Disorganized alpha activity in a child. Diffuse changes in cortical rhythms - what is it?

Sometimes there are disruptions in the transmission of these signals to other parts of the body, which can affect a person’s well-being. These changes occur evenly throughout the brain and can affect different parts.

Symptoms such as dizziness, fatigue, discomfort, etc. appear. To determine whether diffuse changes in the bioelectrical activity of the brain have occurred, it is necessary to test the patient with an electroencephalograph. This procedure is often performed after severe injuries, meningitis, encephalitis and other diseases related to the brain to ensure that there is no developing disease.

Symptoms of diffuse changes

Problems with the brain are significantly different from diseases of other organs, and therefore their symptoms are special. Often changes in the body occur gradually, while symptoms increase. Thus, moderate changes in the bioelectrical activity of the brain mainly cause such changes as:

• decreased performance of the patient;
• the emergence of problems at the psychological level;
• inattention to detail;
• the patient becomes sluggish and finds it difficult to switch between different activities.

If a person exhibits such symptoms after an injury, an electroencephalogram should be performed to determine whether the patient's brain is exhibiting activity different from normal. It is worth noting that even the results of such a study are not always true, since some abnormalities can occur in the brain of a healthy person, and he will not suffer from characteristic symptoms.

Electroencephalogram

Conducting a study of the bioelectrical activity of the brain is absolutely painless. Electrodes are attached to the patient's head, which record electrical activity and elementary processes in neurons. When analyzing the results, the doctor pays attention to the frequency of vibrations, their amplitude and many other factors. In addition, to make an accurate diagnosis, a study of rhythms is required, which determines the presence of diffuse changes. This procedure also helps determine the presence of other brain diseases.

Manifestations and consequences

Diffuse changes in the brain can cause a lot of discomfort to the patient. The first signs in the form of dizziness and poor health usually appear in the initial stages. If the patient experiences more serious difficulties, headaches, and surges in blood pressure, this may indicate a tendency to epilepsy. If, during an electroencephalogram, foci of excessively high bioelectrical activity are detected, this indicates that the patient may soon begin to have seizures.

Causes of diffuse changes

The disease can occur against the background of other health problems, and develop as a result of previously suffered:

• injuries;
• meningitis;
• encephalitis;
• atherosclerosis;
• toxic brain damage.

An electroencephalogram can show polymorphic activity and pathological fluctuations that have any deviations from the norm. An accurate diagnosis can only be made if all these signs are present. They can also be directly related to damage to the pituitary gland and hypothalamus.

Diffuse changes after injury

Sometimes the disease manifests itself as a consequence of head injuries and severe concussions, which can cause serious problems. In such cases, an electroencephalogram will show changes occurring in the subcortex and brain. The patient’s well-being will depend on the presence of complications and their severity. Mild diffuse changes in the bioelectrical activity of the brain usually do not cause a noticeable deterioration in health, although they may cause slight discomfort.

Diagnosis and treatment

A diagnosis that is scary at first glance will actually not cause much harm to the body if you pay attention to the problem in time. This is a fairly common disorder that often occurs in children, but it does not affect the main systems of the body.

It is possible to completely get rid of diffuse changes in the brain within just a few months, or in difficult cases – a year. Restoring normal brain activity is a top priority and cannot be delayed, since without treatment complications may arise that will lead to serious and irreversible consequences.

Diffuse changes in bioelectrical activity of the brain

The human body is a complex system, the activity of which occurs according to its own laws and rules. The slightest, seemingly insignificant failure of his work inevitably affects the general condition of a person.

Back in the 19th century, scientists realized that the human brain, like the brain of animals, is capable of emitting certain bioelectric signals. They pass through millions of nerve cells - neurons. It is these cells that form our brain.

Such electrical signals, passing through the brain cells, penetrate the cranial bones, then into the muscles, from where they are sent to the scalp. These signals are amplified by special sensors attached to the head and transmit information to an electroencephalograph.

A specialist who has studied the electroencephalogram in detail proceeds to make a diagnosis, which sometimes sounds like diffuse changes in the bioelectrical activity of the brain. Adequate functioning of the brain requires neurons to constantly communicate with each other in order to transmit information about the operation of all systems of the human body, in connection with this the so-called bioelectrical activity of the brain occurs.

Often in the conclusions you can see the following entry: dysfunction of stem cell structures is recorded against the background of changes in the BEA of the brain.

Disorganization of the BEA of the brain - what is this diagnosis?

Practice shows that a diagnosis can only be confirmed by the patient’s complaints about certain abnormalities and complaints about his well-being. Such changes in the body are accompanied by dizziness, discomfort, and headaches that do not stop for a long time. Very often, such deviations can be found in the EEG of people who do not complain about anything and are absolutely healthy.

If the conclusion to the EEG indicates information about significant diffuse changes in combination with a significant decrease in the level of convulsive readiness, then all this will mean that the person is predisposed to the manifestation of epilepsy. In other words, the cerebral cortex is affected by foci of bioelectrical activity at an increased level. This can cause a person to experience frequent epileptic seizures.

In a normal state, a person’s electromagnetic activity is diagnosed as conditionally normal. When conducting electroencephalography, activities may be revealed that are slightly different from the norm, but have not yet developed into pathology. In such cases, doctors in conclusion indicate that there are slight diffuse changes in the bioelectrical activity of the brain.

If disorganization of bioelectrical activity is detected in a person, impaired blood circulation in the brain is diagnosed.

About the reasons

If the changes in the BEA of the brain are not severe, then they most likely appeared as a result of an infectious or traumatic factor, or vascular diseases.

Doctors believe that changes in general cerebral processes, and in bioelectrical activity in particular, can be caused by the following catalysts:

1. Head injuries (possible concussions). The intensity of the disorder directly depends on the complexity of the damage. Diffuse changes of a moderate nature can bring discomfort to the patient. Such manifestations do not require long-term therapy. Severe injuries can cause pronounced diffuse changes in the bioelectrical activity of the brain, which entails severe dysfunction in the entire central nervous system.
2. Inflammation affecting the substance of the brain. Mild changes in BEA can be observed due to meningitis or encephalitis.
3. Atherosclerotic vascular lesions. At the initial stage, moderately pronounced diffuse changes in the bioelectrical activity of the brain appear. In the process of tissue death, due to insufficient blood supply, an increasingly progressive deterioration in the patency of neurons is observed every day.
4. Irradiation (poisoning): Radiological damage is characterized by general changes. Signs of toxic pathological poisoning are considered irreversible. They significantly affect the patient’s ability to cope with everyday activities and require very serious therapy.
5. Associated abnormalities: diffuse changes in regulatory function are associated with changes in the lower part of the brain structure: the hypothalamus and pituitary gland.

Manifestations and clinic

With a disorganized BEA, it is impossible to notice any manifestations (either to others or to oneself).

Moderate diffuse changes in BEA, if hardware diagnostics indicate a problem, but if diseases dangerous to health are not identified, will not appear immediately, but will intensify significantly over time.

Symptoms for moderate and severe dysfunction:

• decreased performance, chronic fatigue;
• decreased concentration of attention, intellectual abilities, deteriorating memory, these manifestations are especially noticeable in preschoolers and students;
• frequent chills, colds, aching in the muscles;
• hair and skin are dry, nails are too brittle;
• sexual activity is reduced to a minimum, weight fluctuates significantly;
• neurosis, psychosis and depression occur;
• Hormonal imbalances and problems with stool begin.

Diagnosis and treatment of BEA brain

If the brain tissue is inflamed or covered with scars, or if cells die, this process can be shown by an electroencephalogram. This diagnostic method helps not only to characterize the process, but also to reliably determine the location of the localization, and therefore make the correct diagnosis. The EEG examination is completely painless.

The doctor should carefully examine the medical history. The pattern of manifestations of disorders can be seen in identical diseases of the nervous system.

A cap with electrodes is placed on the head. Through them, the process of neuron activity is recorded: how often oscillations occur, what is their amplitude, what is the rhythm of their work.

Any deviation will indicate to the specialist what exactly bioelectric changes have occurred. MRI is called upon to clarify the diagnosis. The device will help to reliably determine the source of the pathology detected by the EEG. Only after a complete examination can you proceed to the treatment stage.

A person who has nothing to do with medicine, hearing the diagnosis “diffuse changes in the BEA of the brain,” will be significantly wary and frightened.

But everything is much easier and simpler, especially in cases where the diagnosis is made on time - the patient will receive adequate treatment and will be able to get rid of the disease, bringing the level of vital activity of brain cells to a normal rhythm.

It is very important not to delay contacting a specialist, since even the slightest delay can significantly complicate the treatment process and even provoke complications.

How quickly neural activity is restored depends on the severity of the affected brain tissue. It is logical that the more moderate the changes, the more effective the treatment process will be. It usually takes many months for a patient with a similar diagnosis to return to a full life.

Treatment tactics depend on the cause that caused the changes in the BEA. It is much easier to restore brain activity during the initial manifestation of atherosclerosis, and much more difficult after radiation and chemical damage. Treatment of BEA dysfunction occurs with medication. Exceptional cases of the disease require surgical measures. This often occurs when concomitant diseases are identified.

Self-medication is extremely dangerous!

If moderately pronounced deviations in BEA are detected in a timely manner, then human health will not suffer critically. Abnormalities in the BEA of the brain often appear in children. Impaired conductivity is also detected in adults. It is very dangerous to leave such a problem unattended.

Changes of a global nature will definitely lead to consequences that will be impossible to reverse. Chronic nonconductivity of impulses, depending on the location, can manifest itself in psycho-emotional disorders, impaired motor skills, and developmental retardation. The main consequence of untimely treatment will be convulsive syndromes and epileptic seizures.

For prevention purposes

To try to avoid diffuse changes in BEA, you should minimize, or better yet completely avoid, the consumption of alcohol, strong coffee/tea, and tobacco.

You should not overeat, overheat or overcool, you should avoid staying at altitude and other adverse effects.

A plant-dairy diet, frequent exposure to air, minimal exercise, and adherence to the most appropriate rest and work regimen are very useful.

It is prohibited to work near fire, on water, near moving mechanisms, on any transport, or to come into contact with toxic products. Living constantly with nervous tension and fast rhythm.

This section was created to take care of those who need a qualified specialist, without disturbing the usual rhythm of their own lives.

My great-grandson is 2 years old and 10 months old. He has speech delay. They did an EEG. In conclusion, they wrote moderately pronounced diffuse changes in the brain bea of ​​a regulatory nature and signs of disorganization of the brain bea. From what I read here, I concluded that this is very bad. But we haven’t come across any reason for this from what you wrote. There were no prerequisites for such violations to occur. We are simply in shock. Please write what should we do? Of course, we will undergo treatment if necessary, but will the great-granddaughter start talking or not?

Causes and consequences of changes in the bioelectrical activity of the brain

Electrical impulses are used to quickly transmit signals between brain neurons. Disturbances in conduction function affect a person’s well-being. Any disturbances are reflected in the bioelectrical activity of the brain (BEA).

What is disorganization of bioelectrical activity of the brain

Slight diffuse changes in the bioelectrical activity of the brain often accompany injuries and concussions. With proper treatment, the patency of the impulses is restored after several months or even years.

