Flexibility is a key component of executive function, and is related to everyday functioning and adult outcomes. However, existing informant reports do not densely sample cognitive aspects of flexibility; the Flexibility Scale (FS) was developed to address this gap. This study investigates the validity of the FS in 221 youth with ASD and 57…

We examined the reliability, validity and factor structure of the Eye Contact Avoidance Scale (ECAS), a new 15-item screening tool designed to measure eye contact avoidance in individuals with fragile X syndrome (FXS). Internal consistency of the scale was acceptable to excellent and convergent validity with the Social Responsiveness Scale, Second…

Research has highlighted potential differences in the phenotypic and clinical presentation of autism spectrum conditions across sex. Furthermore, the measures utilised to evaluate autism spectrum conditions may be biased towards the male autism phenotype. It is important to determine whether these instruments measure the autism phenotype…

This study examined differences between mothers' and fathers' style of interaction and engagement with their preschool-aged children with Down syndrome (DS) and autism. Data was collected from a sample of 27 mother-child and 27 father-child dyads in which all the children were diagnosed with DS or autism. Participants were both parents and their…

The purpose of this study was to examine the measurement properties of the Social Responsiveness Scale in an accelerated longitudinal sample of 4-year-old preschool children with the complementary approaches of categorical confirmatory factor analysis and Rasch analysis. Measurement models based on the literature and other hypothesized measurement…

Attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) often co-occur. Factor analyses of ASD traits in children with and without ASD indicate the presence of social and restrictive-repetitive behaviour (RRB) factors. This study used exploratory factor analyses to determine the structure of ASD traits (assessed using…

Objective: Comparative studies of social responsiveness, an ability that is impaired in autism spectrum disorders, can inform our understanding of both autism and the cognitive architecture of social behavior. Because there is no existing quantitative measure of social responsiveness in chimpanzees, we generated a quantitative, cross-species…

The factor structure of the Autism Diagnostic Interview-Revised (ADI-R) algorithm items was examined using exploratory (EFA) and confirmatory factor analyses (CFA) factor methods. The ADI-R was completed for 1,170 youths and adults (ages 2-46). Results of EFAs indicated strong support for two-factor structure, with social communication and…

Background: Although DSM-IV requires symptoms in three criterion domains for a diagnosis of autistic disorder, the extent to which those domains are phenotypically independent is an unanswered and important question. The identification of "endophenotypes" of the autistic syndrome may be very useful for genetic and neurobiologic studies of autism,…