SYMPTOMS OF PERVASIVE DEVELOPMENTAL DISORDERS AS OBSERVED IN PREDIAGNOSTIC HOME VIDEOS OF INFANTS AND TODDLERS

Objectives: The objectives of this study were (1) to show prediagnosti c abnormalities in social and communicative behaviors on home videos o f children who later received a diagnosis of one of the pervasive deve lopmental disorders (PDD) and (2) to demonstrate that prediagnostic ab normalities in social and communicative behaviors for children with PD D not otherwise specified will be less prominent than those in childre n with autistic disorder but still distinguishable from those of typic ally developing peers. Study design: Parents of children with PDD each submitted home videos of social events that were made when their chil d was between the ages of 12 and 30 months, before diagnosis. Two inde pendent observers, unaware of the subjects' diagnoses or purpose of th e study, scored the rates of specific anomalies in social and communic ative behavior. Two additional observers scored the percentage of time the children were engaged socially or with objects. Data from the exp erimental group were compared with those of 25 age-matched children wi th no developmental disabilities. Results: Significant differences wer e found between the rates of social engagement and 8 of the 25 specifi c behaviors of the children in whom PDD was later diagnosed and those of the typical children. The children later given the diagnosis of PDD not otherwise specified had mean frequencies of some social interacti ons and communicative skills that fell between those of children later given the diagnosis of autistic disorder and those of children with t ypical development. Conclusion: In our sample children in whom PDD was later diagnosed could be differentiated from their typically developi ng peers on the basis of specific anomalies noted in their social and communicative behaviors, especially joint attention. In our sample chi ldren with PDD not otherwise specified could have been further differe ntiated on the basis of the rates of social interaction. Careful asses sment of social interaction and communicative behaviors may help to id entify children with PDD before the age of 30 months.