Evaluation of neuronal effects of electroconvulsive therapy by magnetoencephalography (MEG)

1. Interictal spontaneous MEG was investigated in five male patients with major depressive disorder (according to DSM IV) treated with right hemispheric ECT over a period of five weeks. Spontaneous MEG-activity was also recorded in five male patients treated with tricyclic antidepressants during the same time period. 2. The analysis of slow (0-7Hz) and fast (12.5-30Hz) MEG activity was done with the dipole density plot, which uses consecutively estimated dipoles across a given analyzing time and delivers quantified dipole concentrations in three dimensions 3. In the ECT group the authors found a significant increase in the dipole concentration in the slow activity range (0-7Hz) after the first and the subsequent treatments, which could not be found in patients treated with tricyclic antidepressants. The localisation of the dipoles showed an "anteriorposterior"--gradient with a maximum concentration in the frontal and temporal region. 4. In the fast activity range (12.5-30Hz) the ECT group differed from the control group by a significant decrease of dipole activity, which was concentrated in the temporal and parietal region. 5. These results in part confirm interictal EEG findings after right hemispheric ECT and also lend strong support to ECT-effects in the fast activity ranges.