The Consortium to Investigate Vascular Impairment of Cognition: methods and first findings

BACKGROUND: The Consortium to Investigate Vascular Impairment of Cognition (CIVIC) is a Canadian, multi-centre, clinic-based prospective cohort study of patients with Vascular Cognitive Impairment (VCI). We report its organization and the impact of diagnostic criteria on the study of VCI. METHODS: Nine memory disability clinics enrolled patients and recorded their usual investigations and care. A case report form included all vascular dementia (VaD) individual criteria for each of four sets (National Institute of Neurological Disorders and Stroke (NINDS-AIREN), Alzheimer's Disease Diagnostic Treatment Centers (ADDTC), the ICD-10 Classification of Mental and Behavioural Disorders (ICD-10), and the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV)) of consensus-based diagnostic criteria and for the Hachinski Ischemia Score (HIS). Investigators, having completed the case report form, were asked to make a clinical judgement about the cognitive diagnosis based on the best available information, including neuroimaging. RESULTS: Of 1,347 patients (mean age 72 years; 56% women), 846 (63%) were diagnosed with dementia and 324 (24%) were diagnosed with VCI. The proportion of patients diagnosed with VaD by the diagnostic criteria was: 23.9% (n = 322) by DSM-IV, 10.2% (n = 137) by HIS, 4.3% (n = 58) by ICD-10, 3.8% (n = 51) by ADTCC, and 3.6% (n = 48) by NINDS-AIREN. Judged against a clinical diagnosis of VaD, the sensitivity/specificity of each was: DSM-IV (0.77/0.80); HIS (0.41/0.92); ICD-10 (0.29/0.98); ADTCC (0.24/0.98); NINDS-AIREN (0.42/0.995). Compared with a clinical diagnosis of VCI, sensitivities were lower for the diagnostic criteria, reflecting the exclusion of patients who did not have dementia. CONCLUSIONS: Consensus-based criteria for VaD omit patients who do not meet dementia criteria that are modeled on Alzheimer's disease. Even for patients who do, the proportion identified with VaD varies widely. Criteria based on empirical analyses need to be developed and validated.     

Vascular dementia

Vascular dementia (VaD) is a term used to describe a particular constellation of cognitive and functional impairment, and is now generally seen as a subset of the larger syndrome of vascular cognitive impairment (VCI). The latter is seen as cognitive impairment in the face of cerebrovascular disease. VCI can be classified clinically by whether patients meet criteria for dementia, and whether the syndrome is distinct or overlaps with primary neurodegenerative diseases, such as Alzheimer's disease. This clinical classification can be further classified by neuroimaging, with subgroups that show cortical infarction, subcortical infarction and white matter changes, each alone or in combination. Understood in this way, VCI is likely the most common form of cognitive impairment in the population. Attempts to treat VaD had varying degrees of success, but it now appears that many forms of VCI might be preventable, especially with good control of vascular risk factors in middle age.     

Vascular cognitive disorder: a new diagnostic category updating vascular cognitive impairment and vascular dementia

Vascular cognitive impairment (VCI) was proposed as an umbrella term to include subjects affected with any degree of cognitive impairment resulting from cerebrovascular disease (CVD), ranging from mild cognitive impairment (MCI) to vascular dementia. VCI may or may not exclude the host of "focal" circumscribed impairments of specialized functions such as language (aphasia), intentional gesture (apraxia), or categorical recognition (agnosia), among others, that may result from a stroke. Therefore, there are no universally accepted diagnostic criteria for VCI. We conclude that this concept could be more useful if it were to be limited to cases of vascular MCI without dementia, by analogy with the concept of amnestic MCI, currently considered the earliest clinically diagnosable stage of Alzheimer disease (AD). In agreement with our view,the Canadian Study on Health and Aging successfully implemented a restricted definition of VCI, excluding cases of dementia (i.e., vascular cognitive impairment no dementia, VCI-ND). The Canadian definition and diagnostic criteria could be utilized for future studies of VCI. This definition excludes isolated impairments of specialized cognitive functions.Vascular dementia (VaD): The main problem of this diagnostic category stems from the currently accepted definition of dementia that requires memory loss as the sine qua non for the diagnosis. This may result in over-sampling of patients with AD worsened by stroke (AD+CVD). This problem was minimized in controlled clinical trials of VaD by excluding patients with a prior diagnosis of AD, those with pre-existing memory loss before the index stroke, and those with amnestic MCI. We propose a definition of dementia in VaD based on presence of abnormal executive control function, severe enough to interfere with social or occupational functioning. Vascular cognitive disorder (VCD): This term, proposed by Sachdev [P. Sachdev, Vascular cognitive disorder. Int J Geriat Psychiatry 14 (1999)402-403.] would become the global diagnostic category for cognitive impairment of vascular origin, ranging from VCI to VaD. It would include specific disease entities such as post-stroke VCI, post-stroke VaD, CADASIL, Binswanger disease, and AD plus CVD. This category explicitly excludes isolated cognitive dysfunctions such as those mentioned above.     

