Intellectual development in young children with autism spectrum disorders: A longitudinal study

Abstract

Intelligence profiles in autism have been characterized by great variability. The questions of how autistic children's intelligence changes over time, and what factors influence these changes deserve study as part of efforts to document child autism profiles, but also because the relationship between intellectual functioning and children's background characteristics is poorly understood, particularly in a longitudinal context. A total of 39 autistic children and 39 age‐matched neurotypical children (5–9 years old) completed two IQ assessments at preschool age and up to 4 years later. Repeated‐measures analyses assessed longitudinal changes in the children's verbal (VIQ), performance (PIQ), and full‐scale IQ (FSIQ) at group level. We further sought to identify clusters with distinct profiles in each group by adopting an unsupervised K‐means clustering approach, and detect possible between‐subgroup differences in terms of children's socioeconomic status and autism severity. The largest cluster in the autistic group was composed of children whose PIQ significantly dropped at follow‐up, while the second largest cluster improved in all quotients; the smallest cluster, wherein children had more highly educated mothers than the rest of the clusters, was characterized by large improvement in VIQ. For the neurotypical children, there was a two‐cluster division; the majority of them improved in the three quotients, while very few dropped in PIQ at follow‐up. The relation between socioeconomic status and IQ changes was significant for both groups. The findings demonstrate both the complexity of intelligence changes in autism and the need to view this complexity through the lens of the children's socioeconomic diversity.

Reading comprehension differences between children with Autism Spectrum Disorder and low cognitive abilities and children with Autism Spectrum Disorder and intact cognitive skills: the roles of decoding, fluency and morphosyntax

“…There is significant variability in the academic achievements of school-aged children with ASD ( Keen et al, 2016 ); some perform as expected, given their symptomatology and IQ, and might perform better in some tasks such as visual reasoning ( Mayes and Calhoun, 2003 ). Many children with ASD, however, perform worse academically than their IQ would predict ( Manti et al, 2011 ; Kim et al, 2018 ; Peristeri and Andreou, 2024 ). For the children with ASD and high IQ, the variability in academic achievement is even higher, since some perform well in mainstream schools, while others need to attend special education settings ( Church et al, 2000 ).…”

Editorial: Neural mechanisms of language and cognitive performance in individuals with neurodevelopmental disorders

“…The domains that have been shown to be mostly negatively affected in language is pragmatic language comprehension (e.g., Solari et al, 2019 ), auditory processing (O'Connor, 2012 ), and expressive language (Peristeri et al, 2017 ). Individuals with autism have also been reported to experience difficulties with executive functions (Andreou et al, 2022 ), intellectual functioning (Peristeri and Andreou, 2024 ), and social cognition (Andreou et al, 2020 ; Peristeri et al, 2023 ), which often impede their daily functioning and adaptive behavior (Tsermentseli et al, 2018 ). The current Research Topic aims to expand the current understanding of language and cognitive skills of individuals with autism through the utilization of multiple methodological approaches and the consideration of less well-studied language and cognitive phenomena.…”