Characteristics of the parental EEG related to the course of schizophrenia in children.

Abstract

The electrical activity of the brain of parents of children with schizophrenia has received comparatively little study. In the few publications on this subject stress is lald on determination of the frequency with which various types of bioelectrical anomalies of the EEG are found in population groups of parents and other direct relatives of patients. On this basis the authors of these publications drew attention to the greater abundance of EEG disturbances in the sibs of patients than in their parents [i], the increased frequency of mental disturbances in the parents in cases when the EEG of the children showed indications of delayed development [2], and suggested that the EEG features in schizophrenia are genetically determined [3, 4] and that the results of electroencephalographic investigations of the patients' relatives can be used to distinguish between nuclear (simple) and atypical varieties of schizophrenia in probands [5, 6]. As a rule the works cited above were based on the study of numerically small groups. Their authors did not undertake any statistical verification of their data. Considering that most workers deny the existence of significant differences in the frequency of bioelectrical abnormalities in patients with schizophrenia and healthy subjects, it is unlikely that during the study of relatives of these patients a useful purpose will be served by concentratlng on the study of these aspects of brain electrical activity. Attempts to study differences in the distribution of many quantitative characteristics of biopotentlals in the cortical rhythm pattern are more justified in this case. The advantages of research in this direction have repeatedly been demonstrated [7-9]. This state of affairs determined the techniques used both in our earlier studies of brain electrical activity in schizophrenic patients from the genetic aspect [10-12] and in the present investigation. Many years of study of mono- and dlzygotlc twins, among whom one or both partners was affected with schizophrenia, and of the parents of children with schizophrenia have yielded the following result. In relatives of patients concentration of features and combinations of features which are found significantly more often in the EEG of patients than of normal subjects is found in the relatives of patients with schizophrenia. Hence it was concluded that the characteristic features of electrical activity of the schizophrenic brain are due not only to the disease itself, but also to hereditary factors. However, even the meticulous clinical differentiation of probands used in the previous stages of the investigation did not permit sufficiently clear correlations to be established between the patterns of electrical activity of the brain in the patients' parents and the type of course of the schizophrenia process in their children. Nevertheless these data are important not only from the point of view of obtaining additional evidence for the study of the hereditary principles governing the formation of different clinical varieties of schizophrenia, but also for use in clinical pediatric practice in the solution of problems concerned with the type and prognosis of schizophrenia in children. Accordingly in the investigation described below various quantitative parameters of brain electrical activity were compared and the character of differences between them elucidated in the parents of patients with .an episodic type of sphiz0phrenia , on the one hand, and in parents of patients with a continuous and with an episodic-progressive type of schizophrenia with predominantly continuous features On the other hand. This paper is based on the analysis of results of a comparative clinical and electroencephalographic study of i00 parents (55 mothers and 45 fathers) of 55 probands with schizophrenia. Depending on the course of the disease in the probands, the parents were divided into two groups.