A recent study found that frontoparietal and peri-ependymal white matter disconnection is associated with disability in neuromyelitis optica spectrum disorder patients.
Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system. Evidence suggests a distinct pattern of brain lesions in NMOSD, and it may be related to disability.
A study in the journal Brain Imaging and Behavior explored the association between neurological impairment and brain lesions in terms of lesion location and structural disconnection.
The study comprised 20 patients. The mean age was 46.16 years, and six (15%) patients were male. The mean disease duration was 46.2 months. The mean Expanded Disability Status Scale (EDSS) score was 3.31. All patients were aquaporin-4-IgG-seropositive. Three patients were free of brain lesions.
Frontoparietal White Matter Disconnection Predicts NMOSD Disability
Brain magnetic resonance imaging (MRI) was performed, and the white matter lesions were drawn manually, section by section. Whole-brain structural disconnection was estimated, and connectome-based predictive modeling (CPM) was used for the estimation of the patients’ EDSS score from their disconnection severity matrix.
CPM was able to successfully predict the EDSS scores using the disconnection severity matrix (r = 0.506, p = 0.028; q2 = 0.274). The number of edges included in the “consensus edges” was 165. The “consensus edges” were further grouped into predefined canonical networks; these included subcortical, cerebellum, motor, medial frontal, visual I, visual II, visual association, salience, default mode, and frontoparietal networks.
The 165 edges included 19 motor–frontoparietal connecting edges, followed by 16 edges connecting the nodes within the motor and 15 edges connecting the nodes within the frontoparietal network. Hence, the model showed that frontoparietal white matter disconnection is predictive of and associated with disability in NMOSD.
Peri-Ependymal White Matter Disconnection and NMOSD Disability
Diffusion MRI correlational tractography was performed to assess the fractional anisotropy and axial diffusivity of white matter fibers. The fractional anisotropy of the white matter tracts passing the left fornix, corpus callosum, forceps major, right fornix, and left optic radiation decreased significantly as the EDSS scores increased (FDR: 0.048). A similar relationship was found between axial diffusivity and EDSS scores (FDR: 0.053).
These findings suggest a significant negative correlation between tract integrity and EDSS scores for all of these peri-ependymal tracts. Hence, the local connectome analysis revealed that the peri-ependymal white matter disconnection is predictive of and associated with disability in NMOSD patients.
Kim, M., Choi, K. S., Hyun, R. C., Hwang, I., Kwon, Y. N., Sung, J. J., Kim, S. M., & Kim, J. (2023). Structural disconnection is associated with disability in the neuromyelitis optica spectrum disorder. Brain Imaging and Behavior. https://doi.org/10.1007/s11682-023-00792-4