脑心通治疗血管性认知障碍的临床研究

目的评价脑心通胶囊治疗血管性认知障碍的临床疗效和安全性。方法本研究从三个分中心招募血管性认知功能障碍(VCI)患者240例,并随机分为治疗组121例,其中无痴呆血管认知功能障碍(VCIND)患者45例,血管性痴呆(VaD)患者76例;对照组120例,其中VCIND患者44例,VaD患者76例。治疗组给予脑心通胶囊每日口服3次,每次4粒;对照组给予复方丹参片每日口服3次,每次4粒,连续服用3月。比较不同阶段的VCI患者治疗前后简易智能精神状态量表(MMSE)、日常生活能力量表(ADL)的变化。结果治疗组VCIND患者治疗后MMSE和ADL评分均有明显改善,差异有统计学意义(P<0.01)。治疗组VaD患者治疗后MMSE略有改善,差异无统计学意义(P>0.05),而ADL评分有改善,差异有统计学意义(P<0.01)。结论脑心通胶囊能够改善无痴呆血管性认知障碍(VCIND)患者的认知功能。     

Inter-rater reliability of the diagnosis of vascular cognitive impairment at a memory clinic

Consensus criteria for the diagnosis of vascular dementia (VaD) are gradually being replaced with data-based criteria. We report the inter-rater reliability of a new set of empirically-derived criteria for vascular cognitive impairment (VCI). Stratified sampling, with optimal allocation, was employed to randomly select 36 patients from the Queen Elizabeth II Health Science Centre's Memory Disability Clinic. Chart reviews were conducted independently by 4 physicians. Each physician classified the patients as having either: no cognitive impairment, VCI or Alzheimer's disease (AD). VCI was further classified both clinically (VCI without dementia, VaD or AD with a vascular component) and radiographically (infarcts, white matter changes, single strategic stroke). The intraclass correlation coefficient (ICC) for the diagnosis by physicians of VCI or otherwise was based on a repeated-measures analysis of variance with raters as the independent variable. A significant coefficient of reliability (average ICC = 0.88, 95% CI = 0.80-0.93) was obtained (H(o): rho 相似文献   

Clinical and radiographic subtypes of vascular cognitive impairment in a clinic-based cohort study

BACKGROUND AND PURPOSE: There is a need for empirical studies to define criteria for vascular cognitive impairment (VCI) subtypes. In this paper, we report the predictive validity of a subtype classification scheme based on clinical and radiographic features. METHODS: Nine Canadian memory clinics participated in the Consortium to Investigate Vascular Impairment of Cognition. This cohort consisted of 1347 patients, of whom 324 had VCI, and was followed for up to 30 months. RESULTS: Clinical and neuroimaging features defined three subtypes: vascular cognitive impairment, no dementia, (n=97), vascular dementia (n=101) and mixed neurodegenerative/vascular dementia (n=126). Any ischemic lesion on neuroimaging increased the odds (odds ratio=9.31; 95% confidence interval 6.46, 13.39) of a VCI diagnosis. No VCI subtype, however, was associated with a specific neuroimaging abnormality. Compared to those with no cognitive impairment, patients with each VCI subtype had higher rates of death and institutionalization (hazard ratio for combined adverse events=6.08, p<0.001). CONCLUSIONS: Both clinical features and radiographic features help establish a diagnosis of VCI. The outcomes of VCI subtypes, however, are more strongly associated with clinical features than with radiographic ones.     

