Purpose: The present study explored the extent to which early prelinguistic communication skills predict expressive language in toddlers with autistic siblings (Sibs-autism), who are known to be at high likelihood for autism and language disorder, and a comparison group of toddlers with non-autistic older siblings (Sibs-NA). Method: Participants…

Identifying infants at elevated likelihood for autism and other developmental differences in the first year of life remains a significant challenge. This study explored associations between behavioral differences in infancy and developmental outcomes in toddlerhood. We conducted a secondary data analysis of 256 infants with an older autistic…

Approximately 3-4 boys for every girl meet the clinical criteria for autism in studies of community diagnostic patterns and studies of autism using samples of convenience. However, girls with autism have been hypothesized to be underdiagnosed, possibly because they may present with differing symptom profiles as compared to boys. This secondary…

Autistic youth often experience challenges in interactions with neurotypical peers. One factor that may influence successful interactions with peers is interpersonal synchrony, or the degree to which interacting individuals align their behaviors (e.g. facial expressions) over time. Autistic and neurotypical youth were paired together into three…

Fragile X syndrome (FXS), the leading heritable cause of intellectual disability, has a co-occurrence rate of autism spectrum disorder (ASD) estimated at ~60%. The onset and rates of motor development in FXS are slower relative to neurotypical development, and even more so in the context of co-occurring FXS + ASD. Extant evidence suggests these…

Purpose: Gesture delay in autistic infants and toddlers has been widely reported. The developmental trajectory of gesture production during early childhood is understudied. Thus, little is known about the possible changes of gesture production over time. The present study aimed to document the development of gesture production in autistic children…

Purpose: The current study addresses a gap in the literature regarding syntactic development of adolescent boys with fragile X syndrome (FXS) and Down syndrome (DS). Specifically, we ask whether syntactic skills plateau or continue to change during adolescence for these groups and whether the profile of syntactic change differs between boys with…

A recent study suggests that parent report on the Social Symptom and Prosocial scales of the Childhood Joint Attention Rating Scale provides useful information about differences in the social development of school-aged autistic children. The current study provides additional psychometric data on the Childhood Joint Attention Rating Scale regarding…