Cause of brain BEA disorders

Slight diffuse changes in the BEA of the brain are a consequence of traumatic and infectious factors, as well as vascular diseases.

• Concussions and injuries - the severity of the manifestation depends on the severity of the injury. Moderate diffuse changes in the bioelectrical activity of the brain lead to mild discomfort and usually do not require long-term treatment. The consequence of severe injuries are volumetric lesions of impulse conduction.

Signs of brain disorganization

Desynchronization of bioelectrical activity immediately affects the patient’s well-being and discomfort. Initial signs of disturbances appear already in the initial stages.

Why are BEA changes dangerous to health?

Timely detection of moderately severe disorganization of the BEA is not critical for the health of the human body. It is enough to pay attention to deviations in time and prescribe restorative therapy.

Diagnostics of deviations

Disorganization of the bioelectrical activity of the brain can be detected using several methods.

• History - a picture of diffuse disorders of BEA is visible in clinical manifestations identical to other diseases of the central nervous system. The doctor diagnosing pathological changes will conduct a full examination of the patient and pay attention to concomitant diseases and injuries.

Decoding the EEG does not make it possible to see the cause of the anomalies caused. EEG is useful in diagnosing advanced rates of BEA formation. In this case, it is possible to prevent the development of epileptic seizures.

Treatment of changes in the BEA of the brain is prescribed only after a complete examination of the patient, since to improve well-being, it is critical to eliminate the causes of the disorder.

What are diffuse changes in the BEA of the brain?

Rough diffuse changes are a consequence of scar formation, necrotic transformations, swelling and inflammatory processes. Conduction disturbances are heterogeneous. Functional instability of the BEA in this case is necessarily accompanied by pathological disorders of the pituitary gland or hypothalamus.

How to increase brain BEA

Moderate or significant diffuse polymorphic disorganization of the BEA of the brain is treated exclusively in specialized medical institutions.

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BEA brain

The human brain is the most complex, constantly interacting system in the human body. Many people know that the work of the brain is associated with bioelectric signals that interact with the nerve cells of our brain. But sometimes the process of transmitting these signals is disrupted, which leads to malfunctions not only in our brain, but throughout the body.

Therefore, it is very important that nerve cells and the signals they receive work together without failure. For example, if signals do not reach nerve cells, a person may experience abnormal physical and psychological changes.

If the symptoms are severe and the location of the damaged brain cells cannot be detected, then specialists determine diffuse changes in the BEA of the brain; this can manifest itself in a significant decrease in vitality.

Reasons for violations

Disorganization of the BEA can be a sign of completely different disorders, but to a greater extent it occurs due to injuries, infections or vascular pathologies.

Experts identify the following common factors that lead to BEA variability:

• Traumatic brain injuries of varying severity and nature of injury (concussions, bruises, etc.). How general cerebral activity changes largely depends on the severity of the injury. For example, a mild concussion causes virtually no significant changes in the brain, but if a severe injury has been received, volumetric disturbances in the conduction of impulses are observed.
• Inflammatory processes that affect the cerebrospinal fluid. Smooth diffuse variability of BEA indicates previous meningitis or encephalitis.
• Vascular atherosclerosis. The early stage is characterized by no significant changes in BEA, but progressive vascular disease, when blood flow to the brain is disrupted, this leads to a significant deterioration in neural communication.
• Radiation exposure or toxic poisoning. When irradiated, some diffuse variability occurs, which depends on the degree of irradiation received. Toxic poisoning is often irreversible and requires intensive therapeutic treatment, which ultimately does not guarantee the appearance of some pathological manifestations in the future.

Symptoms

If there is a violation of the organization of the BEA, then this is quite easy to notice by the signs that appear. If the diagnosis shows moderate diffuse changes, then this only indicates the beginning of a pathological process in the brain, which will gradually intensify if proper treatment is not started.

Symptoms in this case may be as follows:

• Decreased performance
• Absent-mindedness, inability to concentrate
• Fast fatiguability
• Brittle nails, dry hair and skin
• Decreased sexual activity
• Frequent fever (chills, muscle and joint aches)
• Decreased self-esteem
• Apathy, depression, neurosis

Therefore, pathological indicators of BEA greatly affect the well-being and life of the patient. Moderate changes do not cause noticeable inconvenience, but should already make you wary.

Initial signs of moderate diffuse changes are as follows:

Quite common symptoms, which can mean standard physical fatigue, a concomitant disease or a violation of the BEA. Therefore, often these symptoms remain unattended, and the person associates this with ordinary fatigue, however, if this has begun the process of diffuse changes, further symptoms will become increasingly severe.

Diagnostic methods

If the bioelectrical activity of the brain is somewhat disorganized, this can be determined using several techniques. The most common and effective diagnostic method is electroencephalography (EEG), which we will discuss in more detail. Mainly, the following methods are included in the diagnosis of BEA:

1. Anamnesis. Includes the patient’s medical history, the presence of clinical manifestations of another disease, and examination of the patient
2. EEG is the main method for studying the bioelectrical activity of the brain, which makes it possible to detect any deviations from normal indicators and determine their localization
3. MRI. This magnetic resonance imaging study is mainly used to identify tumors that may be causing changes in the BEA of the brain. Also, by introducing contrast, you can get a more informative picture, which allows you to identify serious vascular disorders, for example, atherosclerosis, which is a provoking factor for diffuse changes

EEG as the main method for studying BEA

EEG diagnostics are based on recording the electrical activity of nerve cells (neurons) in different areas of the brain, which is subsequently recorded on paper in the form of waves. These indicators are recorded thanks to electrode sensors that are attached to the patient’s head.

The purpose of EEG is to assess the activity of the brain in case of damage to the central nervous system, for example, meningitis, encephalitis and other diseases. The EEG result allows the specialist to assess the current state of the brain, the extent and area of ​​its damage.

Examination using EEG occurs according to a standard protocol, which includes recording in states of wakefulness or sleep, using functional loads. Such loads include:

• Photostimulation (light exposure)
• Opening and closing eyes
• Hyperventilation (use of special breathing techniques during the EEG procedure)
• Additional loads (diagnosis with preliminary lack of sleep, psychological tests, medication and other methods)

Additional loads are included in the diagnosis to clarify the results and are prescribed by the attending physician.

The BEA parameter at the conclusion of the EEG is a characteristic that describes complex indicators of brain rhythms. A normal BEA reading should be rhythmic and synchronous. As a rule, at the conclusion of the EEG, the specialist enters information about the current state of the BEA.

If the bioelectrical activity of the EEG brain is somewhat disorganized, this does not always indicate the presence of pathological activity, given that no other disturbances have been identified. However, if indicators of pathological activity are present, this may indicate developing or existing epilepsy, as well as a tendency to seizures. A low BEA score is usually detected in depression.

Restoring BEA

In most cases, patients are frightened by the diagnosis - “diffuse changes in the BEA of the brain.” In fact, such a diagnosis does not pose a danger if it was made on time and the patient was prescribed competent therapeutic treatment. In this case, activity indicators can be easily restored to normal.

The main danger is that patients very often delay visiting a specialist, which can lead to quite serious complications. How neural activity is restored will depend on the state of the brain tissue and the degree of its damage. Complete recovery of the patient and his return to normal life depends on the indicators of diffuse changes and may require from 2 months to several years.

Recovery is faster if reduced activity is associated with early vascular damage than with radiation or toxic damage, which, in turn, can lead to irreversible changes. Treatment of BEA is based on drug therapy, and surgery is used in very rare cases or for concomitant diseases.

• Avoid consumption of strong coffee and tea
• Give up bad habits (alcohol and tobacco)
• Hypothermia should be avoided
• Light exercise in the fresh air

Possible consequences of gross diffuse changes

If the bioelectrical activity of the brain is disorganized and gross diffuse changes are observed, then this is characterized by the appearance of swelling, necrotic transformations or inflammatory processes. Functional instability of the BEA is accompanied by damage to the pituitary gland or hypothalamus.

If the patient did not undergo the examination on time and ignored the manifesting symptoms, then in this case certain negative processes may occur in his body and brain, which can lead to the following consequences:

• Severe tissue swelling and metabolic disorders
• Sharp deterioration in health
• Violation of basic brain functions
• Impaired motor functions, development of psychoemotional disorders
• Children have developmental delays
• Development of epilepsy

Do not forget that this negative variability may indicate a developing tumor process, which poses a great danger to the patient’s life in the absence of timely treatment.

Can you please decipher the EEG conclusion? The bioelectrical activity of the brain is disorganized with signs of moderate cortical-stem irritation, the activation reaction is preserved. There is no clear interhemispheric asymmetry, paroxysmal or epileptiform activity.

EEG (Electroencephalogram) - interpretation

Electroencephalogram of the brain - definition and essence of the method

1. Photostimulation (exposure to flashes of bright light on closed eyes).

2. Opening and closing the eyes.

3. Hyperventilation (rare and deep breathing for 3 - 5 minutes).

• 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.

Additional EEG tests are determined by a neurologist who wants to evaluate certain functions of a person's brain.

What does an electroencephalogram show?

Where and how to do it?

Electroencephalogram for children: how the procedure is performed

Electroencephalogram rhythms

Electroencephalogram results

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. Asymmetry between the hemispheres of the brain and paroxysmal activity were not detected”).

3. Determining the correspondence of 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

Alpha - rhythm

• constant registration of the alpha rhythm in the frontal parts of the 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%.

What do common alpha rhythm disturbances indicate?

Severe interhemispheric asymmetry may indicate the presence of a brain tumor, cyst, stroke, heart attack or scar at the site of an old hemorrhage.

• 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.

A decrease in the amplitude of the alpha rhythm, a shift in the focus of activity from the back of the head and crown, and a weak activation reaction indicate the presence of psychopathology.

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.

What do beta rhythm disturbances on the EEG indicate?

The presence of diffuse beta waves with an amplitude not higher than V indicates a concussion.

Theta rhythm and delta rhythm

Delta waves with high amplitude indicate the presence of a tumor.

Bioelectric activity of the brain (BEA)

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.

Other indicators

• 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.

In general, residual changes in brain structures are the consequences of damage of various types, for example, after injury, hypoxia, or a viral or bacterial infection. Residual changes are present in all brain tissues and are therefore diffuse. Such changes disrupt the normal passage of nerve impulses.

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

Changes progress as the volume of education increases.

Electroencephalogram: cost of the procedure

Read more:

Reviews

Compared to the previous EEG recording, a slowdown in the alpha rhythm and a slight increase in the p.a. index are noted. Pronounced diffuse changes in the biopotentials of the g.m. are recorded. paroxysmal in nature. Alpha rhythm with an average index, fragmented (8Hz to 80µV); zonal features with a tendency to smooth out. There is no reliable interhemispheric asymmetry. Against this background, rare outbreaks of PA are recorded. in all leads of the g.m., slightly intensifying during the GV test. There are no typical forms of epiactivity or reliable signs of APA.

The reaction to OG and SG is a long-term activation reaction. Hyperventilation - slightly increases the voltage of background activity in all areas. Diffuse severe irritation of the cerebral cortex. Shift of nervous processes towards excitation. The functional state of the cerebral cortex is reduced. Thank you

Thank you very much in advance!

