General information on the electroencephalography (EEG) method

What does EEG mean?

EEG stands for electroencephalography. The EEG method measures electrical potential changes on the surface of the head completely painlessly and without the administration of medication. These potential changes are caused by the joint activity of a large number of nerve cells in the brain. Such joint activity of the nerve cells can be caused by simple stimuli (e.g. sounds, pictures) or cognitive processes (e.g. the idea of moving a certain part of the body), but they also reflect the basic activity of the brain at rest. With the EEG, brain functions can be examined with a very high temporal accuracy. Based on the measured electrical activity on the surface of the head, important conclusions can be drawn about the brain regions involved during the performance of a task. EEG is a safe method and is one of the standard procedures in clinical diagnostics and brain research. For EEG measurement, sensors are placed at various points on the head to establish a connection between the surface of the head and the measuring device. In order to establish sufficiently good contact between the skin and the sensors, the sensors are fixed to a special cap (similar to a bathing cap). To improve conductivity, the space between the head surface and the sensors is filled with a special skin-friendly contact gel. Beforehand, the top layer of skin is cleaned with a cotton swab soaked in alcohol. The preparation of the EEG sensors (contact gel and cotton swab) may cause slight local reddening of the skin in rare cases. These usually disappear within a few hours.

Procedure of an EEG examination

First, you wash and dry your hair with us on site. Shampoo and towels are provided for you. Then an elastic EEG cap with integrated sensors is placed on your head and the skin underneath the sensors is cleaned with a cotton swab soaked in alcohol. A special skin-friendly contact gel is used to establish contact between the surface of the head and the sensors. Once the preparations are complete, you will be led into the experimental room and the sensors will be connected to the measuring device. During the EEG examination, you will sit on a comfortable chair in the experimental room. The actual experiment begins with a short demonstration of the task and some trial runs. During the demonstration and the trial runs, you can ask comprehension questions about the task and the procedure of the experiment. The EEG measurement will take a maximum of 60 minutes. The measurement will be divided into several sub-examinations in which you will perform a previously practised task. After the experiment, the EEG cap and the sensors will be removed and you will be given the opportunity to wash your hair.