Electroencephalography is a brain research method based on the registration of the difference in electrical potentials that occurs during the life of the brain.
The first in 1849 began to study the electrical processes of the brain D. Reymond, who proved that the brain has electrogenic properties, along with nerves and muscles. In 1913, V.V. Pravdich-Neminsky published the first electroencephalogram of the dog’s brain, laying the foundation for electroencephalographic research there. But the first EEG recording of the human brain appeared only in 1928, it was obtained by Hans Berger, an Austrian psychiatrist.
EEG data recording of the brain is performed using electrodes located in certain areas of the head, taking into account the main parts of the brain. From 16 to 24 (or more) amplification-recording channels (blocks) are provided, which allow simultaneously recording the electrical activity recorded by the electrodes. The resulting record is called an electroencephalogram, and is an indicator of the total electrical activity of millions of neurons, which is mainly represented by the potentials of the bodies of nerve cells and dendrites. After the procedure, the EEG is decrypted.
Very often, during the examination, a change of rhythms is recorded, having their own amplitude, reactivity, morphology and topography. The following frequency ranges of rhythms are: delta rhythm (up to four Hertz), theta rhythm (four to eight Hertz), alpha rhythm (eight to thirteen Hertz) and beta rhythm (fourteen or more Hertz). The most physiological for a mature, calm, awake person is the alpha rhythm, which is determined when the eyelids are lowered above the posterior lobes of the brain. However, there are various types of physiological norms that take into account the nervous state and age of the patient. Throughout a person’s life, various variations of rhythm change are determined on an EEG.
Electroencephalography, or EEG of the brain, reflects the state of the cerebral cortex, subcortical brain structures, as well as the quality of the cortical-subcortical interaction, which makes it possible to determine the presence of latent pathology, residual lesion, and other abnormalities that have not yet been identified. In addition, the EEG of the brain provides the necessary diagnostic information on the rate of maturation of the nervous system (for diagnosis in childhood), cerebral changes and brain damage, pathological foci, epileptiform or epileptic activity. Also, this type of diagnosis allows you to track the course of the disease, adjust treatment and make any predictions.
The expanded EEG conclusion helps to correctly diagnose the type of epileptic seizures, as well as in the differential diagnosis of other paroxysmal diseases, such as migraine, fainting, panic attacks and autonomic crises.
This examination is absolutely painless and harmless. During the examination, the patient sits with his eyes closed, relaxed, in a comfortable chair, that is, in a state of passive wakefulness. In the case of an EEG, the child must be convinced of the painlessness of the examination and tell what exactly will happen. During the study, the patient should be full, because a feeling of hunger can affect the results of the EEG. The head must be thoroughly washed, which will make the contact of the electrodes with the scalp more high-quality. In addition, the results depend on the age of the patient, the medication taken, the presence of tremor of the head and limbs, skull defects and visual impairment. All these factors can affect the correct interpretation of EEG data and their further use.