Diagnostic Accuracy of the ADOS-2

Poster Presentation
Thursday, May 2, 2019: 11:30 AM-1:30 PM
Room: 710 (Palais des congres de Montreal)
T. Hutchins1, H. Morris2 and S. Habermehl3, (1)UVM, Burlington, VT, (2)University of Vermont, Burlington, VT, (3)Communication Sciences & Disorders, University of Vermont, Burlington, VT
Background: The Autism Diagnostic Observation Schedule, 2nd Edition (ADOS-2) is an observational assessment component for the identification of autism spectrum disorder (ASD). The ADOS-2 has come into routine use and is widely regarded as the gold standard for the diagnostic classification of ASD across clinical and educational settings. Nevertheless, very little independent research has examined the diagnostic accuracy of the ADOS-2.
Objectives: The aim of this study was to examine the sensitivity and specificity of the ADOS-2 when used as part of the standard clinical evaluation of children referred to a specialty diagnostic clinic to identify or rule out ASD.
Methods: A total of 155 available reports from the Autism Assessment Clinic at the University of Vermont Medical Center were reviewed representing modules 1 through 4 of the ADOS-2. All ADOS-2s were administered by a speech-language pathologist specializing in ASD who had extensive training in the ADOS-2 and the diagnosis of ASD. Final clinical diagnosis was made following a multidisciplinary team assessment including a child psychiatrist, child psychologist, and speech-language pathologist. ADOS-2 data were submitted to a series of 2X2 contingency tables to calculate the classification accuracy of the instrument by module.
Results: Overall accuracy across modules was 70.4% (sensitivity = 90.9%; specificity = 66.0%) with a high rate of false positives (27.9%). Overall accuracy tended to decrease as module number increased (module 1 = 90.9%; module 2 = 93.9%; module 3 = 62.5%; module 4 = 58.8%). The most common non-spectrum diagnosis for children classified as ASD by the ADOS-2 for modules 2 – 4 (approximately 88%) was ADHD and anxiety.
Conclusions: The ADOS-2 can provide valuable information to a diagnostic team for the clinical evaluation of a child with ASD, however, for the higher modules and in settings where children with numerous developmental disorders are evaluated, the specificity of the instrument is low and the risk is an unacceptable rate of over-identification.