China has a large population of older people, but has not yet undertaken a comprehensive study on the prevalence, risk factors, and management of both dementia and mild cognitive impairment (MCI).For this national cross-sectional study, 46 011 adults aged 60 years or older were recruited between March 10, 2015, and Dec 26, 2018, using a multistage, stratified, cluster-sampling method, which considered geographical region, degree of urbanisation, economic development status, and sex and age distribution. 96 sites were randomly selected in 12 provinces and municipalities representative of all socioeconomic and geographical regions in China. Participants were interviewed to obtain data on sociodemographic characteristics, lifestyle, medical history, current medications, and family history, and then completed a neuropsychological testing battery administered by a psychological evaluator. The prevalence of dementia (Alzheimer's disease, vascular dementia, and other dementias) and MCI were calculated and the risk factors for different groups were examined using multivariable-adjusted analyses.Overall age-adjusted and sex-adjusted prevalence was estimated to be 6·0% (95% CI 5·8-6·3) for dementia, 3·9% (3·8-4·1) for Alzheimer's disease, 1·6% (1·5-1·7) for vascular dementia, and 0·5% (0·5-0·6) for other dementias. We estimated that 15·07 million (95% CI 14·53-15·62) people aged 60 years or older in China have dementia: 9·83 million (9·39-10·29) with Alzheimer's disease, 3·92 million (3·64-4·22) with vascular dementia, and 1·32 million (1·16-1·50) with other dementias. Overall MCI prevalence was estimated to be 15·5% (15·2-15·9), representing 38·77 million (37·95-39·62) people in China. Dementia and MCI shared similar risk factors including old age (dementia: odds ratios ranging from 2·69 [95% CI 2·43-2·98] to 6·60 [5·24-8·32]; MCI: from 1·89 [1·77-2·00] to 4·70 [3·77-5·87]); female sex (dementia: 1·43 [1·31-1·56]; MCI: 1·51 [1·43-1·59]); parental history of dementia (dementia: 7·20 [5·68-9·12]; MCI: 1·91 [1·48-2·46]); rural residence (dementia: 1·16 [1·06-1·27]; MCI: 1·45 [1·38-1·54]); fewer years of education (dementia: from 1·17 [1·06-1·29] to 1·55 [1·38-1·73]; MCI: from 1·48 [1·39-1·58] to 3·48 [3·25-3·73]); being widowed, divorced, or living alone (dementia: from 2·59 [2·30-2·90] to 2·66 [2·29-3·10]; MCI: from 1·58 [1·44-1·73] to 1·74 [1·56-1·95]); smoking (dementia: 1·85 [1·67-2·04]; MCI: 1·27 [1·19-1·36]), hypertension (dementia: 1·86 [1·70-2·03]; MCI: 1·62 [1·54-1·71] for MCI), hyperlipidaemia (dementia: 1·87 [1·71-2·05]; MCI: 1·29 [1·21-1·37]), diabetes (dementia: 2·14 [1·96-2·34]; MCI: 1·44 [1·35-1·53]), heart disease (dementia: 1·98 [1·73-2·26]; MCI: 1·17 [1·06-1·30]), and cerebrovascular disease (dementia: 5·44 [4·95-5·97]; MCI: 1·49 [1·36-1·62]). Nine of these risk factors are modifiable.Dementia and MCI are highly prevalent in China and share similar risk factors. A prevention strategy should be developed to target the identified risk factors in the MCI population to thwart or slow down disease progression. It is also crucial to optimise the management of dementia and MCI as an important part of China's public health system.Key Project of the National Natural Science Foundation of China, National Key Scientific Instrument and Equipment Development Project, Mission Program of Beijing Municipal Administration of Hospitals, Beijing Scholars Program, Beijing Brain Initiative from Beijing Municipal Science & Technology Commission, Project for Outstanding Doctor with Combined Ability of Western and Chinese Medicine, and Beijing Municipal Commission of Health and Family Planning.Copyright © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.

