An electroencephalogram (EEG) is a test that finds electrical activity in your brain using tiny, flat metal discs (electrodes) placed on your scalp. Your brain cellular material communicate via electrical impulses and so are active all the time, even when you happen to be asleep. This activity shows up as wavy lines while on an EEG recording. Electroencephalography (EEG) is an electrophysiological monitoring method to record electrical activity in the brain.