Purpose: The goal of this work was to examine the semantic and syntactic properties of the vocabularies of autistic and non-autistic infants and toddlers to see if children in these two groups know different kinds of words. We focused on both receptive and expressive vocabularies. For expressive vocabulary, we looked only at the "active"…

Purpose: Toddlers with Down syndrome (DS) showcase comparable or higher rates of gestures than chronological age-- and language-matched toddlers without DS. Little is known about how gesture use in toddlers with DS relates to multiple domains of development, including motor, pragmatics, language, and visual reception (VR) skills. Unexplored is…

Autism is often associated with early developmental delays in language and motor skills. However, little is known about the complex dynamic processes that drive the co-development of such early difficulties. The aim of the present study was to model the parallel growth of language and motor skills in a cohort of infants and to explore differences…

This study examined an insufficiently studied predictor of functional language, social motivation, in a group of 87 young children with autism spectrum disorder. Participants (age 14-31 months at the start of the study) were assessed at four times over 24 months. We tested total and indirect associations between early social motivation and later…

Purpose: The purpose of this study was to understand how joint attention and sensory-regulatory features are related in early childhood and predict language and social-communication outcomes in preschool in order to build mechanistic theories that can inform early intervention directed at improving these outcomes. Method: Cross-lagged panel…

Considerable evidence on autism spectrum disorder emergence comes from longitudinal high-risk samples (i.e. younger siblings of children with autism spectrum disorder). Diagnostic stability to age 3 is very good when diagnosed as early as 18-24 months, but sensitivity is weaker, and relatively little is known beyond toddlerhood. We examined…

Retrospective studies indicate 2 major classes of autism spectrum disorder (ASD) onset: early and later, after a period of relatively healthy development. This prospective, longitudinal study examined social, language, and motor trajectories in 235 children with and without a sibling with autism, ages 6-36 months. Children were grouped as: ASD…

The development of imitation during the second year of life plays an important role in domains of sociocognitive development such as language and social learning. Deficits in imitation ability in persons with autism spectrum disorder (ASD) from toddlerhood into adulthood have also been repeatedly documented, raising the possibility that early…