Early features of autism: Repetitive behaviours in young children.

This study examined whether repetitive behaviours were a differentiating feature of autism in children aged less than 51 months. The study also examined the relationship between age (chronological and developmental) and repetitive behaviours in young children with autism. Standardised developmental and diagnostic assessments were conducted on 55 children aged between 22 and 51 months, consisting of 40 developmentally delayed children with DSM-IV-TR Autistic Disorder and 15 developmentally delayed children without Autistic Disorder. Results indicated that several measures of repetitive behaviour, particularly more complex high-level ones, were significantly positively associated with the probability of receiving a diagnosis of autism. No significant relationships were found between developmental age and the presence of repetitive behaviours in children with autism, but younger chronological age was associated more with simple or low-level repetitive behaviours.