Baseline differences between vascular cognitive impairment no dementia reverters and non-reverters

White matter hyperintensities and longitudinal cognitive decline in cognitively normal populations and across diagnostic categories: A meta-analysis, systematic review, and recommendations for future study harmonization

INTRODUCTION

The primary aim of this paper is to improve the clinical interpretation of white matter hyperintensities (WMHs) and provide an overarching summary of methodological approaches, allowing researchers to design future studies targeting current knowledge gaps.

METHODS

A meta-analysis and systematic review was performed investigating associations between baseline WMHs and longitudinal cognitive outcomes in cognitively normal populations, and populations with mild cognitive impairment (MCI), Alzheimer's disease (AD), and stroke.

RESULTS

Baseline WMHs increase the risk of cognitive impairment and dementia across diagnostic categories and most consistently in MCI and post-stroke populations. Apolipoprotein E (APOE) genotype and domain-specific cognitive changes relating to strategic anatomical locations, such as frontal WMH and executive decline, represent important considerations. Meta-analysis reliability was assessed using multiple methods of estimation, and results suggest that heterogeneity in study design and reporting remains a significant barrier.

DISCUSSION

Recommendations and future directions for study of WMHs are provided to improve cross-study comparison and translation of research into consistent clinical interpretation.

Development and validation of a clinical model (DREAM-LDL) for post-stroke cognitive impairment at 6 months

Introduction: This multicenter, retrospective study assessed the prevalence of post-stroke cognitive impairment (PSCI) 6 months after acute ischemic stroke (AIS) and its risk factors to build a bedside early predictive model for PSCI using the Montreal Cognitive Assessment (MoCA).

Methods: Records of consecutive patients with AIS treated at 4 stroke centers in Shanghai had MoCA assessments within 2 weeks after AIS onset and 6 months later were reviewed. Prevalence of PSCI (MoCA<22) was calculated and risk factors were identified by multivariate logistic regression analysis. The modeling and validation and identified risk factors were included in a predictive model using multivariate regression.

Results: There were 383 patients included and prevalence of PSCI 6 months after AIS was 34.2%, significantly lower than prevalence of patients with acute cognitive impairment (49.6%). Aging, less education, higher glucose level and severe stroke were PSCI risk factors, while level of low-density lipoprotein cholesterol (LDL-C) had a paradox effect on the risk of PSCI. 40.0% of the patients with cognitive impairment at acute phase reverted to normal, and patients with LDL-C 1.8-2.5 mmol/L were more likely to revert. The predictive model we built, DREAM-LDL (Diabetes [fasting blood glucose level], Rating [NIHSS], level of Education, Age, baseline MoCA and LDL-C level), had an AUROC of 0.93 for predicting PSCI at 6 months.

Conclusion: PSCI was common among AIS patients 6 months after AIS. We provided a practical tool to predict PSCI based on MoCA and risk factors present during acute phase of AIS.

Cerebral Microbleeds and White Matter Hyperintensities are Associated with Cognitive Decline in an Asian Memory Clinic Study

BACKGROUND

Cerebral Small Vessel Disease (SVD); lacunes, Cerebral Microbleeds (CMBs), and White Matter Hyperintensities (WMH) have a vital role in cognitive impairment and dementia. SVD in lobar location is related to cerebral amyloid angiopathy, whereas SVD in a deep location with hypertensive arteriopathy. It remains unclear how different locations of SVD affect long-term cognitive decline. The present study aimed to analyse the association between different locations and severity of SVD with global and domain-specific cognitive decline over the follow-up interval of 3 years.

METHODS

We studied 428 participants who had performed MRI scans at baseline and at least 3 neuropsychological assessments. Locations of lacunes and CMBs were categorized into strictly lobar, strictly deep and mixed-location, WMH volume into anterior and posterior. The National Institute of Neurological Disorders and Stroke-Canadian Stroke Network Harmonization Neuropsychological Battery was used to assess cognitive function. To analyse the association between baseline location and severity of SVD with cognitive decline, linear regression models with generalized estimated equations were constructed to calculate the mean difference, 95% confidence interval and two-way interaction factor between time and SVD.

RESULTS

Increased numbers of baseline CMBs were associated with a decline in global cognition as well as a decline in executive function and memory domains. Location-specific analysis showed similar results with strictly lobar CMBs. There was no association with strictly deep and mixed-location CMBs with cognitive decline. Baseline WMH volume was associated with a decline in global cognition, executive function and memory. Similar results were obtained with anterior and posterior WMH volumes. Lacunes and their locations were not associated with cognitive decline.

