It is critical that care be taken during electrode application to insure a high quality EEG signal that is free of non-EEG electrical signals or “noise.” With the cap/gel technique, we use one gel to prepare the scalp and another gel to conduct the electrical signal. These techniques reduce the likelihood of recording non-EEG electrical signals. In the past, researchers had to be mindful of ambient electrical interference from lighting and other equipment in the EEG room. With contemporary EEG bioamplifiers, this is less of a concern.
