Core lexicon in aphasia: A longitudinal study

Background: General consensus exists between clinicians as to the incorporation of discourse outcome measures into language assessment for persons with aphasia (PWA). The development of core lexicon measures (CoreLex) has enabled clinicians to reduce time and labor intensive preparatory work for discourse analysis, which has been considered as an alternative measure to quantify word retrieval ability in discourse in a clinical context. Although previous studies have investigated the quality of the measure, CoreLex has rarely been longitudinally explored. Aims: We aimed to investigate the adequacy of CoreLex to document linguistic changes in PWA over time. Specifically, we examined (1) whether natural language recovery from acute to chronic stages is manifested differentially by tasks and (2) the extent to which the ability to retrieve words in isolation predicts the ability to retrieve words in context. Methods: A total of 19 PWA participated in the study. They completed a language assessment including confrontation naming tasks (Boston Naming Test [BNT] and Hopkins Action Naming Assessment [HANA]) and a picture description task using the Cookie Theft picture at acute and chronic stages. Discourse samples from the picture description task were quantified using CoreLex. Results: We found significant differences across tasks and time-points by PWA. Moderate correlations between the confrontation naming tasks and CoreLex were found at the acute stage but not at the chronic stage. Additionally, McNemar’s tests demonstrated a significant difference in PWA’s performance in CoreLex from the acute to the chronic stages. Conclusions: Our findings show that performance by PWA improves over time on all tasks, but language gains are manifested differentially by tasks. Performance in confrontation naming moderately predicts word retrieval in context acutely. However, lack of correlations between confrontation naming tasks and CoreLex later endorse inadequacy of using confrontation naming tasks as a proxy measure for discourse-level performance and improvement for PWA.