Alexithymia, a personality trait characterized by difficulties interpreting one’s own emotional states, is commonly elevated in autistic adults, and a growing body of literature suggests that this trait underlies a number of cognitive and emotional differences previously attributed to autism, such as difficulties in facial emotion recognition and reduced empathy. Although questionnaires such as the twenty-item Toronto Alexithymia Scale (TAS-20) are frequently used to measure alexithymia in the autistic population, few studies have attempted to determine the psychometric properties of these questionnaires in autistic adults, including whether differential item functioning (I-DIF) exists between autistic and general population adults. We conducted an in-depth psychometric analysis of the TAS-20 in a large sample of 743 verbal autistic adults recruited from the Simons Foundation SPARK participant pool and 721 general population controls enrolled in a large international psychological study (the Human Penguin Project). The factor structure of the TAS-20 was examined using confirmatory factor analysis, and item response theory was used to further refine the scale based on local model misfit and I-DIF between the groups. Correlations between alexithymia and other clinical outcomes such as autistic traits, anxiety, and quality-of-life were used to assess the nomological validity of the revised alexithymia scale in the SPARK sample. The TAS-20 did not exhibit adequate global model fit in either the autistic or general population samples. Empirically driven item reduction was undertaken, resulting in an eight-item unidimensional scale (TAS-8) with sound psychometric properties and practically ignorable I-DIF between diagnostic groups. Correlational analyses indicated that TAS-8 scores meaningfully predict autistic trait levels, anxiety and depression symptoms, and quality of life, even after controlling for trait neuroticism. Limitations of the current study include a sample of autistic adults that was overwhelmingly female, later-diagnosed, and well-educated; clinical and control groups drawn from different studies with variable measures; and an inability to test several other important psychometric characteristics of the TAS-8, including sensitivity to change and I-DIF across multiple administrations. These results indicate the potential of the TAS-8 as a psychometrically robust tool to measure alexithymia in both autistic and non-autistic adults. A free online score calculator has been created to facilitate the use of norm-referenced TAS-8 latent trait scores in research applications (available at http://asdmeasures.shinyapps.io/TAS8_Score ).

中文翻译：

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改善自闭症成人述情障碍的测量：心理测量学调查和二十项多伦多述情障碍量表的完善


述情障碍是一种人格特质，其特征是难以解释自己的情绪状态，在自闭症成年人中通常会升高，越来越多的文献表明，这种特质是许多先前归因于自闭症的认知和情感差异的基础，例如面部情绪困难认可和同理心减少。尽管二十项多伦多述情障碍量表 (TAS-20) 等问卷经常用于测量自闭症人群的述情障碍，但很少有研究试图确定这些问卷在自闭症成人中的心理测量特性，包括差异项目功能（I -DIF）存在于自闭症患者和普通成年人之间。我们对从西蒙斯基金会 SPARK 参与者库中招募的 743 名言语自闭症成年人和参加一项大型国际心理学研究（人类企鹅项目）的 721 名普​​通人群对照的大样本进行了 TAS-20 的深入心理测量分析。使用验证性因子分析检查 TAS-20 的因子结构，并使用项目响应理论根据组间局部模型失配和 I-DIF 进一步细化量表。述情障碍与其他临床结果（如自闭症特征、焦虑和生活质量）之间的相关性被用来评估 SPARK 样本中修订后的述情障碍量表的法理有效性。 TAS-20 在自闭症或一般人群样本中都没有表现出足够的全局模型拟合。进行了经验驱动的项目减少，形成了八项目单维量表（TAS-8），具有良好的心理测量特性，并且诊断组之间的 I-DIF 几乎可以忽略不计。 相关分析表明，即使在控制了特质神经质之后，TAS-8 评分也能有意义地预测自闭症特质水平、焦虑和抑郁症状以及生活质量。当前研究的局限性包括自闭症成人样本绝大多数是女性、较晚诊断且受过良好教育；临床组和对照组来自不同的研究，采用不同的测量方法；以及无法测试 TAS-8 的其他几个重要心理测量特征，包括对变化的敏感性和多次管理中的 I-DIF。这些结果表明 TAS-8 作为心理测量学上强大的工具来测量自闭症和非自闭症成人的述情障碍的潜力。我们创建了一个免费的在线分数计算器，以方便在研究应用中使用常模参考的 TAS-8 潜在特征分数（可在 http://asdmeasures.shinyapps.io/TAS8_Score 获取）。