Objectives: 1) To determine how well the Repetitive Behavior Scale (RBS) and the Interests Scale discriminate between AS/HFA and typically developing (TD) controls, and 2) to explore relationships between repetitive and other behaviors.
Methods: Participants were recruited for multimodal research studies conducted at Children’s National Medical Center/Georgetown University and the NIMH. Participants completed an extensive battery that included diagnostic measures (ADI-R, ADOS for AS/HFA subjects only), cognitive (WASI), the RBS, the Interests Scale, the Behavior Rating Inventory of Executive Functioning (BRIEF), and the Social Responsiveness Scale (SRS). Study measures were obtained from 63 youth with AS/HFA (mean age 12.8, range 7.3-22; 54 male; mean FSIQ=112, sd=18) and 26 TD children (mean age=10.4, range 7.3-13.8; 18 male; mean FSIQ=118, sd=11).
Results: AS/HFA individuals had more repetitive behaviors (F=50.34, df=86, p=.000) and more intense interests (F=10.27, df=53, p=.002) than TD children. Children with AS/HFA did not have a greater number of interests than TD children, though qualitative analyses suggest different areas of interests. The topographies of the repetitive behaviors and intense interests will be presented. Controlling for FSIQ, scores on the RBS were related to intensity of interests (r=.51, p=.000), ADI-R Repetitive Behaviors (r=.57, p=.000), the Global Executive Composite on the BRIEF (r=.67, p=.000), and SRS total score (r=.81, p=.000). RBS scores were not correlated with scores on the ADOS. The Interests Scale was related to the ADOS diagnostic algorithm score (r=-.48, p=.02), the BRIEF GEC (r=.82, p=.000), and the SRS (r=.63, p=.000).
Conclusions: The RBS and the Interests Scale capture core symptoms associated with AS/HFA and are strongly related to each other, autistic traits, communication skills, and executive functioning.