing a child for an EEG

An electroencephalogram is performed in a clinic and requires some preparation. For the procedure to be successful, consider the following rules:

• On the eve of the EEG, wash your child’s hair with shampoo and dry thoroughly. The use of gels and mousses for styling is prohibited.
• Before the doctor's office, remove all metal objects (earrings, hairpins, clips) from your head and let your hair down.
• If the procedure is being done on an infant, feed him or her before starting the procedure. Coordinate with your doctor the time of the EEG, taking into account the sleep schedule and activity of the newborn.
• For children over one year old, an encephalogram is performed in a state of brain activity. To keep your child focused and relaxed, take his favorite book or toy with you to the office.
• Do not feed your baby tightly for at least 2 hours before the procedure. Strong tea, chocolate, and sweets are prohibited during the day.
• If an appointment is scheduled medicines, inform the doctor who will interpret the analysis in advance. Some medications need to be stopped 1-3 days before the child has an EEG.

Methods for performing electroencephalography

Brain examinations in children are carried out in three ways: at rest, routinely, with complete or partial sleep deprivation. All procedure options follow this scenario:

• First stage- Preparation. Children from one year old are placed on a couch or seated on a chair, infants remain in the arms of their mother. Electrical conductive gel is applied to the child’s head, a mesh helmet is put on, or 12 electrodes are attached.

• Second phase- conducting research. To eliminate excessive activity of the nervous system, the room is darkened - the curtains are lowered or the lights are turned off. Turn on the device. A video recording is made synchronously with the encephalogram to record the patient’s movements.

• Third stage– interpretation of the results. The doctor studies the record and compares its data with the age norm. Gives conclusions about brain activity and the functioning of the central nervous system.

Routine method

The first study, which is carried out after examination by a pediatrician or neurologist. A routine encephalogram helps to establish paroxysmal conditions and make the correct diagnosis. The procedure lasts 10-15 minutes and includes the following functional tests:

• photostimulation– eye strain with rhythmically flashing electrodes;
• hyperventilation– the child is asked to take several deep breaths and exit slowly;
• audio stimulation– the study is carried out with loud background sound;
• with monotonous light switching on and off.

Child's sleep EEG

Conducted during “quiet hour”. The technique helps to identify disturbances in the functioning of the brain centers that appear after falling asleep. If deep structural damage is suspected, diagnostics are carried out at night. Data recording begins before falling asleep and ends after natural awakening.

With sleep deprivation

An encephalogram with deprivation (reduced sleep duration) is prescribed to children only if the previous diagnostic options did not give a detailed answer. The duration of wakefulness depends on the age of the child:

• For children preschool age give 4-6 hours of rest, then perform an EEG.
• Child 7-11 years old They go to bed at 6-8 o'clock in the evening, and wake up at 12. An encephalogram is prescribed at 8-9 o'clock in the morning.
• Children over 12 years old An EEG is done after sleep deprivation for 18 hours or more.

To facilitate the electroencephalogram, partial deprivation is used. Extend the evening period of wakefulness by 2-3 hours and provide an early rise at 4-5 am. After the procedure, the child is placed in a rest room under the supervision of medical staff.

Decoding the EEG of the brain in children

The results of the study are ready the next day. A neurologist analyzes the data. Decoding EEG in children takes into account the following criteria:

• Oscillation frequency. It is recorded in Hertz (Hz) and describes the change in wave state per second.
• Range (amplitude) of curves. Recorded in microvolts (µV). Shows the gap between the peaks of waves of opposite activity.
• Phase. Characterizes the current state of the brain.

When decoding, the rhythm of cardiac activity and the coherence of the neurons of the hemispheres (right and left) are additionally taken into account. After studying all the factors and clinical symptoms, the doctor describes brain activity and gives a conclusion that refutes or confirms the primary diagnosis.

Normal indicators

Rhythm is responsible for the type of brain activity. It is the main evaluation criterion. For ease of decoding the results of the encephalogram, each rhythm is assigned its own letter of the Greek alphabet:

• Alpha. Determined at rest. Its frequency is 8-14 Hz, amplitude is up to 100 μV. The rhythm gradually fades away when mental activity begins, eyes open, and exposure to external stimuli. Registered in the parietal and occipital zones.
• Beta. Appears when the child is in an active state, during the activation of memory, mental activity, and when experiencing emotions. Normal rhythm frequency is 13-30 Hz, range is 3-5 µV. The rhythm occurs in the area of ​​the central and anterior gyri.
• Delta. Appears on the EEG during sleep. Registered in all parts of the brain. Frequency – 1-4 Hz, amplitude – 30-40 µV.
• Theta. It is a key sleep rhythm in children 3-6 years old. Characterized by a frequency of 4-8 Hz and a swing of 30-35 µV. Appears in the hippocampus and frontal areas of the brain.

When deciphering the parameters, the age of the child is taken into account. Normally, the following waves predominate:

• In premature babies, peaks of delta and theta rhythms with a range of up to 25 μV are repeated every 3-15 seconds.
• In full-term newborns, these indicators during the waking stage are 5 Hz and 55-60 μV, during REM sleep - 5-7 Hz with a low amplitude, and during quiet sleep - a high range of delta waves.
• From the age of six months, these rhythms slowly fade away, alpha and beta waves increase.
• During puberty, alpha rhythms predominate over the rest.
• At the age of 18, the final formation of brain activity and stabilization of indicators occurs.

Deviations from the norm and their meanings

Violation of rhythm and asymmetry of the hemispheres indicates the presence of pathologies. The type of disease can be determined by deviations in a particular rhythm. Preliminary diagnoses for deviations of the alpha wave from the norm are as follows:

• increased frequency, rhythm instability – concussion, brain injury;
• absence of alpha wave – mental retardation;
• slow frequency, but normal synchrony - increased impressionability, mental excitability in the child;
• absence or weakening of the alpha rhythm, a sharp surge in the wave – epilepsy, hysterical neurosis;
• high amplitude, enhanced reaction to deep inspiration, displacement of the recording point from the occipital part of the brain - delayed psychomotor, speech and intellectual development.

