Abstract
Objective: To determine if there are structural differences in gray-matter volumes between motor conversion disorder (MCD) patients compared to healthy volunteers (HV). Background MCD patients demonstrate medically-unexplained movements that appear similar to volitional movements, but are experienced as involuntary. The cortical correlates of self-agency remain unknown, although the temporoparietal junction has been proposed as the comparator region in the forward model of action. Previous studies have identified increased amygdala activity to arousing stimuli in MCD with greater functional connectivity to the supplementary motor area, but it is unknown if differences exist on a structural level. Design/Methods: We imaged 16 MCD patients and 16 HV, using T1-weighted 3D-MPRAGE sequences (1.5T MRI). Mood symptoms were measured with Beck depression (BDI) and anxiety (BAI) inventories. Gray-matter volumes and cortical thickness were evaluated with FSL and FreeSurfer with a region-of-interest-based approach. Results: Amygdala VBM showed no difference between patients and HV, nor was there correlation between amygdala size and BDI/BAI scores. We found a trend towards smaller hippocampi in patients which did not reach significance (LH, p=0.261, RH, p=0.052). Right hippocampal volumes were negatively correlated with BDI scores in patients (r= -0.55). There was increased cortical thickness in patients (t=2.0) in the left pars opercularis, right superior and inferior parietal areas, and decreased thickness in the left superior temporal, right pars opercularis, supramarginal and postcentral areas. Conclusions: Smaller hippocampal volumes are associated with mood disorders and negatively correlated with BDI scores in our study. Smaller hippocampi in MCD patients may be a correlate of stress as the hippocampus serves to regulate stress responses. We identified differences in regions involved in motor planning and control, which may contribute to symptomatology. Future studies with larger sample sizes are needed to assess if structural changes are a consistent finding in MCD and determine functional significance. Supported by: Funded by and conducted at the intramural National Institute of Neurological Disorders and Stroke, National Institutes of Health. Disclosure: Dr. Czarnecki has nothing to disclose. Dr. Kranick has nothing to disclose. Dr. Horovitz has nothing to disclose. Dr. Voon has nothing to disclose. Dr. Ostuni has nothing to disclose. Dr. Hallet has received personal compensation for activities with Neurotoxin Institute, Cambridge University Press, Springer Verlag, Taylor & Francis Group, Oxford University Press, John Wiley & Sons, AAN Enterprises, Lippincott, Williams &Wilkins, and Elsevier. Dr. Hallet has received (royalty or license fee or contractual rights) payments from the National Institutes of Health. Dr. Hallet has received research support from The National Institutes of Health.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
