Abnormal white matter development during early childhood in autism and developmental disability

The abnormal maturation of white matter microstructure in autism spectrum disorder (ASD) compared with typical developing (TD) and developmental delay/intellectual disorder (DD/ID) during early childhood and their associations with clinical implications remain unclear. Here, we characterized spatial and temporal patterns of white matter development in 364 children (including ASD, DD/ID and TD) under 8 years old using neurite orientation dispersion and density imaging. Using neurite density index (NDI), we consistently detected three white matter clusters across all the groups through clustering analysis, indicating the conserved spatial layout in atypical development. Further, three developmental stages with successively lower growth rates were identified in ASD, similar to those in TD but delayed overall. Meanwhile, DD/ID children showed the slowest growth rates and lacked staging features. Finally, for ASD children, the NDI was correlated with cognitive impairments at the fast developmental stage but associated with social deficits during the moderate-to-slow stage.