MRI and CT in the diagnosis of vascular dementia

Neuroimaging is necessary to demonstrate cerebrovascular disease (CVD) and is therefore an important examination in vascular dementia (VaD) and vascular cognitive impairment (VCI). MRI is preferred over CT because multiple planes and sequences are needed to assess various types of pathology in relevant regions. These protocols allow differentiation of VaD from other forms of dementia and sometimes identify specific underlying disorders. Different diagnostic criteria for VaD exist but the NINDS-AIREN criteria are widely used in controlled clinical trials in VaD. These criteria have relatively low sensitivity but are highly specific and include radiological requirements. The radiological criteria have poor interobserver agreement. In general, the radiological portion of the diagnostic criteria for VaD needs revision and refinement to include bone fide cases of VaD not currently accepted by imaging rules, and for the early detection of patients with VCI.     

不同类型的血管性认知损害的执行功能障碍

目的 分析不同类型的血管性认知功能损害(VCI)患者的执行功能损害特征.方法 经头颅MRI证实为皮质下缺血性小血管病(SIVD)患者64例,其中16例单一的执行功能损害(s-VCI-ND)、26例多个认知领域损害(m-VCI-ND)和22例血管性痴呆(VaD)患者,完成一系列神经心理测验,包括总体认知水平、记忆、语言、注意/执行功能、空间结构能力等各个认知领域.其中执行功能检查包括定势转移、优势抑制、工作记忆、概念形成和流畅性5个分因子,共15种独立的分测验.结果 汉诺塔测验、示踪排序测验、同步听觉连续加法测验等在非痴呆VCI(VCI-ND)患者中的完成率低于50%,不适合VCI-ND的检测;s-VCI-ND组与健康对照组比较,分别反映4种执行功能成分的连线测验B耗时数(216.5±69.3、137.4±37.9)、Stroop色词测验卡片C耗时数(115.4±30.1、72.9±17.5)、卡片分类测验(1.9±1.4、2.7±1.2)和范畴流畅性测验(列举动物14.2±2.3、17.7±4.4)差异具有统计学意义(t=4.73、5.72、2.04、3.53,均P<0.05);VCI-ND的认知表现介于健康老人组和VaD组之间,其中m-VCI-ND有比较严重的执行功能损害和情景与语义记忆障碍,其认知缺损模式接近VaD,很可能是VaD的前期状态.结论 SIVD所致VCI的执行功能损害缺乏选择性,部分执行功能测验可以作为早期检测VCI-ND的敏感工具.     

尼莫地平联合阿托伐他汀治疗血管性认知障碍的疗效观察

目的探讨尼莫地平联合阿托伐他汀治疗血管性认知障碍的临床疗效及其不良反应。方法将96例血管性认知障碍患者随机分为对照组和治疗组,每组48例,再根据神经心理学评分将每组分为VCIND和VaD两个亚组。对照组给予了常规治疗＋安慰剂治疗,治疗组予尼莫地平＋阿托伐他汀治疗,尼莫地平30mg/d,1日3次,阿托伐他汀20mg/d,晚上1次,疗程均为6个月。采用MoCA和ADL评分对患者进行神经心理学评分。结果与同组治疗前相比,治疗组治疗6个月后MoCA和ADL评分分值明显提高（P〈0.01）;与对照组相比,治疗组治疗后MoCA和ADL评分值提高（P〈0.05）。对照组中VCIND患者MoCA和ADL较治疗前降低（P〈0.05）;治疗组中VCIND患者较治疗前及对照组MoCA和ADL分值明显提高（P〈0.01）,VaD患者无明显提高（P〉0.05）。2组均未见严重的不良反应。结论尼莫地平联合阿托伐他汀治疗血管性认知障碍的临床疗效较好,不良反应少。     

