White matter integrity and its correlation with symptom severity in adolescents with high-functioning autism spectrum...

Increasing evidence links disrupted brain connectivity to autism spectrum disorder (ASD), with white matter alterations as a core mechanism. Diffusion tensor imaging (DTI) has detected white matter abnormalities in ASD, but findings lack consistency, and few studies have correlated these abnormalities with clinical symptoms. Forty-two high-functioning ASD (HFASD) adolescents and 56 matched typically developing (TD) controls underwent DTI scans, analyzed via tract-based spatial statistics (TBSS) for fractional anisotropy (FA) changes. HFASD participants were assessed for symptom severity using the Autism Behavior Checklist (ABC), with voxel-wise correlation analyzing FA-symptom relationships in regions showing group differences. Compared to TD controls, HFASD adolescents exhibited increased FA in bilateral inferior cerebellar peduncle (ICP) and corticospinal tract (CT), and decreased FA in bilateral ICP, middle cerebellar peduncle (MCP), uncinate fasciculus (UF), plus left anterior corona radiata (ACR), inferior fronto-occipital fasciculus (IFOF), superior longitudinal fasciculus (SLF), and CT (all P < 0.005, TFCE-corrected). Correlation analysis revealed FA alterations in left/right UF correlated with language function (R=0.57/0.49, P < 0.005, TFCE-corrected), while right MCP FA changes correlated with sensory ability (R=-0.64, P < 0.005, TFCE-corrected). These findings indicate white matter integrity abnormalities may underpin ASD's neuropathological and clinical basis.