New Article in the Journal of Autism and Developmental Disorders
June 23, 2010
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Key Findings: Avchen, R., Wiggins, L.D., Devine, O. , Van Naarden-Braun, K., Rice, C., Hobson, N., Schendel, D., & Yeargin Allsopp, M. (2010). Evaluation of a Records-Review Surveillance System Used to Determine the Prevalence of Autism Spectrum Disorders. Journal of Autism and Developmental Disorders. Advanced On-line Publication.
Autism spectrum disorders (ASDs) are a group of developmental disabilities that can cause social, communication and behavioral challenges. ASDs are "spectrum disorders." Thus, ASDs affect each person in different ways, and can range from mild to severe. People with ASDs share some similar symptoms, such as problems with social interaction; however, there are differences in the age of onset, severity and exact nature of these symptoms. Determining the prevalence of ASDs is challenging because of the difference in symptoms and the fact that ADS diagnoses are based on behaviors.
The Centers for Disease Control and Prevention (CDC) developed a population-based tracking system to estimate the number of children with ASDs (prevalence) and collect information on characteristics of these children. This tracking system relies on review of health and education records. The study by Avchen and colleagues is the first evaluation of CDC's records-review tracking system used to determine the prevalence of ASDs. Validation studies that evaluate tracking systems, such as this one, allow CDC to make informed changes to provide the most complete prevalence estimates.
Important findings from the study by Avchen and colleagues include:
- The CDC tracking system is likely not over-estimating the prevalence of ASDs.
- Most children classified with an ASD by a clinical examination were also detected by the tracking system.
- The CDC tracking system missed 12 of 177 children who were examined and found to have an ASD. This result shows we are likely not counting some children with ASD.
- CDC has identified ways to improve the tracking system in order to provide the most complete prevalence estimates; some of these improvements have already been made. For example, some children classified with ASD by a clinical examination did not have health or education records available for review. Therefore, CDC has intensified efforts to locate hard-to-find records.
Records-Based Approaches to Tracking ASD Prevalence
The results of the study by Avchen and colleagues are not directly comparable to other studies because it is the first population-based, records-review validation study for ASD. This study showed that CDC's records-review based tracking is a valuable tool for estimating ASD prevalence. This tool is more feasible than examining every child in a given population. It also may be more comprehensive than other methods since CDC counts children who have behaviors consistent with an ASD regardless of diagnosis. CDC is continuously improving its tracking system in order to provide the most complete ASD prevalence estimates.
More Information
· Metropolitan Atlanta Developmental Disabilities Surveillance Program
· Autism and Developmental Disabilities Monitoring (ADDM) Network
