Exploring receptive and expressive language components at the age of 36 months in siblings at risk for autism spectrum disorder

Background: Language difficulties are highly prevalent in children with autism spectrum disorder (ASD) as well as in their younger siblings (high-risk (HR) sibs). Children with ASD show substantial heterogeneity in difficulties with different language components, but it remains unknown whether this variability is also present in HR-sibs. Method: Receptive (RL) and expressive language (EL) were evaluated in siblings of typically developing children (low-risk (LR) sibs, N = 33) and HR-sibs (N = 30) at 36 months, using the Mullen Scales of Early Learning (MSEL), the Dutch version of the Reynell Developmental Language Scales - 2nd edition (RDLS-2) and spontaneous language analysis (SL). Next, composite scores for receptive and expressive phonology, grammar, semantics and pragmatics were formed. Group comparisons were performed and delays in the different language components were explored. Results: HR-sibs scored significantly lower than LR-sibs on all standardized measures of RL. For EL, significantly lower scores were only found using the MSEL and not using the RDLS-2 nor using SL. HR-sibs scored significantly lower than LR-sibs for receptive and expressive semantics and receptive grammar. HR-sibs with characteristics of ASD presented with less language difficulties than HR-sibs without characteristics of ASD. The majority of HR-sibs showed a delay in one or more language components but these were not consistently detected by the different measures. Conclusions: Language delays are highly prevalent in HR-sibs and their representation resembles the language profile of children with ASD. Evaluation of language at the level of phonology, grammar, semantics and pragmatics will detect considerably more children experiencing delayed language than holistic approaches.