Conclusion: Moderate disorgenization of cortical rhythms.

On the background EEG recording, diffuse changes in the biopotentials of the brain are recorded in the form of irregularities in the amplitude and frequency of rhythms. The activity of the theta range dominates, alpha activity is well expressed and predominates in the parieto-occipital leads. Zonal differences can be traced. The assimilation reaction to the presented stimuli is not complete. During hyperventilation, a reaction of brainstem structures is noted in the form of bilateral synchronization of high-amplitude, bilaterally synchronous waves of the theta range with their emphasis on the frontal and parieto-occipital leads. No foci of pathological activity were identified.

Alpha rhythm: average index, modulated into spindles, amplitude up to 60 μV, localized in the occipital region, electrode asymmetry is noted with an amplitude decrease on the left. The reaction to opening the eyes is pronounced.

Beta rhythm: low index, represented by rare single waves with an amplitude of up to 15 μV, localized in the frontal regions of the brain, without signs of interhemispheric asymmetry.

Theta waves: medium index, presented in the form of single waves and groups of waves A up to 30 µV

with predominant localization in the anterior-central leads, with moderate amplitude predominance in the right posterior-temporal region.

Epi-complexes, sharp waves: not registered.

during photostimulation, the assimilation reaction was detected at frequencies of 23,25,27 Hz, photoparoxysmal activity was not detected.

When hyperventilation is carried out, there is an increase in the amplitude of the alpha rhythm, a gradual diffuse increase in the number of single slow waves of the theta range, with signs of amplitude asymmetry in the posterior parts of the brain (A on the right - up to 60 μV, on the left - μV)

No focus of paroxysmal activity was identified.

Please decipher the EEG conclusion

Increased excitability of the cerebral cortex against the background of moderate diffuse changes.

The background EEG is dominated by irregular alpha activity with a frequency of 8-9 Hz and an amplitude of µV. Modulations of alpha waves are weakly expressed. Zonal differences are smoothed out. Responses to afferent stimuli are adequate. Multiple sharp waves of the alpha range are recorded in the parietal-occipital leads with a frequency of 9-10 Hz with an amplitude of up to 110 µV, single groups of bilaterally synchronous sharp waves of the alpha range are recorded in the frontal-central-parieto-occipital leads with a frequency of 10 Hz with an amplitude of up to 100 µV. Single theta waves are bilaterally synchronous in the frontal-central leads with a frequency of 7 kHz and an amplitude of up to 50 μV. Two spontaneous discharges of acute-slow wave complexes were recorded in the frontotemporal leads on the left. Carrying out hyperventilation for one minute causes increased disorganization of background activity, provokes single generalized outbreaks of acute-slow wave complexes with maximum amplitude in the temporo-central leads.

Conclusion: EEG data reflect, against the background of moderate diffuse changes in the BEA of the brain, signs of moderate dysfunction of the mesodiencephalic structures of the brain; a cortical focus of epileptiform activity was identified in the left frontotemporal region.

On the EEG at rest and during functional tests, pronounced changes in bioelectrical activity of a general cerebral nature are revealed with signs of irritation of cortical structures. Rapid oscillations of the beta range are diffusely enhanced, spikes and isolated sharp waves of the alpha-beta range are recorded. The reaction of rhythm assimilation during RFS is not clearly visible. Photoparoxysmal no response was received. During the GV test, frequent generalized epileptiform discharges of polyspikes are recorded. The threshold for convulsive readiness may be reduced.

My 23-year-old daughter had an EEG. Conclusion: Moderate cerebral changes in the bioelectrical activity of the brain of a regulatory nature against the background of dysfunction of the middle structures at the mesencephalic level. with increased manifestations under conditions of a hyperventilation test. The reactivity of the convexity cortex and afferent stimuli is reduced. After fsp at medium frequencies, a bilateral synchronized peak-slow wave discharge was recorded. When conducting an EEG, generalized paroxysmal activity is recorded.

If possible, please decipher it. Best regards, Karina

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3. Hyperventilation (rare and deep breathing for 3 - 5 minutes).

• 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.

Additional EEG tests are determined by a neurologist who wants to evaluate certain functions of a person's brain.

What does an electroencephalogram show?

Where and how to do it?

Electroencephalogram for children: how the procedure is performed

Electroencephalogram rhythms

Electroencephalogram results

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. Asymmetry between the hemispheres of the brain and paroxysmal activity were not detected”).

3. Determining the correspondence of 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

Alpha - rhythm

• constant registration of the alpha rhythm in the frontal parts of the 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%.

What do common alpha rhythm disturbances indicate?

Severe interhemispheric asymmetry may indicate the presence of a brain tumor, cyst, stroke, heart attack or scar at the site of an old hemorrhage.

• 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.

A decrease in the amplitude of the alpha rhythm, a shift in the focus of activity from the back of the head and crown, and a weak activation reaction indicate the presence of psychopathology.

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.

What do beta rhythm disturbances on the EEG indicate?

The presence of diffuse beta waves with an amplitude not higher than V indicates a concussion.

Theta rhythm and delta rhythm

Delta waves with high amplitude indicate the presence of a tumor.

Bioelectric activity of the brain (BEA)

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.

Other indicators

• 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.

In general, residual changes in brain structures are the consequences of damage of various types, for example, after injury, hypoxia, or a viral or bacterial infection. Residual changes are present in all brain tissues and are therefore diffuse. Such changes disrupt the normal passage of nerve impulses.

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

Changes progress as the volume of education increases.

Electroencephalogram: cost of the procedure

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Reviews

1) On a flattened background EEG, general cerebral BEA disturbances of moderate severity with cortical dysrhythmia, mild irritation, reduction of the d-rhythm and fragmentation of brain stem structures, which intensify during loading tests

2) noting an increase in B-activity in all parts of the cerebral cortex.

What does this mean?

Male, 24 years old.

Beta rhythm of low index, low frequency, diffusely distributed, more pronounced in the fronto-central regions.

When opening the eyes, there is a slight depression of the alpha rhythm

Upon photostimulation, absorption of rhythms in the alpha frequency range is observed.

In response to hyperventilation, a slight increase in the severity of the alpha rhythm is observed in the form of periods of synchronization of alpha activity at a frequency of 10 Hz.

Mild cerebral changes in the bioelectrical activity of the brain of a regulatory nature.

signs of dysfunction of nonspecific mid-stem structures.

No local or paroxysmal activity was recorded.

Rhythmic photostimulation in the frequency range 1-25 Hz: increase in the index and amplitude of a-activity, sharp waves in the a-groups in the parietal-central, occipital and posterior temporal regions, emphasis in amplitude on the right.

Hyperventilation: rhythmic disorganization, sharp waves and reduced EMV complexes in the right temporal region.

EEG during sleep: no physiological sleep patterns were recorded.

Beta activity in the form of groups of waves of high index (up to 75%), high amplitude (up to 34 μV), low frequency, most pronounced in the right occipital-parietal region (O2 P4). A myogram may be present.

slow activity in the form of a rhythm, high amplitude (up to 89 μV).

In OH there is a clear depression of the alpha rhythm.

ZG alpha rhythm has recovered completely.

EEG changes during provoking AF: FT-3 delta activity: increased power; rhythm amplitude increased

FT-5 Alpha activity: rhythm amplitude decreased

FT-10 delta activity: rhythm amplitude increased

FT-15 Alpha activity: rhythm amplitude decreased

PP Alpha activity: increased power, rhythm amplitude increased.

no significant interhemispheric asymmetry was recorded at the time of the study. Thanks a lot

The main rhythm corresponds to age according to the index, but at a reduced frequency, signs of a moderate slowdown in the rate of formation of the cortical rhythm, moderate regulatory changes with slight disorganization of the cortical rhythm. No local pathological activity was detected.

There are no dynamics of maturation of cortical activity; the frequency and index of cortical rhythmics have not increased in comparison with the results of 2 years and 6 months.

Thank you in advance! I hope for your possible help!

Moderate diffuse changes in the bioelectrical activity of the brain. In a state of wakefulness, during a hyperventilation test, generalized discharges of theta waves lasting 2 seconds were recorded. In the structure of theta waves, sharp-slow wave complexes were periodically recorded in the frontal sections of both hemispheres.

The superficial stages of slow-wave sleep have been reached. The physiological phenomena of slow-wave sleep have been formed. No pathological epileptiform activity was recorded during sleep.

Thanks in advance for your answer

Thank you very much in advance.

We did an EEG to help us understand.

The background EEG is symmetrical, zonal differences are formed correctly.

The main wave activity is not clear enough alpha activity, predominant in the occipital regions:

disorganized, irregular, in the form of individual waves and groups of waves domkV, 8-10 Hz.

High-frequency activity (Beta) is physiologically expressed: up to 15-25 µV, Hz.

Slow wave activity: physiologically expressed - delta waves 3Hz no more than 30 µV and theta waves 4-6 Hz, no more than 100 µV mainly in the parietal regions.

Paroxysmal activity: not detected.

Functional tests: no pathological changes. No specific epilepsy activity was detected in this recording.

Moderate cerebral EEG changes in the form of disorganization of rhythms with signs of a decrease in the threshold of convulsive readiness.

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Decoding the electroencephalogram (EEG) indicators of the brain

Using the method of electroencephalography (abbreviation EEG), along with computer or magnetic resonance imaging (CT, MRI), the activity of the brain and the state of its anatomical structures are studied. The procedure plays a huge role in identifying various anomalies by studying the electrical activity of the brain.

EEG is an automatic recording of the electrical activity of neurons in brain structures, performed using electrodes on special paper. Electrodes are attached to various areas of the head and record brain activity. In this way, the EEG is recorded in the form of a background curve of the functionality of the structures of the thinking center in a person of any age.

A diagnostic procedure is performed for various lesions of the central nervous system, for example, dysarthria, neuroinfection, encephalitis, meningitis. The results allow us to evaluate the dynamics of the pathology and clarify the specific location of the damage.

The EEG is carried out in accordance with a standard protocol that monitors activity during sleep and wakefulness, with special tests for the activation response.

For adult patients, diagnosis is carried out in neurological clinics, departments of city and regional hospitals, and a psychiatric clinic. To be confident in the analysis, it is advisable to contact an experienced specialist working in the neurology department.

For children under 14 years of age, EEGs are performed exclusively in specialized clinics by pediatricians. Psychiatric hospitals do not perform the procedure on young children.

What do EEG results show?

An electroencephalogram shows the functional state of brain structures during mental and physical stress, during sleep and wakefulness. This is an absolutely safe and simple method, painless, and does not require serious intervention.

Today, EEG is widely used in the practice of neurologists in the diagnosis of vascular, degenerative, inflammatory brain lesions, and epilepsy. The method also allows you to determine the location of tumors, traumatic injuries, and cysts.

EEG with the impact of sound or light on the patient helps to express true visual and hearing impairments from hysterical ones. The method is used for dynamic monitoring of patients in intensive care units in a coma state.