Deviations in beta parameters indicate the following violations:

• increased activity – nervousness, development of depression;
• flash wave activity – inflammatory diseases of the brain;
• rhythm frequency up to 18 Hz, amplitude above 30 μV – delayed development of psychomotor skills;
• the appearance of a beta rhythm in uncharacteristic parts of the brain is a disorder of the central nervous system (neurosis).

Violations of delta and theta rhythm parameters indicate the following pathologies:

• increased wave amplitude – brain tumors;
• fixation large quantity rhythms in the back of the head, increased frequency during hyperventilation - delayed psychomotor development;
• increased amplitude against the background of constant theta and delta waves – acquired mental retardation (dementia);
• sudden changes in rhythm - neurosis;
• high-frequency flashes - irritation of the brain centers that are responsible for excitability, excitement, irritation.

When deciphering the results, any nuances are taken into account. If there are deviations, the doctor pays attention to the following parameters:

• Relatively rhythmic biological activity of the brain (BAE) indicates possible migraines.
• BAE with paroxysms ( high peaks waves) – a tendency to epilepsy, convulsive seizures.
• Irritation (irritation) of individual brain structures is a circulatory disorder. Occurs after injuries, with high intracranial pressure. Irritative changes occur with meningitis and encephalitis.
• Increased response to irritating tests, paroxysm in all parts of the brain - attention deficit disorder, hyperactivity of the child.
• Desynchronization or hypersynchronization of rhythms. Characteristic of diseases of the cerebral vessels of the brain.
• Asymmetry of the work of the right and left hemispheres - a cyst or brain tumor.

Contraindications to the procedure

There are no absolute prohibitions on the procedure. An encephalogram of the brain is not prescribed for a child if there is open wounds on the head due to the inability to connect the electrodes correctly. It is also recommended to reschedule the procedure if the child has an acute infectious viral disease.

Price

You can undergo the examination in public hospitals or private clinics where special equipment is available. Cost of the service in Moscow:

• European MC on the street. Shchepkina – 21,300 rubles;
• Family Clinic – 1280 rubles;
• JSC Medicine - 12,900 rubles;
• NIARMedik – 3000 rub.;
• Clinical Hospital Lapino - 3900-4000 rubles;
• MedicCity – 2700 rub.

Video

Unreasonable headaches bad dream, fatigue, irritability - all this can be a consequence of poor blood circulation in the brain or abnormalities in the nervous system. For timely diagnosis of negative disorders in blood vessels, EEG - electroencephalogram of the brain is used. This is the most informative and accessible examination method, which does not harm the patient and can be safely used in childhood.

An electroencephalogram is used to examine the blood vessels of the brain.

EEG of the brain - what is it?

An encephalogram of the head is a study of a vital organ by exposing its cells to electrical impulses.

The method determines the bioelectrical activity of the brain, is very informative and the most accurate, as it shows the complete clinical picture:

• level and distribution of inflammatory processes;
• the presence of pathological changes in blood vessels;
• early signs of epilepsy;
• tumor processes;
• the degree of impairment of brain functioning due to pathologies of the nervous system;
• consequences of a stroke or surgery.

EEG helps identify signs of epilepsy

EEG helps monitor changes in the brain, both structural and reversible. This allows you to monitor the activity of a vital organ during therapy and adjust the treatment of identified diseases.

Where can the examination be done and the price?

Electroencephalography can be done in any specialized medical center. Institutions can be either public or private. Depending on the form of ownership, the level of qualifications of the clinic, as well as the equipment used, prices for the procedure vary significantly.

In addition, the following factors influence the cost of an encephalogram:

• duration of the diagnostic procedure;
• carrying out functional tests;
• usage special programs(for mapping, studying epileptic impulses, comparing zones of symmetrical brain zones).

average cost for an electroencephalogram is 2680 rubles. Prices in Russian clinics start at 630 rubles.

Indications for an electroencephalogram

Before prescribing an encephalography to a patient, a specialist examines the person and analyzes his complaints.

The following conditions may be the reason for an EEG:

• sleep problems - insomnia, frequent awakenings, sleepwalking;
• regular dizziness, fainting;
• fatigue and constant feeling of tiredness;
• causeless headaches.

The day before the examination you should not eat chocolate.

How is an electroencephalogram performed?

The electrical activity of brain cells is assessed using an encephalograph. It consists of sensors (electrodes) that resemble a swimming pool cap, a block and a monitor, where monitoring results are transmitted. The study is carried out in a small room that is isolated from light and sound.

The EEG method takes little time and includes several stages:

1. Preparation. The patient takes a comfortable position - sits on a chair or lies down on the couch. Then the electrodes are applied. The specialist puts a “cap” with sensors on the person’s head, the wiring of which is connected to the device, which records the bioelectric impulses of the brain.
2. Study. After turning on the encephalograph, the device begins to read information, transmitting it to the monitor in the form of a graph. At this time, the power of electric fields and its distribution in different parts of the brain can be recorded.
3. Use of functional tests. This is performing simple exercises - blinking, looking at flashes of light, breathing rarely or deeply, listening to sharp sounds.
4. Completion of the procedure. The specialist removes the electrodes and prints out the results.

During the EEG, the patient take a comfortable position and relax

If the study requires a more in-depth study (day monitoring), breaks in the procedure are possible. The sensors are disconnected from the wires, and the patient can go to the toilet, have a snack, and communicate with relatives.

Features of EEG in children

Monitoring brain activity in children has its own nuances. If the child is under one year old, then the study is carried out in a state of sleep. To do this, the baby should be fed and then rocked to sleep. After a year, children are examined while awake.

