Neuroimaging in patients with conversion disorder

Background: Medically unexplained symptoms are not uncommon in the clinical setting. Conversion disorder is a psychological disorder in which there is no neurological explanation for patients’ physical symptoms. These physical symptoms can be both positive or negative, e.g. tremor or paresis. This thesis searches for differences in brain activity in patients with different subtypes of conversion disorder. This is done by comparing fMRI-data of patients with either conversion tremor (n=4) or conversion paresis (n=17). Based on earlier research, regions of interest are the precuneus and the temporoparietal junction (TPJ). Method: A study was set up in which patients performed a task while in the MRI-scanner. They were asked to move either their left or right hand. Functional MRI data were flipped for patients affected on the left side in order to generate results in terms of affected side versus non-affected side. Statistical non-Parametric Mapping(SnPM) was used to compare both patient groups for differences in brain-activity when moving either the affected or the non-affected side. Results: Results showed significant differences between patients with conversion tremor (CT) and conversion paresis (CP). The right TPJ and precuneus proved more activated in patients with CP when moving the affected hand compared to patients with CT. Other differences were found around the central sulcus, cingulate gyrus, and the midbrain. Discussion: Results are discussed in terms of intentionality and self-agency, and limitations of the study are discussed. Future research should focus on possible treatments for conversion disorder in the field of neuromodulation