EEG decoding in childhood, norm and pathology

The main methods for diagnosing epilepsy are magnetic resonance imaging and electroencephalogram. The article will discuss the EEG of the brain: what is it, decoding in children.

An encephalogram is a method for studying the bioelectrical activity of the brain. This study allows you to determine the activity of neurons in different parts of the brain, the presence of pathological patterns (discharges) that indicate pathology. The harmlessness of diagnostics allows it to be widely used in childhood. Based on the results of the study, epileptiform activity, indications for MRI and the direction of further treatment are determined.

Epileptiform activity on the EEG in a child – what does it mean? The term epileptiform activity is understood as electrical oscillations recorded on the EEG in the form of sharp waves and peaks that differ from the general activity by more than 50%. The presence of epileptiform activity on the EEG may indicate the presence of epilepsy.

Indications for research in children

A study is prescribed to diagnose various neurological and psychiatric diseases in children. Such diseases include:

• Delayed speech development: a differential diagnosis between dysarthria (a disorder in the speech apparatus) and pathology of the speech centers of the brain.
• Different types of epilepsy, from generalized to myoclonus in certain muscle groups.
• Tics: to exclude the central genesis of the disease and disturbances in the electrical activity of the brain.
• Autism, impaired behavior of the child (aggressiveness, etc.), attention deficit hyperactivity disorder.
• Enuresis or bedwetting.
• Sleep disorders, including somnambulism (sleepwalking – sleepwalking): it is necessary to conduct an EEG during a night’s sleep.
• Brain trauma (concussions, bruises, and so on) – to identify foci of abnormal bioelectrical activity.
• If a child’s brain cancer is suspected , the lesion will show pathological signals, while it may not yet be visualized on MRI.
• Frequent headaches for which no explanation has been found.
• Cognitive impairments: poor memory, poor school performance, attention deficit, excessive distraction, and so on.

How is the research done?

Electrodes are installed on the scalp in the projection of various parts of the brain, there are usually 19 of them, they are attached symmetrically on both sides of the head and in the center, a “cap” can be immediately put on, without the need to attach each electrode separately. An ECG sensor is also attached to the chest area; additional sensors ( myographic ) are often needed . At the same time, the child leads a normal life: walks, eats, plays in sedentary games (mosaics, dolls and others), and smart technology records the activity of the baby’s brain.

On the eve, the mother needs to prepare the child for the examination:

• Wash your hair, as excess sebum breaks the tight contact of the electrode with the scalp and distorts the examination result.
• Remove jewelry (earrings, hairpins, piercings).
• If the child is very small or shows aggression, is too restless, then it is recommended to carry out premedication , in the capacity of which sedatives act.
• Sometimes sleep deprivation is recommended, which is carried out in order to increase the information content of the study.
• It is not recommended to feed the child with energy products on the eve of the study: chocolate, strong tea, coffee, energy drinks, and so on.
• Warn the functional diagnostics doctor about all medicines that the child receives in detailed dosages and frequency of use.

How is it decrypted and what can you see?

Deciphering the EEG indicators of the brain in children takes quite a long time. Results are usually given after a few days. Since electrical indicators from all leads are analyzed, all peaks and waves are evaluated, their synchronicity, symmetry.

Parents are given a conclusion, a printout of the fragments of the recording selected by the doctor and, in specialized centers, a disc with a recording of the entire study. Sometimes the doctor can give recommendations for further examination.

It will not be possible to independently understand how to decipher the EEG of the brain in children, even with a very strong desire. Only a specialist can decipher the waves of electrical activity, especially in children, in whom even the norm has many variations, depending on the age of the child.

It is customary to distinguish the following basic rhythms of electrical activity on the EEG:

• Alpha rhythm (or the predecessor of the alpha rhythm in children under 5 years of age). It is recorded in a state of rest, in which the child sits or lies with his eyes closed and does nothing.
• Beta rhythm. It is detected with maximum concentration of attention: fast waves indicate active wakefulness.
• Theta rhythm. With a normal picture of the EEG in healthy children 2-8 years old, it is one of the main rhythms, it is a wave, in amplitude slightly exceeding the alpha rhythm. The appearance of such indicators in an older age may indicate a delay in mental development, a consultation with a geneticist may be required.

Also, when decoding the EEG in children, the synchronicity of electrical potentials in both hemispheres is assessed. Impaired synchronization indicates the presence of a pathological focus. It can be represented by a tumor, epileptic focus, vascular malformation, and so on.

Registration of epileptiform patterns is an important part of the study. Benign childhood epileptiform patterns are now considered a normal variant in the absence of epileptic seizures and regression in the development of the child.

With multiple occurrence of discharges on the EEG, it is necessary to evaluate the clinic, it may be necessary to consult the baby with a psychologist and psychiatrist. It is necessary to decipher such results and make a diagnosis taking into account additional research methods.

Should you trust research?

Encephalogram is a functional research method, therefore, the results often largely depend on the child’s condition at the time of the examination. If a doctor, for example, sees dysarrhythmia , the presence of a large number of theta waves in a child over 8 years old when decoding an EEG of the brain , do not immediately try to make diagnoses. Perhaps the kid simply reacted negatively to the study, because children are quite emotional.

Of course, if serious deviations are found, with the formation of foci of abnormal activity, indicating the presence of an epileptic focus, additional examination is required. The electrical method will only indicate the approximate localization of the focus (lobe of the brain). The most accurate determination of the localization of the process and the possible cause (vascular, neoplastic, atrophy due to intrauterine oxygen starvation of the brain, and so on) is possible only with the use of neuroimaging methods , primarily MRI.

How often should the study be repeated?

If the diagnostics did not show significant changes in cerebral electrical activity, then re-examination in the absence of new symptoms may not be carried out.

When epileptiform activity is detected, the encephalogram will become the main objective diagnostic criterion for the effectiveness of the prescribed therapy.

The study should be repeated at least every year, preferably once every 6 months. Evaluation of the dynamics will allow adjusting therapy to prevent recurrent seizures (increasing or decreasing doses of antiepileptic drugs).

Even after the diagnosis of epilepsy has been removed, it is necessary to repeat the encephalogram for another 1-5 years (depending on the diagnosis) to prevent a possible relapse. After surgery, an annual study is also recommended for several years. This will avoid many complications.