Executive Functioning and Repetitive Behaviours in Autism

Relating behavioural symptoms of autism to performance on executive function, theory of mind and central coherence tasks

Executive functioning in children with autism and their first-degree relatives

Executive Function and Theory of Mind in Autism: Independent Impairments Underlying Distinct Symptoms?

 

Executive Functioning and Repetitive Behaviours in Autism

This paper was presented at the ASSBI (Australian Society for the Study of Brain Impairment) conference, Magnetic Island, Queensland, May 2001.

WONG, D. K. (University of Western Australia)

Impairments in aspects of executive functioning (EF) such as planning, flexibility, and working memory have been found in children with autism. It has been proposed that executive dysfunction may be a primary cognitive deficit of autism, of particular explanatory value with regard to repetitive behaviours which are characteristic of autism such as stereotyped movements, routines, and rituals. Autistic children’s performance on EF tasks, as compared with other cognitive tasks, has been found to show the strongest association with the nature and severity of repetitive behaviours. One problem with an EF account of repetitive behaviours in autism is that executive dysfunction has also been found in other disorders in which repetitive behaviours are symptomatic. However, if the broad domain of EF is divided into multiple components, particular patient groups may show different profiles of strength and weakness. This study measured the performance of autistic children and IQ-matched controls on tasks purported to measure different aspects of EF (the Tower of London, a set-shifting task, a go-nogo inhibition task, and two ideational fluency tasks), and examined the relationship between results on these tasks and different types of repetitive behaviour. Results will be discussed in the context of both theories of autism and conceptual models of EF.

back to top

 

Relating behavioural symptoms of autism to performance on executive function, theory of mind and central coherence tasks

This paper was presented at the Biennial National Autism Conference, Adelaide, September 2001, and at the Autism Research Symposium, Perth, May 2002.

Wong, D.*, Maybery, M.*, Hallmayer, J.†, Bishop, D‡., Maley, A.†, Petterson, N.†, & Hill, W.†

*Department of Psychology, University of Western Australia.
†Department of Psychiatry & Behavioural Science, University of Western Australia.
‡Department of Experimental Psychology, University of Oxford, UK.

Three major cognitive theories have been proposed to account for the behavioural symptoms of autism. The theory of mind account proposes a deficit in the ability to appreciate that others’ beliefs and desires are different from one’s own; the central coherence account proposes an impairment in the ability to process a wider context or meaning; and the executive dysfunction account proposes a deficit in executive processes such as mental flexibility, inhibition, monitoring, and planning. These three theories have had varying degrees of success in accounting for the language impairments, communicative difficulties, and repetitive behaviours which are symptomatic of autism. In this study, children with autism and age- and non-verbal IQ-matched controls were tested on several theory of mind, central coherence and executive tasks, and their performance was compared with measures of language and social functioning and repetitive behaviour. Results will be discussed in relation to the idea that several different cognitive deficits underlie the symptoms of autism, rather than one single deficit.

back to top

Executive functioning in children with autism and their first-degree relatives

This poster was displayed at the APS College of Clinical Neuropsychologists Conference in Melbourne in October 2001, and at the UWA Psychology Department Conference in October 2001.

WONG, DK., MAYBERY, M. (University of Western Australia), HALLMAYER, J., (Stanford University), MALEY, A., PETTERSON, N., HILL, W., (Centre for Clinical Research in Neuropsychiatry), & BISHOP, D. (Oxford University).

Previous studies have shown that individuals with autism demonstrate impairments in components of executive functioning (EF) such as planning, flexibility, and generativity. There is also extensive evidence for genetic involvement in the aetiology of autism. If executive dysfunction is a primary cognitive deficit of autism, similar though more subtle impairments in EF would be expected in relatives of individuals with autism. Furthermore, a characteristic pattern of strength and weakness on tests measuring different components of EF has been identified in children with autism, but it is not known whether their first-degree relatives display a similar profile. In this study, parents and siblings of children with autism and controls were tested on a battery of tasks purported to measure various components of EF (the Tower of London, a computerised set-shifting task, two go-nogo type inhibition tasks, and two ideational fluency tasks). Interest centres on whether the relatives of affected children show atypical performance on EF tests, and whether the pattern of performance displayed by children with autism on components of EF is mirrored in their relatives. Results are discussed with reference to both theories of EF and the heritability of autistic traits.

back to top

 

Executive Function and Theory of Mind in Autism: Independent Impairments Underlying Distinct Symptoms?

This paper will be presented at the International Neuropsychological Society conference in Berlin in July, 2003.

Wong, D.*, Maybery, M.*, Bishop, D.**, Maley, A.†, Hill, W.†, & Hallmayer, J.‡

*School of Psychology, University of Western Australia.
** Department of Experimental Psychology, University of Oxford, UK.
†Department of Psychiatry & Behavioural Science, University of Western Australia.
‡Department of Psychiatry & Behavioural Sciences, Stanford University, USA.

Impairments in both executive function (EF) and theory of mind (TOM) have been demonstrated in children with autism spectrum disorders. It has been proposed that TOM tasks rely heavily on executive abilities and that failure on TOM tasks may simply represent executive impairment. However, several recent studies on patients with frontal lobe dysfunction have indicated that while TOM and EF are both subserved by the prefrontal cortex, they are dissociable functions which can be independently impaired. This study examined 1) whether TOM and EF are independent deficits in autism, and 2) whether or not TOM and EF underlie different aspects of autistic symptomatology – with the focus in this study being on repetitive and stereotyped behaviours. Forty-seven children with autism spectrum disorders and 53 control children were tested on tasks measuring TOM and different components of EF (inhibition, planning, flexibility, and fluency). Repetitive behaviours were measured using a parental interview. It was found that group differences in TOM scores disappeared when measures of fluency and planning, but not inhibition or flexibility, were introduced as covariates. Within the autism group, measures of inhibition, flexibility, and fluency were significantly correlated with the presence and severity of different types of repetitive behaviours, but TOM scores were not. These results suggest that TOM is independent from some components of EF but not others. The finding that EFs correlate with repetitive behaviours but TOM does not further implies that the two cognitive domains underlie different aspects of autistic symptomatology.

back to top