Vascular Cognitive Impairment

Abstract: The term vascular cognitive impairment (VCI) is now employed to capture the spectrum of illness and disability arising from impaired cognitive function of vascular origin. As such, it supplants the more narrowly focussed terms "Vascular dementia (VaD)" and "multi-infarct dementia". It is meant to include both those whose cognitive impairment is different from that assumed by the usual criteria for dementia. Traditionally, dementia criteria have been modelled on AD, a disorder with more characteristic neuropathological and clinical disease expression than is seen in VaD, which can occur in many forms. VCI is common, and is associated with many adverse outcomes, including worse cognition, institutionalization, and death.
One form of VCI is coincident AD and VaD, a category which, although it has been comparatively neglected, may be amongst the most common forms of dementia. Another common form of VCI has a predilection for subcortical ischemic lesions, and for a clinical presentation which reflects frontal and subcortical involvement.
At present, there is no specific treatment for VCI, although several agents appear to offer the hope of both treatment and prevention. Further research on the clinical, pathological and mechanistic underpinnings of this important syndrome is needed. For a long time, VaD has been recognized as the second most common cause of dementia.^1,2) More recently, however, the concept of cognitive impairment in relation to cerebrovascular disease has been expanded. This paper will review the notion of "vascular cognitive impairment" (VCI) as it relates to clinical practice, and to our understanding of disease mechanisms in dementia and related disorders. It will propose that while the expanded concept has merit, within it are to be found distinct subgroups, including some of particular importance as targets for clinical trials of therapeutic and even preventive interventions.     

血管性痴呆和血管性认知障碍的临床研究进展

血管性认知障碍和痴呆是认知障碍和痴呆领域以及脑血管病领域研究方面的交叉点。本文综述了血管性痴呆和认知障碍的定义、诊断标准和药物治疗进展。在诊断方面重点介绍了血管性痴呆各个亚型的临床特点。在治疗方面重点介绍了血管性痴呆和认知障碍的胆碱能递质代谢障碍以及胆碱酯酶抑制剂治疗的进展。     

Diagnosis and management of vascular cognitive impairment and dementia

Vascular dementias (VaDs) are the second most common cause of dementia. Cerebrovascular disease (CVD) and stroke relates to high risk of cognitive impairment, but also relate to Alzheimer's disease (AD): Vascular cognitive impairment (VCI) and dementias extend beyond the traditional multi-infarct dementia. Pathophysiology of VaD incorporates interactions between vascular etiologies (CVD and vascular risk-factors), changes in the brain (infarcts, white matter lesions, atrophy), host factors (age, education) and cognition. Variation in defining the cognitive syndrome, in vascular etiologies, and allowable brain changes in current criteria have resulted in variable estimates of prevalence, of groups of subjects, and of the types and distribution of putative causal brain lesions. Should new criteria be developed? Ideally in constructing new criteria the diagnostic elements should be tested with prospective studies with clinical-pathological correlation: replace dogma with data. Meanwhile focus on more homogenous subtypes of VaD, and on imaging criteria could be a solution. Subcortical ischemic vascular disease and dementia (SIVD) incorporate small vessel disease as the chief vascular etiology, lacunar infarct and ischaemic white matter lesions as primary type of brain lesions, subcortical location as the primary location of lesions, and subcortical syndrome as the primary clinical manifestation. It incorporates two clinical entities "Binswanger's disease" and "the lacunar state". AD with VaD (mixed dementia) has been underestimated as a prevalent cause in the older population. In addition to simple co-existence, VaD and AD have closer interaction: several vascular risk factors and vascular brain changes relate to clinical manifestation of AD, and they share also common pathogenetic mechanisms. Vascular cognitive impairment (VCI) is a category aiming to replace the "Alzhemerized" dementia concept in the setting of CVD, and substitute it with a spectrum that includes subtle cognitive deficits of vascular origin, post-stroke dementia, and the complex group of the vascular dementias. As far there is no standard treatment for VaDs, and still little is known on the primary prevention (brain at risk for CVD) and secondary prevention (CVD brain at risk for VCI/VaD). There is no standard symptomatic treatment for VaD. Recently symptomatic cholinergic treatment has shown promise in AD with VaD, as well as probable VaD. Future focus should be directed to the distinct etiological and pathological factors: the vascular and the AD burden of the brain.     

