神经影像在轻度认知障碍研究中的应用

轻度认知障碍(MCI)是介于正常老化和痴呆之间的一种认知功能损害的中间阶段。目前主要依据病史、神经心理评估量表、生物标记物及神经影像学等进行诊断,近年来随着神经影像检查技术快速发展,对于MCI的研究重点逐渐转移到神经影像领域,以期能够为MCI的早期诊断、疗效评估提供客观依据,本文将对神经影像在轻度认知障碍研究中的应用作一简要综述。     

轻度认知功能损害的研究现状和展望

轻度认知功能损害(MCI)正在成为老化和痴呆的早期诊断和防治研究中的极为活跃的领域。研究和识别MCI，有助于发现具有最佳干预时机的个体，为老年性痴呆的防治提供一个最佳的治疗时间窗。目前MCI的研究中存在着诸多问题，限制了研究的深入和研究结果的可比性。本就MCI近些年在神经病理学、神经影像学、神经生物学、神经心理学方面的研究现状和当前MCI研究中存在的若干问题及展望进行综述，以期为进一步研究提供参考。     

轻度认知功能障碍筛查量表分析

轻度认知功能障碍(mild cognitive impairment,MCI)患者如被早期发现是可以积极防治和改善的,在此期间给予恰当的干预可以有效防止或延缓其发展为痴呆。然而目前对MCI的诊断尚无特异性高的检查方法,因而很容易忽视这种过渡状态,因此如何正确快速地评定出MCI状态并确定为哪种痴呆的MCI期,需要有快速有效的筛查工具。量表作为筛查工具已纳入MCI的诊断标准中,为早期发现认知功能障碍,达到早诊断、早治疗的目的,使用方便、针对性强的筛查工具尤为重要。本文将对目前国内外针对MCI患者筛查的量表进行综述。     

事件相关电位在轻度认知障碍中的应用进展

轻度认知障碍(mild cognitive impairment,MCI)描述的是认知功能损害介于正常衰老和痴呆的中间状态,由该状态向痴呆转化的风险较高,对其早期诊治可能会改善患者的长期预后。MCI的诊断及疾病监测除了症状和神经心理量表外,事件相关电位也是一种重要的客观检查方法。本文将对近年来事件相关电位在MCI领域中的应用进展进行综述。     

痴呆领域中的新概念:主观认知功能障碍

主观认知功能障碍(SCI)是介于正常老龄化与轻度认知功能损害(MCI)之间的阶段,表现为个体主观上有认知功能障碍,但无客观证据支持。尽管这一概念作为痴呆最早期阶段一经被提出即存在着争议,但该类症状在临床上较为常见,SCI研究也成为当前痴呆领域中的热点话题。为此,我们将对SCI概念、流行病学、诊断标准、神经影像学、神经病理学、干预等方面进行综述。     

嗅觉障碍与常见神经认知障碍的研究进展

嗅觉障碍在老年人中患病率较高,不仅影响人的生活质量及心理健康,而且是多种神经精神疾病的临床表现,尤其是阿尔茨海默病(Alzheimer's disease,AD)等神经认知障碍。AD是一种常见的以进行性痴呆为主要表现的神经退行性疾病,无法治愈,给个人、家庭及社会带来沉重的负担。通过AD标志物检测,早期发现,早期干预,对延缓AD进展大有帮助。嗅觉障碍与AD及轻度认知障碍(mild cognitive impairment,MCI)密切相关,嗅觉功能检测或许能辅助早期识别MCI及AD,因此我们将重点综述嗅觉障碍与MCI及AD常规诊断手段相关联的最新研究进展,以评估嗅觉障碍在MCI及AD等常见神经认知障碍研究中的价值。     

