Electroencephalogram

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 to 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.

Course of an EEG

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

The EEG is performed at the neurology outpatients clinic. The test can also be performed in the department where the patient was admitted, though this is less common.

The EEG nurse applies the electrodes to your head with a kind 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 wave patterns.
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 examination, you will need to take deep breaths in and out for three minutes.
During the last few minutes of the examination, a flashing light will be used (stroboscopy).
When the test is completed, the EEG nurse will remove the cap with the electrodes.