For the procedure to be successful, it is important to prepare the child:

1. On the eve of the examination, it is recommended to talk with the child and tell him about the upcoming procedure. You can come up with a game to make your baby adapt faster by calling him a superhero or an astronaut.
2. Take your favorite toys with you. This will help distract the fidget and calm him down at the right time.
3. Feed the child before starting the study.
4. Discuss with the doctor the time of manipulation and choose convenient hours when the child is awake and does not feel sleepy.
5. On the eve of the examination, wash your baby’s hair well. If it is a girl, unwind her hair and remove all jewelry (immediately before monitoring).

If your child takes certain medications on an ongoing basis, you should not give them up. It is enough to inform your doctor about this.

How long does the procedure take?

A regular encephalogram is a routine EEG or diagnosis of a paroxysmal state. The duration of this method depends on the area being studied and the application in monitoring functional tests. On average, the procedure does not take more than 20–30 minutes.

During this time, the specialist manages to:

• rhythmic photostimulation of different frequencies;
• hyperventilation (breaths are deep and rare);
• load in the form of slow blinking (open and close your eyes at the right moments);
• detect a number of functional changes of a hidden nature.

If the information received is insufficient, specialists may resort to a more in-depth examination.

There are several options:

1. Encephalogram of night sleep. A long-term period is studied - wakefulness before bedtime, dozing, going to bed and waking up in the morning.
2. EEG with deprivation. The method involves depriving the patient of sleep at night. He should wake up 2-3 hours earlier than usual and stay awake the next night.
3. Continuous electroencephalogram. Monitoring of bioelectrical activity of the brain occurs during daytime sleep. The method is very effective in cases of suspected paroxysm (seizure) or identifying the causes of sleep disturbances.

Based on the EEG method, the duration of such a study can vary from 20 minutes to 8–15 hours.

Decoding EEG indicators

A qualified diagnostician interprets the results of the encephalogram.

When deciphering, the patient’s clinical symptoms and basic EEG indicators are taken into account:

• state of rhythms;
• symmetry of the hemispheres;
• changes in gray matter when using functional tests.

The results obtained are compared with established standards, and deviations (dysrhythmia) are recorded in the conclusion.

Table “EEG interpretation”

Indicators	Norm	Deviations	Possible pathological processes
			In adults	The child has
Alpha rhythm	8–15 Hz – the rhythm is regular, observed at rest or with eyes closed. Maximum concentration of impulses in the area of ​​the back of the skull and crown	The appearance of alpha waves in the frontal part of the brain. The rhythm becomes paroxysmal. Violation of the stability of frequency and symmetry of the hemispheres (above 30%)	Development of tumor processes, appearance of cysts. Condition of stroke or heart attack. Presence of serious skull injuries	Neuroses of varying degrees Psychopathy Delayed psychomotor development – ​​neurophysiological immaturity of brain cells
Beta rhythm	12–30 Hz – reflects excitement, anxiety, nervousness and depression. Sensitive to sedatives. Localized in the suprafrontal lobes	Diffuse beta waves Amplitude increase Violations of hemispheric symmetry Paroxysmal discharges	Concussion Encephalitis
Delta rhythm	0.5–3 Hz – records the state of natural sleep. Does not exceed 15% of all rhythms. Amplitude not higher than 40 µV	High amplitude The appearance of delta and theta waves outside sleep, localization in all parts of the brain High frequency rhythms	Irritation of the structural centers of gray matter (irritation) Dementia
Theta rhythm	3.5–8 Hz – reflects the normal state during sleep in adults. In children, this indicator is dominant

Based on the study of rhythms, a conclusion is made about the bioelectrical activity of the brain. In a normal state, it should be without attacks (paroxysms), have regular rhythm and synchronicity. Diffuse (moderate) changes are acceptable if other pathological disorders are not identified (irritation of parts of the brain, dysfunction of regulatory systems, disorganization of rhythms). In this case, the specialist can prescribe corrective treatment and monitor the patients.

It is important to consider that moderate changes in rhythms (delta and theta), the appearance of paroxysmal discharges and epileptic activity on the EEG in children and people under 21 years of age are the norm and do not relate to deviations in the structures of a vital organ.

Validity period of electroencephalography

Encephalogram results are valid from 1 to 6 months.

Deadlines may vary depending on:

• diseases;
• therapy (repeated EEG is needed when adjusting treatment or assessing the effectiveness of prescribed drugs);
• information content of the chosen EEG method.

If a person is healthy or the electroencephalogram has slight changes, the conclusion is valid for six months. In case of serious abnormalities or the need for regular monitoring of brain activity (especially in children), the EEG period may be a month or a week.

The use of electroencephalography to assess the state of brain activity makes it possible to identify a number of pathologies in the early stages. The EEG method makes it possible to determine developmental delay in children even before the first manifestations. In addition, the procedure is completely harmless, it can be done an unlimited number of times, even in early childhood. An encephalogram is used not only to identify abnormalities, but also as a tool for monitoring the effectiveness of treatment.

Electroencephalography of the brain is a method in electrophysiology that records the bioelectrical activity of brain neurons by removing them from the surface of the head.

The brain has bioelectrical activity. Each nerve cell of the central nervous system is capable of creating an electrical impulse and transmitting it to neighboring cells using axons and dendrites. There are approximately 14 billion neurons in the cerebral cortex, each of which creates its own electrical impulse. Individually, each impulse does not represent anything, but every second the total electrical activity of 14 billion cells creates an electromagnetic field around the brain, which is recorded by a brain electrocyfogram.

EEG monitoring reveals functional and organic pathologies of the brain, such as epilepsy or sleep disorders. Electroencephalography is carried out using a device - an electroencephalograph. Is it harmful to perform the procedure with an electroencephalograph: the study is harmless, since the device does not send a single signal to the brain, but only records outgoing biopotentials.

