Development of a measure of function word use in narrative discourse: core lexicon analysis in aphasia.

Core function word lists consisting of a limited number of items for quantifying function word use in discourse remain in a nascent stage of development. However, the findings are consistent with previous studies analysing the total production of function words in language samples produced by PWA. Therefore, core function words may potentially serve as a clinician-friendly manner of quantifying function words produced in discourse. What this paper adds What is already known on the subject Function word analysis in discourse requires arduous processes of identifying the error production and grammatical category of function words in discourse. Previous studies have demonstrated that core lexicon measures are an efficient, simple means of quantifying discourse in PWA. However, function words have never been considered for generating an independent core lexicon list. What this paper adds to existing knowledge As an exploratory study, we focused primarily on developing a clinician-friendly measure to evaluate function word production in discourse, motivated by the idea of an adaptation strategy within the core lexicon framework. Our findings demonstrated that by using a simple scoring system that the core lexicon measure provides, we differentiated the control group from the PWA group, and persons with fluent aphasia from persons with non-fluent aphasia. Additionally, we found significant correlations between function word production and aphasia severity determined by WAB Aphasia Quotient (AQ). What are the potential or actual clinical implications of this work? The results add empirical evidence for the utility of core function word lists for quantifying function word usage in discourse in PWA. Counting the presence and absence of function words in discourse will allow clinicians to avoid labour-intensive preparatory work, and to obtain useful diagnostic information in a less time-consuming way.