A Systematic Review of Literature and Meta-Analysis of the Cognitive Performance of Children with Autism Spectrum Disorder using the Wechsler Intelligence Scale for Children
Date
2023
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of the Witwatersrand, Johannesburg
Abstract
Autism Spectrum Disorder, which includes previous diagnostic terms such as Asperger Syndrome, Pervasive Developmental Disorder and High Functioning Autism, is a lifelong neurodevelopmental disorder that is characterised by persistent deficits in social communication, difficulties in interaction across multiple contexts, difficulties in non-verbal communicative behaviours, and the exhibition of unusual behaviours. Given that Autism Spectrum Disorder is a spectrum disorder, Autism Spectrum Disorder individuals experience different degrees of signs and symptoms. Given the nature of Autism Spectrum Disorder and the differing levels of severity, individuals also present with varying cognitive capabilities and subsequently cognitive abilities (strengths and weaknesses) when assessed on individual intelligence measures such as the Wechsler Intelligence Scale for Children, which has been revised multiple times since its inception in 1949. The purpose of this research study is to investigate the cognitive performance of Autism Spectrum Disorder children assessed on the Wechsler Intelligence Scale for Children. First, a systematic review was conducted of available literature and research studies focused on the cognitive performance of Autism Spectrum Disorder children who have been assessed on the Wechsler Intelligence Scale for Children, followed by a meta-analysis to investigate the extent to which the performance differences observed between Autism Spectrum Disorder children and typically developing peers, when measured on the Wechsler Intelligence Scale for Children, is meaningful. Although a systematic review of 49 published research studies was undertaken, the meta-analysis included only 12 studies which focused on comparing the cognitive performance of Autism Spectrum Disorder and typically developing children. The results revealed that children diagnosed with Autism Spectrum Disorder, Asperger Syndrome and High Functioning Autism performed the highest on the Perceptual Reasoning Index and the lowest on the Processing Speed Index. Although limited data are available on individuals diagnosed with Pervasive Developmental Disorder, they performed the highest on the Perceptual Organisation Index and the lowest on the Verbal Comprehension Index. The results also revealed that when taking into account all the diagnostic terms used, Autism Spectrum Disorder children performed the highest on the Block Design subtest, followed by the Similarities subtest. They performed the lowest on the Coding subtest, followed by the Comprehension subtest. The meta-analysis revealed that the means and standard deviation differences found among the various Wechsler Intelligence Scale for Children indices between Autism Spectrum Disorder and typically developing children revealed that the typically developing children who participated in the various studies iii performed higher than Autism Spectrum Disorder children across all the Wechsler Intelligence Scale for Children indices except for the following: The High Functioning Autism children obtained a slightly higher mean Full-Scale IQ score than typically developing peers, with a higher mean Verbal Comprehension Index found on the part of the High Functioning Autism children. There is practical value in supporting Autism Spectrum Disorder children to reach their potential and minimising the impact of their diagnosis, as well as its accompanying difficulties on their scholastic progress and performance.
Description
A research report submitted in partial fulfillment of the requirements for the degree of Master of Education in Educational Psychology to the Faculty of Humanities, University of the Witwatersrand, Johannesburg, 2024
Keywords
Autism Spectrum Disorder; Wechsler Intelligence Scale for Children
Citation
Barnard, Helen. (2023). A Systematic Review of Literature and Meta-Analysis of the Cognitive Performance of Children with Autism Spectrum Disorder using the Wechsler Intelligence Scale for Children [Master’s dissertation, University of the Witwatersrand, Johannesburg]