[EN] What is EEG?

Electroencephalography (EEG) is a non-invasive medical test used to measure the electrical activity of the brain.

EEG is performed by using an electroencephalograph. This device can monitor and detect bioelectric activity of the brain by recording the changes of the electrical potential on the scalp surface generated by neurons activity in the cerebral cortex.

EEG examination is usually carried out by trained EEG technician and the recording is analysed by a specialist. The whole procedure is completely painless and harmless. During EEG examination, the electrodes connected to the head of bioelectric amplifier​​ get attached to specific locations on the scalp. This procedure allowes to record the signal in the form of brain waves.

Depending on the indications, the examination may be carried out in several stages:

• in a state of rest (wakefulness), with a relaxed and rested patient, cooperating with the technician performing the examination;
  
• n a state while you’re asleep, depending on the patient’s age – after a sleepless or incomplete night;
  

Furthermore in order to detect abnormalities during EEG recording, the additional stimulation tests are carried out: photostimulation (light flashes of variousfrequencies) and hyperventilation (taking deep and rapid breaths).

Routine EEG recording usually lasts from 30 to 40 minutes.

The examination is helpful in diagnosing neurological disorders of various types including patients of all age groups.

EEG may be useful In diagnosing:

• loss of consciousness and fainting,
• headaches and dizziness,
• convulsions of unclear nature, tics
• seizure disorders
• epilepsy,
• sleep disorders,
• children’s psychomotor development disorders,
• cognitive and learning disorders,
• emotional disorders, concentration, anxiety
• memory disorders
• cerebrovascular diseases,
• stroke,
• previous craniocerebral injuries

The examination is ordered by a doctor, most often a neurologist or psychiatrist but the doctor’s referal is not necessary for it to be carried out.

EEG procedure before the examination:

• the test is carried out after a meal – before the test you should eat a light meal to prevent the drop of blood sugar level, which may affect brain activity,
•  the patient should be completely healthy
• the medicines prescribed by your doctor should be taken as directed
•  substances used on your own should be discontinued 2-3 weeks before the examination date
•  the day before the EEG, you should not drink alcohol or take intoxicants, it is also recommended not to consume drinks containing caffeine (coffee, cola, energy drinks or strong tea)
•  in the 24 hours preceding the examination, you should not take medications that stimulate or depress the central nervous system (hypnotics, sedatives)
•  the patient should have washed hair, not covered with any cosmetics (gels, hair spray, conditioners)
•  depending on the indications, the patient should be rested and well slept before the examination, or deprived of sleep for a specific period of time appropriate to patient’s age.

Detailed instructions on how to prepare for the examination are provided individually by the EEG technician.