失憶型輕度認知障礙族群之情緒強化記憶與臉孔表情再認

Abstract

失憶型輕度認知障礙症被認為是一個從正常老化至失智之間的過渡階段，特別是對阿茲海默氏病。許多研究指出，情緒強化記憶效應在正常老化過程中仍為保留，然此效果在失憶型輕度認知障礙症之研究結果仍存在不一致性。因此，本研究旨在探討對於表情再認正確率較高或較低的不同臉孔表情，其情緒強化記憶是否存在明顯或減弱的效果。本研究招募26位健康對照組與27位失憶型輕度認知障礙症患者，所有參與者皆進行記憶學習階段、2分鐘短延宕之記憶再認測驗與25分鐘長延宕之記憶再認測驗。實驗材料包括了72張臉孔，共分為三組，每組包括快樂、憤怒、害怕與中性各六張。在完成所有記憶測驗後，受試者將進行臉孔表情再認測驗。本研究發現，在臉孔表情再認測驗中，兩組對害怕臉孔之辨識表現皆下降，而對憤怒臉孔之辨識能力則相對保留。值得注意的是，在長延宕之記憶再認測驗中，兩組皆出現明顯的情緒強化記憶效應，特別是針對憤怒臉孔，然此效應卻在害怕臉孔上消失，顯示情緒強化記憶效應可能會因特定臉孔的辨認困難而消失。此外，本研究發現，失憶型輕度認知障礙組之情緒記憶表現與健康控制組無明顯差異，特別是針對憤怒與害怕之臉孔；然而，疾病組對快樂臉孔之情緒記憶表現則明顯差於控制組，顯示被診斷為失憶型輕度認知障礙之東方老年人存在負向效應。綜上述所言，本研究結果強調，針對不同臉孔表情，可能會受失憶型輕度認知障礙症之情緒辨認能力影響，而使其具不同的情緒強化記憶效果。

Amnestic mild cognitive impairment (aMCI) has been considered a transitional stage from normal aging to dementia, particularly Alzheimer’s disease (AD). Several studies have reported that the emotional enhancement of memory (EEM) effect is preserved in normal aging. However, the findings of EEM in aMCI remain controversial. Thus, the study aimed to investigate whether there is an evident or diminished EEM for different emotional faces with higher or lower correct rates for facial emotional identification. The present study recruited 26 healthy control (HC) and 27 aMCI patients. All participants underwent an incidental learning test, 2 minutes short-delayed recognition test, and 25 minutes long-delayed recognition test. A total of 72 faces were selected and divided into three sets. Each set included six happy, angry, fearful, and neutral faces. After performing all memory tasks, facial expression recognition (FER) was conducted. During the FER task, the results revealed that both groups exhibited a specific decrease in recognizing fearful faces, while their recognition of angry faces remained relatively intact. Notably, during the long-delayed recognition test, both groups demonstrated an evident EEM exclusively for angry faces, while the absence of EEM was noticed for fearful faces, indicating that the emotional enhancement effect might be decreased for faces that were difficult to recognize. Furthermore, compared to the HC group, participants with aMCI exhibited intact emotional memory ability, specifically for angry and fearful emotions, while they demonstrated defective memory performance for happy faces, suggesting a negativity effect in Eastern older adults with aMCI. In conclusion, our findings emphasize the importance of considering the distinct emotional expressions and their impact on emotional memory performance in the aMCI population.