Face processing in Alzheimer's disease - defining the deficit

面部识别障碍是阿尔茨海默病（AD）的一种常见的、高度情绪化的早期症状。AD患者变得无法识别已知的人，包括亲戚和亲密的朋友，造成很大的痛苦。识别熟悉面孔的问题通常归因于AD中的标志性情景记忆缺陷和巩固记忆的退化。然而，最近的一项研究表明，面部识别受损可能有不同的病因。Lavallee et al.（2016）要求AD患者同时匹配不熟悉的面孔，无论是直立还是颠倒。使用倒置面孔的理由是基于面孔倒置效应，即识别倒置的不熟悉面孔的障碍。AD患者表现出减少反转效应，反映了受损的能力，建立一个连贯的知觉表征的个人面孔。这表明受损的面部处理可能不仅仅是由于AD的标志性遗忘综合征，也可能是由于受损的高级视觉处理。基本机制的界定对干预和管理具有影响。首先，人脸的处理对于大多数社交互动至关重要。随着疾病负担的进展，AD患者的社会认知受损，这反过来又与患者的不良结局和更大的照顾者痛苦有关。然而，越来越多的文献表明，一些患者可能在疾病过程的早期出现社会缺陷，与受损的面部处理有关。因此，识别AD患者面部识别受损的机制有助于识别更有可能发展为社交缺陷的患者。其次，确定与面部识别相关的记忆与感知过程将有助于为AD患者设计基于证据的，量身定制的康复方案，以支持社交功能并维持更长的生活质量。本研究旨在：（1）确定AD患者面部识别缺陷的记忆与知觉基础;（2）研究面部处理与社会认知之间的关系。参与者：健康的老年人;从NHS和社区招募的阿尔茨海默病患者。方法：实验认知测试;神经心理学评估。

Impaired face recognition is a frequently reported, highly emotive early symptom in Alzheimer's disease (AD). AD patients become unable to recognise known people, including relative and close friends, causing much distress. Problems with recognising familiar faces have typically been attributed to the hallmark episodic memory deficit in AD and the degradation of consolidated memories. However, a more recent study has suggested impaired face recognition may have a different etiology. Lavallee et al. (2016) asked AD patients to match simultaneously presented unfamiliar faces, presented either upright or reversed. The rational for using inverted faces was based on the face-inversion effect, i.e. impairment in recognising inverted unfamiliar faces. AD patients showed a reduced inversion effect reflecting an impaired ability to build a coherent perceptual representation of individual faces. This suggests that impaired facial processing may not be solely due to the hallmark amnesic syndrome that characterises AD, but may also be due to impaired higher-level visual processing. The delineation of the underlying mechanism has implications for intervention and management. Firstly, processing of human faces is critical for most social interaction. Social cognition is impaired in AD patients with progression of disease burden, which in turn is linked to poorer outcomes for patients and greater caregiver distress. However, an increasing body of literature suggests that some patients may develop social deficits earlier in the disease process, with links to impaired face processing. Identifying the mechanisms that underpin impaired face recognition in AD could therefore help to identify those patients more likely to develop social deficits.Secondly, determining the memory vs perceptual processes linked to face recognition will help to devise evidence-based, tailored rehabilitation protocols for AD patients to support social functioning and maintain quality of life for longer. This study aims to: (1) determine memory vs. perceptual underpinnings of face recognition deficits in AD;(2) examine the relationship between face processing and social cognition.Participants: Healthy older adults; patients with Alzheimer's disease recruited from the NHS and community.Methodologies: Experimental cognitive testing; neuropsychological assessment.