A Meta-Analysis of Working Memory Impairments in Autism Spectrum Disorders.

Autism spectrum disorders (ASD) are characterized by executive dysfunction, and working memory (WM) comprises one core component of executive function. Many studies have investigated WM impairments in individuals with ASD, however, a conclusive agreement has not been reached. The present study provided a meta-analytic review of WM impairments in individuals with ASD and evaluated potential moderating variables of this problem. Twenty-eight studies were included in this study, and the participants comprised 819 individuals with ASD and 875 healthy controls. A significant WM impairment (Cohen's d = -0.61) was identified in the individuals with ASD, however, this impairment was not associated with age. Results of moderation analyses showed that (a) spatial WM was more severely impaired than verbal WM and (b) the component of cognitive processing (maintenance vs. maintenance plus manipulation) did not affect the severity of WM impairments. These findings suggest that WM is impaired in individuals with ASD and may have implications for interventions related to WM impairments in these individuals.