Girls, more than boys, experience a decrease in the severity of autism symptoms during childhood. It is unclear, however, which specific autistic behaviors change more for girls than for boys. Trajectories of autism symptoms were evaluated using the Autism Diagnostic Observation Schedule-calibrated severity scores (ADOS-CSS). Change in the…

Autism Spectrum Disorder (ASD) is diagnosed using the same criteria for males and females (e.g., DSM-5, ICD-10). Our understanding of ASD, including its etiology, symptom presentation, and prevalence has evolved significantly over time motivating several changes to the diagnostic criteria and the tools with which symptoms are measured. One aspect…

The smallest subset of items from the 30-item Checklist for Autism Spectrum Disorder (CASD) that differentiated 607 referred children (3-17 years) with and without autism with 100% accuracy was identified. This 6-item subset (CASD-Short Form) was cross-validated on an independent sample of 397 referred children (1-18 years) with and without autism…

Autism Spectrum Disorder (ASD) diagnostic tools are not designed for mental ages (MA) below 12 months. Autism Diagnostic Observation Schedule (ADOS) and Childhood Autism Rating Scale (CARS) were examined in 2-year-olds with ASD-low MA (n = 53), Global Developmental Delay (GDD; n = 175), and ASD-higher MA (n = 425). ADOS and CARS demonstrated…

Purpose: No diagnostic tools exist for identifying social (pragmatic) communication disorder (SPCD), a new "Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition" category for individuals with social communication deficits but not the repetitive, restricted behaviors and interests (RRBIs) that would qualify them for a…

Background: Both parent-report and clinician-administered autism spectrum disorder (ASD) screening instruments are important to accurately inform ASD risk ascertainment. The aim of this study was to adapt a clinician-administered ASD screening instrument, the Autistic Behavioural Indicators Instrument (ABII), as a parent questionnaire equivalent…

The purpose of this study was to examine the utility of the Systematic Observation of Red Flags as an observational level-two screening measure to detect risk for autism spectrum disorder in toddlers when used with a video-recorded administration of the Communication and Symbolic Behavior Scales. Psychometric properties of the Systematic…

Previously, we adapted the Home Situations Questionnaire to measure behavioral non-compliance in everyday settings in children with pervasive developmental disorders. In this study, we further revised this instrument for use in autism spectrum disorder and examined its psychometric properties (referred to as the Home Situations…