An electroencephalogram of the brain is a graphical representation of the electrical activity of the central nervous system. It depicts waves and rhythms. Their qualitative and quantitative indicators are analyzed and a diagnosis is issued. The analysis is based on rhythms—electrical oscillations of the brain.

Computer electroencephalography (CEEG) is a digital way of recording brain wave activity. Outdated electroencephalographs display the graphical result on a long tape. QEEG displays the result on the computer screen.

The following brain rhythms are identified, recorded on the electroencephalogram:

Alpha rhythm.

Its amplitude increases in a state of quiet wakefulness, for example, when resting or in a dark room. Alpha activity on the EEG decreases when the subject moves on to active work that requires high concentration of attention. People who have been blind all their lives have an absence of alpha rhythm on the EEG.

Beta rhythm.

It is characteristic of active wakefulness with high concentration of attention. Beta activity on the EEG is most clearly expressed in the projection of the frontal cortex. Also on the electroencephalogram, the beta rhythm appears with the sudden appearance of an emotionally significant new stimulus, for example, the appearance of a loved one after several months of separation. The activity of the beta rhythm also increases during emotional stress and work that requires high concentration.

Gamma rhythm.

This is a collection of low-amplitude waves. The gamma rhythm is a continuation of beta waves. Thus, gamma activity is recorded under high psycho-emotional stress. The founder of the Soviet school of neuroscience, Sokolov, believes that the gamma rhythm is a reflection of the activity of human consciousness.

Delta rhythm.

These are high amplitude waves. It is recorded in the phase of deep natural and medicated sleep. Delta waves are also recorded in a coma state.

Theta rhythm.

These waves are generated in the hippocampus. Theta waves appear on the EEG in two states: the rapid eye movement phase and during high concentration. Harvard professor Schacter argues that theta waves appear during altered states of consciousness, such as deep meditation or trance.

Kappa rhythm.

It is registered in the projection of the temporal cortex of the brain. It appears in the case of suppression of alpha waves and in a state of high mental activity of the subject. However, some researchers associate the kappa rhythm with normal eye movement and regard it as an artifact or side effect.

Mu rhythm.

Appears in a state of physical, mental and emotional peace. It is registered in the projection of the motor lobes of the frontal cortex. Mu waves disappear during visualization or during physical activity.

Normal EEG in adults:

• Alpha rhythm: frequency – 8-13 Hz, amplitude – 5-100 µV.
• Beta rhythm: frequency – 14-40 Hz, amplitude – up to 20 µV.
• Gamma rhythm: frequency – 30 or more, amplitude – no more than 15 µV.
• Delta rhythm: frequency – 1-4 Hz, amplitude – 100-200 µV.
• Theta rhythm: frequency – 4-8 Hz, amplitude – 20-100 µV.
• Kappa rhythm: frequency – 8-13 Hz, amplitude – 5-40 µV.
• Mu rhythm: frequency – 8-13 Hz, amplitude – on average 50 µV.

Conclusion The EEG of a healthy person consists of precisely these indicators.

Types of EEG

Exist the following types electroencephalography:

1. Night EEG of the brain with video support. During the study, electromagnetic waves of the brain are recorded, and video and audio examination allows assessing behavioral and motor activity studied during sleep. Daily EEG monitoring of the brain is used when it is necessary to confirm the diagnosis of epilepsy of complex origin or establish the causes of convulsive seizures.
2. Brain mapping. This type allows you to create a map of the cerebral cortex and mark pathological emerging foci on it.
3. Electroencephalography with biofeedback. It is used to train control of brain activity. Thus, when a subject is given sound or light stimuli, he sees his encephalogram and tries to mentally change its indicators. There is little information about this method and it is difficult to assess its effectiveness. It is said to be used for patients who are resistant to antiepileptic drugs.

Indications for use

Electrophysiological research methods, including an electroencephalogram, are indicated in the following cases:

• A convulsive seizure was detected for the first time. Convulsive attacks. Suspicion of epilepsy. In this case, the EEG reveals the cause of the disease.
• Assessing the effectiveness of drug therapy in well-controlled and drug-resistant epilepsy.
• Suffered traumatic brain injuries.
• Suspicion of a neoplasm in the cranial cavity.
• Sleep disorders.
• Pathological functional states, neurotic disorders, for example, depression or neurasthenia.
• Assessment of brain performance after stroke.
• Assessment of involutional changes in elderly patients.

Contraindications

EEG of the brain is an absolutely safe non-invasive method. It records electrical changes in the brain by reading potentials with electrodes that do not cause negative influence on the body. Therefore, an electroencephalogram has no contraindications and can be performed on any patient who has a brain.

How to prepare for the procedure

How to prepare:

• For 3 days, the patient must abandon anticonvulsant therapy and other drugs that affect the functioning of the central nervous system (tranquilizers, anxiolytics, antidepressants, psychostimulants, sleeping pills). These drugs affect the inhibition or excitation of the cerebral cortex, which is why the EEG will show unreliable results.
• In 2 days you need to create a small diet. Avoid drinks containing caffeine or other nervous system stimulants. It is not recommended to drink coffee, strong tea, Coca-Cola. You should also limit dark chocolate.
• Preparation for the test includes washing your hair: recording sensors are placed on the scalp, so clean hair will ensure better contact.
• Before the study, it is not recommended to apply hairspray, gel or other cosmetical tools, changing the density and consistency of hair.
• Two hours before the test, you should not smoke: nicotine stimulates the central nervous system and can distort the results.

Preparation for an EEG of the brain will show a good and reliable result that does not require repeated testing.

Description of the process using the example of EEG video monitoring. The study can be carried out during the day or at night. The first one usually starts from 9:00 to 14:00. The night option usually starts at 21:00 and ends at 9:00. Lasts all night.

Before starting the diagnosis, the patient is put on an electrode cap, and a gel is applied under the sensors to improve conductivity. The headdress is fixed on the head with clasps and fasteners. The cap is placed on the person's head during the entire procedure. The EEG cap for children under 3 years of age is additionally strengthened due to the small size of the head.

