Confirmatory factor analysis of the Adult Asperger Assessment: The association of symptom domains within a clinical population

Autism Spectrum Disorder (ASD) is a behaviourally defined disorder characterised by impairments in three domains of social interaction, communication, and repetitive, stereotyped behaviours and activities. Proposed changes to diagnostic criteria suggest that the diagnostic triad may no longer fit as the best way to conceptualise ASD, and that social and communication impairments should be considered as a single domain. The aim of this study was to examine the structure of symptom domains within the Adult Asperger Assessment (AAA; Baron-Cohen, Wheelwright, Robinson, & Woodbury-Smith, 2005), a diagnostic tool for high functioning adults. As theoretical models already exist, confirmatory factor analysis was used to examine data from a clinical population of adults (n = 153) diagnosed with Asperger Syndrome (AS) and High Functioning Autism (HFA). Confirmatory factor analysis was used to fit different models based on the structure proposed by the authors of the AAA, the traditional triad and the newly proposed diagnostic dyad. Analysis suggested that none of the tested models were a good fit on the AAA dataset. However, it did highlight very high correlations between social and communication factors (r > 0.9) within unmodified models. The results of the analysis provide tentative support for the move towards considering ASD as a dyad of 'social-communication' impairments and repetitive/restricted interests behaviours and activities, rather than the traditional triad

The origins, operation and impacts of quality assurance in UK higher education, 1985-2004

The thesis explores the origins of government concerns about the quality of UK higher education during the 1980s and traces legislative processes leading to the reform acts of 1988 and 1992. It demonstrates close links between higher education reforms and Conservative policies in the rest of the public sector and shows how quality assurance was used as an instrument of regulation to increase government control over the universities during the next decade. These developments coincided with the rise of a higher education ‘market’ in which quality assessment scores were translated into league tables to attract students as ‘customers’. The narrative then shows how the issue of student fees increasingly came to dominate the Labour government’s thinking from 1997 onwards and became a major theme in debates leading to the higher education act of 2004. The chronological narrative based on historical accounts and contemporary documents identifies four successive phases of quality assurance between 1992 and 2004. This is combined with a qualitative study which uses a constructivist approach to build up a picture of the unsettled period that followed the introduction of quality assurance systems into universities. A wide range of views from contemporary literature were supplemented by a series of ten semi-structured interviews with individuals who played significant roles in these events and reported their experiences in their own words. The narrative traces the growth of a quality ‘industry’ in higher education and a longrunning ‘quality debate’ among those affected by its impacts. Difficulties of defining ‘quality’ and the political desire for quantitative measurement led to the adoption of unsuitable methodology, emphasising accountability at the expense of improvement. This turbulent period was characterised by a recurring pattern of rising protests from academics which culminated in political intervention and subsequently further change. The thesis analyses the effects of quality assurance on university staff and students and on the developing discourse between higher education and the state. Summarising its impacts in a balance sheet of pros and cons leads to the conclusion that though concerns about quality were justified and some form of regulation was necessary in the expanded and diverse sector, the results of audit and assessment revealed little cause for concern about the quality of UK higher education. Furthermore, though quality assurance produced some benefits in the organisation of courses, staff development and information for prospective students, there was little evidence of benefits to teaching itself. Thus, quality assurance failed to deliver the government’s own aim of value for money, and the effort and time 3 required by the universities could have been put to better use; less insistence on regulation could have given academics more freedom to pursue improvements in teaching. A brief epilogue reflects on the status of quality assurance in 2015 and warns that separate plans for reform announced by HEFCE and the current government risk repeating old mistakes

What range of trait levels can the Autism-Spectrum Quotient (AQ) measure reliably?:An Item Response Theory Analysis

It has previously been noted that inventories measuring traits that originated in a psychopathological paradigm can often reliably measure only a very narrow range of trait levels that are near and above clinical cutoffs. Much recent work has, however, suggested that autism spectrum disorder traits are on a continuum of severity that extends well into the nonclinical range. This implies a need for inventories that can capture individual differences in autistic traits from very high levels all the way to the opposite end of the continuum. The Autism-Spectrum Quotient (AQ) was developed based on a closely related rationale, but there has, to date, been no direct test of the range of trait levels that the AQ can reliably measure. To assess this, we fit a bifactor item response theory model to the AQ. Results suggested that AQ measures moderately low to moderately high levels of a general autistic trait with good measurement precision. The reliable range of measurement was significantly improved by scoring the instrument using its 4-point response scale, rather than dichotomizing responses. These results support the use of the AQ in nonclinical samples, but suggest that items measuring very low and very high levels of autistic traits would be beneficial additions to the inventory

Association between the social and communication impairments and repetitive/restricted interests and behaviours of ASD in a clinical sample: Does the triad still fit?

Introduction: Autism Spectrum Disorder (ASD) is a behaviourally defined disorder characterised by impairments in three domains of social interaction, communication, and repetitive/restricted interests and behaviours (DSM-IV-TR; APA, 2000; ICD-10; WHO, 1992). Recent research suggests that this diagnostic triad may no longer fit as the best way to conceptualise ASD. Although not due for publication until 2013, a proposed revision of autistic disorder for DSM-V has merged three domains into two; i) Social/communication deficits and ii) Fixated interests and repetitive behaviours (APA, 2010). The aim of this study was to examine the structure of ASD symptom domains within the Adult Asperger Assessment (AAA; Baron-Cohen et al., 2005). Method: Confirmatory factor analysis was used to examine data from a clinical population of adults diagnosed with Asperger Syndrome (AS) and High Functioning Autism (HFA). Results: Analysis suggested that none of the theoretically-driven models were supported by the AAA data. However, it did highlight high correlations between social and communication factors (r > 0.9) within unmodified models. Discussion: The results of the analysis did not provide support for the move towards considering ASD as a dyad of ‘social-communication’ impairments and repetitive/restricted interests and behaviours, as none of the models were supported by the AAA data. The validity of the AAA as a diagnostic tool is discussed, as well as limitations and suggestions for future research. Conclusion: This study did not provide the evidence required to endorse a move towards the proposed DSM-V dyad. Further research to understanding the structure of autism symptoms could improve diagnostic and classification systems, and further studies of the genetic and neurobiological bases of ASD