老年人轻度认知功能障碍不同诊断标准的比较

目的 使用广义轻度认知功能损害（MCI）诊断标准了解老年人MCI患病,与Petersen标准进行比较,观察3年后两种标准MCI痴呆发病情况.方法 以465名≥60岁老年人为研究对象,进行神经心理检查,观察MCI患病率,并与Petersen标准进行比较.3年后,对诊断为MCI的患者随访,比较两种标准MCI痴呆发病情况.结果 广义MCI患者76例（16.34％）,与Petersen标准诊断患病情况（50例,10.75％）比较,患病率较高,差异有统计学意义（x2=6.206,P＜0.05）.3年后,76例MCI患者中痴呆发病30例（年发病率为13.16％）,进展为AD者23例,其他类型痴呆7例;按Petersen标准诊断A-MCI组痴呆发病22例（年发病率为14.67％）,全部进展为AD.两种方法诊断的MCI痴呆发病率差异无统计学意义（x2=0.255,P＞0.05）.在广义MCI组内,A-MCI与非A-MCI痴呆发病差异无统计学意义（x2=1.253,P＞0.05）.同时,正常组痴呆发病19例（年发病率为4.54％）,MCI组痴呆发病率高,差异有统计学意义（x2=80.689,P＜0.05）.结论 采用广义MCI诊断标准较Petersen标准诊断MCI患病率高,其包含了更多类型的痴呆临床前体,有利于早期发现MCI及防治.     

轻度认知障碍的转化及相关因素研究进展

轻度认知障碍（MCI）是介于正常衰老与痴呆之间的一种过渡状态,具有发展为痴呆的高度危险性。本文将对近年MCI的转化及转化率,转化的认知功能评估、生物学指标、神经影像学、危险因素及药物干预等研究进展进行全面综述。     

轻度认知功能障碍

正轻度认知功能障碍(mild cognitive impairment,MCI)是一种介于正常衰老与痴呆之间的认知功能障碍。MCI患者易高风险地转化为痴呆,严重影响了老年人的健康。研究和识别MCI,有助于发现最佳干预时机的个体,从而在最佳时间窗进行防治。近几年对MCI的研究已取得了很大进展,但MCI的定义与诊断标准尚不完善,而且预测其进展为痴呆的生物学标记物的敏感性和特异性仍未明确,尚无一套统一的神经心理学评     

多发腔隙性脑梗死与轻度认知功能障碍的关系

目的 探讨多发性腔隙性脑梗死(multiple lacunar infarction,MLI)对轻度认知功能损害(mild cognitive impairment,MCI)患者发展为痴呆的相关关系.方法 采用国际通用标准从门诊和住院患者中筛选轻度认知功能障碍患者.通过MRI和CT扫描,确定这些患者有否多发性腔隙性脑梗死.对轻度认知功能障碍患者进行随访,用Kapaln-Meier生存分析法评定MLI对MCI发展为痴呆的相关关系.结果 经临床和神经心理学评估,有120例MCI患者入选,其中43例(35.8%)经影像学诊断为伴有MLI,77例(64.1%)不伴MLI.经6～24个月随访,伴有MLI的患者有27(62.8%)例进展为痴呆,不伴MLI的患者有15例(19.4%)进展为痴呆.随访期内伴有MLI的MCI患者进展为痴呆的比例显著高于不伴MLI的患者(P＜0.05).结论 伴有MLI的MCI患者更容易进展为痴呆.这类MCI患者必须尽早进行干预,去除可控危险因素,预防痴呆发生.     

