All ETDs from UAB

Advisory Committee Chair

Sarah E O'Kelley

Advisory Committee Members

Fred J Biasini

Kristi C Guest

Maria I Hopkins

Sylvie Mrug

Document Type

Dissertation

Date of Award

2020

Degree Name by School

Doctor of Philosophy (PhD) College of Arts and Sciences

Abstract

Screening and diagnosis of children with autism spectrum disorder (ASD) are crucial for these individuals to receive appropriate ASD-focused intervention as early as possible. Using ASD-specific strategies in early intervention leads to improvement across skill areas. The Autism Diagnostic Observation Schedule, Second Edition (ADOS-2) and the Autism Diagnostic Interview, Revised (ADI-R) are two gold-standard diagnostic instruments used in comprehensive ASD evaluations. These measures have high accuracy in research settings, but evidence of accuracy in clinical settings is less robust. They also require significant training and expertise to administer, and comprehensive ASD evaluations are in high demand. Therefore, it is important to optimize the diagnostic process to ensure that children at-risk for ASD have access to timely evaluations. The first study, a systematic literature review and meta-analysis, showed that these measures had high accuracy overall, with the ADOS-2 performing better than the ADI-R. The ADI-R was less accurate in clinical settings compared with research settings, but results were variable for the ADOS-2. The second study evaluated the accuracy of these measures in a tertiary care center and showed that the ADOS-2 had high accuracy predicting final clinical diagnosis. The ADI-R was additive at times, such as when evaluating older children who may have more complex clinical presentations. In the third study, the clinical utility of using two screening instruments, the Modified Checklist for Autism in Toddlers, Revised (M-CHAT-R) and the Communication and Symbolic Behavior Scales, Infant-Toddler Checklist (CSBS-ITC), in the triage process in a tertiary care center was investigated. Both screening measures had high sensitivity and low specificity in this setting. The CSBS-ITC predicted both the ASD diagnostic measures and final clinical diagnosis. The M-CHAT-R predicted the ADOS-2, but results for the ADI-R and final clinical diagnosis were mixed. Overall, these studies shed light into the clinical utility of screening and diagnostic measures, particularly the accuracy of the ADOS-2 in ASD evaluations and the additive nature of the use of the CSBS-ITC in screening and clinic assignment. Future research should continue to investigate ways to optimize access to screening, evaluation, diagnosis, and appropriate intervention for children at-risk for ASD.

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