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INTRODUCTION
The Boston Diagnostic Aphasia Examination (BDAE) is one of the most commonly used test batteries for aphasia, both nationally and internationally, as well as across hospital settings (Katz et al., 2000). The test battery allows comprehensive assessment of different aspects of language function in people with aphasia with the aims of assisting with the diagnosis of aphasia syndromes, providing guidance in therapy, and measuring treatment outcome (Goodglass et al., 2001a). Given these goals, examining the psychometric properties (i.e., reliability and validity) of BDAE is a clinical necessity.
The BDAE has undergone two significant revisions since the publication of its first edition in 1972 (Goodglass & Kaplan, 1972b); it was revised in 1983 (Goodglass & Kaplan, 1983b) and again in 2001 (Goodglass et al., 2001b). The 2001 revision integrated recent findings on neurolinguistic research while preserving the test’s clinical utility. Some of the changes in BDAE-3 include the addition of abbreviated and extended testing formats, the incorporation of the Boston Naming Test (Kaplan et al., 1983) as a subtest, the addition of subtests assessing ideomotor praxis, and the clarification of scoring procedures and definitions. To demonstrate continued clinical utility, the authors reported that the BDAE-3 has good internal and alternate form reliability overall (Goodglass et al., 2001a).
In contrast, the validity of BDAE-3 has not yet received strong support. In one existing study that examined the validity of BDAE-3, language clusters were predefined (i.e., a priori) based on a conceptual framework. The authors then examined correlations among subtests within each conceptually predefined cluster without considering correlations across clusters (Goodglass et al., 2001a). This limited approach might pose a potential threat to the construct validity of the battery.
Although there are a few studies that examined the factor structure of the earlier versions of BDAE or the non-English versions of BDAE-3, no studies have yet explored the factor structure of the English version of BDAE-3 in people with aphasia. Moreover, prior studies suggested that the factor structure of the earlier versions varied considerably as a function of the subtests included in the analysis. Goodglass and...