Magnetresonanztomographie als Störfaktor bei Untersuchungen von Probanden im Rahmen einer Studie zur Wahrnehmung eigener Handlungen

Das Ziel der vorliegenden Arbeit bestand darin, herauszufinden, ob bei Untersuchungen im MRT-Scanner dieser einen Störfaktor darstellt und somit die Leistung von Probanden beeinflusst. Darüber hinaus wurde untersucht, ob es bereits beim Akquirieren der Probanden Unterschiede bezüglich der Symptomsch...

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Bibliographic Details
Main Author: Schwenzer, Lars Christian
Contributors: Straube, Benjamin (Prof. Dr.) (Thesis advisor)
Format: Doctoral Thesis
Language:German
Published: Philipps-Universität Marburg 2024
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The objective of the dissertation was to find out whether the MRI scanner represents a confounding factor during examinations and thus influences the performance of test participants. In addition, we investigated whether there are differences in symptom severity during the acquisition of the subjects and whether the performance correlates with the symptom severity in the experiment we conducted. In an experiment on the perception of own actions, subjects were asked to recognize different delays (0 - 417 milliseconds) between self-initiated (active) or externally-initiated (passive) actions and their presentation on a screen. Based on the data collected, we evaluated the number of correct statements as to whether there was a delay. Not all subjects completed the examination in the MRI scanner. Half of the subjects performed the test as a pure behavioral test outside the MRI scanner at a desk. Our results show that the two test groups achieved similar performance in detecting delays. Contrary to our hypothesis, the examination in the scanner does not appear to have a negative effect on the subjects' performance. Similarly, using various neuropsychological tests, we found that there were no significant differences in symptom severity between the two experimental groups. When looking at the correlation between symptom severity and performance, it became apparent that subjects with more severe depressive symptoms in some cases performed worse in the different experiments. As already described in Chapter 5.3.2 "Depression as a covariate", this is an important aspect, as there is an accumulation of depression in patients with schizophrenia (Buckley et al., 2009) and treatment of this can lead to an increased quality of life and lower morbidity. Depression also has a negative impact on the symptoms of schizophrenia. This is consistent with the correlation we found between depressive symptoms and poorer performance in the experiments. We see the causes, effects and treatments of depression as a concomitant disorder in patients with schizophrenia as an important starting point for future research. Further research is needed to determine whether examinations in the MRI scanner are influenced by it. As described in Chapter 5.3 "Limitations", several questions could be considered. On the one hand, we consider a closer examination of covariates such as anxiety using neuropsychological tests to be useful. Secondly, different studies with different groups of subjects and tasks could be conducted in other areas in order to cover a broader spectrum. The clinical relevance of the results we obtained suggests that the effects observed using fMRI, which were mentioned in Chapter 1.1.4 "Perceptual disorders in subjects with schizophrenia", were potentially not confounded by measurement in the MRI scanner. Accordingly, the data collected by means of fMRI appear to represent pathologies well. Since fMRI examinations are currently not part of the diagnostic standard for schizophrenia, but are mainly the subject of research, the clinical benefit of our results relates more to the resulting research findings. The correct visualization of mechanisms that may lead to pathologies in patients with schizophrenia in our study using fMRI represents an important approach for future therapeutic interventions. A deeper understanding of the basis of schizophrenia will hopefully lead to new and targeted therapeutic approaches in the future.