Norm and disorders in children

1. EEG for children under 1 year of age is performed in the presence of the mother. The child is left in a sound- and light-proof room, where he is placed on a couch. Diagnostics takes about 20 minutes.
2. The baby's head is wetted with water or gel, and then a cap is put on, under which the electrodes are placed. Two inactive electrodes are placed on the ears.
3. Using special clamps, the elements are connected to wires suitable for the encephalograph. Due to the low current, the procedure is completely safe even for infants.
4. Before monitoring begins, the child's head is positioned level so that there is no forward bending. This may cause artifacts and skew the results.
5. EEGs are done on infants during sleep after feeding. It is important to let the boy or girl get enough immediately before the procedure so that he falls asleep. The mixture is given directly in the hospital after a general medical examination.
6. For children under 3 years old, an encephalogram is taken only in a state of sleep. Older children may remain awake. To keep the child calm, they give him a toy or a book.

An important part of the diagnosis are tests with opening and closing the eyes, hyperventilation (deep and rare breathing) with EEG, squeezing and unclenching of the fingers, which allows disorganization of the rhythm. All tests are conducted in the form of a game.

After receiving the EEG atlas, doctors diagnose inflammation of the membranes and structures of the brain, latent epilepsy, tumors, dysfunction, stress, and fatigue.

The degree of delay in physical, mental, mental, speech development is carried out using photostimulation (blinking a light bulb with eyes closed).

EEG values ​​in adults

For adults, the procedure is carried out subject to the following conditions:

• keep your head motionless during manipulation, eliminate any irritating factors;
• Before diagnosis, do not take sedatives or other drugs that affect the functioning of the hemispheres (Nerviplex-N).

Before the manipulation, the doctor conducts a conversation with the patient, putting him in a positive mood, calming him down and instilling optimism. Next, special electrodes connected to the device are attached to the head, and they read the readings.

The examination lasts only a few minutes and is completely painless.

Provided that the rules described above are observed, even minor changes in the bioelectrical activity of the brain are determined using EEG, indicating the presence of tumors or the onset of pathologies.

Electroencephalogram rhythms

An electroencephalogram of the brain shows regular rhythms of a certain type. Their synchrony is ensured by the work of the thalamus, which is responsible for the functionality of all structures of the central nervous system.

The EEG contains alpha, beta, delta, tetra rhythms. They have different characteristics and show certain degrees of brain activity.

Alpha - rhythm

The frequency of this rhythm varies in the range of 8-14 Hz (in children from 9-10 years old and adults). It appears in almost every healthy person. The absence of alpha rhythm indicates a violation of the symmetry of the hemispheres.

The highest amplitude is characteristic in a calm state, when a person is in a dark room with his eyes closed. When thinking or visual activity is partially blocked.

A frequency in the range of 8-14 Hz indicates the absence of pathologies. The following indicators indicate violations:

• alpha activity is recorded in the frontal lobe;
• asymmetry of the interhemispheres exceeds 35%;
• the sinusoidality of the waves is disrupted;
• there is a frequency scatter;
• polymorphic low-amplitude graph less than 25 μV or high (more than 95 μV).

Alpha rhythm disturbances indicate a possible asymmetry of the hemispheres due to pathological formations (heart attack, stroke). A high frequency indicates various types of brain damage or traumatic brain injury.

In a child, deviations of alpha waves from the norm are signs of mental retardation. In dementia, alpha activity may be absent.

Beta activity

The beta rhythm is observed in the borderline Hz range and changes when the patient is active. With normal values, it is expressed in the frontal lobe and has an amplitude of 3-5 µV.

High fluctuations give grounds to diagnose a concussion, the appearance of short spindles - encephalitis and a developing inflammatory process.

In children, the pathological beta rhythm manifests itself at index Hz and amplitude μV. This signals a high probability of developmental delay. Beta activity may dominate due to the use of various medications.

Theta rhythm and delta rhythm

Delta waves appear in deep sleep and in coma. They are recorded in areas of the cerebral cortex bordering the tumor. Rarely observed in children 4-6 years old.

Theta rhythms range from 4-8 Hz, are produced by the hippocampus and are detected during sleep. With a constant increase in amplitude (over 45 μV), they speak of a dysfunction of the brain.

strong>If theta activity increases in all departments, we can argue about severe pathologies of the central nervous system. Large fluctuations indicate the presence of a tumor. High levels of theta and delta waves in the occipital region indicate childhood lethargy and developmental delays, and also indicate poor circulation.

BEA - Bioelectric activity of the brain

EEG results can be synchronized into a complex algorithm - BEA. Normally, the bioelectrical activity of the brain should be synchronous, rhythmic, without foci of paroxysms. As a result, the specialist indicates which violations have been identified and based on this, an EEG conclusion is made.

• relatively rhythmic BEA – may indicate the presence of migraines and headaches;
• diffuse activity is a variant of the norm, provided there are no other abnormalities. In combination with pathological generalizations and paroxysms, it indicates epilepsy or a tendency to seizures;
• decreased BEA may signal depression.

Other indicators in the conclusions

How to learn to independently interpret expert opinions? Decoding of EEG indicators is presented in the table:

Online consultations with specialists in the field of medicine help people understand how certain clinically significant indicators can be deciphered.

Reasons for violations

Electrical impulses ensure rapid transmission of signals between neurons in the brain. Violation of conduction function affects health. All changes are recorded in bioelectrical activity during an EEG.

• injuries and concussions - the intensity of the changes depends on the severity. Moderate diffuse changes are accompanied by mild discomfort and require symptomatic therapy. Severe injuries are characterized by severe damage to impulse conduction;
• inflammation involving the brain and cerebrospinal fluid. BEA disorders are observed after meningitis or encephalitis;
• vascular damage by atherosclerosis. At the initial stage, the disturbances are moderate. As tissue dies due to lack of blood supply, the deterioration of neural conduction progresses;
• irradiation, intoxication. With radiological damage, general disturbances of the BEA occur. Signs of toxic poisoning are irreversible, require treatment, and affect the patient's ability to perform daily tasks;
• associated disorders. Often associated with severe damage to the hypothalamus and pituitary gland.

EEG helps to identify the nature of BEA variability and prescribe appropriate treatment that helps activate biopotential.

Paroxysmal activity

This is a recorded indicator indicating a sharp increase in the amplitude of the EEG wave, with a designated source of occurrence. This phenomenon is believed to be associated only with epilepsy. In fact, paroxysm is characteristic of various pathologies, including acquired dementia, neurosis, etc.

In children, paroxysms can be a variant of the norm if there are no pathological changes in the structures of the brain.

Paroxysms look like this: pointed flashes predominate, which alternate with slow waves, and with increased activity, so-called sharp waves (spikes) appear - many peaks coming one after another.

Paroxysm with EEG requires additional examination by a therapist, neurologist, psychotherapist, a myogram and other diagnostic procedures. Treatment consists of eliminating causes and consequences.

In case of head injuries, the damage is eliminated, blood circulation is restored and symptomatic therapy is carried out. For epilepsy, they look for what caused it (tumor, etc.). If the disease is congenital, the number of seizures, pain and negative effects on the psyche are minimized.

If paroxysms are a consequence of problems with blood pressure, treatment of the cardiovascular system is carried out.

Dysrhythmia of background activity

It means irregular frequencies of electrical brain processes. This occurs due to the following reasons:

1. Epilepsy of various etiologies, essential hypertension. There is asymmetry in both hemispheres with irregular frequency and amplitude.
2. Hypertension - the rhythm may decrease.
3. Oligophrenia – ascending activity of alpha waves.
4. Tumor or cyst. There is an asymmetry between the left and right hemispheres of up to 30%.
5. Circulatory disorders. The frequency and activity decreases depending on the severity of the pathology.

To assess dysrhythmia, indications for an EEG are diseases such as vegetative-vascular dystonia, age-related or congenital dementia, and traumatic brain injury. The procedure is also carried out in case of high blood pressure, nausea, and vomiting in humans.

Irritative changes on EEG

This form of disorder is predominantly observed in tumors with a cyst. It is characterized by general cerebral EEG changes in the form of diffuse cortical rhythms with a predominance of beta oscillations.

Also, irritative changes can occur due to pathologies such as:

What is disorganization of cortical rhythmicity?

They appear as a consequence of head injuries and concussions, which can cause serious problems. In these cases, the encephalogram shows changes occurring in the brain and subcortex.

The patient’s well-being depends on the presence of complications and their severity. When insufficiently organized cortical rhythms dominate in a mild form, this does not affect the patient’s well-being, although it may cause some discomfort.

• Migraine
  • Treatment

• Headache
  • At the temples

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Electroencephalography (EEG)

EEG of children has its own characteristics corresponding to the age of the child. The process of EEG formation occurs gradually. It ends by the age of 16-18.

The EEG of an adult is individual; to a certain extent, it reflects his personal characteristics.

In adolescence, the aging processes of the body begin to affect the state of the bioelectrical activity of the brain.

The complex EEG pattern is determined not only by the functional activity of the superficial layers of the brain, but also by distant influences from deep structures.

Forms of bioelectrical activity of the brain

The EEG records regular rhythms corresponding to a certain frequency range. There are: delta rhythm, frequency 1-3.5 per 1 s; theta rhythm, frequency 4-7 per 1 s; alpha rhythm, frequency 8-13 per 1 s; beta rhythm, frequency 14 in 1 s or more.

The bioelectrical activity of the brain is bilaterally symmetrical. This property is determined by the diffuse influences of nonspecific brain systems.

Alpha and beta activity are considered normal components of the EEG. Periodic amplitude modulations give alpha activity a fusiform shape.

There is a gradient in the amplitude of the alpha rhythm across the regions of the hemispheres, its decrease from the posterior to the anterior sections. The alpha rhythm has the greatest amplitude in the occipital regions (up to 100 μV).

The severity of the alpha rhythm can vary significantly. In adults, there are variants when the alpha rhythm is represented very weakly, and sometimes completely absent.

The beta rhythm has an amplitude of 10-15 μV, usually no more than 30 μV, and is better expressed in the fronto-central regions. Depending on the representation of the alpha rhythm, the severity of beta activity also varies. With a weakly expressed alpha rhythm, it becomes the predominant form of biopotentials.

Delta and theta rhythms are classified as pathological components of the EEG. However, the presence of single slow waves or groups of irregular oscillations of small amplitude (15-20 μV), especially in the anterior sections, is acceptable and normal.

A special type of pathological activity of the brain is chemical activity, the basis of which is excessive synchronization of the activity of a huge number of neurons.

Classic electroencephalographic epiphenomena should be considered sharp amplitude waves, peaks, peak-wave complexes, sharp wave - slow wave.

Peak - peak-like potential, duration 5-50 ms, amplitude usually exceeds background activity and can be significant. Peaks are most often grouped into bursts of varying duration.

A sharp wave superficially resembles a peak, but more extended in time, the wave duration is more than 50 ms, the amplitude varies - µV or more.

A peak wave is a complex resulting from the combination of a peak and a slow wave.

A sharp wave - a slow wave is a complex that resembles a peak-wave complex in shape, but has a longer duration.

The listed forms of bioelectrical activity of the brain, depending on their manifestation over time, can be designated by the terms “periods”, “discharges”, “flares”, “paroxysms”, “complexes”.

The identification of hidden brain pathology is facilitated by functional loads: rhythmic light stimulation, sound stimuli, hyperventilation.

EEG studies for various diseases

EEG studies for various diseases - neurological, somatic, mental - provide important information:

1) the presence and severity of brain damage;

2) local diagnosis of brain damage;

3) dynamics of the brain state.

