A comprehensive understanding of executive impairments in children with autism spectrum disorder

Abstract

Background: Autism Spectrum Disorder (ASD) is a neuro-developmental disorder characterized by a triad of impairments in social interaction, communication, and restricted and repetitive behaviors. For children with autism especially those with high functioning (HFA), it is common to discover from clinical observation and from care-givers’ report that there are uneven performance in their cognitive profile and also executive difficulties. In recent years, there were enormous amount of researches attempting to delineate the cognitive deficits and the executive impairments in autism. Executive Functions (EF) was a widely studied construct in autism. The vast pool of researches establishes various focuses of investigation, including: (1) the biological level; (2) the cognitive level; (3) the task performance level; and (4) the everyday functioning level. Each of them has its own significance, and contributes distinctly in delineating the executive impairments in ASD. Taking into account the complexity of the EF construct and the far-reaching impacts it imposing on our everyday functioning, a comprehensive approach encompassing different levels of investigation in one research design is suggested to investigate the performance and specific areas of impairment of children with HFA in respective levels; and to explore the possible relationships between the levels of investigations.

Methods: Forty aged 12-15 children participated in the research, twenty with HFA and twenty typically developing controls (TD), matched by gender, age and IQ. In the first part of the study, the participants were administered four traditional EF tasks including: inhibition, working memory, flexibility and planning to examine EF in the cognitive level. In the second part, they completed a novel multitasking test, the Battersea Multitask Paradigm (BMP) to examine executive difficulties in the task performance level. Parent ratings of the Behavior Rating Inventory of Executive Function (BRIEF) were collected for further investigation of their executive difficulties in the daily functioning level. Results: The 3-levels of investigation demonstrated converged results in examining the executive ability of ASD. From the integrated analyses, more evidence was gained to speculate that the planning inefficiency of children with HFA was due to their inability to cognitively construct the plan rather than their ability to execute or implement the plan. In real-life situations, they have particular difficulties in time management, to prioritize multiple and interleaved tasks, and to coordinate intended actions for future goal attainment. Moreover, their cognitive inflexibility had a pattern of “get stuck” or perseverates on the same task till completion before moving onto the next task. Their inflexibility to switch seemed to be explained by the preference to follow a more structured kind of sequence or action, i.e. to persist and finish one task before moving to another one. They were actually excellent “rule follower”, might not be as rigid of not willing to change. Significant positive relationships were only observed between the EF measures and Multitask variables.