CONCLUSION

Strictly lobar CMBs, as well as WMH volume in anterior and posterior regions, were associated with cognitive decline. Future research focuses are warranted to evaluate interventions that may prevent cognitive decline related to SVD.

A Systematic Review of the Definitions of Vascular Cognitive Impairment, No Dementia in Cohort Studies

BACKGROUND/AIMS

No set operational criteria for vascular cognitive impairment, no dementia (VCI-ND) have yet been established. The aim of this study is to undertake a systematic review to compare definitions of VCI-ND that have been used in cohort studies.

METHODS

Medline, PsycINFO and Embase were searched from inception to October 13, 2015. Initially, 3,142 records were screened, and 30 were included in this review.

RESULTS

No single set of criteria for defining VCI-ND was identified. VCI-ND was broadly defined as an absence of dementia, cognitive impairment in at least one cognitive domain with signs of vascular involvement, and intact activities of daily living.

CONCLUSION

Defining criteria will enable individuals with VCI-ND to be efficiently compared across cohort studies to more accurately determine the prevalence and risk of dementia.

White matter hyperintensity volume predicts persistent cognitive impairment in transient ischemic attack and minor stroke

Background Temporary and permanent cognitive changes following transient ischemic attack/minor stroke have been described previously. It is unknown if persisting cognitive deficits in these patients are correlated with acute infarction identified using magnetic resonance imaging. Aims We tested the hypothesis that persistent cognitive impairment after transient ischemic attack/minor stroke can be predicted by the volume of diffusion-weighted imaging lesions. Methods Acute transient ischemic attack/minor stroke (NIH stroke scale score ≤ 3) patients were prospectively recruited within 72 h of onset. Patients underwent Montreal cognitive assessment and magnetic resonance imaging, including diffusion-weighted imaging and Fluid-Attenuated Inverse Recovery sequences, at baseline, days 7 and 30. Cognitive testing was repeated at day 90. Diffusion-weighted imaging lesion and Fluid-Attenuated Inverse Recovery chronic white matter hyperintensity volumes were measured planimetrically. Cognitive impairment was defined a priori as Montreal cognitive assessment score < 26. Results One hundred fifteen patients were imaged at a median (inter-quartile range) of 24.0 (16.6) h after onset. Acute ischemic lesions were present in 91 (79%) patients. Cognitive impairment rates were similar in patients with (47/91, 52%) and without diffusion-weighted imaging lesions (13/24, 54%; p = 0.83). Although linear regression indicated no relationship between acute diffusion-weighted imaging lesion volume and day 30 Montreal cognitive assessment scores (β = -0.163, [-2.243, 0.334], p = 0.144), white matter hyperintensity volumes at baseline were predictive of persistent cognitive deficits after 30 days (β = 2.24, [1.956, 45.369], p = 0.005). Conclusions In most transient ischemic attack/minor stroke patients who suffer acute cognitive impairment post event, deficits are temporary. Deficits after 30 days of onset are correlated with chronic white matter hyperintensity, suggesting subclinical cognitive impairment and/or impaired ability to compensate for the effects of acute ischemic infarcts.

Post-stroke memory impairment among patients with vascular mild cognitive impairment

Background

The American Stroke Association/American Heart Association recommended the criteria for diagnosis of vascular cognitive impairment and memory impairment (MI) is a feature in the classification of vascular mild cognitive impairment (VaMCI). VaMCI patients with MI may differ in terms of infarct location or demographic features, so we evaluated the clinical characteristics associated with MI in patients with VaMCI.

Methods

A prospective multicenter study enrolled 353 acute ischemic stroke patients who underwent evaluation using the Korean Vascular Cognitive Impairment Harmonization Standard Neuropsychological Protocol at three months after onset. The association between MI and demographic features, stroke risk factors, and infarct location was assessed.

Results

VaMCI was diagnosed in 141 patients, and 58 (41.1%) exhibited MI. Proportions of men and of left side infarcts were higher in VaMCI with MI than those without (75.9 vs. 57.8%, P = 0.03, 66.7 vs. 47%, P = 0.02). Multiple logistic analyses revealed that male sex (odds ratio [OR] 3.07, 95% confidence interval [95% CI] 1.12-8.42), left-side infarcts (OR 3.14, 95% CI 1.37-7.20), and basal ganglia/internal capsule infarcts (OR 4.53, 95% CI 1.55-13.22) were associated with MI after adjusting other demographic variables, vascular risk factors, and subtypes of stroke.

Conclusions

MI is associated with sex and infarct location in VaMCI patients.

