Functional measures of naming in aphasia: Word retrieval in confrontation naming versus connected speech

Abstract

Background: Word-finding difficulties are central to aphasia and as such have received a great deal of attention in aphasia research. Although treatment for lexical retrieval impairments can be effective, studies often use measurement of single-word performance (e.g., confrontation naming) to support such claims. In contrast, what matters most to patients with aphasia and their families is the ability to converse. Few aphasia studies, however, have addressed word retrieval in connected speech. Furthermore, one could debate whether generating names for single pictured stimuli bears resemblance to the online, multifaceted retrieval required during conversation. Aims: The purpose of this study was to assess the adequacy of Percent Word Retrieval (%WR) as well as two supplementary analyses, Percent Substantive Verbs (%SV) and Percent Corrected Errors (%CERR), to depict word retrieval in connected and conversational speech with respect to lexical class (noun vs verb) and aphasia severity (mild vs moderate). Specifically, we examined: (1) the relationship between lexical retrieval in confrontation naming, composite description, and conversational samples; and (2) the clinical utility and feasibility of %WR, %SV, and %CERR in quantifying such data. Methods & Procedures: A total of 14 individuals with aphasia, divided into mild (n = 7) and moderate (n = 7) groups based on aphasia severity, participated. Word retrieval was tested in three different contexts: single-word confrontation naming, composite description, and conversational speech. Lexical retrieval was analysed in each context using the analyses described above (%WR, %SV, and %CERR). The effects of context, grammatical class, and measurement technique were explored using repeated measures ANOVA and correlational analyses. Outcomes & Results: Statistical analyses revealed a significant effect of context for both %WR and %CERR, with superior lexical retrieval and self-correction of errors in connected speech versus single-word naming tasks. Moreover, %SV in conjunction with %WR was sensitive to possible verb retrieval deficits undetected by %WR alone, particularly for mild patients. Confrontation naming scores were strongly related to aphasia severity classification (mild vs moderate), but were not significantly correlated with naming abilities in connected speaking tasks. Conclusions: These findings endorse the incorporation of discourse-level tasks into aphasia assessment and treatment protocols. Use of simple and easily quantifiable measures (e.g., %WR) may be an option to extend current methodology and reconcile issues of ecological validity and clinical feasibility.