Der Einfluss positiver und negativer formaler Denkstörungen auf die Lateralisierung von Sprache bei Patienten mit Schizophrenie

Background: According to previous imaging studies in the investigation of neural correlation of spontaneous speech in schizophrenia patients and formal thought disorder, right hemispheric neural network activation can be assumed, including STG and IFG as traditional speech-relevant areas. To date, comparable imaging data for the linkage between speech production in those areas and psychopathology is missing. Methods: Fifteen right-handed, native German patients with schizophrenia were matched with fifteen healthy control subjects for age, sex and education. Formal thought disorders were objectified by using SAPS, SANS and TLI. Subjects described eight pictures from TAT, for one minute each, while BOLD signal changes were measured with 3-T-fMRI. Spontaneous speech was recorded, divided into episodes of twenty seconds and then words per episode were correlated with psychopathologic tests. Results: In contrast to control subjects, patients showed right hemispheric neural activation during production of spontaneous speech. In right STG and IFG/ Rolandic operculum, words per episode were negatively correlated with positive formal thought disorder. Conclusion: As possible causes for those present findings of inverse lateralization of classical speech-relevant areas in schizophrenia, structural abnormalities as well as genetic aberrations and deviant transmitter systems – particularly in speech-relevant areas – should be discussed. Negative correlation between speech production and positive FTD can be explained by heterogeneity of the clinical group and their chronically antipsychotic medication. In further research, neuropsychological aspects like verbal fluency should also be considered.