急性缺血性卒中患者血管性认知障碍及其亚型的相关因素分析

目的探讨急性缺血性卒中患者血管性认知障碍(vascular cognitive impairment,VCI)及其亚型非痴呆性血管性认知障碍(VCI-no dementia,VCIND)与血管性痴呆(vascular dementia,Va D)发生的主要相关因素。方法选择2014年6月至2015年6月就诊于天津医科大学总医院神经内科的491例急性缺血性卒中患者为研究对象,应用前期已建立的血管性认知障碍数据库记录患者的一般人口学信息、病史、体格检查、血管危险因素、生化及影像检查信息,对患者进行美国国立卫生研究院卒中量表(National Institutes of Health Stroke Scale,NIHSS)评分、Essen评分及低分子肝素治疗急性卒中试验(the Trial of Org 10172 in Acute Stroke Treatment,TOAST)分型,于发病(10±2)d进行蒙特利尔认知量表(Montreal Cognitive Assessment,Mo CA)、临床痴呆量表(Clinical Dementia Rating,CDR)、日常生活能力量表(Activities of Daily Living,ADL)评分,依据血管性认知障碍诊治指南中VCI的诊断及分类诊断标准将患者分为认知正常组(no cognitive impairment,NCI)和VCI组,VCI组包括VCIND组和Va D组,分析上述各项因素的组间差异及相关性。结果 491例急性缺血性卒中患者中VCI占69.86%,其中包括37.68%的VCIND和32.18%的Va D患者。1VCI组低受教育程度(P0.001)、糖尿病(P=0.005)、心脏病(P=0.045)、卒中家族史(P=0.005)、幕上病变(P0.001)的比例及卒中次数(P=0.014)、D-二聚体水平(P=0.001)、Essen评分(P=0.024)、NIHSS评分(P0.001)显著高于NCI组,女性(P=0.004)、幕下病变(P0.001)的比例及受教育年(P0.001)显著低于NCI组,差异均有显著性;Logistic回归分析显示低受教育程度、糖尿病、幕上病变和高D-二聚体水平是VCI的独立危险因素。2与VCIND组比较,Va D组患者既往卒中史(P=0.013)、TOAST分型中大动脉粥样硬化型梗死(P0.001)的比例及卒中次数(P=0.001)、Essen评分(P=0.032)、神经功能缺损程度(P=0.005)显著高于VCIND组,TOAST分型中小动脉闭塞型梗死(P0.001)、幕下病变(P0.001)的比例显著低于VCIND组,差异均有显著性;Logistic回归分析显示卒中次数、神经功能缺损程度、大动脉粥样硬化型梗死是Va D的独立危险因素,而幕下病变患者发生Va D的风险明显小于幕上病变患者。结论 VCI及其亚型的影响因素不同,与NCI比较,低受教育程度、糖尿病、幕上病变和高D-二聚体水平是VCI的独立危险因素;与VCIND比较,卒中次数、严重的神经功能缺损、TOAST分型中大动脉粥样硬化型梗死是Va D的独立危险因素。     

Cognitive and functional decline in African Americans with VaD, AD, and stroke without dementia.

OBJECTIVE: To compare the rates of cognitive and functional decline in African American patients diagnosed at baseline with vascular dementia (VaD) (n = 79), AD (n = 113), or stroke without dementia (SWD) (n = 56) and followed for up to 7 years with annual neuropsychological and other examinations. METHODS: Study patients were diagnosed using established criteria for dementia and were administered cognitive screening, functional screening, and neuropsychological measures. Baseline dementia severity was rated using the Clinical Dementia Rating Scale. Random effects modeling was used to examine rates of decline and to compare the rates of decline in the three groups. RESULTS: Both patients with VaD and those with AD showed significant cognitive and functional decline during follow-up; patients with VaD declined at a slower rate than patients with AD; and patients diagnosed with SWD at baseline did not show cognitive or functional decline during follow-up. CONCLUSIONS: Patients with VaD decline at a slower rate than patients with AD. Patients who do not meet criteria for dementia soon after stroke may not be at high risk for developing dementia. Future studies are needed to follow VaD patients with longitudinal, specialized MR protocols, concurrent neuropsychological examinations, and neuropathologic examination to determine possible neuroimaging predictors of progressive cognitive and functional decline and to assess the contribution of Alzheimer's pathology to decline in patients diagnosed with VaD.     

