Improving the measurement of alexithymia in autistic adults: a psychometric investigation of the 20-item Toronto Alexithymia Scale and generation of a general alexithymia factor score using item response theory.
TL;DR: Williams et al. as mentioned in this paper conducted an in-depth psychometric analysis of the TAS-20 in a large sample of 743 cognitively able autistic adults recruited from the Simons Foundation SPARK participant pool and 721 general population controls enrolled in large international psychological study.
Abstract: Background Alexithymia, a personality trait characterized by difficulties interpreting emotional states, is commonly elevated in autistic adults, and a growing body of literature suggests that this trait underlies several cognitive and emotional differences previously attributed to autism. Although questionnaires such as the 20-item Toronto Alexithymia Scale (TAS-20) are frequently used to measure alexithymia in the autistic population, few studies have investigated the psychometric properties of these questionnaires in autistic adults, including whether differential item functioning (I-DIF) exists between autistic and general population adults. Methods This study is a revised version of a previous article that was retracted due to copyright concerns (Williams and Gotham in Mol Autism 12:1-40). We conducted an in-depth psychometric analysis of the TAS-20 in a large sample of 743 cognitively able autistic adults recruited from the Simons Foundation SPARK participant pool and 721 general population controls enrolled in a large international psychological study. The factor structure of the TAS-20 was examined using confirmatory factor analysis, and item response theory was used to generate a subset of the items that were strong indicators of a "general alexithymia" factor. Correlations between alexithymia and other clinical outcomes were used to assess the nomological validity of the new alexithymia score in the SPARK sample. Results The TAS-20 did not exhibit adequate model fit in either the autistic or general population samples. Empirically driven item reduction was undertaken, resulting in an 8-item general alexithymia factor score (GAFS-8, with "TAS" no longer referenced due to copyright) with sound psychometric properties and practically ignorable I-DIF between diagnostic groups. Correlational analyses indicated that GAFS-8 scores, as derived from the TAS-20, meaningfully predict autistic trait levels, repetitive behaviors, and depression symptoms, even after controlling for trait neuroticism. The GAFS-8 also presented no meaningful decrement in nomological validity over the full TAS-20 in autistic participants. Limitations Limitations of the current study include a sample of autistic adults that was majority female, later diagnosed, and well educated; clinical and control groups drawn from different studies with variable measures; only 16 of the TAS-20 items being administered to the non-autistic sample; and an inability to test several other important psychometric characteristics of the GAFS-8, including sensitivity to change and I-DIF across multiple administrations. Conclusions These results indicate the potential of the GAFS-8 to robustly measure alexithymia in both autistic and non-autistic adults. A free online score calculator has been created to facilitate the use of norm-referenced GAFS-8 latent trait scores in research applications (available at https://asdmeasures.shinyapps.io/alexithymia ).
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TL;DR: Both individual symptoms and total symptom burden were related to higher levels of depression, anxiety, and autistic traits, along with lower quality of life in autistic young adults, particularly women.
Abstract: Somatic symptoms are the most common cause of outpatient medical visits in the general population, yet their presence and severity in individuals on the autism spectrum has rarely been studied. We sought to assess the prevalence, impact, and clinical correlates of 14 commonly reported somatic symptoms in a sample of 290 transition‐aged autistic young adults (mean [SD] age: 23.10 [2.38] years, range 18–26; 76.7% diagnosed with autism before age 18) recruited from the Simons Foundation SPARK participant pool. A modified version of the Patient Health Questionnaire–15 was used to assess somatic symptom prevalence/impact, along with measures of depression, anxiety, autistic traits, and quality of life. Somatic symptom burden was much higher in autistic young adults than previously reported in the general population. The most commonly reported current symptoms were fatigue (72.8%), sleep problems (69.0%), and menstrual problems (61.4% of females). Moderate or severe symptom levels were reported by 53.9% of females and 18.75% of males in our cohort, with the odds of females endorsing any given symptom being 2–4 times greater than males. Both individual symptoms and total symptom burden were related to higher levels of depression, anxiety, and autistic traits, along with lower quality of life. Despite little research on this topic previously, somatic symptoms are highly prevalent in autistic young adults, particularly women. Future research is needed to investigate links between somatic symptoms, medical and psychiatric morbidity, and health care utilization in the autistic population.
