轻度认知功能障碍的防治决策

轻度认知功能障碍(mild cognitive impairment,MCI)被认为是阿尔茨海默病(alzheimer disease,AD)的极早期.AD的防治需从MCI开始,早期发现,早期干预,以便延缓和阻止AD的发生.目前我国MCI具有就诊率低,诊断率低,治疗率低和漏诊率高的特点.临床研究要改变MCI三低一高的状况,医师及民众要提高对MCI的认识,应该采取重在预防,重视筛查,早期诊断,早期治疗的决策,可以延迟和阻止AD的发生.     

阿尔茨海默病的早期阶段:主观认知障碍?

主观认知障碍(subjective cognitive impairment,SCI)是指个体有认知障碍主诉,但不存在认知障碍或病理方面的客观证据,近年来成为阿尔茨海默病(AD)研究领域关注的热点问题,不仅是因为其症状本身较为常见,而且研究人员发现SCI的患者相比无SCI患AD的概率更大,极有可能是AD及轻度认知障碍(Mild cognitive impairment,MCI)的更早阶段。但目前学界就该症状的预测效果存在极大分歧。本文对主观认知障碍的研究状况进行了系统梳理,主要包括其概念与测量,脑变化与生物标志物,与MCI和AD的关系及对未来研究方向的展望。     

阿尔茨海默病生物学标志物研究进展

阿尔茨海默病（AD）是常见的中枢神经系统变性疾病,是痴呆最常见的病因,发病率高.病理特征为老年斑及神经元纤维缠结.AD的确诊有赖病理学,临床诊断极其耗时.由于尚无准确的早期诊断方法,常使AD患者错过早期治疗的时机,这成为制约有效防控AD的瓶颈问题.因此寻找高敏感性、特异性、无创性的生物学标志物对AD的早期诊断至关重要.本文仅将目前较为广泛研究的生物学标志物及其研究现状作一概述.分别对脑脊液、血液、尿液及唾液中的AD标志物作逐一介绍.     

认知和情绪冲突的监控与解决：来自轻度认知损伤的证据

轻度认知损伤(mild cognitive impairment, MCI)是介于正常老化和痴呆之间的过渡阶段。近年来, 执行控制的损伤被认为是MCI的核心特征之一。当前, 在MCI执行控制的领域内, 对冲突监控与解决的特征及其神经机制的研究较少。本研究拟通过认知及情绪冲突实验范式, 结合脑成像技术, 探讨遗忘型MCI (amnestic MCI, aMCI)认知和情绪冲突的监控与解决的特征及相应的脑激活模式; 通过对比aMCI和正常老年人在认知和情绪冲突任务中激活的神经环路, 考察aMCI是否在执行加工的神经网络上存在激活异常。在上述研究基础上, 研究者拟探讨aMCI在执行控制的冲突监控与解决上是否存在一般性的损伤机制, 同时试图寻找aMCI在执行控制的冲突监控与解决方面的认知及神经生物学标记。这对深入理解痴呆的发病进程并有针对性的开展痴呆的早期识别与干预具有重要的理论意义和实践意义。     

早老性痴呆病人早期记忆损害的检测方法

采用词语延迟回忆、记忆广度和双任务工作记忆测验,研究可能用于检测(Alzheimer’s disease,AD)早期记忆损害的方法。共有4组被试：两个正常年轻人组、一个正常老年人组、一个很可能患早老性痴呆病人(Probable AD,PAD)组。结果表明：(1)正常年轻人和正常老年人的词语延迟回忆保持率没有显著差异,而PAD患者表现出明显受损;(2)两个正常年轻人组的双任务工作记忆成绩也没有显著不同,与之相比,正常老年人组有一定程度的降低,而PAD患者表现出更大程度的损害;(3)4组被试的记忆广度都不相同。这些结果提示,词语延迟回忆和双任务工作记忆测验可能能够用于检测AD早期的记忆损害。     