All research is carried out in an equipped laboratory, where there is a restroom, refrigerator, kettle and water. You will talk with a doctor who needs to find out your current state of health and readiness for the procedure. First, part of the study is carried out during active wakefulness: the patient reads a book, watches TV, listens to music. The second period begins during sleep: the bioelectrical activity of the brain is assessed during the slow and fast phases of sleep, behavioral acts during dreams, the number of awakenings and extraneous sounds, for example, snoring or talking during sleep, are assessed. The third part begins after waking up and records brain activity after sleep.

Photostimulation with EEG may be used during this process. This procedure is necessary to assess the difference between brain activity during deprivation of external stimuli and during the presentation of light stimuli. What is noted on the electroencephalogram during photostimulation:

1. decrease in rhythm amplitude;
2. photomyoclonus - polyspikes appear on the EEG, which are accompanied by twitching of the facial muscles or muscles of the limbs;

Photostimulation can provoke epileptiform responses or an epileptic seizure. Using this method, hidden epilepsy can be diagnosed.

To diagnose hidden epilepsy, a hyperventilation test with EEG is also used. The subject is asked to breathe deeply and regularly for 4 minutes. This method of provocation makes it possible to detect epileptiform activity on the electroencephalogram or even provoke a generalized convulsive seizure of an epileptic nature.

Daytime electroencephalography is done in a similar way. It is carried out in a state of active or passive wakefulness. The time required is one to two hours.

How to do an EEG without finding anything? Electrical activity of the brain reveals subtle changes in brain wave activity. Therefore, if there is a pathology, for example, epilepsy or circulatory disorders, a specialist will identify it. Normal and pathological EEGs are always visible, despite all attempts to hide unpleasant results.

When it is impossible to transport the patient, an EEG of the brain is performed at home.

For children

Children undergo EEG using a similar algorithm. The child is put on a mesh cap with fixed electrodes and placed on his head, having first treated the surface of the head with conductive gel.

How to prepare: the procedure does not cause any discomfort or pain. However, children are still scared due to the fact that they are in a doctor’s office or in a laboratory, which already initially forms the idea that it will be unpleasant. Thus, before the procedure, the child should be explained what exactly will happen to him and that the examination is not painful.

A hyperactive child may be prescribed a sedative or sleeping pill before the test. This is necessary so that during the study unnecessary movements of the head or neck do not remove the contact between the sensors and the head. For an infant the study is carried out in a dream.

Result and transcript

An EEG of the brain provides a graphical result of the bioelectrical activity of the central nervous system. This could be a recording on tape or an image on a computer. Decoding an electroencephalogram is an analysis of wave and rhythm indicators. Thus, the obtained indicators are compared with normal frequency and amplitude.

The following types of EEG disorders exist:

Normal indicators, or organized type. Characterized by a main component (alpha waves) that have regular and regular frequencies. The waves are smooth. Beta rhythms are predominantly of medium or high frequency with small amplitude. There are few or almost no slow waves.

• The first type is divided into two subtypes:
  • a variant of the ideal norm; here the waves are not changed in principle;
  • subtle disorders that do not affect the functioning of the brain and the mental state of a person.
• Hypersynchronous type. Characterized by a high wave index and increased synchronization. However, the waves retain their structure.
• Disturbance of synchronization (flat type of EEG, or desynchronous type of EEG). The severity of alpha activity decreases with an increase in beta wave activity. All other rhythms are within normal limits.
• Disorganized EEG with pronounced alpha waves. It is characterized by high activity of the alpha rhythm, but this activity is irregular. A disorganized type of EEG with an alpha rhythm does not have sufficient activity and can be recorded in all areas of the brain. High activity of beta, theta and delta waves is also recorded.
• Disorganization of the EEG with a predominance of delta and theta rhythms. Characterized by low alpha wave activity and high slow rhythm activity.

First type: electroencephalogram shows normal brain activity. The second type reflects weak activation of the cerebral cortex, more often indicating a disruption of the brain stem with a violation of the activating function of the reticular formation. The third type reflects increased activation of the cerebral cortex. The fourth type of EEG shows dysfunction in the functioning of the regulatory systems of the central nervous system. The fifth type reflects organic changes in the brain.

The first three types in adults occur either normally or with functional changes, for example, in neurotic disorders or schizophrenia. The last two types indicate gradual organic changes or the onset of brain degeneration.

Changes in the electroencephalogram are often nonspecific, but some pathognomonic nuances make it possible to suspect a specific disease. For example, irritative changes in the EEG are typical nonspecific indicators that can manifest themselves in epilepsy or vascular diseases. With a tumor, for example, the activity of alpha and beta waves decreases, although this is considered irritative changes. Irritative changes have the following indicators: alpha waves intensify, beta wave activity increases.

Focal changes can be recorded on the electroencephalogram. Such indicators indicate focal dysfunction of nerve cells. However, the nonspecificity of these changes does not allow us to draw a limiting line between cerebral infarction or suppuration, since in any case the EEG will show the same result. However, it is known for sure: moderate diffuse changes indicate an organic pathology, not a functional one.

EEG is of greatest value for diagnosing epilepsy. Between individual attacks, epileptiform phenomena are recorded on the tape. In addition to obvious epilepsy, such phenomena are recorded in people who have not yet been diagnosed with epilepsy. Epileptiform patterns consist of spikes, sharp rhythms, and slow waves.

However, some individual characteristics of the brain can produce spikes even when the person does not have epilepsy. This happens in 2%. However, in people suffering from falling illness, epileptiform spikes are recorded in 90% of all diagnostic cases.

Also, using electroencephalography, it is possible to determine the spread of convulsive brain activity. Thus, EEG allows us to establish: pathological activity extends to the entire cerebral cortex or only to some of its areas. This is important for the differential diagnosis of forms of epilepsy and the choice of treatment tactics.

