CSD-tractography revealed bilateral WM changes, suggestive of degenerative process in post stroke aphasic patients.

Injury of the left AF and left ILF correlate with comprehension impairment.

White matter micro-structural changes of the right AF correlate with repetition impairment.

Diffusion measures can act as biomarkers for detection of post stroke white matter changes.

Using constrained spherical deconvolution (CSD)-based tractography, we aimed to obtain conjoint analysis of diffusion measures of major language white matter (WM) tracts in post-stroke aphasic patients bilaterally, and to correlate the measures of each tract to the different language deficits.

17 aphasic patients with left hemispheric stroke, at the subacute stage, and ten age- matched controls underwent diffusion MRI examination. CSD-based tractography was performed. Diffusion measures [fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), axial diffusivity (AD)] were extracted after dissection of major language tracts bilaterally. Aphasia was assessed using language subset of hemispheric stroke scale. Comparisons of diffusion measures, for all tracts, between the two groups were performed. Partial correlations between the diffusion measures and different language components were obtained.

In the left hemisphere, significant lower FA and or higher MD with higher RD of patients' WM tracts compared to the control group. Significant differences of diffusion measures were also evident in the right hemisphere yet, less prominent. All changes reflected damage of the tracts' integrity. Significant correlations were found between comprehension and FA of the left arcuate fasciculus (AF) and left inferior longitudinal fasciculus. Additionally, a significant correlation was found between MD of the right AF and repetition.

Conjoint analysis of diffusion measures, based on CSD tractography, can provide important markers for the underlying WM changes bilaterally. Moreover, our findings emphasize that language processing can be mediated by both ventral and dorsal streams and further highlight the contribution of the right AF in repetition.

© 2022 Published by Elsevier Inc.