One of the basic tests used in neurology is electroencephalography (EEG). Individual cells, which belong to the nervous system, communicate with each other by means of electrical impulses and during EEG a recording of the bioelectrical activity of the brain is made. It is not uncommon for patients to be unfamiliar with the details of an EEG - so what is particularly important to know about this test? How to prepare for it and what to expect?