The neural bases of language processing during social and non-social contexts: a fNIRS study of autistic and neurotypical preschool-aged children.

Background: Little is known about how autistic children's brains process language during real-world "social contexts," despite the fact that challenges with language, communication, and social interaction are core features of Autism Spectrum Disorder (ASD).

Methods: We investigated the neural bases of language processing during social and non-social contexts in a sample of autistic and neurotypical (NT) preschool-aged children, 3-6 years old, living in the United States. Functional near-infrared spectroscopy was used to measure children's brain response to "live language" spoken by a live experimenter during an in-person social context (i.e., book reading) and "recorded language" played via an audio recording during a non-social context (i.e., screen time). We examined within-group and between-group differences in the strength and localization of brain response to live language and recorded language, as well as correlations between children's brain response to live language versus recorded language and their language skills, as measured by the Preschool Language Scales.

Results: In the NT group, brain response to live language was greater than brain response to recorded language in the right temporal parietal junction (TPJ). In the ASD group, the strength of brain response did not differ between conditions in any brain regions of interest after correction for multiple comparisons. Children who showed a greater difference in right TPJ brain response to live language versus recorded language had higher language skills; this significant correlation was driven by the ASD group.

Limitations: Findings should be considered preliminary until they are replicated in a larger sample.

Conclusions: Group level findings indicate that for NT children, but not autistic children, the right TPJ responds more strongly to live language presented during a social context compared to recorded language presented during a non-social context. However, individual differences in how the right TPJ responds to language during social versus non-social contexts may help to explain why language skills are so variable across children on the autism spectrum.