This study aimed to investigate factors associated with a delayed autism spectrum (ASD) diagnosis when compared to children with either no or early ASD diagnosis. Among 893 children assessed for ASD before age 8, 39% had no ASD at baseline, of which 21% received a later ASD diagnosis. Autism symptoms, diagnostic history of other developmental…

Early diagnosis of Autism Spectrum Disorder is considered best practice, increasing access to early intervention. Yet, many children are diagnosed after 3-years. The current study investigated the school age outcomes of children who received an early and later diagnosis of ASD. The cognitive and behavioural outcomes of children diagnosed early (n…

Students who enter kindergarten without school readiness skills are more likely to demonstrate academic, behavioral, and social struggles during school. Children with autism spectrum disorder (ASD) are particularly at risk for underdeveloped school readiness skills, which can undermine academic achievement and result in poor long-term outcomes.…

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder whose symptoms may involve deficits across three domains: communication, socialization and atypical behaviors or interests. With a high prevalence across populations and a tendency to impact males more than females, early and accurate diagnosis appears critical. The most…

This study aimed to identify determinants of a late autism spectrum disorder diagnosis, including diagnoses made 'very late' (i.e., in adolescence), using the Millennium Cohort Study, a nationally representative population-based cohort in the United Kingdom. Children diagnosed with autism spectrum disorder by age 14 (N = 581) were included and…

Autism spectrum disorder diagnoses in toddlers have been established as accurate and stable across time in high-risk siblings and clinic-referred samples. Few studies have investigated diagnostic stability in children prospective identified in community-based settings. Furthermore, there is a dearth of evidence on the individual behaviours that…

We examined the stability of cognitive and adaptive behaviour standard scores in children with autism spectrum disorder (ASD) between diagnosis and school entry approximately age 6. IQ increased 18 points in 2-year-olds, 12 points in 3-year-olds, and 9 points in 4-year-olds (N = 281). Adaptive behaviour scores increased 4 points across age groups…

The Wechsler Intelligence Test for Children -- Fifth Edition (WISC-V) is a comprehensive intellectual ability assessment for children. The WISC-V was developed over the course of five years by an expert team including doctoral-level scientists and clinicians and an advisory panel, who provided expert advice about intellectual ability testing,…

Impairments in cognitive flexibility have been used to characterize the neuropsychological presentation of persons with autism spectrum disorders (ASDs). Previous studies have yielded mixed results. Our objective was to systematically review the sensitivity of cognitive flexibility measures in ASD using quantitative methods employed by…

Purpose: The purpose of this research forum article is to provide an overview of a collection of invited articles on the topic "specific language impairment (SLI) in children with concomitant health conditions or nonmainstream language backgrounds." Topics include SLI, attention-deficit/hyperactivity disorder, autism spectrum disorder,…

Research on Autism Spectrum Disorder (ASD) is thriving; however, scant empirical research has investigated how ASD manifests in high ability youth. Further research is necessary to accurately differentiate high ability students with ASD from those without the disorder, and thus decrease the risk of misdiagnosis. The purpose of the present study is…

This prospective, longitudinal, study charted the developmental profiles of young children with Autism Spectrum Disorders (ASD) identified through routine developmental surveillance. 109 children with Autistic Disorder (AD), "broader" ASD, and developmental and/or language delays (DD/LD) were assessed using the Mullen Scales of Early Learning…

We investigated the relationship among cognitive level, autistic severity and adaptive function in a Taiwanese sample of 94 high-functioning children with autism spectrum disorders (ASD) (mean full scale intelligent quotients FSIQ = 84.8). Parents and teachers both completed the Adaptive Behavior Assessment System-II and the Social Responsiveness…

Assessment of children's restricted and repetitive behaviours offers potential opportunities to improve early diagnosis of autism spectrum disorder (ASD) and timely access to interventions and support. To facilitate this requires understanding of the phenomenology of repetitive behaviours in ASD, including differentiating behaviours seen in ASD…

We examined whether clinically distinct subgroups can be derived from a sample of toddlers (n = 186) who failed the Modified Checklist for Autism in Toddlers, received a comprehensive clinical evaluation, and were diagnosed with an autism spectrum disorder (ASD). Three subgroups emerged from cluster analysis distinguished by (a) social,…