Modelling confrontation naming and discourse performance in aphasia

Abstract

Background: It is well documented in the literature that the ability to produce discourse is what matters most to people with aphasia (PWA) and their families. However, quantifying discourse in typical clinical settings is a challenging task due to its dynamic and multiply determined nature. As a result, professionals often depend on confrontation naming tests to identify and measure impaired underlying cognitive mechanisms that are also hypothesised to be important for discourse production.

Aims: The main goals of the study were to investigate the extent to which confrontation naming test (CNT) scores are predictive of (i) the proportion of paraphasias in connect speech, and (ii) the amount of information PWA can effectively communicate.

Methods & Procedures: Data from 98 monolingual PWA were retrieved from AphasiaBank and analysed using structural equation modelling. Performance in CNTs was modelled as a latent variable based on the Boston Naming Test, the Western Aphasia Battery–R Naming Subtest, and the Verb Naming Test. Performance at the discourse level was modelled based on the observed proportions of paraphasias in three discourse tasks (free speech, eventcasts, and story retell). Informativeness was quantified using the percentage of Correct Information Units based on story re-tell.

Outcomes & Results: For the first question, the regression coefficient between the two latent factors was estimated to be –0.52. When the latent factor based on the CNTs was regressed on informativeness, the estimated regression coefficient was equal to 0.68.

Conclusions: Performance on CNTs was not a strong predictor of the proportion of paraphasias produced in connected speech but was substantially higher for the amount of information communicated by PWA. Clinicians are cautioned not to predict a speaker’s performance at the discourse level after establishing CNT performance. Other anomic behaviours (e.g., pauses) during discourse production may be associated with CNT performance and should be considered in future investigations.

Keywords:

• aphasia
• word retrieval deficits
• diagnostic procedures
• structural equation modelling

Acknowledgements

We are especially grateful to the study participants and AphasiaBank. We also thank the volunteers in the Aging and Adult Language Disorders Lab at Portland State University and especially Caroline Crone, Jade Horton, and Audrey Cohen for assistance with language analyses.