It should be emphasized that EEG changes are nosologically nonspecific. EEG data should be used only in comparison with clinical data and the results of other research methods.

The main indications for conducting EEG studies are:

1) epilepsy, non-epileptic crisis conditions, migraines;

2) volumetric brain lesions;

3) vascular lesions of the brain;

4) traumatic brain injury;

5) inflammatory diseases of the brain.

The diagnostic role of EEG in various diseases is controversial. In the case of severe focal brain lesions (tumor, stroke, trauma), topical diagnosis is of greatest importance. Local shifts in the EEG most often manifest themselves as slow oscillations that stand out in amplitude above the background activity. Changes in biopotentials turn out to be more clear and localized when the pathological process is superficial, more extensive, and spread to other parts of the brain - with damage deep in the hemisphere. Lesions of the brainstem or other midline structures of the brain are usually accompanied by discharges of bilateral synchronous oscillations.

In diseases with severe focal symptoms, assessing the state of working capacity usually does not cause difficulties. In these cases, the presence of persistent local EEG changes is an objective confirmation of the severity of the condition.

Local EEG disturbances after injuries, strokes, persisting for a long time, for several years indicate a persistent lack of functioning of the corresponding areas of the brain.

EEG has a special purpose for detecting and localizing epileptic changes that occur in personal cerebral diseases leading to disability, for example, after severe traumatic brain injury, neuroinfections. The absence of corresponding epileptic potentials on the EEG turns out to be a decisive factor in the differential diagnosis in the case of crisis states of a non-epileptic nature.

When analyzing EEG, in addition to indicating local shifts in biopotentials, the characteristics of diffuse changes are important. With focal cerebral lesions, they reflect the reaction of the brain as a whole to the local pathological process. The general functional state of the central nervous system reflects its compensatory capabilities. There are cases when, despite severe morphological changes, there is a high adaptability of the central nervous system, ensuring the preservation of working capacity, and sometimes, on the contrary, with relatively minor symptoms of a chronic disease, working capacity is reduced due to insufficient compensatory adaptability of the body. The compensatory capabilities of the central nervous system can be judged from dynamic EEG studies. The absence or negative dynamics of local or diffuse EEG shifts indicates low functional reserves of the body, and vice versa.

In connection with the above, information about the characteristics of the general functional state in a wide variety of diseases is of great value: vascular disorders, such as hypertension, atherosclerosis, vertebrobasilar insufficiency, often developing as a result of spinal osteochondrosis, migraines, vegetative-vascular dystonia, endocrine disorders, consequences of traumatic brain injuries and neuroinfections, neuroses, various asthenic, neurasthenic and psychasthenic conditions. Many of the listed diseases occur as additional to the main suffering that leads to disability.

Limbic-reticular complex

According to modern neurophysiological data, the state of the limbic-reticular complex, which is a complex multi-level system of nervous formations united morphologically and functionally, plays an important role in the disruption of integral brain activity. The complex includes the reticular structures of the medulla oblongata, the structures of the ponto-mesencephalic tegmentum, the subthalamic region, the median and intrathalamic nuclei of the thalamus, the region of the posterior hypothalamus, some structures of the olfactory brain, some limbic formations, some basal ganglia (caudal nucleus) and associative zones of the frontal cortex.

The activity of various parts of the brain is realized through the mechanisms of the limbic-reticular complex, which controls the level of wakefulness, regulates cerebral homeostasis, and controls many autonomic and behavioral reactions of the body. It has an organizing effect on the bioelectrical activity of the brain.

Changes in the activity of regulatory systems can be caused by various reasons: primary destructive changes in certain parts of the brain or the state of the regulatory mechanisms themselves as a result of disruption of the blood supply to the corresponding deep structures or as long-term consequences of injuries, neuroinfections leading to increased activity, loss of individual parts of the limbic-reticular complex .

Classification by E. A. Zhirmunskaya and V. S. Losev

To assess the holistic pattern of the EEG, you can use the classification of E. A. Zhirmunskaya and V. S. Losev (1994), who divided all encountered EEG variants into five types.

Type I - organized. The main component of the EEG is the alpha rhythm, characterized by a high degree of regularity, well modulated, and has a good or slightly changed amplitude gradient across brain regions. Refers to a norm or acceptable variants of a norm.

Type II - hypersynchronous (monorhythmic). It is characterized by excessively high regularity of oscillations and violation of zonal differences. Options for enhancing synchronization are possible: with increased oscillations of the alpha range; with the disappearance of the alpha rhythm and its replacement with low-frequency beta activity or theta activity. With a small and medium amplitude of biopotentials, EEG changes can be assessed as slightly or moderately disturbed, and with a large amplitude (from 70-80 μV or more) - as significantly disturbed.

Type III is desynchronous, characterized by an almost complete absence or sharp weakening of alpha activity, with or without an increase in the number of beta oscillations, as well as the presence of a small number of slow waves. The overall amplitude level is low, sometimes low or very low (up to 15 µV). Depending on the amplitude, EEG changes are assessed as mildly or moderately disturbed.

Type IV - disorganized (with a predominance of alpha activity). Alpha activity is insufficiently regular or completely irregular in frequency, has a fairly high amplitude, and can dominate in all areas of the brain. Beta activity is often increased, often represented by low-frequency oscillations of increased amplitude. Along with this, theta and delta waves, which have a fairly high amplitude, can be recorded. Depending on the degree of disorganization of alpha activity and the severity of pathological components, the changes are assessed as moderately or significantly impaired.

Type V - disorganized (with a predominance of theta and delta activity). Alpha activity is poorly expressed. Biopotentials of alpha, beta, theta and delta frequency ranges are recorded without a clear sequence; the non-dominant nature of the curve is observed. Amplitude level is medium or high. The EEG of this group is assessed as very grossly disturbed.

Dysfunction of different levels of the brain, different levels of the limbic-reticular complex is characterized by corresponding changes in the EEG. Desynchronization of biopotentials with dominance of high-frequency beta activity on the EEG and a decrease in the overall amplitude level indicates high activity of the reticular formation of the midbrain and medulla oblongata. Increased synchronization of biopotentials is associated with increased influence from thalamic and hypothalamic formations, as well as the Moruzzi inhibitory center in the caudal part of the brain.

EEG assessment, taking into account the role of the limbic-reticular complex in the organization of integrative brain activity, contributes to the understanding of the pathogenetic mechanisms of a number of diseases and pathological conditions accompanied by instability: autonomic reactions and disorders of the psycho-emotional status of a person.

Reflection in EEG indicators of the state of the regulatory systems of the brain significantly expands the possibilities of practical use of EEG data in the system of medical and labor examination, employment and rehabilitation of disabled people.

Medical rehabilitation / Ed. V. M. Bogolyubova. Book I. - M., 2010. pp. 22-25.

Interpretation of electroencephalography results

EEG analysis is carried out during recording and finally upon its completion. During recording, the presence of artifacts is assessed (induction of mains current fields, mechanical artifacts of electrode movement, electromyogram, electrocardiogram, etc.), and measures are taken to eliminate them. The EEG frequency and amplitude are assessed, characteristic graph elements are identified, and their spatial and temporal distribution is determined. The analysis is completed by the physiological and pathophysiological interpretation of the results and the formulation of a diagnostic conclusion with clinical-electroencephalographic correlation.

The main medical document on EEG is a clinical electroencephalographic report written by a specialist based on the analysis of the “raw” EEG. The EEG conclusion must be formulated in accordance with certain rules and consist of three parts:

1. description of the main types of activity and graphic elements;
2. summary of the description and its pathophysiological interpretation;
3. correlation of the results of the previous two parts with clinical data. The basic descriptive term in EEG is “activity,” which defines any sequence of waves (alpha activity, sharp wave activity, etc.).

• Frequency is determined by the number of vibrations per second; it is written down with the corresponding number and expressed in hertz (Hz). The description provides the average frequency of the assessed activity. Usually, 4-5 EEG segments lasting 1 s are taken and the number of waves in each of them is calculated.
• Amplitude - the range of fluctuations in the electrical potential on the EEG; measured from the peak of the preceding wave to the peak of the subsequent wave in the opposite phase, expressed in microvolts (µV). A calibration signal is used to measure amplitude. So, if the calibration signal corresponding to a voltage of 50 μV has a height of 10 mm in the recording, then, accordingly, 1 mm of pen deflection will mean 5 μV. To characterize the amplitude of activity in the description of the EEG, the most characteristically occurring maximum values ​​are taken, excluding outliers.
• The phase determines the current state of the process and indicates the direction of the vector of its changes. Some EEG phenomena are assessed by the number of phases they contain. Monophasic is an oscillation in one direction from the isoelectric line with a return to the initial level, biphasic is such an oscillation when, after the completion of one phase, the curve passes the initial level, deviates in the opposite direction and returns to the isoelectric line. Vibrations containing three or more phases are called polyphasic. In a narrower sense, the term “polyphasic wave” defines a sequence of a- and slow (usually 5) waves.

Rhythms of the electroencephalogram of an adult awake person

The concept of “rhythm” in EEG refers to a certain type of electrical activity corresponding to a certain state of the brain and associated with certain cerebral mechanisms. When describing a rhythm, its frequency is indicated, typical for a certain state and region of the brain, amplitude and some characteristic features of its changes over time with changes in the functional activity of the brain.

1. Alpha(a) rhythm: frequency 8-13 Hz, amplitude up to 100 µV. It is registered in 85-95% of healthy adults. It is best expressed in the occipital regions. The a-rhythm has the greatest amplitude in a state of calm, relaxed wakefulness with eyes closed. In addition to changes associated with the functional state of the brain, in most cases spontaneous changes in the amplitude of the a-rhythm are observed, expressed in an alternating increase and decrease with the formation of characteristic “spindles” lasting 2-8 s. With an increase in the level of functional activity of the brain (intense attention, fear), the amplitude of the a-rhythm decreases. High-frequency, low-amplitude irregular activity appears on the EEG, reflecting desynchronization of neuronal activity. With a short-term, sudden external irritation (especially a flash of light), this desynchronization occurs abruptly, and if the irritation is not of an emotional nature, the a-rhythm is restored quite quickly (after 0.5-2 s). This phenomenon is called “activation reaction”, “orienting reaction”, “a-rhythm extinction reaction”, “desynchronization reaction”.
2. Beta rhythm: frequency Hz, amplitude up to 25 µV. The beta rhythm is best recorded in the area of ​​the central gyri, but also extends to the posterior central and frontal gyri. Normally, it is expressed very weakly and in most cases has an amplitude of 5-15 μV. The beta rhythm is associated with somatic sensory and motor cortical mechanisms and produces an extinction response to motor activation or tactile stimulation. Activity with a frequency of Hz and an amplitude of 5-7 μV is sometimes called the y-rhythm; it has no clinical significance.
3. Mu rhythm: frequency 8-13 Hz, amplitude up to 50 µV. The parameters of the mu rhythm are similar to those of the normal a rhythm, but the mu rhythm differs from the latter in physiological properties and topography. Visually, the mu rhythm is observed only in 5-15% of subjects in the rolandic region. The amplitude of the mu rhythm (in rare cases) increases with motor activation or somatosensory stimulation. In routine analysis, the mu rhythm has no clinical significance.