Generalized seizures (convulsions throughout the body) are associated with bilateral abnormal activity and polyspikes. So, the following relationship has been established:

1. Partial epileptic seizures correlate with spikes in the anterior temporal gyrus.
2. Sensory impairment during or before epilepsy is associated with abnormal activity near the Rolandic fissure.
3. Visual hallucinations or decreased visual accuracy during or before a seizure are associated with spikes in the projection of the occipital cortex.

Some syndromes on EEG:

• Hypsarrhythmia. The syndrome is manifested by a disturbance in the rhythm of waves, the appearance of sharp waves and polyspikes. Manifests itself in infantile spasms and West syndrome. Most often it confirms a diffuse disorder of the regulatory functions of the brain.
• The appearance of polyspikes with a frequency of 3 Hz indicates a minor epileptic seizure, for example, such waves appear in a state of absence. This pathology is characterized by a sudden loss of consciousness for several seconds while muscle tone is preserved and there is no reaction to any external stimuli.
• A group of polyspike waves indicates a classic generalized epileptic seizure with tonic and clonic seizures.
• Low-frequency spike waves (1-5 Hz) in children under 6 years of age reflect diffuse changes in the brain. In the future, such children are susceptible to psychomotor development disorders.
• Commissures in the projection of the temporal gyri. They may be associated with benign epilepsy in children.
• Dominant slow-wave activity, in particular delta rhythms, indicates organic brain damage as the cause of seizures.

Electroencephalography data can be used to judge the state of consciousness in patients. Thus, there is a wide variety of specific signs on the tape, which can be used to suggest a qualitative or quantitative impairment of consciousness. However, here too nonspecific changes often appear, as, for example, with encephalopathy of toxic origin. In most cases, pathological activity on the electroencephalogram reflects the organic nature of the disorder rather than functional or psychogenic.

What signs are used to determine impairment of consciousness on the EEG against the background metabolic disorders:

1. In a state of coma or stupor, high beta wave activity indicates drug intoxication.
2. Triphasic broad waves in the projection of the frontal lobes indicate hepatic encephalopathy.
3. A decrease in the activity of all waves indicates a decrease in the functionality of the thyroid gland and hypothyroidism in general.
4. In a state of coma in the background diabetes mellitus The EEG shows wave activity in an adult that resembles epileptiform phenomena.
5. In a state of lack of oxygen and nutrients (ischemia and hypoxia), the EEG produces slow waves.

The following parameters on the EEG indicate a deep coma or possible death:

• Alpha coma. Alpha waves are characterized by paradoxical activity, this is especially clearly recorded in the projection of the frontal lobes of the brain.
• About a strong decline or complete absence brain activity is indicated by spontaneous neural bursts that alternate with occasional high-voltage waves.
• “Electrical silence of the brain” is characterized by generalized polyspikes and island-wave rhythms.

Brain disease due to infection manifests itself in nonspecific slow waves:

1. Herpes simplex virus or encephalitis is characterized by slow rhythms in the projection of the temporal and frontal cortex of the brain.
2. Generalized encephalitis is characterized by alternating slow and acute waves.
3. Creutzfeldt-Jakob disease manifests itself on the EEG as three- and two-phase sharp waves.

EEG is used in diagnosing brain death. Thus, with the death of the cerebral cortex, the activity of electrical potentials decreases as much as possible. However, a complete stop of electrical activity is not always permanent. Thus, the dulling of biopotentials can be temporary and reversible, as, for example, with a drug overdose, respiratory arrest

In the vegetative state of the central nervous system, the EEG shows isoelectric activity, which indicates the complete death of the cerebral cortex.

For children

How often can it be done: the number of procedures is not limited, since the study is harmless.

EEG in children has its own peculiarities. An electroencephalogram shows in children under one year old (full-term and painless child) periodic low-amplitude and generalized slow waves, predominantly delta rhythm. This activity has no symmetry. In the projection of the frontal lobes and parietal cortex, the amplitude of the waves increases. Slow wave activity on the EEG in a child of this age is the norm, since the regulatory systems of the brain have not yet been formed.

EEG norms in children aged from one to three months: the amplitude of electrical waves increases to 50-55 μV. There is a gradual establishment of the rhythm of the waves. EEG results in three-month-old children: a mu rhythm with an amplitude of 30-50 μV is recorded in the frontal lobes. The asymmetry of waves in the left and right hemispheres is also recorded. By 4 months of life, the rhythmic activity of electrical impulses is recorded in the projection of the frontal and occipital cortex.

Interpretation of EEG in children one year of age. The electroencephalogram shows oscillations of the alpha rhythm, which alternate with slow delta waves. Alpha waves are characterized by instability and lack of a clear rhythm. In 40% of the entire electroencephalogram, the theta rhythm and delta rhythm (50%) dominate.

Decoding indicators for two-year-old children. Alpha wave activity is recorded in all projections of the cerebral cortex as a sign of gradual activation of the central nervous system. Beta rhythm activity is also noted.

EEG in children 3-4 years old. The theta rhythm dominates in the electroencephalogram; slow delta waves predominate in the projection of the occipital cortex. Alpha rhythms are also present, but they are hardly noticeable against the background of slow waves. With hyperventilation (active forced breathing), sharpening of the waves is noted.

At the age of 5-6 years, the waves stabilize and become rhythmic. Alpha waves already resemble alpha activity in adults. Slow waves no longer overlap alpha waves in their regularity.

EEG in children 7-9 years old records the activity of alpha rhythms, but to a greater extent these waves are recorded in the projection of the crown. Slow waves recede into the background: their activity is no more than 35%. Alpha waves make up approximately 40% of the total EEG, and theta waves make up no more than 25%. Beta activity is recorded in the frontal and temporal cortex.

