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Functional neurological disorders (FND) are common and debilitating disorders of the nervous system which can present with motor, sensory, and cognitive impairments. Psychosocial adversities such as stressful life events, interpersonal difficulties, childhood maltreatment and psychological traumas are well-established risk factors for FND, yet there is inadequate integration of psychosocial models and neurobiology. Imaging studies in FND have shown heightened connectivity between the amygdala and motor control regions, alterations within the temporoparietal junction neural circuits, salience network and sensorimotor circuits. Nevertheless, the literature is inconsistent and heterogeneous. Comparisons with disease controls may help improve understanding of the specific underlying neurobiology of FND.Methods This project utilised the South London and Maudsley image bank, a database of naturalistic clinical data and structural magnetic resonance imaging (MRI) scans. An analysis of the natural language processed (NLP) domain from patients’ radiology reports was conducted, comparing frequencies of each exaction between FND and post-traumatic stress disorder (PTSD) cohort. MRI scans were parcellated and morphometric, including cortical volume and subcortical volumes Morphometrics were compared between FND, PTSD controls, and healthy controls at the whole-brain level. An uncorrected ANOVA was formed, and surviving regions were compared with a Bonferroni-corrected MANCOVA with age, gender, and total intracranial volume as covariates.Results There were no significant differences in the NLP radiology report extractions between FND and PTSD patients. FND showed a significantly larger volume in the bilateral cerebellar white matter compared to both PTSD (p<0.001, ηp2 = 0.043), and healthy controls (p<0.001, η 2 = 0.043). FND patients also had significantly larger volume in the right thalamus compared to healthy controls (p=0.014, ηp2 = 0.022), but not compared to PTSD patients.Conclusion Although clinical reports of structural scans were not reported differently in FND and PTSD, there were structural alterations in the brain of FND patients, particularly in the cerebellar white matter. This could represent a key neurobiological underpinning which separates FND from PTSD. Further research should focus on the role of confounders such as anxiety and depression. Similarly, further large-data research analysing structural changes in the varying phenotypes of FND is warranted.