老年高血压患者认知功能与血浆Hcy水平及颈动脉内膜-中层厚度的相关性研究

探讨老年高血压患者认知功能与血浆同型半胱氨酸(Hcy)水平及颈动脉内膜-中层厚度(IMT)的相关性。选取2014年9月~2016年11月于笔者所在医院就诊的高血压患者233例。进行MMSE量表评估后分为轻度认知障碍组(MCI组)及对照组。采集一般资料、检测Hcy水平及测量IMT值。结果显示,MCI组的年龄、BMI明显高于对照组,心率明显低于对照组,差异有统计学意义。MCI组较对照组Hcy值及IMT值明显增高(P0.05)。Hcy及IMT均与MMSE得分呈负相关,Hcy与IMT呈正相关。二元Logistic回归显示,年龄、Hcy、IMT是老年高血压患者轻度认知功能障碍发生的危险因素。提示老年高血压患者轻度认知功能障碍发生与血浆Hcy水平及颈动脉IMT值相关。     

轻度认知损伤的语义记忆研究述评

轻度认知损伤（Mild cognitive impairment,MCI）是介于正常老化与痴呆之间的过渡阶段,表现为与年龄和教育程度不相称的认知功能减退。本文回顾了近期有关MCI语义记忆的研究,分析比较了各研究的实验任务及结果,得出MCI患者存在一定程度的由多种原因造成的语义记忆损伤,语义记忆测验对MCI的早期筛查和转归预测有重要作用。最后指出将来的研究需要将包括语义记忆成分在内的多种认知测验相结合,以便及早发现有可能发展为痴呆的危险个体并开展相应干预。     

医护人员对预先指示的认知及影响因素研究

了解医护人员对预先指示(AD)的认知并探讨影响因素。应用自行设计的调查问卷对305名医护人员进行调查。结果显示,AD的知晓率为18.7%,其中分别有88.5%、54.1%的人赞同生前预嘱和指定医疗代理人。死亡态度、教育程度、接受姑息培训等为AD态度的影响因素;而行为意向仅受科别的影响。由此可见,医护人员对AD的知晓率低,受多种因素的影响,应对医护人员进行广泛深刻的AD教育。     

高、低趋近积极情绪对不同注意加工阶段的影响

本研究采用事件相关电位(ERP)技术和Flanker任务, 探讨由甜点和风景图片分别诱发的高、低趋近积极情绪对注意的早期和晚期加工的影响。同时, 为更精细考察情绪对视觉注意范围早期加工阶段的影响, 在75%的Flanker试次中加入了一个白色方块探测刺激, 该刺激位于中央Flanker字母的左侧或右侧。研究结果表明, 在注意加工的早期感知阶段, 高趋近积极情绪下, 带有白色探测刺激的Flanker字母比低趋近积极情绪条件下诱发了更小的P1, 表明高趋近积极情绪窄化了早期注意加工范围; 在注意加工的晚期选择阶段, 高趋近积极情绪下的Flanker字母诱发了更大的N2b成分, 低趋近积极情绪下诱发了更大的P3成分, 表明高趋近积极情绪增强了对干扰的抑制能力, 而低趋近积极情绪下个体调用了更多的注意资源用以加工周边刺激。     

认知分心的强度对创伤性信息加工的影响

结合ERP技术、创伤电影范式和改进的工作记忆范式探讨了认知分心的强度对创伤性信息加工的影响。结果发现, (1)高负荷上的N2波幅显著大于低负荷上的。(2)在低工作记忆负荷上, 创伤负性图引发的LPP波幅显著大于创伤中性图和无关中性图; 而在高工作记忆负荷上, 三类图片引发的LPP波之间差异不再显著。(3)在创伤负性图上高、低负荷工作记忆任务诱发的LPP波差异显著, 且高负荷条件下的LPP波幅显著小于低负荷条件。结果表明, 相比低认知控制, 早期高认知控制对创伤性信息的调节更有效, 支持了认知控制理论。     

The occurrence of different intrusive errors in patients with Alzheimer's disease, multiple cerebral infarctions, and major depression.