Impact of applying NINDS-AIREN criteria of probable vascular dementia to clinical and radiological characteristics of a stroke cohort with dementia

BACKGROUND: There are no data concerning the relative representation of clinical vascular risk factors and radiological lesions in cases that have been ruled in and ruled out for probable vascular dementia (VaD) according to NINDS-AIREN criteria. METHODS: Three months after their index stroke, a psychiatrist interviewed patients and made a diagnosis of VaD according to both DSM-IV and NINDS-AIREN criteria for probable VaD. Patients who fulfilled the DSM-IV criteria for VaD were divided into two groups: those who were ruled in and ruled out according to NINDS-AIREN criteria as probable VaD. Demographic characteristics, vascular risk factors, clinical features of the index stroke and radiological findings were then compared between the two groups. RESULTS: Of the 297 patients screened, 56 (18.8%) had a DSM-IV diagnosis of dementia. Among these demented patients, 55 (98.2%) and 22 (39.3%) fulfilled DSM-IV and NINDS-AIREN diagnosis of VaD, respectively. The concordance and level of agreement (kappa statistic) between DSM-IV and NINDS-AIREN diagnoses were 40% and 0.02, respectively. Reasons of failure to meet NINDS-AIREN criteria included the lack of temporal relationship between dementia and stroke (n = 20), the absence of focal neurological signs and/or radiological evidence of stroke (n = 6) and both of the above (n = 7). There was no significant difference between the above two groups in terms of demographic data, features of index stroke, vascular risk factors and CT scan findings, except that leukoaraiosis (p = 0.021) and bilateral lesions (p = 0.015) were more frequent in subjects diagnosed according to NINDS-AIREN criteria of probable VaD. The difference between these two groups with respect to the number of lesions was borderline for significance (p = 0.052). CONCLUSIONS: The use of NINDS-AIREN criteria for VaD for case selection in poststroke dementia research may exclude a number of subjects with VaD.     

Predictive accuracy of MCI subtypes for Alzheimer's disease and vascular dementia in subjects with mild cognitive impairment: a 2-year follow-up study

AIM: The aim of this study was to investigate the prognostic accuracy of different subtypes of mild cognitive impairment (MCI): amnestic MCI, multiple domain MCI, and single non-memory domain MCI, for the development of Alzheimer's dementia (AD) and vascular dementia (VaD). PATIENTS: Nondemented patients from a memory clinic cohort (n = 118), and a stroke cohort (n = 80, older than 55 years and with a cognitive impairment). RESULTS: 'Multiple domain MCI' had the highest sensitivity for both AD (80.8%) and VaD (100%), and 'amnestic MCI' had the highest specificity (85.9% for AD, 100% for VaD). The positive predictive value was low for all subtypes (0.0-32.7%), whereas the negative predictive value was high (72.8-100%). DISCUSSION: The subtype 'multiple domain MCI' has high sensitivity in identifying people at risk for developing AD or VaD. The predictive accuracy of the MCI subtypes was similar for both AD and VaD.     

Treatment of vascular dementia--evidence from clinical trials with cholinesterase inhibitors

Cerebrovascular disease (CVD), as well as secondary ischemic brain injury from cardiovascular disease, are common causes of dementia and cognitive decline in the elderly. In addition, CVD frequently contributes to cognitive loss in patients with Alzheimer's disease (AD). Progress in understanding the pathogenetic mechanism involved in vascular cognitive impairment (VCI) and vascular dementia (VaD) has resulted in promising treatments of these conditions. Cholinergic deficits in VaD are due to ischemia of basal forebrain nuclei and of cholinergic pathways and can be treated with the use of the cholinesterase inhibitor agents used in AD. Controlled clinical trials with donepezil, galantamine and rivastigmine in VaD, as well as in patients with AD plus CVD, have demonstrated improvements in cognition, behavior and activities of daily living.     

