Reliability and validity of the Toronto Structured Interview for Alexithymia in a mixed clinical and nonclinical sample from Italy
Introduction
Over the past two decades several instruments have been developed to assess alexithymia, a construct characterized by difficulties in identifying and describing feelings, an impoverished fantasy life, and an externally oriented cognitive style (Nemiah et al., 1976). The currently available instruments include self-report scales, observer-rated questionnaires, structured interviews, and a projective test (Lumley et al., 2007, Porcelli and Mihura, 2010, Taylor et al., 2000). The most widely and frequently used instrument to assess alexithymia is the self-report 20-item Toronto Alexithymia Scale (TAS-20) (Bagby et al., 1994a), which has been translated into many different languages and validated in diverse cultural groups (Taylor et al., 2003, Zhu et al., 2007). As several researchers have noted, however, a potential limitation of the TAS-20 is whether respondents with high alexithymia are able to accurately appraise their capacity to identify and describe their feelings (Lane et al., 1998, Lumley et al., 2007). Other limitations include an overlap with self-report measures of negative affect, and an absence of items for assessing fantasy activity (these self-report items were found to be associated with a socially desirable response bias) (Bagby et al., 1994a, Leising et al., 2009, Lumley, 2000).
Recognizing that all methods of assessing psychological constructs have some shortcomings, personality psychologists recommend the use of a multimethod approach to measurement as a way of controlling for potential measurement artifacts and thereby increasing the validity of research findings; although the correlations between different measures are often modest, an examination of both the convergences and divergences between measures can increase understanding of the underlying construct (Eid and Diener, 2006). In this same vein, Taylor and Bagby, 2004, Taylor et al., 2000 have long recommended using a multimethod approach to assess alexithymia. Given that the construct was formulated originally on the basis of observations made during clinical interviews (Nemiah et al., 1976), Bagby et al. (2006) developed the Toronto Structured Interview for Alexithymia (TSIA) as an interview-based method for measuring this construct.
The TSIA is composed of 24 interview items (i.e., questions), six for each of the four salient facets of the alexithymia construct: difficulty identifying feelings (DIF); difficulty describing feelings to others (DDF); an externally oriented style of thinking (EOT); and imaginal processes (IMP). Some example questions are: “Are you sometimes puzzled or confused by what emotion you are feeling?”; “Is it usually easy for you to find words to describe your feelings to others?”; “Do you tend to talk to others more about daily activities rather than feelings?”; and “When you think about some past events do you relive and imagine them in your mind?” For each interview question there are standardized prompts and/or probes designed to elicit responses that are scored according to guidelines outlined in a manual (Bagby et al., 2005).
Factor analysis of the original English-language version of the TSIA with community and psychiatric outpatient samples identified a hierarchical model with four lower-order factors nested within two higher-order factors consistent with the theoretical underpinnings of the construct (Bagby et al., 2006). The DIF and DDF facet scales formed a single higher-order domain scale labeled Affect Awareness (AA) and the EOT and IMP facet scales formed a single higher-order domain scale labeled Operative Thinking (OT). The TSIA also demonstrated acceptable levels of interrater, internal, and retest reliability, as well as concurrent validity with the TAS-20.
Given the international interest in alexithymia research, it is important to develop different translations of the TSIA and evaluate the reliability and validity of these translations, as was done for the TAS-20. A German-language translation of the TSIA was developed and its psychometric properties evaluated with a mixed sample of psychiatric inpatients and outpatients (Grabe et al., 2009). Confirmatory factor analysis supported the hierarchical, four-factor structure obtained with the original English version, and acceptable levels of internal and inter-rater reliability were also demonstrated. Support for the concurrent validity of the German translation of the TSIA was provided by significant correlations with the German translation of the TAS-20.
The aim of the current study was to evaluate whether an Italian translation of the TSIA would demonstrate similar psychometric properties as the original TSIA and the German version of this instrument. We chose a mixed clinical and nonclinical sample to increase the variability of TSIA scores across the various analyses. For the clinical subsample, we chose diagnostic groups known to score higher on alexithymia measures than healthy individuals (Taylor, 2004), thereby increasing the distribution of scores in our combined sample.
Section snippets
Translation procedures
As previously noted, the original English-language TSIA is composed of 24 interview items, six items for each of the four facets of the alexithymia construct — DIF, DDF, EOT, and IMP. Each interview question includes a set of prompts and/or probes, keyed to the thematic content of the item, to elicit information assisting in the accuracy of the scoring. All items are scored on a three-point scale ranging from 0 to 2 with some scores based on the frequency of the presence of a characteristic,
Confirmatory factor analyses and model comparisons
Prior to performing CFA and obtaining estimates of goodness-of-fit, we computed Mardia's coefficient of multivariate kurtosis to determine if the assumption of multivariate normality was met (Mardia, 1970). The sample was multivariate normally distributed at the 0.05 level of significance (Mardia's statistic = − 1.726, P = 0.08). The goodness-of-fit indices for each of the models are shown in Table 1. The indices indicate that the four-factor models (4a, 4b, and 4c) provided good fits to the data,
Discussion
In this study, we were successful in replicating the hierarchical, four-factor model of the TSIA using an Italian translation of the instrument and a mixed sample comprised of medical and psychiatric outpatients and healthy subjects from various parts of Italy. As in the development of the TSIA (Bagby et al., 2006), and in the study with German-speaking psychiatric patients (Grabe et al., 2009), we used confirmatory factor analysis to test several different structural models. Model comparison
Acknowledgments
The authors are grateful to Alessandra Ciolfi, Arianna Franchi, Marta Lepore, Fabio Monticelli, Alessia Zangrilli, Francesca Amati, Maria Bonadies, Michela Di Trani, Silvia Ferrara, and Luisa Pepe for their valuable contribution in performing the interviews.
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