<> "The repository administrator has not yet configured an RDF license."^^ . <> . . . "Fiber-specific white matter analysis reflects upper motor neuron impairment in amyotrophic lateral sclerosis"^^ . "Background and purpose: To clarify the relationship between fiber-specific white matter changes in amyotrophic lateral sclerosis (ALS) and clinical signs of upper motor neuron (UMN) involvement, we performed a fixel-based analysis (FBA), a novel framework for diffusion-weighted imaging analysis. Methods: We enrolled 96 participants, including 48 nonfamilial ALS patients and 48 age- and sex-matched healthy controls (HCs), in this study and conducted whole-brain FBA and voxel-based morphometry analysis. We compared the fiber density (FD), fiber morphology (fiber cross-section FC), and a combined index of FD and FC (FDC) between the ALS and HC groups. We performed a tract-of-interest analysis to extract FD values across the significant regions in the whole-brain analysis. Then, we evaluated the associations between FD values and clinical variables. Results: The bilateral corticospinal tracts (CSTs) and the corpus callosum (CC) showed reduced FD and FDC in ALS patients compared with HCs (p < 0.05, familywise error-corrected), and the comparison of FCs revealed no region that was significantly different from another. Voxel-based morphometry showed cortical volume reduction in the regions, including the primary motor area. Clinical scores showed correlations with FD values in the CSTs (UMN score: rho = �0.530, p < 0.001; central motor conduction time CMCT in the upper limb: rho = �0.474, p = 0.008; disease duration: rho = �0.383, p = 0.007; ALS Functional Rating Scale-Revised: rho = 0.340, p = 0.018). In addition, patients whose CMCT was not calculated due to unevoked waves also showed FD reduction in the CSTs. Conclusions: Our findings suggest that FD values in the CST estimated via FBA can be potentially used in evaluating UMN impairments. © 2021 European Academy of Neurology"^^ . "2022" . . "29" . "2" . . "John Wiley and Sons Inc"^^ . . . "European Journal of Neurology"^^ . . . "13515101" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . "K."^^ . "Hara"^^ . "K. Hara"^^ . . "M."^^ . "Katsuno"^^ . "M. Katsuno"^^ . . "N."^^ . "Atsuta"^^ . "N. Atsuta"^^ . . "R."^^ . "Nakamura"^^ . "R. Nakamura"^^ . . "E."^^ . "Bagarinao"^^ . "E. Bagarinao"^^ . . "K."^^ . "Imai"^^ . "K. Imai"^^ . . "G."^^ . "Sobue"^^ . "G. Sobue"^^ . . "K."^^ . "Kawabata"^^ . "K. Kawabata"^^ . . "S.W."^^ . "Choy"^^ . "S.W. Choy"^^ . . "T."^^ . "Nakamura"^^ . "T. Nakamura"^^ . . "T."^^ . "Kato"^^ . "T. Kato"^^ . . "R."^^ . "Ohdake"^^ . "R. Ohdake"^^ . . "H."^^ . "Watanabe"^^ . "H. Watanabe"^^ . . "M."^^ . "Masuda"^^ . "M. Masuda"^^ . . "A."^^ . "Ogura"^^ . "A. Ogura"^^ . . . . . "HTML Summary of #17154 \n\nFiber-specific white matter analysis reflects upper motor neuron impairment in amyotrophic lateral sclerosis\n\n" . "text/html" . .