主觀記憶缺損者對非熟悉刺激之嗅覺再認能力

Abstract

背景：本研究主要目的為透過評估主觀記憶缺損者（SMD）、輕度認知功能障礙（MCI）、以及早期阿茲海默型失智症（DAT）患者對非熟悉刺激之嗅覺再認能力，探索該功能於早期偵測阿茲海默症（AD）病理、及鑑別診斷主觀記憶缺損者（SMD）在臨床應用的可能性。方法：本研究受試者包括60名來自神經醫學部門診、帶有記憶抱怨的病人，並依據臨床神經心理衡鑑結果診斷為主觀記憶缺損者（SMD）、輕度認知功能障礙（MCI）、與早期阿茲海默型失智症（DAT），以及30名來自社區、無記憶抱怨的正常老年人控制組（HC）。受試者嗅覺再認功能皆以採用「酒鼻子」（Le Nez du Vin） 嗅覺訓練教材，做為非熟悉嗅覺刺激項目的再認測驗（ORT）進行評估。結果：就ORT總分方面，HC組明顯高於MCI患者與DAT患者，然而HC組與SMD組，以及SMD 組與MCI組間的差異在統計上並未達顯著。在ORT總分與錯誤接受（False-Alarm）指數分數上， SMD組的表現皆優於DAT患者。然而，四組受試者在正確接受（Hit）分數上並無顯著差異。二因子變異數分析與階層迴歸分析顯示受試者年齡與ORT總分之間無顯著交互作用。臨床應用方面，ROC曲線分析顯示SMD, MCI 與DAT三組在嗅覺再認功能表現上呈現逐漸減退之趨勢，顯示ORT分數表現似乎可做為AD早期偵測的參考指標。結論：本研究結果顯示嗅覺再認功能的改變，具備識別AD的臨床前階段與前驅期的可能性，然而，有鑑於SMD群體異質性的問題，未來縱向的研究有其必要性。

Objective: To evaluate the odor-recognition function of individuals with subjective memory decline (SMD), mild cognitive impairment (MCI), and early dementia of the Alzheimer’s type (DAT) in order to explore the clinical utility of this function in the early detection of Alzheimer’s disease (AD) and in the differential diagnosis of SMD. Methods: Sixty patients with memory complaints were recruited from a neurology clinic and diagnosed as having either SMD, MCI, or AD through clinical neuropsychological assessments. Thirty healthy community-dwelling volunteers without memory complaints were recruited as the healthy control (HC) group. The odor-recognition function of all participants was evaluated through the Odor Recognition Test (ORT) with unfamiliar odor stimuli involving the Le Nez du Vin olfactory training tool. Results: On the ORT scores, the score differences between HC and two patient groups were significantly different while there were no significant differences between HC and SMD, and between SMD and MCI. The SMD group outperformed the DAT groups on both overall ORT and the “false-alarm” scores. By contrast, the “hit” scores of the four groups did not differ significantly. Moreover, two-way ANOVA and Hierarchical regression analysis revealed no significant interaction between participant age and total ORT scores. Regarding the clinical utility of the ORT, the Receiver Operator Characteristic Curves Analysis revealed a gradually-declined trend from SMD, MCI to DAT in odor-recognition functioning, suggesting that the ORT scores might provide another reference measure to early detection of AD. Conclusions: The findings of this cross-sectional study indicate that the performance differential in the odor-recognition function may be a possible way for identifying the preclinical stage and prodromal stage of AD. However, the heterogeneity of SMD still needs longitudinally–monitoring studies.