The socioeconomic costs of Alzheimer's disease (AD) in China and its impact on global economic burden remain uncertain.We collected data from 3098 patients with AD in 81 representative centers across China and estimated AD costs for individual patient and total patients in China in 2015. Based on this data, we re-estimated the worldwide costs of AD.The annual socioeconomic cost per patient was US $19,144.36, and total costs were US $167.74 billion in 2015. The annual total costs are predicted to reach US $507.49 billion in 2030 and US $1.89 trillion in 2050. Based on our results, the global estimates of costs for dementia were US $957.56 billion in 2015, and will be US $2.54 trillion in 2030, and US $9.12 trillion in 2050, much more than the predictions by the World Alzheimer Report 2015.China bears a heavy burden of AD costs, which greatly change the estimates of AD cost worldwide.Copyright © 2017 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

More than 100 years ago, Alois Alzheimer first described the clinical and pathological features of an unusual brain disease during the meeting of the Society of Southwest German Psychiatrists in Tübingen: the patient, Auguste Deter, suffered memory loss, disorientation, hallucinations and delusions and died at the age of 55. In 1910, Emil Kraepelin named the condition with the eponym of "Alzheimer's disease" (AD) that is, now, the most common neurodegenerative disease with more than 25 million cases worldwide and a major medical problem nearing catastrophic levels. The present article discusses Alzheimer's work in the context of his life and time.

Structural imaging based on magnetic resonance is an integral part of the clinical assessment of patients with suspected Alzheimer dementia. Prospective data on the natural history of change in structural markers from preclinical to overt stages of Alzheimer disease are radically changing how the disease is conceptualized, and will influence its future diagnosis and treatment. Atrophy of medial temporal structures is now considered to be a valid diagnostic marker at the mild cognitive impairment stage. Structural imaging is also included in diagnostic criteria for the most prevalent non-Alzheimer dementias, reflecting its value in differential diagnosis. In addition, rates of whole-brain and hippocampal atrophy are sensitive markers of neurodegeneration, and are increasingly used as outcome measures in trials of potentially disease-modifying therapies. Large multicenter studies are currently investigating the value of other imaging and nonimaging markers as adjuncts to clinical assessment in diagnosis and monitoring of progression. The utility of structural imaging and other markers will be increased by standardization of acquisition and analysis methods, and by development of robust algorithms for automated assessment.

阿尔茨海默病是一种病因复杂的严重智力致残疾病，目前尚无有效的治疗方法。我国是世界上老年人口最多、增长最快的国家之一,也是阿尔茨海默病发病率较高的国家。因此，如何早期预防阿尔茨海默病的发生，是现今健康领域最重要的课题之一。我们在国内外相关研究的基础上，通过文献循证、干预研究实践、案例分析、经验总结和专家咨询，结合中国老年健康和社会文化特点，体现中国传统医学、武术、养生以及社区组织优势，制订出具有中国特色的阿尔茨海默病早期预防指南，涵盖了个人、家庭和社会三个层面的预防策略，从积极生活态度、社会活动参与、认知训练、体育锻炼、戒烟限酒、营养、睡眠，血压、血糖、血脂管理，体重和其他慢病管理以及中医开展针对阿尔茨海默病的一级预防。本指南仅供个人、家庭和社会开展阿尔茨海默病预防时参考。

老年人痴呆或认知障碍多由一种以上年龄相关的常见脑部疾病所致。阿尔茨海默病（Alzheimer's disease, AD）是其中最常见的神经变性疾病，且是全球前10位死因中唯一无法治愈或缺乏长期对症疗效的疾病，给个人、家庭和全球经济都带来了巨大的负担。早期及时发现和干预是对抗AD的最佳策略。在过去的 30 年中，许多研究都提出了降低痴呆风险的方法，2020年《柳叶刀》杂志的痴呆预防报告已阐明通过应对风险因素可以预防或延缓超过40%的痴呆。然而，目前全球医疗体系尚未具备早期或及时发现AD的足够能力。最近的一项研究发现，只有不到 10%的轻度认知障碍（mild cognitive impairment, MCI）是在初级医疗机构中诊断出来的。近来，抗淀粉样蛋白β（Amyloid beta，Aβ）抗体药物lecanemab和donanemab被批准上市用于早期AD治疗，以及30年的随访研究证明改善风险因素显著减少AD痴呆的发病率并延长了寿命，使得人们对AD早期识别的关注迅速增加。阿尔茨海默病防治协会（China Association for Alzheimer's Disease，CAAD）认识到居家早期和及时发现 AD 的重要性，并成立了一个由协会成员、临床医生和研究人员组成的全球 AD 多领域专家团队，就以下目标达成共识： ①为个人、家庭、社区、协会和组织提供专家指导意见；②介绍用于认知障碍和痴呆居家筛查的数字工具和可用资源，并为AD高危人群或疑似患者制定下一步应对策略；③讨论现有可用或将来可能的居家筛查适宜AD生物标志物；④为未来的改进和全球应用建立可行性框架。专家组对于当前可用的证据、工具和资源进行综述，并进一步考量其在AD 居家筛查中的价值。

