An electroencephalogram (EEG) machine EEG machine works by tracking and recording electrical activity of the brain in form of wave pattern. The instrument has electrode discs which are placed on ones scalp and then the electrical activity of the brain is detected and signals send to the computer which shows the result in form of a wave pattern. The doctors can there be able to detect any abnormal wave pattern and be able to diagnose if one is having seizure, stroke, tumor, epilepsy, brain death, coma or any other brain related abnormality.