Altered white matter connectivity is linked to language abilities in children with autism spectrum disorder: An...

Recent studies using Automated Fiber Quantification (AFQ) have revealed localized white matter connectivity alterations in individuals with autism spectrum disorder (ASD), offering insights beyond traditional tract-wise Diffusion Tensor Imaging (DTI) analyses. However, the relationship between these alterations and language variability in preschool-aged children with ASD remains poorly understood.

This study included 28 children with ASD and 22 typically developing (TD) peers aged 1.5-6.07 years. Using AFQ, we examined eight language-related tracts-bilateral arcuate fasciculus, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, and superior longitudinal fasciculus-at both tract-wise and point-wise levels. We analyzed the white matter alterations in metrics including fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity, and correlated these metrics with language abilities and ASD symptom severity.

Both groups exhibited significant lateralization patterns, though no between-group differences in lateralization were found. However, ASD and TD groups showed distinct associations between white matter lateralization and language abilities. Tract-wise comparisons revealed no significant group differences, but point-wise analyses identified localized alterations in DTI metrics within the ASD group. While these alterations showed different patterns of association with language abilities in the ASD and TD groups, the between-group comparison of these association patterns did not reach statistical significance. Additionally, DTI metrics correlated significantly with ASD symptom severity.

Our findings underscore the importance of white matter lateralization and microstructural integrity in supporting language abilities in young children with ASD. The study provides novel insights into the neuroanatomical foundations of language deficits and their association with symptom severity, highlighting the value of point-wise analyses in understanding ASD-related connectivity alterations.