Restricted and repetitive behaviors are a core feature of autism spectrum disorder. This descriptive study documented the presence of restricted and repetitive behaviors in 85 toddlers with autism spectrum disorder as they interacted with their caregiver in a play interaction. For each child restricted and repetitive behavior, a caregiver…

Findings of three studies indicate that young children with Down syndrome perform similarly to typical controls matched on mental ages (MAs) of approximately 3 years. However, by developmental age of 4 years, children with Down syndrome performed worse than both MA-matched typical children and children with non-Down syndrome types of mental…