Types of activities that are pathological for an adult awake person

• Theta activity: frequency 4-7 Hz, amplitude of pathological theta activity >40 μV and most often exceeds the amplitude of normal brain rhythms, reaching 300 μV or more in some pathological conditions.
• Delta activity: frequency 0.5-3 Hz, amplitude same as theta activity.

Theta and delta oscillations may be present in small quantities on the EEG of an adult awake person and are normal, but their amplitude does not exceed that of the a-rhythm. An EEG containing theta and delta oscillations with an amplitude of >40 μV and occupying more than 15% of the total recording time is considered pathological.

Epileptiform activity is a phenomenon typically observed on the EEG of patients with epilepsy. They arise from highly synchronized paroxysmal depolarization shifts in large populations of neurons, accompanied by the generation of action potentials. As a result of this, high-amplitude, acute-shaped potentials arise, which have appropriate names.

• Spike (English spike - tip, peak) is a negative potential of an acute form, lasting less than 70 ms, with an amplitude >50 μV (sometimes up to hundreds or even thousands of μV).
• An acute wave differs from a spike in that it is extended in time: its duration is ms.
• Sharp waves and spikes can combine with slow waves to form stereotypical complexes. Spike-slow wave is a complex of a spike and a slow wave. The frequency of the spike-slow wave complexes is 2.5-6 Hz, and the period, respectively, is ms. Acute-slow wave - a complex of an acute wave and a slow wave following it, the period of complexes.

An important characteristic of spikes and sharp waves is their sudden appearance and disappearance and a clear difference from background activity, which they exceed in amplitude. Acute phenomena with appropriate parameters that are not clearly distinguished from background activity are not designated as sharp waves or spikes.

Combinations of the described phenomena are designated by some additional terms.

• Burst is a term used to describe a group of waves with a sudden appearance and disappearance, clearly different from background activity in frequency, shape and/or amplitude.
• A discharge is a flash of epileptiform activity.
• An epileptic seizure pattern is a discharge of epileptiform activity typically coinciding with a clinical epileptic seizure. The detection of such phenomena, even if it is not possible to clearly assess the patient's state of consciousness clinically, is also characterized as an “epileptic seizure pattern.”
• Hypsarrhythmia (Greek “high-amplitude rhythm”) is a continuous generalized high-amplitude (>150 μV) slow hypersynchronous activity with sharp waves, spikes, spike-slow wave complexes, polyspike-slow wave, synchronous and asynchronous. An important diagnostic feature of West and Lennox-Gastaut syndromes.
• Periodic complexes are high-amplitude bursts of activity, characterized by a constant form for a given patient. The most important criteria for their recognition are: close to constant interval between complexes; continuous presence throughout the entire recording, subject to a constant level of functional brain activity; intra-individual stability of form (stereotyping). Most often they are represented by a group of high-amplitude slow waves, sharp waves, combined with high-amplitude, pointed delta or theta oscillations, sometimes reminiscent of epileptiform acute-slow wave complexes. The intervals between complexes range from 0.5-2 to tens of seconds. Generalized bilateral synchronous periodic complexes are always combined with profound disturbances of consciousness and indicate severe brain damage. If they are not caused by pharmacological or toxic factors (alcohol withdrawal, overdose or sudden withdrawal of psychotropic and hypnosedative drugs, hepatopathy, carbon monoxide poisoning), then, as a rule, they are a consequence of severe metabolic, hypoxic, prion or viral encephalopathy. If intoxication or metabolic disorders are excluded, then periodic complexes with high certainty indicate a diagnosis of panencephalitis or prion disease.

Variants of the normal electroencephalogram of an adult awake person

The EEG is essentially uniform across the entire brain and symmetrical. The functional and morphological heterogeneity of the cortex determines the characteristics of the electrical activity of various areas of the brain. Spatial changes in EEG types of individual brain regions occur gradually.

In the majority (85-90%) of healthy adults, with their eyes closed at rest, the EEG shows a dominant a-rhythm with maximum amplitude in the occipital regions.

In 10-15% of healthy subjects, the amplitude of oscillations on the EEG does not exceed 25 μV; high-frequency low-amplitude activity is recorded in all leads. Such EEGs are called low-amplitude. Low-amplitude EEGs indicate the predominance of desynchronizing influences in the brain and are a normal variant.

In some healthy subjects, instead of the alpha rhythm, Hz activity with an amplitude of about 50 μV is recorded in the occipital regions, and, like the normal alpha rhythm, the amplitude decreases in the anterior direction. This activity is called the “fast a-variant.”

Very rarely (0.2% of cases), regular, close to sinusoidal, slow waves with a frequency of 2.5-6 Hz and an amplitude of µV are recorded on the EEG with the eyes closed in the occipital regions. This rhythm has all the other topographic and physiological characteristics of the alpha rhythm and is called the “slow alpha variant.” Not being associated with any organic pathology, it is considered as borderline between normal and pathological and may indicate dysfunction of diencephalic nonspecific brain systems.

Electroencephalogram changes in the sleep-wake cycle

• Active wakefulness (during mental stress, visual tracking, learning and other situations requiring increased mental activity) is characterized by desynchronization of neuronal activity; low-amplitude, high-frequency activity predominates on the EEG.
• Relaxed wakefulness is the state of the subject resting in a comfortable chair or on a bed with relaxed muscles and closed eyes, not engaged in any special physical or mental activity. Most healthy adults in this condition show a regular alpha rhythm on the EEG.
• The first stage of sleep is equivalent to dozing. The EEG shows the disappearance of the alpha rhythm and the appearance of single and group low-amplitude delta and theta oscillations and low-amplitude high-frequency activity. External stimuli cause bursts of alpha rhythm. Duration of the stage is 1-7 minutes. By the end of this stage, slow oscillations with an amplitude of 5

The EEG of healthy children may contain excessive diffuse slow waves, bursts of rhythmic slow oscillations, discharges of epileptiform activity, so that from the point of view of traditional assessment of the age norm, even in obviously healthy individuals under the age of 21 years, only 70-80 can be classified as “normal”. % EEG.

From 3-4 to 12 years of age, the proportion of EEG with excess slow waves increases (from 3 to 16%), and then this figure decreases quite quickly.

The reaction to hyperventilation in the form of the appearance of high-amplitude slow waves at the age of 9-11 years is more pronounced than in the younger group. It is possible, however, that this is due to less clear performance of the test by younger children.

Representation of some EEG variants in a healthy population depending on age

Slow diffuse activity greater than 50 µV in amplitude, recorded more than 30% of the recording time

Slow rhythmic activity in the posterior leads

Epileptiform activity, bursts of rhythmic slow waves

“Normal” EEG variants

The already mentioned relative stability of the EEG characteristics of an adult remains until approximately 50 years of age. From this period, a restructuring of the EEG spectrum is observed, expressed in a decrease in the amplitude and relative amount of the alpha rhythm and an increase in the number of beta and delta waves. The dominant frequency of afterflights tends to decrease. At this age, in practically healthy individuals, theta and delta waves also appear visible during visual analysis.

Medical Expert Editor

Portnov Alexey Alexandrovich

Education: Kyiv National Medical University named after. A.A. Bogomolets, specialty - “General Medicine”

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What is the alpha rhythm of the brain? This is the rhythm of electrical activity of the brain on the electroencephalogram with a frequency ranging from 7 to 14 Hz. The amplitude of alpha waves is approximately 5-100 µV. The alpha state of the brain is observed in a calm state and during REM sleep. The occipital lobes support the generation of alpha waves during wakefulness. Hypnosis, meditation, and closing the eyes lead to an increase in the amplitude of alpha waves.

The importance of alpha rhythm for the brain

Alpha brain waves are low frequency and occur during periods of calm. They appear due to the synchronous generation of pacemaker cells in the thalamus and cortex of a weak electric current with the same frequency.

It is believed that keeping the brain in the alpha state helps to reboot the central nervous system and relieve stress accumulated during the day. During this period, the parasympathetic system is activated. It is alpha rhythms that set the body up to restore and accumulate resources after hard work.

Psychotherapists and hypnologists, neurophysiologists believe that scientists have made many outstanding discoveries in science precisely in the alpha rhythm state. Hypnotherapists, introducing the patient into this mode of operation of the central nervous system, treat addictions and chronic diseases associated with stress.

What do alpha rhythms activate?

Why are alpha rhythms needed?

1. Processing of information received during the day.
2. Restoring the body's resources through activation of the parasympathetic system.
3. Improving blood circulation in the brain.
4. Excessive activity of the limbic system is inhibited.
5. Elimination of the effects of stress (vasoconstriction, decreased immunity).

Alpha rhythms created by the brain at rest activate the trophotropic function of the hypothalamus, aimed at restoration processes in tissues. They also calm the overstimulated limbic system, which is responsible for the body's basic needs. It is pathological overexcitation of the limbic system, according to neurophysiologists, that leads to abuse and addiction. Among such disorders one can note an increase in appetite up to bulimia, a tendency to drink alcohol and drugs, and smoking. Also typical are menstrual cycle disorders and diseases of the glands that produce hormones.

With a decrease in alpha activity of the brain, a person is more susceptible to cardiovascular diseases (angina), decreased immunity, and oncology. At the same time, in people with insufficient generation of alpha waves in the brain, negative thinking predominates. Such individuals tend to obsess over their problems, which makes it difficult to find productive solutions to them.

Alpha rhythm in normal and pathological conditions

When conducting an (electroencephalogram), the alpha rhythm index of the brain is assessed, the norm of which is 75-95%. When it decreases below 50%, they speak of pathology. The amplitude of the alpha rhythm decreases sharply at the age of 60 years. This is primarily due to impaired cerebral circulation. The normal wave amplitude is 20-90 µV.

In many brain diseases, such as narcolepsy, essential hypertension, there is an asymmetry of the alpha rhythm in the left and right hemispheres, both in frequency and amplitude. This indicates a violation of interhemispheric integration. Hypertension is characterized by a decrease in the frequency of alpha rhythms in the brain. In oligophrenia, the activity of alpha rhythms is increased.

Disturbance in alpha rhythm synchronization also indicates pathology. In narcolepsy, there is hypersynchronization. A decrease in the amplitude (depression) of alpha waves occurs during light stimulation, carried out to assess the integration of the response of the cortex and subcortical formations to stimulation.

An asymmetry between the left and right hemispheres of more than 30% may indicate the presence of a cyst, tumor, or damage to the corpus callosum in one of the hemispheres. Arc-shaped and paroxysmal alpha rhythm is a pathology. With hypertension, the spindles of the fusiform rhythm can be smoothed out.

If the alpha rhythm does not disappear on the EEG in the frontal lobe when the eyes are closed, then there may be injury in these places. The alpha rhythm can disappear with cerebral sclerosis and blindness, acquired dementia (). Poor circulation reduces the activity and amplitude of alpha waves.

Alpha activity is assessed in vegetative-vascular dystonia, suspected congenital or acquired dementia, trauma and brain tumors. An EEG is prescribed for frequent fainting, osteochondrosis, headaches, high blood pressure, and frequent vomiting. The examination is ordered by a neurologist, who interprets the results.

