Electrode Placement Systems and Montages

Abstract

When Hans Berger recorded the first human EEG, he only had two electrodes available, positioned in the anterior and posterior regions of the head. Berger kept using this method for many years, considering it an efficient system to measure the global cortical activity. Later on, other researchers highlighted how, in reality, EEG activity varied significantly, depending on the area of the scalp from which it was recorded. Observation of different regional cerebral rhythms encouraged the use of multiple electrodes and of more recording channels, but the standardization of the recording methods soon became necessary, so that the resulting data could be comparable with one another. A committee of International Federation of Societies for EEG and Clinical Neurophysiology (IFSECN), led by H. Jasper, started then working on a specific electrode positioning system to be used in all laboratories. The first standardized system was presented at the 2nd International Congress of IFSECN in Paris in 1949 and published by Jasper in 1958; it is still universally used and known as the International 10-20 system (SI 10-20) [1].