Description: The EEG test, electroencephalography, is a 20- to 45-minute procedure that provides information about brain function with the use of electrodes. Marked with a grease pencil, measurements of circumference calculate where electrodes will be placed on the scalp. Equidistant electrodes ensure an exact recording of the entire brain. The scalp is cleaned with a slightly abrasive paste to improve recording quality. Oil and hair products on the scalp could hinder recording quality.