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The importance of the normal functioning of parts of the brain is undeniable - any deviation will certainly affect the health of the entire body, regardless of the person’s age and gender. Therefore, at the slightest signal of a violation, doctors immediately recommend undergoing an examination. Currently, medicine successfully uses a fairly large number of different methods for studying the activity and structure of the brain.

But if it is necessary to find out the quality of the bioelectrical activity of its neurons, then the electroencephalogram (EEG) is clearly considered the most suitable method for this. The doctor performing the procedure must be highly qualified, since, in addition to conducting the study, he will need to correctly read the results. Competent interpretation of the EEG is a guaranteed step towards establishing the correct diagnosis and subsequent prescription of appropriate treatment.

More about the encephalogram

The essence of the examination is to record the electrical activity of neurons in the structural formations of the brain. An electroencephalogram is a kind of recording of neural activity on a special tape using electrodes. The latter are attached to areas of the head and record the activity of a certain area of ​​the brain.

The activity of the human brain is directly determined by the work of its midline formations - the forebrain and the reticular formation (connecting neural complex), which determine the dynamics, rhythm and construction of the EEG. The connecting function of the formation determines the symmetry and relative identity of signals between all brain structures.

The structure of the brain, based on these data, the specialist deciphers the diagnosis

The procedure is prescribed if there are suspicions of various disorders of the structure and activity of the central nervous system (central nervous system) - neuroinfections such as meningitis, encephalitis, poliomyelitis. With these pathologies, the activity of the brain changes, and this can be immediately diagnosed on the EEG, and in addition, the localization of the affected area can be established. An EEG is carried out on the basis of a standard protocol, which records measurements taken while awake or asleep (in infants), as well as using specialized tests.

The main tests include:

• photostimulation - exposure of closed eyes to bright flashes of light;
• hyperventilation - deep, rare breathing for 3-5 minutes;
• opening and closing eyes.

These tests are considered standard and are used for encephalograms of the brain in adults and children of any age, and for various pathologies. There are several additional tests prescribed in individual cases, such as: clenching your fingers into a so-called fist, staying in the dark for 40 minutes, depriving yourself of sleep for a certain period, monitoring night sleep, and passing psychological tests.

These tests are determined by a neurologist and are added to the main tests performed during the examination when the doctor needs to evaluate specific brain functions.

What can be assessed with an EEG?

This type of examination allows you to determine the functioning of parts of the brain in different states of the body - sleep, wakefulness, active physical, mental activity and others. EEG is a simple, absolutely harmless and safe method that does not require disruption of the skin and mucous membrane of the organ.

Currently, it is widely in demand in neurological practice, since it makes it possible to diagnose epilepsy and highly identify inflammatory, degenerative and vascular disorders in the brain. The procedure also provides identification of the specific location of tumors, cystic growths and structural damage as a result of trauma.

EEG using light and sound stimuli makes it possible to distinguish hysterical pathologies from true ones, or to identify simulation of the latter. The procedure has become almost indispensable for intensive care units, providing dynamic monitoring of comatose patients.

The disappearance of eclectic activity signals on the EEG indicates the onset of death

Process of studying the results

The analysis of the results obtained is carried out in parallel during the procedure, and during the recording of indicators, and continues after its completion. When recording, the presence of artifacts is taken into account - mechanical movement of electrodes, electrocardiograms, electromyograms, and induction of mains current fields. The amplitude and frequency are assessed, the most characteristic graphic elements are identified, and their temporal and spatial distribution is determined.

Upon completion, a patho- and physiological interpretation of the materials is made, and on its basis an EEG conclusion is formulated. Upon completion, the main medical form for this procedure is filled out, called a “clinical electroencephalographic report”, compiled by a diagnostician based on the analyzed data from the “raw” recording.

The transcript of the EEG conclusion is formed on the basis of a set of rules and consists of three sections:

• Description of the leading types of activity and graphic elements.
• Conclusion after description with interpreted pathophysiological materials.
• Correlation of indicators of the first two parts with clinical materials.

The main descriptive term in EEG is “activity”, it evaluates any sequence of waves (sharp wave activity, alpha activity, etc.).

Types of human brain activity recorded during EEG recording

The main types of activity that are recorded during the procedure and subsequently subjected to interpretation and further study are wave frequency, amplitude and phase.

Frequency

The indicator is estimated by the number of wave oscillations per second, recorded in numbers, and expressed in a unit of measurement - hertz (Hz). The description indicates the average frequency of the activity being studied. As a rule, 4-5 recording sections with a duration of 1 s are taken, and the number of waves in each time interval is calculated.

Amplitude

This indicator is the range of wave oscillations of the eclectic potential. It is measured by the distance between the peaks of waves in opposite phases and is expressed in microvolts (µV). A calibration signal is used to measure the amplitude. If, for example, a calibration signal at a voltage of 50 µV is determined on a record with a height of 10 mm, then 1 mm will correspond to 5 µV. In deciphering the results, interpretations are given to the most common meanings, completely excluding rare ones.

Phase

The value of this indicator evaluates the current state of the process and determines its vector changes. On the electroencephalogram, some phenomena are assessed by the number of phases they contain. Oscillations are divided into monophasic, biphasic and polyphasic (containing more than two phases).

Rhythms of brain activity

The concept of “rhythm” in the electroencephalogram is considered to be a type of electrical activity related to a certain state of the brain, coordinated by appropriate mechanisms. When deciphering the EEG rhythm indicators of the brain, its frequency corresponding to the state of the brain region, amplitude, and its characteristic changes during functional changes in activity are entered.

Characteristics of brain rhythms depend on whether the subject is awake or asleep

Rhythms of a waking person

Brain activity recorded on the EEG in an adult has several types of rhythms, characterized by certain indicators and states of the body.

• Alpha rhythm. Its frequency remains in the range of 8–14 Hz and is present in most healthy individuals – more than 90%. The highest amplitude values ​​are observed when the subject is at rest, in a dark room with his eyes closed. It is best identified in the occipital region. It is fragmentarily blocked or completely subsides during mental activity or visual attention.
• Beta rhythm. Its wave frequency fluctuates in the range of 13–30 Hz, and the main changes are observed when the subject is active. Pronounced fluctuations can be diagnosed in the frontal lobes under the obligatory condition of active activity, for example, mental or emotional arousal and others. The amplitude of beta oscillations is much less than alpha.
• Gamma rhythm. The oscillation interval is from 30, can reach 120–180 Hz and is characterized by a rather reduced amplitude - less than 10 μV. Exceeding the limit of 15 μV is considered a pathology causing a decrease in intellectual abilities. Rhythm is determined when solving problems and situations that require increased attention and concentration.
• Kappa rhythm. It is characterized by an interval of 8–12 Hz, and is observed in the temporal part of the brain during mental processes by suppressing alpha waves in other areas.
• Lambda rhythm. It has a small range - 4–5 Hz, and is triggered in the occipital region when it is necessary to make visual decisions, for example, when searching for something with open eyes. The vibrations disappear completely after concentrating your gaze on one point.
• Mu rhythm. Defined by the interval 8–13 Hz. It starts in the back of the head, and is best observed in a calm state. Suppressed when starting any activity, not excluding mental activity.

Rhythms in sleep

• Delta rhythm. Characteristic of the deep sleep phase and for comatose patients. It is also recorded when recording signals from areas of the cerebral cortex located on the border with areas affected by oncological processes. Sometimes it can be recorded in children 4–6 years old.
• Theta rhythm. The frequency interval is within 4–8 Hz. These waves are triggered by the hippocampus (information filter) and appear during sleep. Responsible for high-quality assimilation of information and forms the basis of self-learning.
• Sigma rhythm. It has a frequency of 10–16 Hz, and is considered one of the main and noticeable oscillations of the spontaneous electroencephalogram, which occurs during natural sleep at its initial stage.

Based on the results obtained during EEG recording, an indicator is determined that characterizes a complete all-encompassing assessment of the waves - bioelectrical activity of the brain (BEA). The diagnostician checks the EEG parameters - frequency, rhythm and the presence of sharp flashes that provoke characteristic manifestations, and on these grounds makes a final conclusion.

Decoding of electroencephalogram indicators

In order to decipher the EEG and not miss any of the smallest manifestations in the recording, the specialist needs to take into account all the important points that may affect the indicators being studied. These include age, the presence of certain diseases, possible contraindications and other factors.

Upon completion of the collection of all data from the procedure and their processing, the analysis is completed and then a final conclusion is formed, which will be provided for making a further decision on the choice of therapy method. Any disturbance in activity may be a symptom of diseases caused by certain factors.

Alpha rhythm

The normal frequency is determined in the range of 8–13 Hz, and its amplitude does not go beyond 100 μV. Such characteristics indicate a healthy state of a person and the absence of any pathologies. The following are considered violations:

• constant fixation of the alpha rhythm in the frontal lobe;
• exceeding the difference between the hemispheres by up to 35%;
• constant violation of wave sinusoidality;
• presence of frequency dispersion;
• amplitude below 25 μV and above 95 μV.

The presence of disturbances in this indicator indicates a possible asymmetry of the hemispheres, which may be the result of oncological tumors or pathologies of cerebral circulation, for example, stroke or hemorrhage. A high frequency indicates brain damage or TBI (traumatic brain injury).

Stroke or hemorrhage is one of the possible diagnoses for functional changes in the alpha rhythm

A complete absence of the alpha rhythm is often observed in dementia, and in children, deviations from the norm are directly related to mental retardation (MDD). Such a delay in children is evidenced by: disorganization of alpha waves, shift of focus from the occipital region, increased synchrony, short activation reaction, overreaction to intense breathing.

These manifestations can be caused by inhibitory psychopathy, epileptic seizures, and a short reaction is considered one of the primary signs of neurotic disorders.

Beta rhythm

In the accepted norm, these waves are clearly detected in the frontal lobes of the brain with a symmetrical amplitude in the range of 3–5 μV, recorded in both hemispheres. A high amplitude leads doctors to think about the presence of a concussion, and when short spindles appear, to the occurrence of encephalitis. An increase in the frequency and duration of spindles indicates the development of inflammation.

In children, the pathological manifestations of beta oscillations are considered to be a frequency of 15-16 Hz and a high amplitude present - 40-50 µV, and if its localization is the central or anterior part of the brain, then this should alert the doctor. Such characteristics indicate a high probability of delayed development of the baby.

Delta and theta rhythms

An increase in the amplitude of these indicators above 45 μV on a constant basis is characteristic of functional brain disorders. If the indicators are increased in all brain regions, then this may indicate severe dysfunction of the central nervous system.

If a high amplitude of the delta rhythm is detected, a tumor is suspected. Inflated values ​​of the theta and delta rhythm recorded in the occipital region indicate a child’s lethargy and a delay in his development, as well as impaired circulatory function.

Decoding values ​​in different age intervals

An EEG recording of a premature baby at 25–28 gestational weeks looks like a curve in the form of slow flashes of delta and theta rhythms, periodically combined with sharp wave peaks 3–15 seconds long with a decrease in amplitude to 25 μV. In full-term infants, these values ​​are clearly divided into three types of indicators. During wakefulness (with a periodic frequency of 5 Hz and an amplitude of 55–60 Hz), the active phase of sleep (with a stable frequency of 5–7 Hz and a fast low amplitude) and quiet sleep with flashes of delta oscillations at a high amplitude.

