Why an EEG?

An electroencephalogram (EEG) measures the electrical activity of the brain.

The most common reason for performing an EEG is to diagnose epilepsy. An EEG can help examine other diseases or disorders such as sleep disorders, a brain infarction, metabolic disorders, ADHD, headache, etcetera. An EEG can also be useful to evaluate brain activity after severe head trauma.

The procedure takes about 25 minutes, is completely pain free and is performed while you are awake. An EEG is a snapshot and only provides information about the time that the measurement was taken.

Course of an EEG

The EEG is performed at the Psychiatry Outpatients Clinic. The test can also be performed in the department where the patient was admitted, though this is less common.

The EEG nurse places the electrodes on your head using a type of cap. Next, a conductive gel is injected between the electrode and the scalp, which may feel slightly cold. Each electrode is connected through a wire with an amplifier and the measuring equipment. The electrical brain signals are then converted into waveforms.

During the test, the light is dimmed and you are asked to move as little as possible to avoid noise in the signal. The EEG nurse will ask you to open and close your eyes. During a second part of the test, you will need to take deep breaths in and out for three minutes. During the last few minutes of the test, a flashing light will be used (stroboscopy).

When the test is completed, the EEG nurse will remove the cap with the electrodes.

Practical information:

  • Do you wear a hearing aid? This may have to be removed to prevent interference.


An EEG is only reimbursed by the health insurance once a year, with the exception of patients who have epilepsy and a reduced level of consciousness.

More information?

You may always contact the attending physician should you have any further questions.

Centres and specialist areas

Psychiatric Department (PAAZ)

Latest publication date: 17/01/2022
Supervising author: Dr Raemdonck Jan, Dr Aers Isabelle