Background: From the point of view of time we can divide the use of EEG in the electroconvulsive therapy into 1) screening before starting the treatment, 2) the EEG correlates of the ECT: recording of the paroxysm, immediate postparoxysmal recording, interparoxysmal recording during a series of ECT, and persistent changes after finishing the series of ECT.
Methods and results: EEG screening has shown that the patients with abnormal EEG do not respond well to ECT. In the recording of the paroxysm EEG correlates with therapeutic effect of ECT are looked for--particularly the length of the paroxysm on the EEG, intensity and pattern of the paroxysmal activity, and the suppression of the EEG curve in the terminal part of the paroxysm. The suppression models are in the focus of interest also in the immediate postparoxysmal recording. In the interparoxysmal recordings during a series of ECT the associations of the generalised slowing in the range of the theta and delta activity with the therapeutic effect were looked for, particularly in the past. Persistent changes after finishing the ECT are usually examined especially to look if ECT does not cause persistent abnormalities of the EEG recording which would be an evidence for brain damage or for epileptic kindling. The results in this direction have been negative so far.