Factors associated with cognition recovery among elders with mild cognitive impairment in Korea

BACKGROUND

Of elders with mild cognitive impairment, around half recover their cognitive function at some point in time. However, very little is known about the factors that influence their cognitive change towards recovery.

AIM

This study evaluated the role of depression, instrumental activity of daily living and sleep quality as they affect cognition recovery among community-dwelling elders.

METHODS

The study follows a longitudinal comparative research design using secondary data analysis. Community-dwelling elders with mild cognitive impairment were assessed twice with a 1-year interval to assess their levels of cognition. Adult participants were drawn from those who visited a community health centre, were aged 65 or over and who were assessed as having MCI.

RESULTS

Those with mild cognitive impairment when compared with the normal cognition group were more likely to be younger, have more education, living with their spouses and had better cognitive function at baseline assessment than other participants. Predictors for cognitive recovery among elders with mild cognitive impairment were age, depression and cognitive function at baseline assessment.

LIMITATIONS

Participants included only those who visit a community health centre in an urban area of Korea, so the findings may not be applicable to other elders with less mobility or who live in rural areas.

IMPLICATIONS FOR NURSING AND HEALTH POLICY

With the understanding that cognitive function and depression predict the recovery of mild cognitive function, nurses might be able to identify and target those older adults who are likely to achieve recovery of cognitive function. Additionally, health policy options, as suggested by the study as having the potential to improve mild cognitive impairment recovery, could include public education strategies.

The effects of cerebral white matter changes on cardiovascular responses to cognitive and physical activity in a stroke population

Autonomic nervous system (ANS) control may be disrupted by cerebrovascular disease. We investigated the relationship between alterations in white matter integrity and regulation of the ANS in 23 participants who sustained a stroke within 5 years. These participants underwent diffusion tensor imaging, and fractional anisotropy values were calculated (DTI-FA) for each hemisphere and lobe. Cognitive and physical exertion tasks were performed while recording an electrocardiogram. Respiratory sinus arrhythmia (RSA) decreased more during a verbal fluency task with lower left hemisphere DTI-FA. Further, the physical stressor yielded decreases in RSA with lower frontal DTI-FA and higher temporal lobe DTI-FA, p < .05 (perhaps a release effect on the central autonomic network). Decrements in ANS regulation may have functional consequences that alter behavior, as well as potentially increasing the risk for further vascular disease.

Absence of Cerebral Microbleeds Predicts Reversion of Vascular ‘Cognitive Impairment No Dementia’ in Stroke

Background

Cerebral microbleeds may contribute to cognitive deficits in stroke. Cognitive impairment that does not meet the criteria for dementia (cognitive impairment no dementia) is common in stroke, and patients with such impairment can revert to normal cognition.

Aims and hypothesis

This study examined the association between cerebral microbleeds and the reversion of cognitive impairment no dementia.

Method

A total of 328 Chinese patients with acute ischemic stroke admitted to the acute stroke unit of a university-affiliated regional hospital in Hong Kong participated in the study. All subjects were assessed for cognitive impairment no dementia with a neuropsychological test battery at three- and 15 months following the index stroke. Of the 180 patients with cognitive impairment no dementia at three-months poststroke, 143 (79·4%) attended the 15-month follow-up. Twenty-nine subjects had reverted from cognitive impairment no dementia to normal cognitive status (reverters), 98 were nonreverters and 16 had progressed to dementia.

Results

In univariate analysis, the reverters were found to be younger, less likely to have hypertension and cerebral microbleeds, and to have smaller white matter hyperintensity volumes. In multivariate analysis, the absence of cerebral microbleeds remained an independent predictor of reversion with an odds ratio of 4·3. Absence of deep cerebral microbleeds predicted the reversion of the language domain, whereas the absence of lobar cerebral microbleeds predicted the reversion of the visuomotor speed domain.

Conclusions

The results suggest that the absence of cerebral microbleeds may be associated with a higher likelihood of a reversible cognitive impairment in stroke patients. The mechanism of how this occurs is not well understood.

Differential patterns of cognitive decline in anterior and posterior white matter hyperintensity progression

BACKGROUND AND PURPOSE

White matter hyperintensities (WMHs) found on brain MRI in elderly individuals are largely thought to be due to microvascular disease, and its progression has been associated with cognitive decline. The present study sought to determine patterns of cognitive decline associated with anterior and posterior WMH progression.

