Associations between executive function, adaptive behaviour, participation and self-reported quality of life in adolescents with autism spectrum disorder without intellectual disability

Abstract

Background ASD is a neurodevelopmental condition that affects an individual’s ability to communicate and interact with others. There has been an increase in the prevalence of ASD diagnosis, with the most considerable increase in adolescents who are intellectually able. These adolescents have difficulties with adaptive behaviour and struggle to participate in society, even if their intelligence is in the average or superior range. A better understanding of the relationship between impairments associated with ASD such as social impairments, executive function, adaptive behaviour, and participation and quality of life (QoL) is needed in intellectually able adolescents with autism.

Aims Using the International Classification of Functioning, Disability and Health (ICF), with subjective functioning added, as a framework, this thesis aimed to study the association between 1) executive function (EF) and adaptive behaviour, over and above the contribution to adaptive behaviour of social impairment and intelligence; 2) EF and participation and the mediating role of adaptive behaviour in their association; 3) participation and self-reported QoL, over and above the contribution to self-reported QoL of social impairment and symptoms of anxiety and depression, in adolescents with ASD and without ID.

Methods To address these aims, a cross-sectional study of 39 adolescents with ASD, aged from 10 to 16 years and 11 months (M = 13 years 4 months; SD = 3 months) and with Full Scale Intelligence Quotient (FSIQ) ranging between 78 and 144 (M = 107.97; SD = 18.25) was conducted. Adolescents completed a battery of tests to assess the ICF domains of Health Condition (social impairment, anxiety and depressive symptoms), Body Functions/impairments (EF, such as cognitive flexibility, inhibition, generativity, planning), Activity (adaptive behaviour), Participation (participation in extra-curricular activities) as well as the domain of subjective functioning (self-reported QoL). The domains of Environmental Factors (family social advantage) and Personal Factors (sex, age and intelligence) were also considered for each participant. Measures were chosen based on their use in clinical practice and research with young people with ASD, with the exception of participation, as there was no clear understanding of how to measure this domain for young people with ASD. To identify how participation has been measured in young people with ASD a systematic review of the literature was performed, with consideration of the measurement properties of the tools identified. As published, nine studies out of the 2539 screened investigated the measurement properties of the tool to assess participation in young people with ASD. These nine studies included seven tests, namely Adolescent and Young Adult Activity Card Sort, the Children’s Assessment of Participation and Enjoyment/Preference for Activities of Children (CAPE/PAC); the Experience Sampling Method; the Pediatric Evaluation of Disability Inventory Computer Adaptive Test (PEDI-CAT) and the School Function Assessment. The tests’ measurement properties were investigated in studies with high risk of bias and therefore, the quality of the evidence for these tools is limited. The PEDI-CAT demonstrated adequate measurement properties but lacked the assessment of the subjective dimension of participation. For this reason, the CAPE was chosen in this study.

Preliminary analysis of the data from the cross-sectional study comprised a description of the sample, univariate analysis of the association between independent and dependent variables by hypothesis, and explorative univariate analysis of the association between covariates and dependent variables. To address the three aims of this thesis, three hierarchical regressions were performed with covariates entered in the first steps, and the independent variables by hypothesis entered last.

Results The descriptive statistics fit well with the conceptualisation of autism as a spectrum condition with scores on measures of the constructs mentioned earlier varying between participants. Hierarchical regression relative to aim 1 showed that inhibition was positively associated with adaptive behaviour, above and beyond social abilities (reversed social impairments) and intelligence. Inhibition and social abilities were positively associated with adaptive behaviour and explained 50% of its variance. There was no association between cognitive flexibility, generativity, planning and adaptive behaviour over and above the contribution of social abilities and intelligence. Hierarchical regression relative to aim 2 showed that there was no association between EF abilities and participation. Furthermore, there was no association between adaptive behaviour and participation and, as such, adaptive behaviour was not found to be a mediator in the association between EF and participation. Hierarchical regression relative to aim 3 showed that there was no association between participation and self-reported QoL, above and beyond reversed anxiety and depressive symptoms. Reversed depressive symptoms were positively associated with self-reported QoL and explained 49% of the variance in self-reported QoL.

Discussion Assessment of EF abilities, together with the assessment of social abilities, should become routine in the care of adolescents with ASD who have difficulties with adaptive behaviour. However, there is a need to investigate other factors in addition to EF abilities and adaptive behaviour which may influence participation in extra-curricular activities as impairments in the former are not associated with those in participation. Treating comorbid mental health symptoms of young people with ASD, in particular depressive symptoms, may result in an improvement of these young people’s self-reported QoL.