An electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which measures the electrical activity of the heart over time. It measures the potential difference between points on the chest as a function of time.
Chadwick Medical Associates
The EEG records brainwave patterns from the continuous tiny electrical signals coming from the brain.
The electrodes are placed on the head. The EEG machine then magnifies the size of these signals, without affecting the brain. The information can be recorded on paper or computer.