Neuropsychological testing and assessment for dementia

This evidence-based review examines the utility of brief cognitive tests and neuropsychological testing (NPT) in the detection and diagnosis of mild cognitive impairment (MCI) and dementia. All patients presenting with cognitive complaints are recommended to have a brief screening test administered to document the presence and severity of memory/cognitive deficits. There is fair evidence to support the use of a range of new screening tests that can detect MCI and mild dementia with higher sensitivity (≥80%) than the Mini-Mental State Exam (MMSE). NPT should be part of a clinically integrative approach to the diagnosis and differential diagnosis of dementia. It should be applied selectively to address specific clinical and diagnostic issues including: 1) The distinction between normal cognitive functioning in the aged, MCI and early dementia: there is fair evidence that NPT can document the presence of specific diagnostic criteria and provide additional useful information on the pattern of memory/cognitive impairment. 2) The evaluation of risk for Alzheimer disease (AD) or other types of dementia in persons with MCI: there is fair evidence that NPT measures or profiles can predict progression to dementia (predictive accuracy ranges from ∼80 to 100%, sensitivities from 53 to 80%, and specificities from 67 to 99%). 3) Differential diagnosis: There is fair evidence that NPT can complement clinical history and neuroimaging in determining the dementia etiology. Different dementia types have distinguishable NPT profiles though these may be stage-dependent, and increased sensitivity may be at the expense of specificity. 4) When NPT is part of a comprehensive assessment, which also entails clinical interviews and consideration of other clinical data, there is good evidence that it can contribute to management decisions in MCI and dementia, including the determination of retained and impaired cognitive abilities, their functional and vocational impact, and opportunities for cognitive rehabilitation.     

Mild cognitive impairment in Parkinson disease: heterogenous mechanisms

Cognitive impairment is common in Parkinson disease (PD), with long-term longitudinal studies reporting that most PD patients develop dementia. A high proportion of patients with PD and mild cognitive impairment (MCI) progress to dementia within a short time. Impairments occur in a range of cognitive domains, but single-domain impairment is more common than multiple one, non-amnestic more common than amnestic impairment. Although the term MCI applied to PD (PD-MCI) is not without controversy due to the lack of uniform diagnostic consensus criteria, the biological validity of PD-MCI is supported by many recent studies that show heterogenous mechanisms in the clinical presentation, neuropsychology, neuroimaging, biomarkers, and neuropathology, suggesting abnormal metabolic network activities involving several cortical and subcortical nervous systems. Prospective studies using specific biomarkers, including amyloid imaging, and cerebro-spinal fluid biomarkers are warranted for an exact diagnosis and prognostic assessment of early cognitive deficits in PD patients.     

轻度认知障碍与卒中后抑郁关系的研究进展

轻度认知障碍（mild cognitive impairment,MCI）是认知正常和痴呆之间的过渡状态,MCI与 卒中后抑郁（post-stroke depression,PSD）关系密切。MCI常伴发抑郁,而PSD亦被认为是MCI向痴呆进展 的重要危险因素。本文就MCI与PSD关系的研究进展进行综述,着重介绍MCI和PSD关系的新进展,包 括流行病学、相关机制及治疗。     

轻度认知功能障碍的认识

轻度认知功能障碍（MCI）是指介于痴呆和正常衰老之间的认知功能损害状态。由于概念的混淆、方法的差异及标准的不同,MCI在临床实践中存在着不少困惑。本文回顾了认知功能损害的研究历史,讨论了MCI的概念、诊断标准、临床分型、与正常老化和痴呆的鉴别以及临床预后,探讨了MCI与阿尔茨海默病的关系。     

Neuroimaging markers for the prediction and early diagnosis of Alzheimer's disease dementia

Alzheimer's disease (AD) is a progressive age-related neurodegenerative disease. At the time of clinical manifestation of dementia, significant irreversible brain damage is already present, rendering the diagnosis of AD at early stages of the disease an urgent prerequisite for therapeutic treatment to halt, or at least slow, disease progression. In this review, we discuss various neuroimaging measures that are proving to have potential value as biomarkers of AD pathology for the detection and prediction of AD before the onset of dementia. Recent studies that have identified AD-like structural and functional brain changes in elderly people who are cognitively within the normal range or who have mild cognitive impairment (MCI) are discussed. A dynamic sequence model of changes that occur in neuroimaging markers during the different disease stages is presented and the predictive value of multimodal neuroimaging for AD dementia is considered.     