Electroencephalogram in children 10-12 years old. Their alpha waves are almost mature: they are organized and rhythmic, dominating throughout the entire graphic tape. Alpha activity makes up approximately 60% of all EEG. These waves show the greatest voltage in the region of the frontal, temporal and parietal lobes.

EEG in 13-16 year old children. The formation of alpha waves has completed. The bioelectrical activity of the brain in healthy children acquired the characteristics of the brain activity of a healthy adult. Alpha activity dominates in all parts of the brain.

Indications for the procedure in children are the same as in adults. For children, EEG is prescribed primarily to diagnose epilepsy and determine the nature of seizures (epileptic or non-epileptic).

Convulsions of non-epileptic nature are manifested by the following indicators on the EEG:

1. Flashes of delta and theta waves are synchronous in the left and right hemispheres, they are generalized and are most expressed in the parietal and frontal lobe.
2. Theta waves are synchronous on both sides and are characterized by low amplitude.
3. Arch-shaped spikes are recorded on the EEG.

Epileptic activity in children:

• All waves become sharpened, they are synchronous on both sides and generalized. Often occur suddenly. May occur in response to opening the eyes.
• Slow waves are recorded in the projection of the frontal and occipital lobes. They are registered during wakefulness and disappear if the child closes his eyes.

Electroencephalography – effective method studies of the state of the nervous system. The EEG of the brain is of great importance: decoding the indicators of this examination allows you to analyze the performance of the brain as a whole, identify changes in its functioning, and identify pathologies and disorders. To carry it out, a cap with electrodes is placed on a person’s head, which record the activity of all parts of the brain. The resulting curve, on which biocurrents are recorded, is called an electroencephalogram. This study serves as the basis for making a diagnosis and prescribing therapy, helps to monitor the dynamics and progress of treatment.

Electroencephalography is effective in cases of suspected brain tumors, epilepsy, and vascular diseases. It also reflects disturbances in brain activity due to traumatic brain injury and inflammatory processes. EEG is also valuable in the case of some mental and neurotic abnormalities and disorders. In addition, electroencephalography reflects age-related changes in the functioning of the nervous system.

Based on the results of the EEG, a neurologist’s report is issued – most often a day or two after the examination. When making a diagnosis and prescribing treatment, not only electroencephalography data are taken into account, but also reactions during examination by a doctor, clinical manifestations, and indicators of other studies.

EEG decoding includes an assessment of the constancy of brain rhythms, the same activity of neurons in both hemispheres and the reaction to routine tests (open-close eyes, photostimulation, hyperventilation).

EEG in children is more difficult to decipher - this is due to the active growth and maturation of the entire nervous system, which can affect the EEG results. Therefore, in children, any disorders and changes should be analyzed over time with a certain periodicity.

Decoding the EEG of the brain must take into account a number of factors, the influence of which may reduce the accuracy of the study. These include:

• age;
• health status and concomitant diseases;
• active movement during the procedure;
• tremor;
• visual impairment;
• taking certain medications that affect the nervous system;
• consumption of products that stimulate the nervous system (containing caffeine);
• conducting an EEG on an empty stomach;
• dirty hair, use of hair styling and treatment products;
• other factors that influence the activity of the brain and neurons.

Decoding the EEG taking into account these conditions will allow you to avoid errors in the conclusion.

Brain rhythms are one of the key parameters when assessing EEG results. These are waves that differ from each other in shape, constancy, periods of oscillation and amplitude. Their regularity reflects the normal coordinated activity of various structures of the central nervous system.

There are several types of rhythms, each of which has its own set of characteristics and records specific brain activity:

1. The alpha rhythm is detected at rest. Normally, when a person does not sleep with drooping eyelids, the frequency of the alpha rhythm is 8-14 Hz, and the amplitude is up to 100 μV. It is most intensely manifested in the area of ​​the back of the head and crown. Alpha waves become almost undetectable during mental activity, flashes of light or opening of the eyes, nervous excitement, or sleep. The frequency of the alpha rhythm may increase in women during menstruation.
2. Beta rhythm is an indicator of active brain function. It may also reflect increased anxiety, nervousness, depression, or taking too much of certain medications. The normal frequency of the beta rhythm in both hemispheres is 14-30 Hz, amplitude is 3-5 μV. The highest intensity of beta waves is recorded in the frontal lobes of the brain.
3. Delta rhythm has normal frequency 1-4 Hz with an amplitude of up to 40 μV and is reflected on the EEG when a person is sleeping. At other times, its waves can account for no more than 15% of all rhythms. In addition, the delta rhythm can reflect being in a coma, the effect of drugs, and indicate the appearance of a tumor or brain damage.
4. The theta rhythm also characterizes the sleep of a healthy adult. In children under 4-6 years of age, it is the main one on the EEG - it can be detected in the central parts of the brain as early as 3 weeks of age. The frequency of the theta rhythm is 4-8 Hz with an amplitude of about 30 μV.

Based on the results of the EEG, another parameter is derived, which is a comprehensive assessment of brain rhythms - bioelectrical activity of the brain (BEA). The doctor examines the rhythms for synchronicity, rhythmicity and the presence of sudden bursts. Based on the analysis, the neurologist writes a conclusion, which must contain the characteristics of the waves, a description of the disorders and their correspondence to clinical manifestations.

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Normally, the manifestations of brain rhythms in a healthy person correspond to the above values ​​and functional states. In addition, the following signs indicate normal functioning of the nervous system:

• predominance of alpha and beta rhythms in the active state;
• synchronization of rhythms in both hemispheres;
• absence of sharp peaks of electrical activity;
• stable brain activity even in the presence of short-term reactions to light exposure and other stimulation options.

In children, slow oscillations are recorded at an early age, and the alpha rhythm is formed by the age of 7 years. The EEG of adolescents 15-17 years old already corresponds to the study of an adult. After 50-60 years, the frequency decreases and the regularity of the delta rhythm is disrupted, and the number of theta waves increases.

