Overview
The Gilliam Asperger’s Disorder Scale (GADS; Gilliam, 2001) is a 32-item norm-referenced questionnaire designed to identify individuals with Asperger’s Disorder. The tool includes four subscales: Social Interaction, Restricted Patterns, Cognitive Patterns, and Pragmatic Skills. The GADS can be completed by parents/caregivers or teachers. Respondents indicate the frequency of behaviors from “never observed” to “frequently observed.” The GADS includes a parent interview form that inquires about language and cognitive development, self-help skills, adaptive behavior, and curiosity. There is also a section of “key questions” for parents/caregivers to complete. In addition to assisting with diagnosis, the test developers assert that the GADS can be used to monitor the effectiveness of intervention, identify individualized education program (IEP) objectives, and assess behavior for research purposes.
Summary
Age: 3 years to 22 years
Time to Administer: 5 - 10 minutes
Method of Administration: 32-item parent/caregiver or teacher questionnaire
Includes a parent interview form to gather information about language and cognitive development, self-help skills, adaptive behavior, and curiosity
Yields standard scores (M = 100, SD = 15) for Quotient score, scaled scores (M = 10, SD = 3) for subtest scores, and percentile ranks
Subscales: Overall Composite Score: Asperger’s Quotient
Subscale Scores: Social Interaction; Restricted Patterns; Cognitive Patterns; Pragmatic Skills
Screening/Diagnosis: S
Autism Related Research
Mayes et al. (2011)
Age Range: 3-11 years
Sample Size: 477
Topics Addressed:
Validity of the GADS
Outcome:Mayes et al. (2011)
Classification accuracy (ASD vs. ADHD) for clinicians’ GADS Quotients was high (92%) and somewhat lower for parents’ Quotients (77%). Both high and low functioning children had similar clinician Quotients. Children with high functioning autism scored significantly higher on the Cognitive Patterns subscale than children with low functioning autism, and the latter had higher scores on the other three subscales. Using clinicians’ quotient and Cognitive Patterns score, 70% of children were correctly identified as having high or low functioning autism or ADHD.
Conclusion: GADS scores alone are not enough to justify differentiating between high and low functioning autism.
Mayes et al. (2009)
Age Range: 2 years, 2 months – 10 years, 7 months
Sample Size: 520
Topics Addressed:
Comparison of diagnostic agreement, reliability, and validity across measures
Outcome:Mayes et al. (2009)
For GADS: Criterion-related validity: Accuracy rates based on clinician scores were: 88% of low functioning scored in the Asperger’s Disorder range; 92% of high-functioning accurately identified; 4% of children with ADHD were misclassified with autism. Accuracy rates based on parent scores were: 72% low functioning scored in the Asperger’s Disorder range; 74% high-functioning; 19% of children with ADHD were misclassified. Inter-rater reliability: parents and clinician ratings did not differ significantly (r = 0.53, p <0.0001).
Conclusion: data supported GADS for identifying high functioning children on the spectrum.
Campbell (2005)
Age Range:
Sample Size: Comparative review of measures for detection of Asperger Syndrome
Topics Addressed:
Psychometric property comparison
Outcome:Campbell (2005)
Large standardization sample (n = 371) but without verified diagnoses. The overall score (GADS Quotient) does not meet the internal consistency reliability criterion of .90, and the median subtest internal consistency falls below the criterion of .80. Average subscale ceiling is inadequate.