Over the course of 3-6 months of a child’s life, the number of theta oscillations is constantly growing, while the delta rhythm, on the contrary, is characterized by a decline. Further, from 7 months to a year, the child develops alpha waves, and delta and theta gradually fade away. Over the next 8 years, the EEG shows a gradual replacement of slow waves with fast ones - alpha and beta oscillations.

Rhythm indicators undergo regular changes depending on age

Until the age of 15, alpha waves predominate, and by the age of 18, the BEA transformation is complete. Over the period from 21 to 50 years, stable indicators remain almost unchanged. And from 50, the next phase of rhythmicity restructuring begins, which is characterized by a decrease in the amplitude of alpha oscillations and an increase in beta and delta.

After 60 years, the frequency also begins to gradually fade, and in a healthy person, manifestations of delta and theta oscillations are noticed on the EEG. According to statistics, age indicators from 1 to 21 years, considered “healthy,” are determined in subjects 1–15 years old, reaching 70%, and in the range of 16–21 – about 80%.

The most common diagnosed pathologies

Thanks to the electroencephalogram, diseases such as epilepsy or various types of traumatic brain injury (TBI) are quite easily diagnosed.

Epilepsy

The study allows you to determine the localization of the pathological area, as well as the specific type of epileptic disease. At the time of a convulsive syndrome, the EEG recording has a number of specific manifestations:

• pointed waves (peaks) - suddenly rising and falling can appear in one or several areas;
• the combination of slow pointed waves during an attack becomes even more pronounced;
• sudden increase in amplitude in the form of flashes.

The use of stimulating artificial signals helps in determining the form of epileptic disease, since they provide visibility of hidden activity that is difficult to diagnose with EEG. For example, intense breathing, requiring hyperventilation, leads to a decrease in the lumen of blood vessels.

Photostimulation is also used, carried out using a strobe (a powerful light source), and if there is no reaction to the stimulus, then most likely there is a pathology associated with the conduction of visual impulses. The appearance of non-standard vibrations indicates pathological changes in the brain. The doctor should not forget that exposure to powerful light can lead to an epileptic seizure.

TBI

If it is necessary to establish a diagnosis of TBI or concussion with all its inherent pathological features, EEG is often used, especially in cases where it is necessary to establish the location of the injury. If the TBI is mild, then the recording will record insignificant deviations from the norm - asymmetry and instability of rhythms.

If the lesion turns out to be serious, then, accordingly, deviations in the EEG will be pronounced. Atypical changes in recordings that worsen over the first 7 days indicate extensive brain damage. Epidural hematomas are most often not accompanied by a special clinical picture; they can only be identified by a slowdown in alpha oscillations.

But subdural hemorrhages look completely different - with them, specific delta waves are formed with bursts of slow oscillations, and at the same time alpha is upset. Even after the disappearance of clinical manifestations, general cerebral pathological changes due to TBI may still be observed on the recording for some time.

Restoration of brain function directly depends on the type and extent of the lesion, as well as its location. In areas exposed to disturbances or injuries, pathological activity may occur, which is dangerous for the development of epilepsy, therefore, in order to avoid complications of injuries, you should regularly undergo an EEG and monitor the status of the indicators.

Regular examination of the brain after TBI will allow timely detection of complications

An encephalogram is a simple way to keep many brain disorders under control.

Despite the fact that EEG is a fairly simple research method that does not require intervention in the patient’s body, it has a fairly high diagnostic ability. Detection of even the smallest disturbances in brain activity ensures a quick decision on the choice of therapy and gives the patient a chance for a productive and healthy life!

It is known that in the human brain there is an innumerable number of synaptic connections that provide our higher nervous activity. The number of neurons themselves - the main cells of the brain - is from 10 billion to 50 billion. Depending on various reasons, the neural network is damaged, and then various diffuse changes in the bioelectrical activity of the brain begin to progress.

Bioelectric activity of the brain: basic rhythms

Bioelectrical activity is literally the electrical vibrations of the brain. The neurons that create a huge network in it have their own electrical wave. These waves are recorded by EEG, and the data obtained through the study can tell a lot about the state of health and psyche of an individual.

Biowaves (or rhythms of brain activity) are divided depending on amplitude and frequency:

• beta waves - 14-40 Hertz, amplitude - up to 20 µV;
• alpha - 8-13 Hz, wave amplitude - 5-100 µV;
• gamma - above 30 Hz, occasionally up to 100 Hz, amplitude - up to 15 μV;
• delta - 1-4 Hz, amplitude - 20-200 µV.

There are other, less studied waves; we have listed only the main ones. And what happens if during the study mild diffuse changes in the bioelectrical activity of the brain are detected? We will now look at this issue.

Diffuse changes: symptoms

How do mild diffuse changes in the bioelectrical activity of the brain manifest themselves? Symptoms of changes will be noticeable even with the slightest changes in the normal activity of the biocomputer. As a rule, they are as follows:

• dizziness;
• slowness, weakness.
• With increasing changes, headaches and cramps appear.

The psyche also changes under the influence of changes in the brain. A person experiences sudden changes in mood, his behavior begins to seem hysterical to others. The circle of interests narrows, the motivation to act disappears. It becomes increasingly difficult for the patient to remember new information.

If these symptoms persist for a long time, you should urgently consult a doctor and get a diagnosis. Diffuse changes in the bioelectrical activity of the brain are a very serious disease. More precisely, its harbinger. If nothing is done, the condition worsens very quickly.

Pronounced and moderate changes

Moderate diffuse changes in the bioelectrical activity of the brain do not cause any harm, at least immediately. But the ultra-precise harmony of the universal system has already been disrupted, and soon these changes are likely to develop into more serious problems.

It happens that along with a disturbance in brain activity, disturbances in the functioning of its basic structures are revealed. This means that the thalamus or hypothalamus may be affected. As a result of such disorders, various endocrine or neurological syndromes arise.

The fact that pronounced diffuse changes in the bioelectrical activity of the brain begin is indicated by the onset of seizures. A person may develop a seizure disorder that has not previously bothered them. Or, more and more often, the pressure jumps for no reason. Seizures are a rather alarming symptom and can lead to the development of epilepsy.

Irritative changes

The term “irritation” belongs to the science of neurology. Under this name lies a large number of potential damage to brain structures. Irritation itself is not a syndrome or a disease; it serves as an indication of irritation of certain brain structures.

Diffuse irritative changes in the bioelectrical activity of the brain lead to changes in the perception of one’s own body or to speech dysfunctions. Problems with the hypothalamus explain the mental phenomenon of depersonalization. This is a personality disorder in which a person perceives himself externally. However, these are complex irritative disorders. Mild deviations are characterized only by a deterioration in general well-being and some mood swings.

Reasons for changes

Diffuse changes in the bioelectrical activity of the brain are not inherited and do not arise out of nowhere. These anomalies are a consequence of disruption of certain brain processes, and sometimes damage to neural connections. What else leads to disturbances in the functioning of the central nervous system:

1. Anemia (anemia). The brain receives little oxygen, and cells—neurons—starve.
2. Atherosclerosis of cerebral vessels.
3. Inflammation due to infection (meningitis, encephalitis, arachnoiditis).
4. Associated disorders. Often the cause of this condition is a persistent metabolic disorder and lack of sleep.

In case of gross changes in brain activity, examination usually reveals:

• necrotic processes;
• scarring;
• brain swelling.

The causes of such serious conditions are injuries and bruises. A neurologist should strictly monitor all changes. Such a disease cannot be left to chance.

Changes in the cortex

Damage to the fields of the cerebral cortex leads to various disorders of behavior and consciousness. After all, this area is responsible for our higher nervous activity.

So, sometimes one zone is damaged, and sometimes several. Let's look at examples:

• If the occipital lobe is subject to any changes, attacks of hallucinations are observed.
• Central gyrus - there are epileptic seizures that begin with twitching of an arm or leg.
• Posterior central gyrus. The patient experiences numbness or tingling sensations throughout the body.
• Adversive field - convulsions with loss of consciousness.

These are local signs of bark irritation. When it is not possible to determine the localization of various attacks during the study, and the EEG shows deviations in rhythms, diffuse changes in the bioelectrical activity of the cerebral cortex are evident. This also results in hearing or vision impairment and olfactory hallucinations. Various attacks of twitching of the head or other parts of the body are also observed when the convulsive threshold is significantly reduced.

Diagnosis and treatment

To establish a diagnosis, the patient must undergo a set of diagnostic procedures and give the doctor a comprehensive anamnesis (history of symptoms that worry the person). The first study is an EEG, then rheoencephalography (REG) is needed. REG is an examination of the blood vessels of the brain, necessary to find out whether there is stagnation of blood. An MRI is also needed. Tomography will give the doctor an accurate answer to the question of the presence of a tumor. And if there is one, then what type.

As for the treatment of such patients, diffuse changes in the biological activity of the brain are treated only in the clinic under the supervision of an expert neurologist.

Immediate contact with a neurologist increases the chances of full recovery, even if parts such as the pituitary gland, pineal gland, thalamus or hypothalamus (diencephalic structures) are affected. It will take almost a year. Unexpressed changes are treated much faster - within just 2 or 3 months.

EEG interpretation

If something in the brain is abnormal, what does the EEG show? The specialist immediately sees diffuse changes in the bioelectrical activity of the brain. After all, disturbances in normal rhythms are significant:

• They manifest themselves in the form of wave asymmetry.
• There are visible disturbances in the distribution of the main beta, gamma). Their usual frequency and amplitude are beyond the normal range. When, for example, the EEG shows an increase in the beta rhythm by 2-3 times against the background of some foci of epileptoid activity, there is about a 50% chance of the onset of epileptic seizures.
• Brain activity is polymorphic and polyrhythmic.

All 3 pathological aspects must be present for the diagnosis to be confirmed.

During EEG, photostimulation is required. Signs of normality when stimulating the brain with light flashes include the appearance of a wave rhythm equal to the frequency of the flashes. An excess of 2 times is also considered normal. However, if the rhythm is lower than the initial frequency of flashes or is repeatedly exceeded, this is an unambiguous sign of deviations.

The amplitude of the waves is measured from one peak to another. In this case, the isoelectric line is not taken into account. The frequency of brain waves on the EEG is determined using the rhythm index. All normal indicators and those that characterize waves of people with various diseases (Parkinson, autism) are in a special database.

For specialists working with these brain problems, it is important to train for a long time in “reading” encephalograms, using such databases. After correlating the patient’s indicators with normal values, the doctor draws up a conclusion.

Prevention

The most common cause of diffuse changes is circulatory disorders due to vascular atherosclerosis. Atherosclerosis develops against the background of poor nutrition. Some drugs can strengthen vascular walls, one of them is Ginkgo Biloba. And drugs of the statin class are now capable of lowering cholesterol levels. Fibrates reduce the ability to synthesize fats, thereby preventing the development of atherosclerosis.

And, of course, you need to take care of your head, since diffuse disorders after blows and head injuries take a long and difficult time to treat. But if you take care of the harmonious system of synaptic connections, monitor your diet and give yourself time for proper rest, your brain will function flawlessly and accurately for a long time.