Brainwave patterns is measured with Electroencephalography (EEG), which is the recording of electrical activity along the scalp. It measure the flows within the neurons of the brain. It is medically used to diagnose illnesses, but is also used for e.g. cognitive psychology, neuroscience, and psychophysiological research. It is divided into four different frequency spans, where the brain waves e.g. can show the over speeding of the brain in a stressed mode.