10 citations
TL;DR: In this article , a new way to score the Patient-Reported Outcomes Measurement Information System Global-10 scale and generate a "general quality of life" score specific to autistic adults was proposed, showing very little measurement error and relating in expected ways to similar constructs, such as physical health and emotional distress.
Abstract: Quality of Life an outcome that both researchers and autistic advocates agree is extremely important to consider when implementing services, interventions, and supports for autistic people. However, there has been little research on the topic of how quality of life can best be measured in autistic people or whether existing quality of life questionnaires are appropriate for use in the autistic population. This study aimed to validate an established quality of life measure, the Patient-Reported Outcomes Measurement Information System Global-10, in a large sample of autistic adults recruited online. We created a new way to score the Patient-Reported Outcomes Measurement Information System Global-10 scale and generate a "General quality of life" score specific to autistic adults. This new score performed very well in this sample, showing very little measurement error and relating in expected ways to similar constructs, such as physical health and emotional distress. Exploratory analyses found that lower quality of life was associated with female sex and self-identification as a sexual or gender minority (i.e. LGBTQ + identity). These findings suggest that the new Patient-Reported Outcomes Measurement Information System Global-10 quality of life score is a reliable and valid measure of quality of life in autistic adults, although additional studies are necessary to further explore its measurement properties in other subsets of the autistic population, such as individuals with intellectual disabilities. This measure is freely available for use as an outcome in both research and clinical practice, and an online score calculator is available to support the use of this measure in real-world applications.
5 citations
TL;DR: In this article , a three-level Bayesian meta-analysis compared heartbeat counting performance, heartbeat discrimination, heartbeat counting confidence ratings, and self-reported interoceptive attention between autistic and neurotypical individuals.
Abstract: Interoception, the body’s perception of its own internal states, is thought to be altered in autism, though results of empirical studies have been inconsistent. The current study systematically reviewed and meta-analyzed the extant literature comparing interoceptive outcomes between autistic (AUT) and neurotypical (NT) individuals, determining which domains of interoception demonstrate robust between-group differences. A three-level Bayesian meta-analysis compared heartbeat counting performance, heartbeat discrimination performance, heartbeat counting confidence ratings, and self-reported interoceptive attention between AUT and NT groups (15 studies; nAUT = 467, nNT = 478). Autistic participants showed significantly reduced heartbeat counting performance [g = − 0.333, CrI95% (− 0.535, − 0.138)] and higher confidence in their heartbeat counting abilities [g = 0.430, CrI95% (0.123, 0.750)], but groups were equivalent on other meta-analyzed outcomes. Implications for future interoception research in autism are discussed.
5 citations
TL;DR: In this article, the authors explored the role of alexithymia in the relationship between depression and quality of life (QOL) and found that depression is a pervasive negative predictor of multiple QOL domains.
3 citations
TL;DR: In this article , the authors explored the role of alexithymia in the relationship between depression and quality of life (QOL) and found that depression is a pervasive negative predictor of multiple QOL domains.
3 citations
References
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Journal Article•
TL;DR: Copyright (©) 1999–2012 R Foundation for Statistical Computing; permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and permission notice are preserved on all copies.
Abstract: Copyright (©) 1999–2012 R Foundation for Statistical Computing. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the R Core Team.
272,030 citations
TL;DR: In this paper, a different approach to problems of multiple significance testing is presented, which calls for controlling the expected proportion of falsely rejected hypotheses -the false discovery rate, which is equivalent to the FWER when all hypotheses are true but is smaller otherwise.
