The electroencephalography, or EEG, is a method to measure electric brainwaves by registering voltage fluctuations of the brain. These forms of voltage fluctuations allow statements about the brain activity and the state of consciousness. See: brain current, event-related potentials (ERP). The recording of electrical activity of the brain, the electroencephalogram, is created by placing surface electrodes on the cranial surface. The EEG was discovered by Hans Berger in 1924 (published in 1929).