What is an eeg medical test. An electroencephalogram (EEG) is a test that measures and records the electrical activity of your brain. . . See additional . WebMD does not provide medical advice . . An electroencephalogram (EEG) is a medical test that is performed by doctors and used to diagnose seizure disorder in patients. . An electroencephalogram (EEG) is a test to detect problems in the electrical activity of . Vorvick, MD, Medical Director, MEDEX Northwest . Describes what an EEG is, and w... more