Systemic Structural Analysis of the Electroencephalogram of Depressed Patients

Abstract

In previous articles, evidence has been presented which supports the hypothesis that detectable neurophysiological changes occur in the course of affective disorders, mainly of a depressive type. The scope of the present report has been to expand the previous investigation to comprise variables not hitherto taken into account and to present a new approach to the analysis of EEG in psychiatry. This new approach, a systemic structural analysis, follows the concepts borrowed from the general system theory, and is based on the assumption that brain activity can be regarded as a type of hierarchical system. Hints about the theoretical principles beyond a systemic structural analysis of EEG are given, and the point is stressed that possible correlations between, e.g., neurophysiological and clinical variables must be sought starting from characteristics which are at a comparable level of integration in both realms. The preliminary findings of an international collaborative study of depressive syndromes are presented. 45 patients suffering from depressive syndromes of different aetiology and of varying severity participated in the study. These patients were rated by means of a rating scale which permitted a division for further analysis into subgroups according to the main symptomatology. The results show that characteristic neurofunctional structures can be identified which correspond to various symptomatological patterns. The occurrence of pronounced interhemispheric differences in electrical activity, related to the severity of the depressive syndrome, has also found further support in the results of this present investigation.

Neurophysiological Correlates of Depressive Symptomatology

“…In a previous paper (7) we presented some evidence in support of the hypothesis that relevant relationships may occur between clini cal symptoms of depression as rated by means of a rating scale, and complex EEG features investigated by means of a systemic structural analysis (SSA) (3,8). In particular, we sug gested that clinical symptoms could be signifi cantly correlated with some EEG characteristic (i.e.…”