Neural responses to linguistic stimuli in children with and without autism spectrum disorder

Atypical neural responses to language have been found in toddlers with autism spectrum disorder (ASD) and in their unaffected siblings. However, given that language difficulties are often seen in these children, it is difficult to interpret whether these neural differences are a result of the diagnosis of ASD or impairments in their language abilities. In this study, we recorded event-related potentials (ERPs) from four groups of 36-month-olds: low-risk control (LRC), high risk for ASD defined as having an older sibling with ASD (HRA) but who do not have ASD or milder autism-like symptoms (HRA-Typ), HRA children who do not have ASD but exhibit milder autism-like symptoms (HRA-Atyp) and HRA children diagnosed with ASD (ASD). Children listened to words expected to be acquired early (e.g. ball) and words expected to be acquired late (e.g. calf). ERPs were analysed over time windows sensitive to word processing as well as frontal and temporo-parietal sites over the left and right hemispheres. When controlling for language abilities, there were group differences within the temporo-parietal sites. Specifically, the HRA-Atyp group showed a different timed response to late words compared to the ASD and LRC groups. In addition, we found a relation between neural responses in the left frontal sites and ASD severity. Our results suggest that both language abilities and ASD diagnoses are important to consider when interpreting neural differences in lexical processing.