Hirnaktivität schizophrener Patienten während syntaktischer und semantischer Verarbeitung: Eine MEG-Studie

Abstract

As shown in many studies, brains of schizophrenic patients exhibit a decreased structural and functional asymmetry compared to healthy controls. Those findings support the theory of T.J. Crow (e.g. 1997), that schizophrenia is a consequence of an adverse variant of those genes determining the development of brain asymmetry, so that the dominance of one hemisphere for language gets disturbed. The objective of this study was to find evidence for a decreased left-lateralisation of language in right-handed schizophrenics.For this aim an aspect of speech production ( lemma -selection, from a linguistic model of speech production, Levelt et al., 1998) was investigated in this study with 12 patients. As a control-group, a sample of 14 healthy subjects were used, measured by Härle et al. (2002) with the same design.The controls showed the expected left-lateralized activation during the lemma -task (relative to baseline-condition) in the period 150-275 ms (interpreted as lemma selection) and in the period 300-400 ms (interpreted as phonological encoding). The patient group differed in both periods by showing bilateral activation patterns.This result is in line with previous findings which also found a decreased asymmetry in comparison to healthy controls, and thus provides further support for Crow´s theory.