An electroencephalogram is one of the main diagnostic tests for epilepsy. The EEG detects abnormalities in the brain waves or electrical activity of the brain. Electrodes attached to your scalp detect tiny electrical charges that result from the activity of the brain cells. Your brain cells communicate via electrical impulses and are active at all times. The charges are amplified and appear as a graph on a computer screen or as a recording that may be printed out on paper for your doctor to interpret. When epilepsy is present, seizure activity will appear as rapid spiking waves on the EEG. The test can also be used to diagnose other disorders that influence brain activity.