Recent evidence suggests that specific types of intrusive errors may occur more often in the protocols of Alzheimer's disease (AD) patients than in those of patients diagnosed with other types of dementia. Using the FULD Object Memory Evaluation, we documented the occurrence of five qualitatively different types of intrusive errors for mildly and moderately impaired patients with AD and multiple cerebral infarctions (MCI). Depressed and normal elderly controls were also studied. Despite an equivalent degree of impairment on a broad array of neuropsychological measures, mildly impaired AD patients evidenced greater deficits on a measure tapping retrieval from semantic memory and demonstrated a higher occurrence of specific types of intrusive errors relative to their mildly impaired MCI counterparts. Further, both of these measures were highly correlated, suggesting that these indices may be particularly sensitive to semantic dysfunction associated with early AD.     

Focused attention deficits in patients with Alzheimer's disease and mild cognitive impairment

Reaction time (RT) tasks take various forms, and can assess psychomotor speed, (i.e., simple reaction time task), and focused attention (i.e., choice reaction time (CRT) task). If cues are provided before stimulus presentation (i.e., cued choice reaction time (CCRT) task), then a cueing effect can also be assessed. A limited number of studies have addressed the nature of focused attention impairments in Alzheimer's disease (AD). Additionally, it is unknown whether similar impairments occur in Mild Cognitive Impairment (MCI). The current study used three RT tasks to address the nature of focused attention impairments in AD and MCI subjects. The results suggest that there were significant CRT and CCRT differences in AD subjects when compared to NECs. Furthermore, slowed RTs were also present in the MCI group, which provides evidence for impaired focussed attention and the inability to benefit from a cue in both the MCI and AD groups. The implications of the impairments related to the MCI group could potentially prove useful in early diagnosis of cognitive impairments in the elderly.     

湿疹？还是特应性皮炎？

特应性皮炎（AD）是一种慢性复发性、瘙痒性、炎症性皮肤疾病,常自幼时发病,可持续终生,严重影响患者的生活质量。目前尚无单一特异性的,洛床表现或实验室检查指标可以鉴别诊断AD与湿疹。然而,与湿疹相比较,AD患者常伴有血清免疫球蛋白IgE增高,个人及家族遗传性AD、过敏性哮喘和／或过敏性鼻炎的病史,且皮疹及瘙痒更为严重,还可合并皮肤感染及皮肤屏障功能的损害。因此,区分湿疹还是AD,对于正确诊断及采取合适的治疗方案具有重要意义。     

Visual Imagery Processing and Knowledge of Famous Names in Alzheimer's Disease and MCI

ABSTRACT

The study of memory for famous people and visual imagery retrieval was investigated in patients in the early stages of Alzheimer's disease (AD) and in the prodromal stage of AD, so-called Mild Cognitive Impairment (MCI). Fifteen patients with AD (MMSE ≥23), 15 patients with amnestic MCI (a-MCI) and 15 normal controls (NC) performed a famous names test designed to evaluate the semantic and distinctive physical features knowledge of famous persons. Results indicated that patients with AD and a-MCI generated significantly less physical features and semantic biographical knowledge about famous persons than did normal control participants. Additionally, significant differences were observed between a-MCI and AD patients in all tasks. The present findings confirm recent studies reporting semantic memory impairment in MCI. Moreover, the current findings show that mental imagery is lowered in a-MCI and AD and is likely related to the early semantic impairment.     

Contribution of temporal preparation and processing speed to simple reaction time in persons with Alzheimer’s disease and mild cognitive impairment

Temporal preparation was assessed in 15 Alzheimer’s disease (AD) patients, 20 persons with mild cognitive impairment (MCI) and 28 healthy older adults. Participants completed a simple reaction time task in which the preparatory interval duration varied randomly within two blocks (short versus long temporal window). Results indicated that AD and MCI patients had difficulty preparing for the shortest preparatory interval of the short temporal window. AD and MCI patients also had difficulty maintaining an optimal level of preparation up to 5 s within the short temporal window. These results suggest that AD and MCI patients might show difficulty preparing for rapidly occurring events and maintaining preparation over time. This phenomenon should be considered when using reaction time measures with such patients.     

