Cerebral microbleeds are hypothesized downstream markers of brain damage caused by vascular and amyloid pathologic mechanisms. To date, whether their presence is associated with cognitive deterioration in the general population remains unclear.To determine whether microbleeds, and more specifically microbleed count and location, are associated with an increased risk for cognitive impairment and dementia in the general population.The Rotterdam Study, a prospective population-based study set in the general community, assessed the presence, number, and location of microbleeds at baseline (August 2005 to December 2011) on magnetic resonance imaging studies of the brain in 4841 participants 45 years or older. Participants underwent neuropsychological testing at 2 points a mean (SD) of 5.9 (0.6) years apart and were followed up for incident dementia throughout the study period until January 1, 2013. The association of microbleeds with cognitive decline and dementia was studied using multiple linear regression, linear mixed-effects modeling, and Cox proportional hazards.Cerebral microbleed presence, location, and number.Cognitive decline measured by a decrease in neuropsychological test battery scores (Mini-Mental State Examination, Letter Digit Substitution Task, Word Fluency Test, Stroop test, 15-word Verbal Learning Test, and Purdue Pegboard Test) and compound scores (eg, G factor, executive function, information processing speed, memory, motor speed) and dementia.In total, 3257 participants (1758 women [54.7%]; mean [SD] age, 59.6 [7.8] years) underwent baseline and follow-up cognitive testing. Microbleed prevalence was 15.3% (median [interquartile range] count, 1 [1-88]). The presence of more than 4 microbleeds was associated with cognitive decline. Lobar (with or without cerebellar) microbleeds were associated with a decline in executive functions (mean difference in z score, -0.31; 95% CI, -0.51 to -0.11; P = .003), information processing (mean difference in z score, -0.44; 95% CI, -0.65 to -0.22; P < .001), and memory function (mean difference in z score, -0.34; 95% CI, -0.64 to -0.03; P = .03), whereas microbleeds in other brain regions were associated with a decline in information processing and motor speed (mean difference in z score, -0.61; 95% CI, -1.05 to -0.17; P = .007). After a mean (SD) follow-up of 4.8 (1.4) years, 72 participants developed dementia, of whom 53 had Alzheimer dementia. The presence of microbleeds was associated with an increased risk for dementia after adjustment for age, sex, and educational level (hazard ratio, 2.02; 95% CI, 1.25-3.24), including Alzheimer dementia (hazard ratio, 2.10; 95% CI, 1.21-3.64).In the general population, a high microbleed count was associated with an increased risk for cognitive deterioration and dementia. Microbleeds thus mark the presence of diffuse vascular and neurodegenerative brain damage.

Stroke is a brain disease that occurs when blood flow stops, resulting in reduced oxygen supply to neurons. Stroke occurs at any time and at any age, but increases after the age of 55. It is the second leading cause of death and the third leading cause of disability-adjusted, life-years. The pathophysiology of ischemic stroke is complex and recent molecular, cellular, and animal models and postmortem brain studies have revealed that multiple cellular changes have been implicated, including oxidative stress/mitochondrial dysfunction, inflammatory responses, micro RNA alterations, and marked changes in brain proteins. These cellular changes provide new information for developing therapeutic strategies for ischemic stroke treatment. Research also revealed that stroke increases with a number of modifiable factors and most strokes can be prevented and/or controlled through pharmacological or surgical interventions and lifestyle changes. Ischemic stroke is the major risk factor for vascular dementia and Alzheimer's disease. This review summarizes the latest research findings on stroke, including causal factors and molecular links between stroke and vascular disease/Alzheimer's disease.

Clinical criteria for the diagnosis of Alzheimer's disease include insidious onset and progressive impairment of memory and other cognitive functions. There are no motor, sensory, or coordination deficits early in the disease. The diagnosis cannot be determined by laboratory tests. These tests are important primarily in identifying other possible causes of dementia that must be excluded before the diagnosis of Alzheimer's disease may be made with confidence. Neuropsychological tests provide confirmatory evidence of the diagnosis of dementia and help to assess the course and response to therapy. The criteria proposed are intended to serve as a guide for the diagnosis of probable, possible, and definite Alzheimer's disease; these criteria will be revised as more definitive information become available.

