Preparation for an EEG

EEG is a functional, non-invasive method that registers the electrical activity of neurons (brain cells). The brain is made up of billions of neurons that are electrically active, thanks to the electrical activity on their membranes. They communicate through electrical impulses and are active all the time, even when you are sleeping. This activity is displayed as a wavy line on the EEG image.

The main value of this examination is in the diagnosis of disorders of consciousness. It is also used for headaches, dizziness, movement disorders (e.g. tics), behavioral and communication disorders, sleep disorders, after head trauma, in some metabolic disorders, etc.

How is EEG performed?

EEG is non-invasive, painless, non-harmful and does not use radiation. It shows the current function (activity) of the brain cells, which may change depending on the condition of the person we are recording (alertness, sleep, drowsiness, hunger, fatigue, headache, sleepless night). Therefore, the same person in different conditions may have different EEG findings.

Recording in children is performed by placing a cap on the head in the form of a net to which electrodes (small metal disks) are fixed, and they are additionally gel-glued to the surface of the head after fixing the cap.

The recording is performed in the lying or sitting position with the eyes closed. Older children are asked to open and close their eyes during the recording. The duration of the recording in an alert state is 30 minutes, and during the activation some activation techniques (which “excite” or provoke brain cell activity), such as deep breathing and photo-stimulation (“flash”), may be performed. Young children are usually recorded in natural sleep for the sake of co-operability. An EEG recording is especially valuable after a sleepless night. It is most commonly used when processing disorders of consciousness. For this type of examination, the child must be specially prepared.


  1. The child should go to sleep at the usual time, waking up around midnight (older children) or around 4 a.m (younger children). It is important that the child, after waking up, does not fall asleep again until the start of the examination, as EEG imaging must be performed when the subject is sleepy or asleep.
  2. For older children, teenagers, it is advisable to omit sleeping medication, tranquilizers, muscle relaxants, coffee, tea or chocolate for 8 hours prior to recording. These agents may affect the finding. The usual prescribed medication should be taken on schedule.
  3. It is also advisable to take a small light meal before recording because hypoglycaemia (hunger) can also affect electrical activity.
  4. As the electrodes are additionally attached with a special gel to the scalp, it is necessary to have freshly washed hair (only using shampoo) without any accessories for styling or fixing the hairstyle (i.e. without hairspray, gel, etc.).