Abstract: SUMMARY The common approach to the multiplicity problem calls for controlling the familywise error rate (FWER). This approach, though, has faults, and we point out a few. A different approach to problems of multiple significance testing is presented. It calls for controlling the expected proportion of falsely rejected hypotheses -the false discovery rate. This error rate is equivalent to the FWER when all hypotheses are true but is smaller otherwise. Therefore, in problems where the control of the false discovery rate rather than that of the FWER is desired, there is potential for a gain in power. A simple sequential Bonferronitype procedure is proved to control the false discovery rate for independent test statistics, and a simulation study shows that the gain in power is substantial. The use of the new procedure and the appropriateness of the criterion are illustrated with examples.
83,420 citations
TL;DR: In this article, the adequacy of the conventional cutoff criteria and several new alternatives for various fit indexes used to evaluate model fit in practice were examined, and the results suggest that, for the ML method, a cutoff value close to.95 for TLI, BL89, CFI, RNI, and G...
Abstract: This article examines the adequacy of the “rules of thumb” conventional cutoff criteria and several new alternatives for various fit indexes used to evaluate model fit in practice. Using a 2‐index presentation strategy, which includes using the maximum likelihood (ML)‐based standardized root mean squared residual (SRMR) and supplementing it with either Tucker‐Lewis Index (TLI), Bollen's (1989) Fit Index (BL89), Relative Noncentrality Index (RNI), Comparative Fit Index (CFI), Gamma Hat, McDonald's Centrality Index (Mc), or root mean squared error of approximation (RMSEA), various combinations of cutoff values from selected ranges of cutoff criteria for the ML‐based SRMR and a given supplemental fit index were used to calculate rejection rates for various types of true‐population and misspecified models; that is, models with misspecified factor covariance(s) and models with misspecified factor loading(s). The results suggest that, for the ML method, a cutoff value close to .95 for TLI, BL89, CFI, RNI, and G...
76,383 citations
Book•
27 May 1998TL;DR: The book aims to provide the skills necessary to begin to use SEM in research and to interpret and critique the use of method by others.
Abstract: Designed for students and researchers without an extensive quantitative background, this book offers an informative guide to the application, interpretation and pitfalls of structural equation modelling (SEM) in the social sciences. The book covers introductory techniques including path analysis and confirmatory factor analysis, and provides an overview of more advanced methods such as the evaluation of non-linear effects, the analysis of means in convariance structure models, and latent growth models for longitudinal data. Providing examples from various disciplines to illustrate all aspects of SEM, the book offers clear instructions on the preparation and screening of data, common mistakes to avoid and widely used software programs (Amos, EQS and LISREL). The book aims to provide the skills necessary to begin to use SEM in research and to interpret and critique the use of method by others.
42,102 citations
TL;DR: A new coefficient is proposed to summarize the relative reduction in the noncentrality parameters of two nested models and two estimators of the coefficient yield new normed (CFI) and nonnormed (FI) fit indexes.
Abstract: Normed and nonnormed fit indexes are frequently used as adjuncts to chi-square statistics for evaluating the fit of a structural model A drawback of existing indexes is that they estimate no known population parameters A new coefficient is proposed to summarize the relative reduction in the noncentrality parameters of two nested models Two estimators of the coefficient yield new normed (CFI) and nonnormed (FI) fit indexes CFI avoids the underestimation of fit often noted in small samples for Bentler and Bonett's (1980) normed fit index (NFI) FI is a linear function of Bentler and Bonett's non-normed fit index (NNFI) that avoids the extreme underestimation and overestimation often found in NNFI Asymptotically, CFI, FI, NFI, and a new index developed by Bollen are equivalent measures of comparative fit, whereas NNFI measures relative fit by comparing noncentrality per degree of freedom All of the indexes are generalized to permit use of Wald and Lagrange multiplier statistics An example illustrates the behavior of these indexes under conditions of correct specification and misspecification The new fit indexes perform very well at all sample sizes
21,588 citations