Vascular dementia is one of the most common causes of dementia after Alzheimer's disease, causing around 15% of cases. However, unlike Alzheimer's disease, there are no licensed treatments for vascular dementia. Progress in the specialty has been difficult because of uncertainties over disease classification and diagnostic criteria, controversy over the exact nature of the relation between cerebrovascular pathology and cognitive impairment, and the paucity of identifiable tractable treatment targets. Although there is an established relation between vascular and degenerative Alzheimer's pathology, the mechanistic link between the two has not yet been identified. This Series paper critiques some of the key areas and controversies, summarises treatment trials so far, and makes suggestions for what progress is needed to advance our understanding of pathogenesis and thus maximise opportunities for the search for new and effective management approaches. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Dementia with Lewy Bodies (DLB) Consortium has refined its recommendations about the clinical and pathologic diagnosis of DLB, updating the previous report, which has been in widespread use for the last decade. The revised DLB consensus criteria now distinguish clearly between clinical features and diagnostic biomarkers, and give guidance about optimal methods to establish and interpret these. Substantial new information has been incorporated about previously reported aspects of DLB, with increased diagnostic weighting given to REM sleep behavior disorder and iodine-metaiodobenzylguanidine (MIBG) myocardial scintigraphy. The diagnostic role of other neuroimaging, electrophysiologic, and laboratory investigations is also described. Minor modifications to pathologic methods and criteria are recommended to take account of Alzheimer disease neuropathologic change, to add previously omitted Lewy-related pathology categories, and to include assessments for substantia nigra neuronal loss. Recommendations about clinical management are largely based upon expert opinion since randomized controlled trials in DLB are few. Substantial progress has been made since the previous report in the detection and recognition of DLB as a common and important clinical disorder. During that period it has been incorporated into DSM-5, as major neurocognitive disorder with Lewy bodies. There remains a pressing need to understand the underlying neurobiology and pathophysiology of DLB, to develop and deliver clinical trials with both symptomatic and disease-modifying agents, and to help patients and carers worldwide to inform themselves about the disease, its prognosis, best available treatments, ongoing research, and how to get adequate support.Copyright © 2017 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Neurology.

The construct of mild cognitive impairment (MCI) has evolved over the past 10 years since the publication of the new MCI definition at the Key Symposium in 2003, but the core criteria have remained unchanged. The construct has been extensively used worldwide, both in clinical and in research settings, to define the grey area between intact cognitive functioning and clinical dementia. A rich set of data regarding occurrence, risk factors and progression of MCI has been generated. Discrepancies between studies can be mostly explained by differences in the operationalization of the criteria, differences in the setting where the criteria have been applied, selection of subjects and length of follow-up in longitudinal studies. Major controversial issues that remain to be further explored are algorithmic versus clinical classification, reliability of clinical judgment, temporal changes in cognitive performances and predictivity of putative biomarkers. Some suggestions to further develop the MCI construct include the tailoring of the clinical criteria to specific populations and to specific contexts. The addition of biomarkers to the clinical phenotypes is promising but requires deeper investigation. Translation of findings from the specialty clinic to the population setting, although challenging, will enhance uniformity of outcomes. More longitudinal population-based studies on cognitive ageing and MCI need to be performed to clarify all these issues.© 2014 The Association for the Publication of the Journal of Internal Medicine.

MRI is more sensitive than CT for detection of age-related white matter changes (ARWMC). Most rating scales estimate the degree and distribution of ARWMC either on CT or on MRI, and they differ in many aspects. This makes it difficult to compare CT and MRI studies. To be able to study the evolution and possible effect of drug treatment on ARWMC in large patient samples, it is necessary to have a rating scale constructed for both MRI and CT. We have developed and evaluated a new scale and studied ARWMC in a large number of patients examined with both MRI and CT.Seventy-seven patients with ARWMC on either CT or MRI were recruited and a complementary examination (MRI or CT) performed. The patients came from 4 centers in Europe, and the scans were rated by 4 raters on 1 occasion with the new ARWMC rating scale. The interrater reliability was evaluated by using kappa statistics. The degree and distribution of ARWMC in CT and MRI scans were compared in different brain areas.Interrater reliability was good for MRI (kappa=0.67) and moderate for CT (kappa=0.48). MRI was superior in detection of small ARWMC, whereas larger lesions were detected equally well with both CT and MRI. In the parieto-occipital and infratentorial areas, MRI detected significantly more ARWMC than did CT. In the frontal area and basal ganglia, no differences between modalities were found. When a fluid-attenuated inversion recovery sequence was used, MRI detected significantly more lesions than CT in frontal and parieto-occipital areas. No differences were found in basal ganglia and infratentorial areas.We present a new ARWMC scale applicable to both CT and MRI that has almost equal sensitivity, except for certain regions. The interrater reliability was slightly better for MRI, as was the detectability of small lesions.

