Autism spectrum disorder symptom emergence is heterogeneous, yet literature comparing young children diagnosed early versus later is relatively scant. Toddlers diagnosed with autism spectrum disorder between 12 and 18 months (n = 20), 19 and 24 months (n = 65), or 25 and 41 months (n = 27) were compared on demographics, developmental functioning,…

This study examined psychometric characteristics of the Diagnostic Analysis of Nonverbal Accuracy--Second Edition (DANVA-2) in 121 children, ages 6 to 13 years, with high-functioning autism spectrum disorder (HFASD). Internal consistency for adult and child faces subtests were 0.70 and 0.75, respectively. Immediate test-retest reliability in the…

Insomnia subtypes have not been characterized in severely affected youth with autism spectrum disorder. We examined indices of clinical impairment (i.e. length of hospital stay, autism severity, nonverbal intelligence quotient, and adaptive and maladaptive behaviors) across insomnia subtypes in 427 psychiatrically hospitalized children with autism…

Understanding that people's ideas may be false is a challenging step in Theory of Mind (ToM) development, which is accomplished around the age of 4-5 years old by typically developing (TD) children. False-belief attribution remains difficult beyond this age for certain clinical populations, such as Autism Spectrum Disorder (ASD), where delays in…

Adaptive behaviour is a crucial area of assessment for individuals with Autism Spectrum Disorder (ASD). This study examined the adaptive behaviour profile of 77 young children with ASD using the Vineland-II, and analysed factors associated with adaptive functioning. Consistent with previous research with the original Vineland a distinct autism…

West Syndrome is a severe, early-onset epilepsy syndrome, with significant implications for subsequent neurological and cognitive development. While most children with a prior diagnosis of West Syndrome initially follow a normal developmental trajectory, there is evidence of subsequent emergence of clusters of difficulties, including autism…

The goals of our study were to (a) compare agreement between autism spectrum disorder diagnosis and outcome of the Modified Checklist for Autism in Toddlers and Parents Evaluation of Developmental Status in a sample of toddlers and (b) examine specific concerns noted for toddlers who screened negative on the Modified Checklist for Autism in…

Background: The Autism Diagnostic Interview-Revised (ADI-R) is a gold standard assessment of Autism Spectrum Disorder (ASD) symptoms and behaviours. A key underlying assumption of studies using the ADI-R is that it measures the same phenotypic constructs across different populations (i.e. males/females, younger/older, verbal/nonverbal). The…

This prospective study of the FIRST WORDS® Project examined restricted and repetitive behaviors in a sample of 55 toddlers at a mean age of 20 months who were later diagnosed with autism spectrum disorder. Restricted and repetitive behaviors were coded using the Repetitive Movement and Restricted Interest Scales in two video-recorded observation…

This study examines the academic abilities of children and adolescents who were once diagnosed with an autism spectrum disorder, but who no longer meet diagnostic criteria for this disorder. These individuals have achieved social and language skills within the average range for their ages, receive little or no school support, and are referred to…

Purpose: To examine which cognitive, environmental, and speech-language variables predict expressive syntax in boys with fragile X syndrome (FXS), boys with Down syndrome (DS), and typically developing (TD) boys, and whether predictive relationships differed by group. Method: We obtained Index of Productive Syntax ( Scarborough, 1990) scores for…