An EEG is a test that detects abnormalities in your brain waves or 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. The charges are amplified and appear as a graph on a computer screen, or as a recording that may be printed out on paper. Your healthcare provider then interprets the reading. 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 test the brain activity of someone in a coma.