Core Lexicon Analysis of a Storytelling Task in Korean-Speaking Individuals With Aphasia

This study aimed to validate newly developed, age-stratified Korean core lexicon (CL) checklists and evaluate their clinical utility in assessing discourse production in persons with aphasia (PWA) using a culturally familiar storytelling task.

Thirty-six PWA and 36 age- and education-matched cognitively healthy adults (CHAs) participated in a Korean picture-based storytelling task. Percentage of core nouns and verbs were calculated using age-specific checklists and compared across group (CHAs vs. PWA) and lexical category (noun vs. verb). We also examined whether core noun and verb percentages were associated with aphasia severity and which word class significantly predicted severity.

PWA exhibited significantly lower percentage of CL than CHAs, with a larger noun-verb difference observed in PWA than in CHAs. Pearson correlation analyses showed that both core nouns and verbs were significantly and positively associated with aphasia severity. Hierarchical regression analyses revealed that core verb percentage was a stronger predictor of aphasia severity than core noun percentage, accounting for significant variance beyond demographic factors, whereas core noun percentage did not explain additional variance when core verb percentage was already included in the model.

This study presents the first empirical validation of Korean CL checklists and supports their clinical utility in identifying discourse impairments in PWA. The findings emphasize the central role of verbs in discourse assessment for verb-salient languages and underscore the broader need for culturally and linguistically tailored assessment tools in aphasia evaluation.