The relative contributions of vascular and degenerative pathology to dementia are unknown. We aim to quantify the proportion of dementia explained by potentially preventable vascular lesions.We systematically searched for population-based cohorts before February 2017 reporting clinicopathological data for individuals with and without dementia. We calculated the summary proportion and absolute risk of dementia comparing subjects with and without the pathology.We identified 10 studies comprising 2856 subjects. Vascular-type pathology and mixed pathology are respectively two and three times more likely in demented patients. The summary proportion of dementia is 77%-86% in subjects with mixed degenerative and vascular pathology and 45% in subjects with pure Alzheimer-type pathology.Patients with mixed pathologies have nearly twice the incremental risk of dementia compared with patients with only Alzheimer-type lesions. Consequently, many cases of dementia could be prevented or delayed by targeting the vascular component.Copyright © 2017 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

Cerebrovascular deposition of beta-amyloid (cerebral amyloid angiopathy [CAA]) is a major cause of hemorrhagic stroke and a likely contributor to vascular cognitive impairment. We evaluated positron emission tomographic imaging with the beta-amyloid-binding compound Pittsburgh Compound B (PiB) as a potential noninvasive method for detection of CAA. We hypothesized that amyloid deposition would be observed with PiB in CAA, and based on the occipital predilection of CAA pathology and associated hemorrhages, that specific PiB retention would be disproportionately greater in occipital lobes.We compared specific cortical PiB retention in 6 nondemented subjects diagnosed with probable CAA with 15 healthy control subjects and 9 patients with probable Alzheimer's disease (AD).All CAA and AD subjects were PiB-positive, both by distribution volume ratio measurements and by visual inspection of positron emission tomographic images. Global cortical PiB retention was significantly increased in CAA (distribution volume ratio 1.18 +/- 0.06) relative to healthy control subjects (1.04 +/- 0.10; p = 0.0009), but was lower in CAA than in AD subjects (1.41 +/- 0.17; p = 0.002). The occipital-to-global PiB ratio, however, was significantly greater in CAA than in AD subjects (0.99 +/- 0.07 vs 0.86 +/- 0.05; p = 0.003).We conclude that PiB-positron emission tomography can detect cerebrovascular beta-amyloid and may serve as a method for identifying the extent of CAA in living subjects.

We sought to determine the incidence and associations of lobar microbleeds (LMBs) in a longitudinal cohort with (11)C-Pittsburgh compound B (PiB) PET imaging.One hundred seventy-four participants from the observational Australian Imaging, Biomarkers and Lifestyle Study of Ageing (97 with normal cognition [NC], 37 with mild cognitive impairment [MCI], and 40 with Alzheimer disease [AD] dementia) were assessed at 3 time points over 3 years with 3-tesla susceptibility-weighted MRI and (11)C-PiB PET. MRIs were inspected for microbleeds, siderosis, infarction, and white matter hyperintensity severity, blind to clinical and PiB findings. Neocortical PiB standardized uptake value ratio, normalized to cerebellar cortex, was dichotomized as positive or negative (PiB+/-, standardized uptake value ratio >1.5). Annualized LMB incidence was calculated, and logistic regression was used to determine the association of incident LMBs with PiB, APOE ε4+ status, and cerebrovascular disease.LMBs were present in 18.6% of NC, 24.3% of MCI, and 40% of AD participants (p < 0.05 vs NC). LMB incidence was 0.2 ± 0.6 per year in NC participants, 0.2 ± 0.5 in MCI, and 0.7 ± 1.4 in AD (p < 0.03 vs NC) and was 6-fold higher in PiB+ than PiB-NC. Incident LMBs were associated with age, APOE ε4+, PiB+, and baseline LMBs. Incidence of multiple LMBs was also associated with lacunar infarction and white matter hyperintensity severity.Older age, baseline LMBs, higher β-amyloid burden, and concomitant cerebrovascular disease may all confer higher risk of incident LMBs. This should be considered when designing protocols for amyloid-modifying clinical trials.

Cerebral microbleeds (CMBs) are increasingly recognised neuroimaging findings in individuals with cerebrovascular disease and dementia, and in normal ageing. There has been substantial progress in the understanding of CMBs in recent years, particularly in the development of newer MRI methods for the detection of CMBs and the application of these techniques to population-based samples of elderly people. In this Review, we focus on these recent developments and their effects on two main questions: how CMBs are detected, and how CMBs should be interpreted. The number of CMBs detected depends on MRI characteristics, such as pulse sequence, sequence parameters, spatial resolution, magnetic field strength, and image post-processing, emphasising the importance of taking into account MRI technique in the interpretation of study results. Recent investigations with sensitive MRI techniques have indicated a high prevalence of CMBs in community-dwelling elderly people. We propose a procedural guide for identification of CMBs and suggest possible future approaches for elucidating the role of these common lesions as markers for, and contributors to, small-vessel brain disease.