There are many deviations from the norm in the EEG of the brain. Definition possible reasons Disturbances of brain rhythms are the task of an experienced specialist. Below are some abnormal EEG findings that may be signs of neurological, mental or speech disorders.

1. Lack of synchrony and symmetry in the work of neurons in the right and left hemispheres.
2. Sudden changes in rhythm frequency: acute bursts of activity and sharp declines. This happens with infections, tumors, injuries, strokes.
3. Alternating peaks and valleys, high amplitude fluctuations with different frequencies, single or serial bursts of activity can be a sign of epilepsy. However, it should be taken into account that between attacks the EEG of patients with epilepsy may show normal results.
4. The presence of delta and theta rhythms in a awake person indicates possible diseases or brain injuries.
5. A number of infections, poisonings and metabolic disorders can be characterized by changes in brain activity in several areas at once.
6. In a coma and when the nervous system is suppressed by potent drugs, zero electrical activity in the brain can be observed. This happens when the flow of blood to the brain is disrupted and it stops functioning.

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Possible causes of violations

1. Alpha rhythm disorders. Asymmetry of the alpha rhythms of the two hemispheres of the brain (a difference of more than 30%) may be a sign of neoplasms, stroke or heart attack. An unstable or high-frequency alpha rhythm occurs with brain damage, in particular as a result of a head injury or concussion. In case of serious mental disorders, the amplitude may decrease to less than 20 μV, the rhythm index drops below 50%, and the zone of alpha rhythm manifestation shifts from the occipital and crown areas. With dementia, there may be an absence of alpha waves or their arrhythmia. In a child, deviations from the norm of the alpha rhythm may be evidence of delayed psychomotor development.
2. Beta rhythm disorders. Concussion is usually characterized by the presence of high-amplitude (50-60 μV) diffuse beta waves. With encephalitis, short spindles are recorded. An increase in the duration and frequency of occurrence of these spindles may indicate a developing inflammatory process. In children, beta waves with a frequency of 16-18 Hz and high amplitude (30-40 μV) in the anterior and central parts of the brain are abnormal - this is a sign of a child’s developmental delay.
3. Disturbances of theta and delta rhythm. A constant increase in the amplitude of the delta rhythm - more than 40 μV - is an indicator of impaired brain functions. If the delta rhythm is recorded in all parts of the brain, then we can talk about serious illnesses central nervous system. Large fluctuations in delta waves occur in the presence of tumors. Developmental delay in children is characterized by maximum manifestations of theta and delta waves in the back of the head. An increased frequency of these rhythms sometimes reflects impaired cerebral circulation and other neurological problems.

Timely EEG of the brain and competent interpretation of the results will help establish a diagnosis in case of disorders and prescribe adequate therapy for brain diseases.

Electroencephalography (EEG) is an excellent method for diagnosing epilepsy and various brain injuries. Unfortunately, EEG is often prescribed to everyone, including patients who do not need it at all.

The essence of the method

EEG is a method that records electrical signals from neurons (nerve cells in the brain). Indeed, some diseases can manifest as severe disturbances in the electrical activity of the brain.

Most often this is epilepsy, in which a group of neurons exhibits excessive activity, and structural changes in the brain (tumor, cyst, consequences of stroke and hemorrhage). Almost always, using an EEG, a doctor (neurophysiologist) can determine where this focus of excitation is located.

In our country there are diagnostic standards for all diseases. Unfortunately, in accordance with Russian standards, such an excellent method as EEG is often used to diagnose not only epilepsy and brain tumors, but also any neurological disorders.

For example, a patient complains of fainting in a stuffy room, with a crowd of many people, in a confined space. Or paroxysmal headache. Here are the readings for the EEG according to the standards.

Moreover, in most cases, a routine EEG is used with a recording of up to 20 minutes. Unfortunately, such a short recording often does not record even some types of epilepsy, in which changes in activity are quite pronounced. For a detailed assessment of electrical activity in epilepsy, a longer EEG recording is needed, and preferably overnight monitoring or recording after a sleepless night (sleep deprivation). And if we are talking about “vegetative-vascular dystonia” or headaches, then the EEG will most likely only confuse both the doctor and the patient.

Problems decoding results

The doctor receives the EEG report and the patient waits hopefully for the verdict. If a stroke or tumor has already been identified, then usually there is no intrigue. Even such a short recording will show that yes, indeed, there is a focus of pathological activity. The recording, in particular, will help evaluate the effectiveness of treatment for excessive neuronal activity in the affected area.

But in other cases, such as headaches or panic attacks, there may be options. Often the conclusion indicates “dysfunction of the midline structures” or “reduced threshold for convulsive readiness.”

Such a conclusion is not a diagnosis or an indication of any disease! But for the patient, this can seem like a scary find. But in fact, all these “dysfunctions” may indicate that the patient had anxiety at the time of the study or simply had a headache.

Only focal EEG changes should alert the doctor. This is a reason to prescribe an additional examination, such as magnetic resonance imaging (MRI), to exclude a tumor or cyst.

The value of EEG

It turns out that a routine 20-minute EEG often does not carry the key to diagnosis. If we are looking for a tumor, it is better to do an MRI or CT (computed tomography). If we are looking for epilepsy or assessing the effectiveness of its treatment, then it is better to do long-term EEG recording (monitoring).

EEG monitoring is a relatively expensive study, but it provides significantly more information compared to routine EEG.

In practice, it turns out that, following the diagnostic standards for such common diseases as headaches, vegetative dystonia, panic attacks, the doctor sends the patient for an EEG, sometimes guessing in advance about the results of the examination. Unfortunately, this delays making a correct diagnosis, and sometimes leads both the doctor and the patient in the wrong direction who want to deal with the “lowering the seizure threshold.”

To paraphrase a well-known aphorism, I would like to add that the doctor should treat the patient, and not examine him.

Be healthy!

Maria Meshcherina

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