Neuropsychological predictors of conversion to probable Alzheimer disease in elderly with mild cognitive impairment

In the field of neuropsychology, it is essential to determine which neuropsychological tests predict Alzheimer's disease (AD) in people with mild cognitive impairment (MCI) and which cut‐off points should be used to identify people at greater risk for converting to dementia. The aim of the present study was to analyse the predictive value of the cognitive tests included in a neuropsychological battery for conversion to AD among MCI participants and to analyse the influence of some sociodemographic variables – sex, age, schooling – and others, such as follow‐up time and emotional state. A total of 105 participants were assessed with a neuropsychological battery at baseline and during a 3‐year follow‐up period. For the present study, the data were analysed at baseline. During the follow‐up period, 24 participants (22.85%) converted to dementia (2.79 ± 1.14 years) and 81 (77.14%) remained as MCI. The logistic regression analysis determined that the long delay cued recall and the performance time of the Rey figure test were the best predictive tests of conversion to dementia after an MCI diagnosis. Concerning the sociodemographic factors, sex had the highest predictive power. The results reveal the relevance of the neuropsychological data obtained in the first assessment. Specifically, the data obtained in the episodic verbal memory tests and tests that assess visuospatial and executive components may help to identify people with MCI who may develop AD in an interval not longer than 4 years, with the masculine gender being an added risk factor.     

Differential Memory Test Sensitivity for Diagnosing Amnestic Mild Cognitive Impairment and Predicting Conversion to Alzheimer's Disease

ABSTRACT

Episodic memory is the first and most severely affected cognitive domain in Alzheimer's disease (AD), and it is also the key early marker in prodromal stages including amnestic mild cognitive impairment (MCI). The relative ability of memory tests to discriminate between MCI and normal aging has not been well characterized. We compared the classification value of widely used verbal memory tests in distinguishing healthy older adults (n = 51) from those with MCI (n = 38). Univariate logistic regression indicated that the total learning score from the California Verbal Learning Test-II (CVLT-II) ranked highest in terms of distinguishing MCI from normal aging (sensitivity = 90.2; specificity = 84.2). Inclusion of the delayed recall condition of a story memory task (i.e., WMS-III Logical Memory, Story A) enhanced the overall accuracy of classification (sensitivity = 92.2; specificity = 94.7). Combining Logical Memory recognition and CVLT-II long delay best predicted progression from MCI to AD over a 4-year period (accurate classification = 87.5%). Learning across multiple trials may provide the most sensitive index for initial diagnosis of MCI, but inclusion of additional variables may enhance overall accuracy and may represent the optimal strategy for identifying individuals most likely to progress to dementia.     

阿尔茨海默病的诊治新进展

流行病学数据的更新表明阿尔茨海默病（A D ）已成为全球健康问题。早期应用生物标志物的AD新诊断标准广泛应用和临床试验不断失败的鲜明反差提示AD治疗的艰巨性。AD和其他慢性疾病的共病研究不断深入。生活方式干预作为非药物治疗备受重视。     

Prosaccade and Antisaccade Paradigms in Persons with Alzheimer’s Disease: A Meta-Analytic Review

Persons with Mild Cognitive Impairment (MCI) are at high Alzheimer’s Disease (AD) risk but the development of sensitive measures to assess subtle cognitive decline in this population poses a major challenge for clinicians and researchers. Eye movement monitoring is a non-invasive, sensitive way to assess subtle cognitive processes in clinical populations. We conducted a critical review and a meta-analysis of the literature on pro and antisaccade paradigm in AD/MCI. The meta-analysis included 20 studies, all of which used the prosaccade paradigm and 13 of which studied the antisaccade paradigm as well. Our meta-analysis showed that AD but not MCI patients showed longer prosaccade latencies when compared to controls. While antisaccade latencies did not differentiate between patients from controls, antisaccade error rate were significantly increased among patients in comparison to controls in over 87% of the studies. These findings highlight antisaccade error rate as a reliable tool to distinguish inhibition abilities between AD/MCI and healthy older persons.