Vascular cognitive impairment causes significant disability in the elderly and is common following ischaemic stroke. Although the underlying mechanisms and prognostic factors remain unclear, small vessel diseases are known to contribute. Cerebral microbleeds (CMBs) are a magnetic resonance imaging (MRI) manifestation of small vessel diseases and may contribute to vascular cognitive impairment, particularly frontal-executive functions. We hypothesized that baseline CMBs would predict long-term cognitive outcome, specifically frontal-executive function.A cohort of consecutive patients found to have CMBs when first referred to a stroke clinic, together with a CMB-free control group matched for age, gender and clinicoradiological characteristics, were invited for follow-up cognitive assessment a median of 5.7 years later. MRI and detailed cognitive assessment (including current intellectual function, verbal memory, visual memory, naming skills, perceptual functions, frontal-executive functions; and speed and attention) were performed at baseline and follow-up. Patients were classified (blinded to MRI and clinical data) as impaired or unimpaired in each domain using predefined criteria. We compared the prevalence of cognitive impairments in each domain at baseline and follow-up and investigated clinical and radiological predictors [including baseline CMBs and white matter changes (WMCs)] of frontal-executive cognitive impairment.Of the original cohort of 55 patients, 13 died without follow-up. Twenty-six of the surviving patients (9 with, 17 without baseline CMBs) agreed to follow-up neuropsychological assessment; 21 of these patients had a repeat MRI scan. The median number of cognitive domains impaired increased, regardless of the presence of baseline CMBs (with baseline CMBs: median 3, range 0-5 at follow-up vs. median 2, range 0-2 at baseline, p = 0.016; without CMBs: median 1.0, range 0-5 at follow-up vs. median 0, range 0-5 at baseline, p = 0.035). Frontal-executive impairment at follow-up was more prevalent in patients with baseline CMBs than in those without (78 vs. 29%, p = 0.038). The presence of baseline CMBs predicted frontal-executive impairment at follow-up (OR 8.40, 95% CI 1.27-55.39, p = 0.027). Fifty percent of patients with CMBs versus 8% of patients without baseline CMBs developed new CMBs (p = 0.047). The severity of WMCs increased; the difference was statistically significant only in patients without baseline CMBs (p = 0.027). There were no new cortical infarcts.In stroke clinic patients, CMBs are consistently associated with frontal-executive impairment; baseline CMBs are associated with frontal-executive impairment at follow-up after 5.7 years. The presence of CMBs has prognostic relevance for long-term cognitive outcome in stroke clinic patients, and may help to optimally target preventive strategies in individuals at highest risk of cognitive decline.Copyright © 2012 S. Karger AG, Basel.

Cognitive decline is one of the clinical hallmarks of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a cerebrovascular disease caused by NOTCH3 mutations. In this 7-year follow-up study, we aimed to determine whether there are associations between the different radiologic hallmarks in CADASIL and decline in specific cognitive domains.Twenty-five NOTCH3 mutation carriers and 13 controls had standardized neuropsychological testing and MRI examinations at baseline and after a follow-up of 7 years. To identify longitudinal associations between MRI abnormalities and cognitive decline, correlation analysis was used.At follow-up, mutation carriers showed a decline in global cognitive function (CAMCOG, p < 0.01) and in the cognitive domains language, memory, and executive function, compared to controls. Cognitive decline, especially executive dysfunction, was associated with increase in lacunar infarcts, microbleeds, and ventricular volume. In contrast, WMHs and brain atrophy were not associated with cognitive decline.Increase in lacunar infarcts, microbleeds, and ventricular volume, but not white matter lesions or atrophy, are associated with cognitive decline in the process of CADASIL in younger-aged, mildly affected patients with CADASIL.

Despite the well-documented relationship between lobar cerebral microbleeds (lCMB) and Alzheimer's disease (AD), there is limited knowledge about the role of lCMB in AD pathology.To understand the nature of this relationship, we investigated the association between lCMB, amyloid load, perfusion, and metabolism.Participants with AD, mild cognitive impairment (MCI), and healthy controls were recruited and scanned with 11C-Pittsburg-Compound B (PiB), Fluorodeoxyglucose (FDG) PET, and susceptibility-weighted MRI. Early PiB-PET frames were used to estimate perfusion. The association between lCMB and PET uptake in each anatomical lobe was measured using multiple regression models.The presence of lCMB predicted increased total (p < 0.001) and regional (p = 0.0002) PiB uptake, as well as decreased cerebral perfusion (p = 0.03). Cases with lCMB had hypometabolism in their temporal lobe (p = 0.04).There are significant relationships between lCMBs and various markers of AD pathology. lCMB has a spatial association with Aβ load and a complex effect on perfusion and metabolism.