Autism Speaks, Science, Latest Research

R. Luyster
Autism Consortium, Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetic Research, 185 Cambridge St., 6th Floor, Boston, MA 02114

W. Guthrie
K. Gotham
S. Risi
University of Michigan Autism and Communication Disorders Center, 1111 E. Catherine St., Ann Arbor, MI 48109

P. DiLavore
University of North Carolina, Division TEACCH, 1418 Aversboro Road, Garner, NC 27529

C. Lord
Autism Consortium, Psychiatric and Neurodevelopmental Genetics Unit, Center for Human Genetic Research, 185 Cambridge St., 6th Floor, Boston, MA 02114

Abstract
Background: The Autism Diagnostic Observation Schedule (ADOS; Lord et al., 2000) is widely accepted as a "gold standard" diagnostic instrument, but its downward limits restrict utility in research samples of very young children at risk for ASD.

Objectives: The objective of the present investigation was to modify the ADOS for use in very young children.

Methods: A modified ADOS, the ADOS-Toddler module (ADOS-T), was used in 272 evaluations. Participants included children 12-30 months of age with either best estimate diagnoses of ASD, non-spectrum developmental delay or typical development. A final set of protocol and algorithm items was selected based on their success in discriminating the diagnostic groups.

Results: For all children ages 12-20 months and nonverbal children 21-30 months, a new ADOS-T algorithm yielded a sensitivity and specificity both of 95%. For verbal children 21-30 months, the revised "Some Words" Module 1 algorithm (Gotham et al., 2007) yielded a sensitivity of 93% and a specificity of 95%.

Because of the variability in early development, we proposed to use scores on the algorithm to indicate a range of concern, rather than employ the traditional cutoffs. For all children ages 12-20 months and nonverbal children 21-30 months, a score of 12-15 on the ADOS-T algorithm indicates mild concern, and scores >15 indicate significant concern. Similarly, for verbal children 21-30 months, scores of 7-10 on the "Some Words" algorithm indicate mild concern, and scores >10 indicate significant concern.

Conclusions: The ADOS-T appears to be a useful addition to the existing ADOS. It is appropriate for use in children as young as 12 months and successfully discriminates between diagnostic groups, yielding high sensitivity and specificity. Given the variability of behavior in very young children, the proposed "range of concern" may be a more useful interpretation of algorithm results than the traditional "cutoffs" approach.

Lay Abstract
The Autism Diagnostic Observation Schedule (ADOS; Lord et al., 2000) is widely accepted as a "gold standard" diagnostic instrument for individuals referred for possible autism spectrum disorder (ASD). In its current version, it is not appropriate for use in very young children (generally, those who are developmentally under 16 months). In light of many recent research endeavors which are investigating early symptoms in infants and toddlers at risk for autism spectrum disorders, it was considered important to modify the ADOS for use in very young children.

The current project used a modified version of ADOS, the ADOS-Toddler module (ADOS-T), in 272 evaluations with children between the ages of 12 and 30 months. Some of the children were diagnosed with ASD, some had other, non-ASD developmental delays/disorders, and some were typically developing. A final set of codes for the ADOS-T were selected based on their success in discriminating the diagnostic groups.

Using a cutoff (as with the original ADOS), the results indicated that the ADOS-T was highly accurate in classifying very young children into the right diagnostic group. We also introduced a new way to use ADOS scores. In addition to the traditional cutoff for scores, there are also now "ranges of concern" which correspond to certain ranges of scores. Low scores are associated with little-to-no concern, moderately high scores are associated with mild-to-moderate concern, and high scores are associated with moderate-to-severe concern.

The ADOS-T appears to be a useful addition to the existing ADOS. It is appropriate for use in children as young as 12 months and successfully discriminates between diagnostic groups. Given the variability of behavior in very young children, the proposed "range of concern" may be a more useful interpretation of algorithm results than the traditional "cutoffs" approach. We hope that the ADOS-T will be helpful for both clinicians and researchers who work with young children at risk for ASD.