Evoked Brain Potentials and Psychometric Data in Children at Risk for Schizophrenia

Abstract

While we have learnt to manage psychotic schizophrenic symptomatology with hallucinations fairly well, most schizophrenic patients with only negative symptoms are not diagnosed and treated — many of them are socially maladjuste (Kornhuber 1983, 1985). We still lack early diagnostic parameters that allow an earlier diagnosis. This is especially true for cases in which no typical “positive ”symptoms, e.g. paranoia and hallucinations, are prevailing, but vague “negative” symptoms, like social retreat or lack of will. For the latter impaired information processing due to an attentional deficit is considered a basic dysfunction (Kraepelin 1909–1915; E.Bleuler 1911; Mc Ghie and Chapman 1961; Huber et al. 1979; Kornhuber 1983; Kornhuber 1985, Schmid-Burgk et al 1982). Besides in clinical observations (McGhie and Chapman 1961) this attention deficit could be objectified by various kinds of psychometric and cognitive tests, such as reaction times (Shakov 1963) and recording of slow evoked potentials, especially the P3 component (Roth et al. 1980). On the assumption that there is an important hereditary factor in schizophrenia, these methods have been used in groups genetically at risk for the disease (Friedman et al. 1986; Stolz and Kornhuber 1984, unpublished data; Rothmeier and Kornhuber 1985). The aim of the present study is to clarify further whether there can be found early diagnostic signs for a schizophrenic disposition by focusing on a comparison of slow event-related potentials with performance on mental and psychomotor tasks and saccadic eye movements. For this purpose a high-risk group and a control group of children were tested.