Study explores characteristic developmental patterns in autism

July 1, 2012

To describe the typical longitudinal developmental trajectories of social and communication functioning and repetitive behavior in children with autism, investigators analyzed data from birth records and a database of the California Department of Developmental Services that recorded symptom severity and functioning in nearly 7,000 children aged from 2 to 14 years with autism.

To describe the typical longitudinal developmental trajectories of social and communication functioning and repetitive behavior in children with autism, investigators analyzed data from birth records and a database of the California Department of Developmental Services that recorded symptom severity and functioning in nearly 7,000 children aged from 2 to 14 years with autism.

The analysis, which relied on group-based trajectory modeling and created scores for communication and social functioning, showed 4 features of note: 1) Many children, particularly those who begin with high-functioning scores, show considerable development over time; 2) The extent of this development was substantially heterogeneous, with some children improving much more than others; 3) The most rapid development was before 6 years; and 4) A group of bloomers moved rapidly from being classified as severely affected to high functioning.

In contrast to communication and social functioning, repetitive behavior remained relatively stable. Only about 15% of children seemed to change significantly over time in this area; one-half of this group improved, and one-half got worse.

COMMENTARY

This careful description of developmental streams in autism helps to clarify the condition while helping to frame questions for further research. Do children in different trajectories have different conditions grouped under the diagnosis of autism? Is there a way to predict the developmental course of a child at the time of diagnosis?

In this study, the bloomers (7%-10% of children who were low functioning at diagnosis and progressed quickly through the course of the study) were more likely to be from families of higher socioeconomic means. Can early provision of resources and advocacy for poorer children in the low-performing group move more of them into the bloomer trajectory? We still have lots to learn about autism. -Michael Burke, MD