正常不識字老人與早期阿茲海默型失智症老人在語意流暢度測驗表現的比較研究

The Performance Pattern of Normal Illiterate and Patients with Early Alzheimer's Disease on the Semantic Association of Verbal Fluency Test

低教育程度（特別是不識字）時常被視為失智症認知功能評估的干擾變項，且容易因為認知篩檢工具不適當的臨界分數而出現診斷的偽顯性。本研究的目的是希望能夠確認可否藉由語意流暢度測驗來區辨正常不識字老人與早期阿茲海默型失智症老人之間的差異，同時釐清早期阿茲海默型失智症老人之執行功能受損是否是受其記憶功能下降所影響。本研究共收案94名受試者，其中正常不識字組17名，正常受教育對照組36名，疑似失智症組21名，以及輕度失智症組20名，男性有42人，女性有52人，年齡分佈在60〜89歲之間，平均年齡為75.64±6.43歲，除了正常不識字組之外，其他三組老人的平均教育年數為7.08±4.43年。所有的受試者均接受臨床失智評分量表、知能篩檢測驗以及語意流暢度測驗的評估。結果發現語意流暢度測驗適用於區辨正常不識字老人與失智症患者的臨床評估。另外，在排除記憶能力下降之影響後，早期失智症的老人在蔬菜流暢度測驗以及知能篩檢測驗之四腳動物流暢度分量表的表現仍有困難，因此，早期阿茲海默型失智症的老人在這兩項語意流暢度測驗的問題有可能是執行功能受損所致。

Very low level of education, particularly illiterate has been as a confounding effect and raised false-positive diagnostic errors for AD based on the inappropriate cutoff points of mental status screening tests. The current study was to examine the usefulness of the verbal fluency test in differentiating normal versus incipient dementia, as well as to clarify the issue of whether memory dysfunction contributes to defective performance on the verbal fluency test. Methods: Ninety-four subjects were recruited and classified into four groups, normal educated control, normal illiterate, questionable AD (qAD) and mild AD (mAD) . All subjects received the Clinical Dementia Rating, the Cognitive Abilities Screening Instrument, and verbal fluency test. Results: No significant differences between normal illiterate and normal educated control groups on the verbal fluency test were noted. However, demented patients were impaired in performing the verbal fluency test. Performance differences between AD patients and normal educated control subjects on the vegetable fluency and four-legged animal fluency test could not be attributed to memory impairment. Conclusion: Based on the present result, it appears that the verbal fluency test might be useful for differentiating normal illiterate from incipient dementia. Meanwhile, the result also suggests that deficits of vegetable fluency and four-legged animal fluency observed in the early AD patients might be merely due to executive dysfunction.