An EEG is a test that detects abnormalities in your brain waves, or in the electrical activity of your brain. During the procedure, electrodes consisting of small metal discs with thin wires are pasted onto your scalp. The electrodes detect tiny electrical charges that result from the activity of your brain cells.

What is an EEG test used to diagnose?

The electroencephalogram (EEG) is a medical test used to measure the electrical activity of the brain. A number of electrodes are applied to your scalp. EEG can help diagnose a number of conditions including epilepsy, sleep disorders and brain tumours.

Why would a doctor order an EEG?

Most commonly, healthcare providers use an EEG to check for seizure activity related to epilepsy. EEGs can also help monitor health conditions or find out what's causing certain symptoms. Healthcare providers may use an EEG during brain surgery or to test the brain activity of someone in a coma.