Eon'eo Cheong'gag Jang'ae Yeon'gu/Communication Sciences & Disorders · Sep 30, 2026
Exploring a Korean-Specific Expanded Controlled Oral Word Association Test for the Early Detection of Cognitive Decline and Verification of Prefrontal Cortex Activation
By Bin Lee S, Song YG, An SK et al.
Objectives: This study aimed to examine the discriminative ability of the Korean-Specific Expanded Controlled Oral Word Association Test (KSE-COWAT), which reflects linguistic characteristics of the Korean language, and to investigate its neurophysiological validity by measuring prefrontal cortex activation using functional near-infrared spectroscopy (fNIRS). Methods: Participants were 49 individuals with subjective cognitive decline (SCD) with normal cognitive function, and 50 individuals with mild cognitive impairment (MCI). Results: (1) In the Initial-syllable, final-syllable, onomatopoeia, Ideophone, orthographic constraint, and orthographic letter fluency tasks, the MCI group produced significantly fewer correct responses than the SCD group. (2) During the verb inflection fluency task, the MCI group showed significantly greater activation than the SCD group. (3) Significant prefrontal activation was observed in the left orbitofrontal cortex (OFC) during the phonemic fluency task, the left dorsolateral prefrontal cortex (DLPFC) during the Two-syllable orthographic fluency task, and the bilateral OFC during the orthographic letter fluency task. Conclusion: The findings of this study suggest that the language and executive functions required vary according to the characteristics of the language task, which may consequently affect the discriminative ability between individuals with SCD and those with MCI. In addition, the findings suggest that prefrontal cortical activation increases as a compensatory mechanism during the process of cognitive decline. Furthermore, the combined use of the KSECOWAT and fNIRS may serve as a useful approach for the early identification of cognitive decline and the development of intervention plans.