非痴呆性血管性认知障碍的研究进展

血管性认知障碍（vascular cognitive impairment,VCI）是由脑血管病危险因素（如高血压、 糖尿病、高脂血症和高同型半胱氨酸血症等）、显性脑血管病（出血性及缺血性卒中）及非显性脑血 管病（脑白质疏松和慢性脑缺血等）引起的一组从轻度认知功能损害到痴呆的临床综合征。非痴呆 性血管性认知障碍（vascular cognitive impairment-no dementia,VCIND）是VCI的早期阶段,其中约一半 患者会在5年内进展为痴呆。血管性痴呆（vascular dementia,VD）在治疗上尚未发现行之有效的方法, 但又是唯一可以预防的痴呆。发现VCIND危险因素并进行早期干预,对于寻求延缓痴呆进展的二级 预防策略至关重要。现从VCIND的概念、流行病学、诊断标准及影响因素等方面进行综述,以期能够 早期识别相关危险因素,防治VCI。     

The role of neuroimaging in mild cognitive impairment

The main purposes of neuroimaging in Alzheimer's disease (AD) have been moved from diagnosis of advanced AD to diagnosis of very early AD at a prodromal stage of mild cognitive impairment, prediction of conversion from mild cognitive impairment (MCI) to AD, and differential diagnosis from other diseases causing dementia. Structural MRI studies and functional studies using F‐18 fluorodeoxyglucose‐positron emission tomography (FDG‐PET) and brain perfusion single‐photon emission computed tomography (SPECT) are widely used in diagnosis of AD. Outstanding progress in diagnostic accuracy of these neuroimaging modalities has been obtained using statistical analysis on a voxel‐by‐voxel basis after spatial normalization of individual scans to a standardized brain‐volume template instead of visual inspection or a conventional region of interest technique. In a very early stage of AD, this statistical approach revealed gray matter loss in the entorhinal and hippocampal areas and hypometabolism or hypoperfusion in the posterior cingulate cortex and precuneus. These two findings might be related in view of anatomical knowledge that the regions are linked through the circuit of Papez. This statistical approach also offers prediction of conversion from MCI to AD. Presence of hypometabolism or hypoperfusion in parietal association areas and entorhinal atrophy at the MCI stage has been reported to predict rapid conversion to AD.     

Fortschritte in der Diagnostik der Alzheimer-Demenz

Due to the demographic developments, diagnosis and treatment, dementia constitutes an increasing medical challenge and is likely to have an increasing socioeconomic impact. Dementia does not reflect a single disease but encompasses a variety of underlying conditions, heterogeneous clinical courses and therapeutic approaches, among which Alzheimer's disease represents the most common cause. Therefore, a thorough differential diagnosis of dementia is of major importance. To date the current diagnosis of dementia according to ICD-10/DMS-IV is based on clinical criteria. In addition, the concept of mild cognitive impairment comprises early cognitive dysfunction without clinically apparent dementia. Alzheimer's disease is more and more conceptualized as a disease continuum with mild cognitive impairment as an early and manifest dementia as the later stage of the disease. This review gives an overview on the current diagnostic approaches and the proposed revisions of diagnostic and research criteria for Alzheimer's disease.     

Amnestic MCI or prodromal Alzheimer's disease?

The concept of mild cognitive impairment (MCI) draws attention to cognitive changes not severe enough to warrant the diagnosis of dementia. As used today, it covers many pathological disorders and characterises a diverse population of patients who attend memory clinics. Our concern is the underlying heterogeneity. We suggest that it will soon be possible (if it is not already) to identify the underlying pathological disorders before the affected patients meet the criteria of dementia, thanks to specific neuropsychological assessments, neuroimaging, and biomarkers. In particular, patients with Alzheimer's disease (AD), the most important subgroup of patients with MCI, can already be identified before appearance of the fully developed clinical dementia syndrome. Accordingly, this paper proposes diagnostic criteria for "prodromal AD".