Research Paper
Completeness of case ascertainment for surveillance of autism spectrum disorders using the autism developmental disabilities monitoring network methodology

An abstract related to this topic was presented at the 2011 International Meeting for Autism Research, but this is the first manuscript submission.
https://doi.org/10.1016/j.dhjo.2012.03.004Get rights and content

Abstract

Background

The Autism and Developmental Disabilities Monitoring Network (ADDM), sponsored by the Centers for Disease Control and Prevention, is the largest-scale project ever undertaken to identify the prevalence of Autism Spectrum Disorders (ASD) in the United States.

Objective

The objective of the present study was to examine the accuracy of the ADDM methodology in terms of completeness of case ascertainment; that is, to assess the success of the ADDM Network in identifying and accurately classifying all existing cases of ASD among 8-year-old children in the target study areas.

Methods

To accomplish this objective, the ADDM methodology was applied to a selected region of South Carolina for 8-year olds in 2000 (birth year 1992) and again seven years later for the same region and birth year.

Results

For this region and birth year, completeness of case ascertainment was high, with prevalence estimates of 7.6 per 1000 at both ages 8- and 15-years. For children common to both surveillance years, concordance in case status was also high (82%).

Conclusions

Given that prevalence did not change within this region and birth year, continued research is needed to better understand the changes in prevalence estimates being found by the ADDM network across surveillance groups.

Section snippets

Methods

The ADDM Network methodology and prevalence results have been previously described [1], [2], [3], [5], [6], [7]. Briefly, the ADDM Network is an active, population-based surveillance program monitoring the prevalence of developmental disabilities among 8-year-old children through retrospective review of records from both school and clinical sources (e.g., clinics, disability centers). Children are classified as having an ASD if behaviors documented in evaluation records are consistent with the

Results

The prevalence of ASDs among 8-year-old children residing in the three-county sub-region in 2000 (birth year 1992) was 7.6 (61 identified cases from a total population of 8069 8 year olds), 95% CI: 5.7-9.5. The prevalence of ASDs among 15-year-old children (birth year also 1992) residing in the same sub-region in 2007 was 7.6 (67 identified cases from a total population of 8786 15 year olds), 95% CI: 5.8-9.4. These results indicate no change in overall prevalence of ASDs for children born in

Discussion

The results of this study provide evidence supporting the consistency of the ADDM Network’s prevalence estimates among children born in the year 1992 when the same methods are applied to the same geographical area 7 years apart. ASD prevalence among children born in 1992 was virtually identical for those residing in the selected region in 2000 (age 8 years) and those residing in the same region in 2007 (age 15 years) (7.6 per 1000 for both study years), suggesting a high level of completeness

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Cited by (6)

The authors have no conflicts of interest.

This work was supported by Grant/Cooperative Agreement Number CDC-RFA-DD06-601 from the Centers for Disease Control and Prevention.

Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention.

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