Development of Core Lexicon Lists for Cognitively Healthy Adults across Age Groups in a Korean Storytelling Task

Abstract

Objectives: This study aimed to develop core noun and verb lists by age groups (young, middle-aged, and older adults) using a familiar Korean folktale. It sought to examine agerelated differences in lexical selection during discourse tasks and to establish the validity of core lexicon analysis as a clinically applicable method for discourse evaluation. Methods: A total of 180 cognitively healthy Korean adults (60 per age group) participated in a storytelling task based on an 8-picture sequence depicting "Heungbu and Nolbu." Participants' narratives were transcribed, and core nouns and verbs were identified if produced by at least 40% of participants within each group. Percent agreement between groups was calculated, and LASSO logistic regression analyses were performed to identify age group-differentiating lexical items for nouns and verbs. Results: Core noun agreement ranged from 76.47% to 93.33%, whereas core verb agreement was lower, ranging from 50.00% to 72.73%. The noun 'sister-in-law' and the verb 'split' served as distinguishing items in the comparisons between the young and middle-aged groups, as well as between the young and older groups. In contrast, only the noun 'younger brother' differentiated the middleaged and older groups, with no distinguishing verbs identified. Conclusion: This study is the first to develop age-specific core noun and verb lists in Korean discourse tasks. The findings highlight significant age-related differences in lexical usage, particularly between young and older adults. These results underscore the necessity and validity of establishing age-specific core lexicon lists for Korean, which can enhance clinical discourse assessment.