Background: Topographical disorientation is one of the early symptoms of Alzheimer’s disease (AD). The nature of this symptom, however, remains unclear. Objective: The aim of the study was to investigate egocentric and allocentric spatial cognition in patients with amnestic mild cognitive impairment (aMCI) and early AD. Participants and Methods: The participants consisted of normal healthy volunteers (n = 23), patients with aMCI (n = 26), and patients with early AD (n = 22). We administered the card placing test (CPT), in which a subject was required to recreate an array of 3 cards, each of which was randomly placed on 8 grids around the individual, before (part A) and after (part B) the individual’s rotation. With this design, the CPT can reveal an individual’s ability to represent spatial information either egocentrically (CPT-A) or allocentrically (CPT-B). A qualitative analysis of errors in performing the CPT was also conducted. Results: Compared with the controls, the aMCI patients showed significantly poorer CPT-B performance, while there was no significant difference in CPT-A performance between these 2 groups. In contrast, the AD patients demonstrated significantly poorer performance on both the CPT-A and CPT-B than the controls and aMCI patients. There was no significant difference in the profile of errors on the CPT-B between the controls and aMCI patients, whereas there was a notable difference in those on the CPT-A between the controls and AD patients and the aMCI and AD patients. Conclusion: Allocentric spatial cognition is selectively impaired in aMCI patients, while an egocentric spatial cognition is additionally impaired in AD patients.

中文翻译：

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遗忘性轻度认知障碍和早期阿尔茨海默病的自我中心和异体空间认知

背景：地形定向障碍是阿尔茨海默病 (AD) 的早期症状之一。然而，这种症状的性质仍不清楚。目的：本研究的目的是调查遗忘型轻度认知障碍 (aMCI) 和早期 AD 患者的自我中心和异体中心空间认知。参与者和方法：参与者包括正常健康志愿者（n = 23）、aMCI 患者（n = 26）和早期 AD 患者（n = 22）。我们进行了卡片放置测试 (CPT)，其中要求受试者重新创建 3 张卡片的阵列，每张卡片随机放置在个人周围的 8 个网格上，在个人之前（A 部分）和之后（B 部分）回转。有了这个设计，CPT 可以揭示个人以自我为中心 (CPT-A) 或以异地为中心 (CPT-B) 表示空间信息的能力。还对执行 CPT 中的错误进行了定性分析。结果：与对照组相比，aMCI 患者的 CPT-B 表现明显较差，而这 2 组之间的 CPT-A 表现无显着差异。相比之下，AD 患者在 CPT-A 和 CPT-B 上的表现明显低于对照组和 aMCI 患者。对照组和 aMCI 患者之间的 CPT-B 错误分布没有显着差异，而对照组和 AD 患者以及 aMCI 和 AD 患者之间的 CPT-A 错误分布有显着差异。结论：