Relationship between Irregular Word Reading and Writing Performance and Frontal-Executive Functions in Amnestic and Non-amnestic Mild Cognitive Impairment

Purpose: This study compared reading and writing performance between older adults with amnestic mild cognitive impairment (aMCI) and non-amnestic mild cognitive impairment (naMCI), and examined whether frontal-executive functions were associated with task performance. Methods: Twenty-two older adults participated: 11 with aMCI and 11 with naMCI. Reading tasks included regular words, irregular words, regular nonwords, and irregular nonwords from the Korean Languagebased Reading Assessment (KOLRA), as well as irregular word and nonword reading tasks from the Paradise·Korean version of the Western Aphasia Battery-Revised (PK-WAB-R). Writing was assessed using irregular word and nonword dictation tasks from the PK-WAB-R. Frontal-executive functions were evaluated using semantic and phonemic verbal fluency, the Korean-Color Word Stroop Test, and the Korean-Trail Making Test for the Elderly. Group differences were analyzed using Mann-Whitney <i>U</i>-tests, and Spearman correlations were conducted for tasks showing significant group differences. Results: Compared with the naMCI group, the aMCI group showed significantly poorer performance on irregular nonword reading (KOLRA) and irregular word reading and writing (PKWAB-R). In the overall MCI group, irregular nonword reading was positively correlated with Stroop word reading, irregular word reading was correlated with semantic verbal fluency, and irregular word writing was correlated with Stroop word/color reading and semantic verbal fluency. Conclusion: Older adults with aMCI showed selective impairment in linguistically demanding reading and writing tasks requiring irregularity processing. These findings suggest that such tasks rely not only on lexical processing but also on frontal-executive control, and may serve as sensitive indicators of languagerelated vulnerability in aMCI.