Apolipoprotein E phenotypes in demented and cognitively impaired patients with and without cerebrovascular disease

Controversy exists regarding the apolipoprotein E (ApoE) epsilon4 allele association with vascular dementia (VaD), ranging from increased epsilon4 frequency, similar to that found for Alzheimer's disease (AD), to no association between the epsilon4 allele and VaD. To clarify further the relationship between ApoE alleles polymorphism and cerebrovascular disease (CVD) in demented and cognitively impaired patients, we examined the ApoE phenotypes in a sample of 280 patients: 155 with AD, 21 with VaD, 32 with mixed dementia (MD), 45 with mild cognitive impairment (MCI) but without CVD, and 27 in which vascular disease was the most probable cause of cognitive decline [vascular mild cognitive impairment (VMCI)]. Our results show that the frequency of the ApoE epsilon4 allele in patients over 70 years old with clinically diagnosed VaD and VMCI does not differ significantly from that of controls. In contrast, ApoE epsilon4 allele-bearing individuals had greater risk of having late-onset AD (OR = 8.8; 95% CI 3.7-21.0), or non-vascular cognitive impairment (OR = 7.0; 95% CI 2.5-19.0).     

Vascular aspects of cognitive impairment and dementia

Hypertension and stroke are highly prevalent risk factors for cognitive impairment and dementia. Alzheimer''s disease (AD) and vascular dementia (VaD) are the most common forms of dementia, and both conditions are preceded by a stage of cognitive impairment. Stroke is a major risk factor for the development of vascular cognitive impairment (VCI) and VaD; however, stroke may also predispose to AD. Hypertension is a major risk factor for stroke, thus linking hypertension to VCI and VaD, but hypertension is also an important risk factor for AD. Reducing these two major, but modifiable, risk factors—hypertension and stroke—could be a successful strategy for reducing the public health burden of cognitive impairment and dementia. Intake of long-chain omega-3 polyunsaturated fatty acids (LC-n3-FA) and the manipulation of factors involved in the renin–angiotensin system (e.g. angiotensin II or angiotensin-converting enzyme) have been shown to reduce the risk of developing hypertension and stroke, thereby reducing dementia risk. This paper will review the research conducted on the relationship between hypertension, stroke, and dementia and also on the impact of LC-n3-FA or antihypertensive treatments on risk factors for VCI, VaD, and AD.     

Therapeutic issues in vascular dementia: studies, designs and approaches

Vascular dementia (VaD) is a heterogeneous disorder resulting from various cerebrovascular diseases (CVD) causing cognitive impairment that reflects severity and location of damage. Epidemiological studies suggest VaD is the second commonest cause of dementia, but autopsy series report that pure VaD is infrequent, while combined CVD and Alzheimer's Disease(AD) is likely the commonest pathological-dementia correlate. Both diseases share vascular risk factors and benefit from their treatment. The most widely used diagnostic criteria for VaD are highly specific but not sensitive. Vascular Cognitive Impairment (VCI) is a dynamic, evolving concept that embraces VaD, Vascular Cognitive Impairment No Dementia (VCIND) and mixed AD and CVD. Clinical trials to date have focused on probable and possible VaD with beneficial effects evident for different drug classes, including cholinergic agents and NMDA agonists. Limitations have included use of cognitive tools suitable for AD that are insensitive to executive dysfunction. Disease heterogeneity has not been adequately controlled and subtypes require further study. Diagnostic VaD criteria now 13 years old need updating. More homogeneous subgroups need to be defined and therapeutically targeted to improve cognitive-behavioural outcomes including optimal control of vascular risk factors. More sensitive testing of executive function outlined in recent VCI Harmonization criteria and longer trial duration are needed to discern meaningful effects. Imaging criteria must be well-defined, with centralized review and standardized protocols. Serial scanning with quantification of tissue atrophy and lesion burden is becoming feasible, and cognitive interventions, including rehabilitation pharmacotherapy, with drugs strategically coupled to cognitive -behavioural treatments, hold promise and need further development.