Based on clinical observations of severe episodic memory (EM) impairment in dementia of Alzheimer's disease (AD), a brief, computerized EM test was developed for AD patient evaluation. A continuous recognition task (CRT) was chosen because of its extensive use in EM research. Initial experience with this computerized CRT (CCRT) showed patients were very engaged in the test, but AD patients had marked failure in recognizing repeated images. Subsequently, the test was administered to audiences, and then a two-minute online version was implemented (http://www.memtrax.com). The online CCRT shows 50 images, 25 unique and 25 repeats, which subjects respectively either try to remember or indicate recognition as quickly as possible. The pictures contain 5 sets of 5 images of scenes or objects (e.g., mountains, clothing, vehicles, etc.). A French company (HAPPYneuron, SAS) provided the test for 2 years, with these results. Of 18,477 individuals, who indicated sex and age 21-99 years and took the test for the first time, 18,007 individuals performed better than chance. In this group, age explained 1.5% of the variance in incorrect responses and 3.5% of recognition time variance, indicating considerable population variability. However, when averaging for specific year of age, age explained 58% of percent incorrect variance and 78% of recognition time variance, showing substantial population variability but a major age effect. There were no apparent sex effects. Further studies are indicated to determine the value of this CCRT as an AD screening test and validity as a measure of EM impairment in other clinical conditions.

A valid, reliable, accessible, engaging, and affordable digital cognitive screen instrument for clinical use is in urgent demand.To assess the clinical utility of the MemTrax memory test for early detection of cognitive impairment in a Chinese cohort.The 2.5-minute MemTrax and the Montreal Cognitive Assessment (MoCA) were performed by 50 clinically diagnosed cognitively normal (CON), 50 mild cognitive impairment due to AD (MCI-AD), and 50 Alzheimer's disease (AD) volunteer participants. The percentage of correct responses (MTx-% C), the mean response time (MTx-RT), and the composite scores (MTx-Cp) of MemTrax and the MoCA scores were comparatively analyzed and receiver operating characteristic (ROC) curves generated.Multivariate linear regression analyses indicated MTx-% C, MTx-Cp, and the MoCA score were significantly lower in MCI-AD versus CON and in AD versus MCI-AD groups (all with p≤0.001). For the differentiation of MCI-AD from CON, an optimized MTx-% C cutoff of 81% had 72% sensitivity and 84% specificity with an area under the curve (AUC) of 0.839, whereas the MoCA score of 23 had 54% sensitivity and 86% specificity with an AUC of 0.740. For the differentiation of AD from MCI-AD, MTx-Cp of 43.0 had 70% sensitivity and 82% specificity with an AUC of 0.799, whereas the MoCA score of 20 had 84% sensitivity and 62% specificity with an AUC of 0.767.MemTrax can effectively detect both clinically diagnosed MCI and AD with better accuracy as compared to the MoCA based on AUCs in a Chinese cohort.

Cognitive impairment is a leading cause of dysfunction in the elderly. When mild cognitive impairment (MCI) occurs in elderly, it is frequently a prodromal condition to dementia. The Montreal Cognitive Assessment (MoCA) is a commonly used tool to screen for MCI. However, this test requires a face-to-face administration and is composed of an assortment of questions whose responses are added together by the rater to provide a score whose precise meaning has been controversial. This study was designed to evaluate the performance of a computerized memory test (MemTrax), which is an adaptation of a continuous recognition task, with respect to the MoCA. Two outcome measures are generated from the MemTrax test: MemTraxspeed and MemTraxcorrect. Subjects were administered the MoCA and the MemTrax test. Based on the results of the MoCA, subjects were divided in two groups of cognitive status: normal cognition (n = 45) and MCI (n = 37). Mean MemTrax scores were significantly lower in the MCI than in the normal cognition group. All MemTrax outcome variables were positively associated with the MoCA. Two methods, computing the average MTX score and linear regression were used to estimate the cutoff values of the MemTrax test to detect MCI. These methods showed that for the outcome MemTraxspeed a score below the range of 0.87 - 91 s-1 is an indication of MCI, and for the outcome MemTraxcorrect a score below the range of 85 - 90% is an indication for MCI.