Brief report:An evaluation of the AQ-10 as a brief screening instrument for ASD in adults

There is a need for brief screening instruments for autistic spectrum disorders (ASD) that can be used by frontline healthcare professionals to aid in the decision as to whether an individual should be referred for a full diagnostic assessment. In this study we evaluated the ability of a short form of the autism spectrum quotient (AQ) questionnaire, the 10 item AQ-10, to correctly classify individuals as having or not having ASD. In a sample of 149 individuals with ASD and 134 controls without an ASD diagnosis, we found that the full AQ (AQ-50) abridged AQ (AQ-S) and AQ-10 all performed well as a screen for ASD. ROC analysis indicated that sensitivity, specificity and area under the curve were very similar at suggested cut-off's for ASD across measures, with little difference in performance between the AQ-10 and full AQ-50. Results indicate the potential usefulness of the AQ-10 as a brief screen for ASD

Investigating Sex Bias in the AQ-10: A Replication Study

There are concerns that females with autism spectrum disorders (ASD) may be underidentified because of factors such as better camouflaging and poorer recognition of the signs of ASD in females. One stage at which females may be underidentified is during screening. In this study, we, therefore, evaluated whether the autism spectrum quotient (AQ-10), a brief recommended screening instrument for ASD in adults suspected of having ASD, showed any evidence of underestimating symptoms in females. Our results broadly replicate those of an earlier study in finding no strong evidence that the AQ-10 is biased against females. However, to achieve better performance in females, we suggest that one item be replaced with an item measuring more “female” manifestations of ASD

Are autistic traits measured equivalently in individuals with and without an Autism Spectrum Disorder?:An invariance analysis of the Autism Spectrum Quotient Short Form

It is common to administer measures of autistic traits to those without autism spectrum disorders (ASDs) with, for example, the aim of understanding autistic personality characteristics in non-autistic individuals. Little research has examined the extent to which measures of autistic traits actually measure the same traits in the same way across those with and without an ASD. We addressed this question using a multi-group confirmatory factor invariance analysis of the Autism Quotient Short Form (AQ-S: Hoekstra et al. in J Autism Dev Disord 41(5):589-596, 2011) across those with (n = 148) and without (n = 168) ASD. Metric variance (equality of factor loadings), but not scalar invariance (equality of thresholds), held suggesting that the AQ-S measures the same latent traits in both groups, but with a bias in the manner in which trait levels are estimated. We, therefore, argue that the AQ-S can be used to investigate possible causes and consequences of autistic traits in both groups separately, but caution is due when combining or comparing levels of autistic traits across the two group

Do the Autism Spectrum Quotient (AQ) and Autism Spectrum Quotientsahort form (AQ-S) primarily reflect general ASD traits or specific ASD traits?:A bi-factor analysis

In the current study, we fit confirmatory bi-factor models to the items of the Autism Spectrum Quotient (AQ) and Autism Spectrum Quotient Short Form (AQ-S) in order to assess the extents to which the items of each reflect general versus specific factors. The models were fit in a combined sample of individuals with and without a clinical diagnosis of autism spectrum disorders. Results indicated that, with the exception of the Attention to Details factor in the AQ and the Numbers/Patterns factors in the AQ-S, items primarily reflected a general factor. This suggests that when attempting to estimate an association between a specific symptom measured by the AQ or AQ-S and some criterion, associations will be confounded by the general factor. To resolve this, we recommend using a bi-factor measurement model or factor scores from a bi-factor measurement whenever hypotheses about specific symptoms are being assessed

The Latent Structure of Autistic Traits:A Taxometric, Latent Class and Latent Profile Analysis of the Adult Autism Spectrum Quotient

Autistic traits are widely thought to operate along a continuum. A taxometric analysis of Adult Autism Spectrum Quotient data was conducted to test this assumption, finding little support but identifying a high severity taxon. To understand this further, latent class and latent profile models were estimated that indicated the presence of six distinct subtypes: one with little probability of endorsing any autistic traits, one engaging in ‘systemising’ behaviours, three groups endorsing multiple components of Wing and Gould’s autistic triad, and a group similar in size and profile to the taxon previously identified. These analyses suggest the AQ (and potentially by extension autistic traits) have a categorical structure. These findings have important implications for the analysis and interpretation of AQ data

Psychometric properties of the Mandarin version of the Childhood Autism Spectrum Test (CAST):an exploratory study

Limited studies have investigated the latent autistic traits in the mainland Chinese population for autism spectrum conditions (ASC). This study explored the psychometric properties of a Mandarin Chinese version of the CAST in a sample consisting of 737 children in mainstream schools and 50 autistic cases. A combination of categorical data factor analysis and item response theory suggested a good-fit model of a two-factor solution for 28 items on the Mandarin CAST including social and communication, and inflexible/stereotyped language and behaviours (Goodness-of-fit indices: RMSEA = 0.029, CFI = 0.957, TLI = 0.950, SRMR = 0.064). The correlation between the two factors was moderate (GFC = 0.425). This study provided evidence for the CAST as a multidimensional measure for ASC screening in a Chinese population and also showed that the symptom manifestation of ASC in Chinese children shares similarity with western populations. © 2014 Springer Science+Business Media