METHODS

Subjects included 110 normal controls, aged >or=60 years, who were participants in the Duke Neurocognitive Outcomes of Depression in the Elderly study. All subjects had comprehensive cognitive evaluations and MRI scans at baseline and after 2 years. Cognitive composites were created in 5 domains: complex processing speed, working memory, general memory, visual-constructional skills, and language. Change in cognition was calculated using standard regression-based models accounting for variables known to impact serial testing. A semiautomated segmentation method was used to measure WMH extent in anterior and posterior brain regions. Hierarchical multiple linear regression models were used to evaluate which of the 5 measured cognitive domains was most strongly associated with regional (anterior and posterior) and total WMH progression after adjusting for demographics (age, sex, and education).

RESULTS

Decline in complex processing speed was independently associated with both anterior (r(2)=0.06, P=0.02) and total WMH progression (r(2)=0.05, P=0.04). In contrast, decline in visual-constructional skills was uniquely associated with posterior progression (r(2)=0.05, P<0.05).

CONCLUSIONS

Distinct cognitive profiles are associated with anterior and posterior WMH progression among normal elders. These differing profiles need to be considered when evaluating the cognitive correlates of WMHs.

Vascular dementia: a review of recent evidence for prevention and treatment

Vascular dementia is a common cause of late-life cognitive decline. Vascular risk factors, transient ischemic attacks, silent and clinically evident strokes, and ischemic changes on brain imaging studies are all associated with the development of dementia. Prevention of vascular dementia involves treatment of risk factors and the same preventive measures used to avoid heart attacks and strokes. Other treatments for vascular dementia, although promising, remain unproved.

Current Concepts in Vascular Cognitive Impairment and Pharmacotherapeutic Implications

Objective:

To review evolution of the vascular cognitive impairment (VCI) construct, including diagnosis, pharmacotherapeutic implications, and address challenges that will shape future developments.

Data Sources:

Literature retrieval was accessed through PubMed, from 1966 to December 2008, using the terms vascular cognitive impairment, vascular dementia, post-stroke dementia, vascular cognitive disorder, mild cognitive impairment, criteria, disease progression, outcomes, treatment, prevention, biomarkers, and neuroimaging.

Study Selection and Data Extraction:

All articles in published English identified from the data sources were evaluated for inclusion. Regarding pharmacotherapy, prospective double-blind, placebo-controlled studies were included as well as extensions or relevant post hoc analyses.

Data Synthesis:

In the 1970s, “senile dementia due to hardening of the arteries” was used to describe dementia due to vascular causes. This was a narrow view of what is now known to be a common form of cognitive impairment in older people. Multiple infarct dementia (MID) was first proposed to describe dementia attributable to multiple cerebral infarcts, followed by the vascular dementia (VaD) construct, itself meant to be an improvement over MID. The VaD construct had limitations, not the least of which was that, by the time a patient was diagnosed with VaD, the opportunity for prevention was lost. Thus arose the concept of VCI, representing a group of heterogeneous disorders that share presumed vascular causes. The importance of VCI is centered on the fact that vascular risk factors are treatable, and thus should lead to a reduction in the incidence of cognitive impairment due to vascular causes. There is evidence that treatment of hypertension can lead to a reduction in the incidence of cognitive impairment and dementia, and that treatment of VaD with acetylcholinesterase inhibitors may be beneficial.

Conclusions:

Careful attention needs to be given to controlling vascular risk factors in at-risk patients. Pharmacists should play an active role in this important area of geriatric pharmacotherapy.

Criteria for the neuropathological diagnosis of dementing disorders: routes out of the swamp?

There are several consensus criteria for both the clinical and neuropathological diagnosis of different types of dementias. The clinical diagnostic accuracy using revised research criteria and newly developed biomarkers (MRI, PET, CSF analysis, genetic markers) ranges from 65 to 96% (for Alzheimer disease) with a specificity of diagnostic criteria versus other dementias of 23-88%. Neuropathological assessment of dementing disorders using immunohistochemistry, molecular biologic and genetic methods can achieve a diagnosis/classification, based on the homogeneous definitions, harmonized inter-laboratory methods and standards for the assessment of nervous system lesions, in about 99%, without, however, being able to clarify the causes/etiology of most of these disorders. Further prospective and concerted clinicopathological studies using revised methodological and validated protocols and uniform techniques are required to establish the nature, distribution pattern and grades of lesions and; thus, to overcome the limitations of the current diagnostic framework. By data fusion this my allow their more uniform application and correlation with the clinical data in order to approach a diagnostic "gold standard", and to create generally accepted criteria for differentiating cognitive disorders from healthy brain aging. The detection of disease-specific pathologies will be indispensable to determinate the efficacy of new therapy options.