Factor analytic study of repetitive behaviours in young children with Pervasive Developmental Disorders.

The aim of the current study was to investigate the manifestation of repetitive behaviour profiles in young children with a Pervasive Developmental Disorder. The sample consisted of 137 developmentally delayed children with a DSM-IV-TR Pervasive Developmental Disorder (PDD) and 61 developmentally delayed children without a PDD. An exploratory factor analytic investigation using 12 ADI-R repetitive behaviour items from parent report of children with a PDD reported the emergence of two factors. The first factor consisted of higher-level, "insistence on sameness" behaviours, and the second of lower-level, repetitive "sensory-motor" behaviours. This factor structure was also applicable to a more general group of young children with developmental delay, regardless of their diagnosis. Correlational analyses highlighted contrasting relationships between developmental variables and the different repetitive behaviour factors. These relationships were different for children with a PDD and those without a PDD. The findings have potential implications for the early assessment and diagnosis of PDDs in young children.