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.

Do age-related word retrieval difficulties appear (or disappear) in connected speech?

“…Scores on a standard naming task predicted retrieval of nouns in the narrative task, accounting for 60% of the variance in retrieval in context. Furthermore, Fergadiotis and Wright (2016) found that scores on picture naming tasks predicted the percent of paraphasias in discourse as well as the proportion of correct information units in 98 people with various types of aphasia. As these studies suggest, when individuals have significant word retrieval impairment, difficulties occur across tasks.…”

“…Some of these studies found significant associations between scores on tasks of single-word retrieval and measures of retrieval in context (e.g., Fergadiotis & Wright, 2016; Herbert, Hickin, Howard, Osborne, & Best, 2008; Hickin, Best, Herbert, Howard, & Osborne, 2001; Pashek & Tompkins, 2002; Williams & Canter, 1982). For instance, Williams and Canter (1982) compared production of the same nouns in isolation and in context in 40 people with varying types of aphasia.…”

AphasiaBank as BigData

“…The effect of discourse type on lexical diversity and productive vocabulary was investigated by Fergadotis and Wright using 27 PWA and 27 age-and education-matched nonaphasic participants from the AphasiaBank database. 31,32 Lexical diversity was quantified using a lemma-based analysis of content words as well as a computational tool that reduced the impact of sample length and genre. Results showed that lexical diversity was significantly lower in PWA for all discourse tasks.…”

Neural organization of speech production: A lesion-based study of error patterns in connected speech

“…Further evaluation by other groups suggested that naming ability may relate more to the ability to retrieve nouns, in particular, during everyday conversation (Herbert et al, 2008). Further, a recent study in 98 participants with aphasia found that picture naming ability was not predictive of the proportion of paraphasias made during connected speech, finding that paraphasias produced in discourse in isolation were not well predicted by performance on confrontation naming tests (Fergadiotis and Wright, 2015). Taken together, these studies encourage the direct comparison of the distribution of paraphasias between connected speech and naming for improved understanding of the dynamic lexical retrieval system employed during natural speech.…”

“…While models explaining single word retrieval have been developed and studied heavily, relatively few models have focused on modeling the complex lexical retrieval system engaged during sentence production (Garrett, 1975;Dell, 1986;Chang, 2002;Chang et al, 2006). Indeed, connected speech production likely depends on cognitive operations that extend beyond lexical processing (Fergadiotis and Wright, 2015) alongside a lexical retrieval system where activation of word forms is dynamically changing across the course of the utterance. One step in evaluating the lexical retrieval processes during connected speech has been through the use of blocked cyclic picture naming, where subjects repeatedly name pictures in sets of either semantically related or unrelated pictures, cycling several times through the pictures in each block.…”