Cognitve Deficits in Huntington's Disease Associated to White Matter.xlsx

Fractional anisotropy (FA) and mean diffusivity (MD) were assessed in 22 HD patients and 20 healthy controls to investigate the relationship between cognitive performance, measured by the Montreal Cognitive Assessment (MoCA), and white matter (WM) microstructural changes in Huntington’s disease (HD).All images were acquired using a 3T MRI scanner (Philips Medical Systems, Eindhoven, The Netherlands). The high-resolution anatomical acquisition consisted of a T1-3D Fast FieldEcho sequence with the following parameters: TR/TE: 8/3.7 ms; FOV: 256 × 256 mm2 ; Flip angle = 8˚; acquisition and reconstruction matrix: 256 × 256; and isometric resolution: 1 × 1 × 1 mm3.Voxelwise statistical analysis of the FA and MD data was carried out using TBSS (Tract-Based Spatial Statistics]), part of FSL. First, FA images were created by fitting a tensor model to the raw diffusion data using FDT, and then brain-extracted using BET. All subjects' FA data were then aligned into a common space using the nonlinear registration tool FNIRT, which uses a b-spline representation of the registration warp field. Next, the mean FA image was created and thinned to create a mean FA skeleton which represents the centres of all tracts common to the group. Each subject's aligned FA data was then projected onto this skeleton and the resulting data fed into voxelwise cross-subject statistics.MD maps were computed using dtifit, linearly registered to MNI152 space via flirt, and projected onto the FA skeleton using tbss_skeleton and analyzed with tbss_non_FA.Group comparisons were modeled using design matrices created with FSL’s GLM Setup, and statistical inference was performed using the randomise tool with 10,000 permutations and threshold-free cluster enhancement (TFCE).<b>References</b>Estevez-Fraga C, Scahill R, Rees G, Tabrizi SJ, Gregory S. Diffusion imaging in Huntington’s disease: comprehensive review. J Neurol Neurosurg Psychiatry 2020;92:62–9. https://doi.org/10.1136/jnnp-2020-324377. De Azevedo PC, Guimarães RP, Piccinin CC, Piovesana LG, Campos LS, Zuiani JR, et al. Cerebellar Gray Matter Alterations in Huntington Disease: A Voxel-Based Morphometry Study. The Cerebellum [Internet]. 20 de mayo de 2017;16(5-6):923-8. https://doi.org/10.1007/s12311-017-0865-6. Cauda F, Nani A, Manuello J, Premi E, Palermo S, Tatu K, et al. Brain structural alterations are distributed following functional, anatomic and genetic connectivity. Brain. 12 de septiembre de 2018;141(11):3211-32. https://doi.org/10.1093/brain/awy252. Penney JB Jr, Vonsattel J-P, Macdonald ME, Gusella JF, Myers RH. CAG repeat number governs the development rate of pathology in Huntington’s disease. Ann Neurol 1997;41:689–92. https://doi.org/10.1002/ana.410410521.Hernandez-Castillo CR, Galvez V, Mercadillo R, Diaz R, Campos-Romo A, Fernandez-Ruiz J. Extensive White Matter Alterations and Its Correlations with Ataxia Severity in SCA 2 Patients. PLoS ONE. 2015;10(8):e0135449. https://doi.org/10.1371/journal.pone.0135449.  <br>