구어유창성(verbal fluency, VF) 과제는 초기 알츠하이머치 매(dementia of alzheimer’s type, DAT)나 경도인지장애(mild cognitive impairment, MCI)와 같은 인지·언어능력의 손상을 감별하는 데 매우 민감한 과제로 알려져 있다(Cooper et al., 2004; Forbes-McKay et al., 2005). VF 과제를 통해 집행기능, 의미기억, 작업기억 및 어휘-의미론적 처리과정 등의 문제를 확인할 수 있기 때문이다. VF를 평가하는 가장 대표적인 방법 은 제한된 시간 내에 특정 범주나 글자로 시작하는 단어를 최 대한 많이 말하도록 하는 것이다. 특정 의미 범주(예: 동물)를 제시하는 의미 구어유창성(semantic verbal fluency, SVF) 과 제와 특정 글자나 음소(예: ‘ㄱ’)를 제시하는 음소 구어유창성 (phonetic verbal fluency, PVF) 과제가 있다. 일반적으로 PVF 과제는 자소와 음소의 대응 지식, 음운 인식, 글자 체계에 대한 전략적 탐색 등과 같이 문해능력과 밀접한 관련이 있다. 따라서 PVF 과제는 대상자의 교육수준의 영향을 크게 받는다.
Purpose: Semantic (e.g., animal category) verbal fluency (SVF) tasks are widely utilized to measure subtle cognitive and language impairment caused by aging and neurological diseases. Mild cognitive impairment (MCI) regarded as transitional stage in aging with increased risk of incident dementia might show differential performances on SVF tasks according to MCI subtypes and different administration time. Methods: Three MCI subtypes of amnestic single-domain MCI (asMCI), amnestic multi-domain MCI (amMCI), non-amnestic MCI (non-aMCI), and age- and education-matched normal elderly (NE) participated in this study. Both the SVF tasks with 60- and 30-second administration time were conducted to four groups. Results: In 60-second SVF tasks, patients with amMCI and non-aMCI exhibited significantly lower performances than NE, but asMCI did not. In contrast, no significant differences were observed in 30-second SVF tasks between the groups. In receiver operating characteristics (ROC) curve analysis, 60-second SVF task showed fair discriminant power between amMCI and NE [area under ROC curve (AUC) = 0.779] as well as between non-aMCI and NE (AUC = 0.733). Conclusion: The results indicated that subtle cognitive decline of MCI might not be revealed during short administration time because automatic access for lexico-semantic process during the initial phase of SVF task is relatively preserved. The present study suggests that 60-second SVF tasks are useful to differentiate amMCI and non-aMCI groups from NE, but not asMCI.
INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSIONS REFERENCES
