Neuroanatomical basis of language ability in an autism subgroup with moderate language deficits

Children with autism spectrum disorder (ASD) are highly heterogenous in their language abilities. A number of studies have shown neural correlates of language deficits in children with ASD, but the underlying neuroanatomical foundation of early language deficits in ASD remains largely elusive. In this study, we analyzed MRI data from a cohort of Chinese children with ASD (n = 67) and typical development (TD, n = 37) aged 1.5 to 6.5 years. The ASD sample was classified into two subgroups based on the median of the language scores: ASD with moderate language deficits (ASD_moderate, n = 34) and ASD with severe language deficits (ASD_severe, n = 34). We tested the group differences in the brain volumes between TD and two ASD subgroups, and also examined the associations between cortical grey matter volume and language abilities in TD and ASD subgroups, separately. We observed significant group differences in grey matter and white matter volume, with post-hoc analyses specifically indicating significant differences between TD and ASD_moderate subgroup. Significant correlations between grey matter volume and language scores were observed exclusively within the ASD_moderate subgroup, including positive associations in the bilateral superior temporal gyrus, hippocampus, and left inferior parietal lobe, and negative correlations in the bilateral precuneus. These findings provide novel evidence for the neuroanatomical basis related to language ability in an ASD subgroup with moderate language deficits, and offer new insights into the heterogeneity of language deficits in children with ASD.