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

Cognitive impairment after a stroke in young adults: A systematic review and meta-analysis

BACKGROUND

Information about cognitive functioning is vital in the management of stroke, but the literature is mostly based on data from individuals older than 50 years of age who make up the majority of the stroke population. As cognitive functioning is subject to change due to aging, it is unclear whether such cognitive impairment patterns from the general stroke literature apply to the growing population of younger people with a stroke.

AIM

The aim of the study was to conduct a systematic review and meta-analysis of the proportion and severity of cognitive impairment in young-stroke patients.

SUMMARY OF REVIEW

MEDLINE, Embase, PsycINFO, and Web of Science were systematically searched up to 11 October 2022. Studies were included if they reported on a population of young-stroke patients, evaluated cognitive functioning as an outcome measure, and reported original data. We estimated the pooled prevalence rates for cognitive impairment and for aphasia. In addition, we calculated the pooled estimates for the severity of impairment per cognitive domain in the chronic phase (defined as >6 months post-stroke). Six hundred thirty-five articles were identified, of which 29 were eligible for inclusion. The pooled prevalence of cognitive impairment was 44% (k = 10; 95% confidence interval (CI): 34-54%) and of aphasia 22% (k = 13; 95% CI: 12-39%). Young-stroke patients in the chronic phase performed worse than stroke-free healthy age-appropriate controls across all cognitive domains examined, with Hedges' g effect sizes ranging from -0.49 to -1.64.

CONCLUSION

Around half of all young-stroke patients present with cognitive impairment and around a quarter with aphasia. Our data suggest that patterns of impairment in young-stroke patients follow those in the general stroke literature.

Exploring what progress is being made in the development of health promotion material for vascular dementia: A systematic review of the evidence

A systematic review conducted by Price and Keady (Journal of Nursing and Healthcare of Chronic Illness, 2, 88 and 2010) demonstrated that there was a dearth of health-promoting literature available for people diagnosed with vascular dementia. The correlation between health behavior and the onset of cardiovascular change that can lead to vascular dementia had demonstrated a need for health education and health-promoting information to be made accessible to vulnerable populations to ameliorate the risk of cognitive decline because of cardiovascular disease. Dementia is a progressive and life-limiting condition and with limited treatment options and a lack of progress in identifying a way to delay onset or even cure the condition. Focus must be targeted towards risk reduction strategies that serve to reduce onset and decline and limit the global burden on not only the individual with the condition and their carers but also to the health and social care economy. To identify the progress that has been made in developing health-promoting literature and patient education guidance since 2010 a systematic literature review was undertaken. Using thematic analysis, CINAHL, MEDLINE, and psych INFO databases were accessed and following PRISMA guidelines an inclusion and exclusion criteria was developed in order to locate peer-reviewed articles. Titles and abstracts were reviewed to identify a match with key terms, and from 133 screened abstracts eight studies met the inclusion requirements. From the eight studies, thematic analysis was implemented to identify shared understanding of experiences relating to health promotion in vascular dementia. The methodology for the study was replicated from the authors' previous systematic review in 2010. Five key themes were identified in the literature (Healthy heart healthy brain; Risk factors; Risk reduction/modification; Interventions; Absence of targeted health promotion). From what little evidence was available to review the thematic analysis has demonstrated developments in knowledge into the link between the onset of cognitive impairment and vascular dementia because of compromised cardiovascular health. Modifying health behavior has become essential in ameliorating the risk of vascular cognitive decline. With these developments the synthesis of the literature demonstrates that even with these insights there continues to be a lack of targeted material that individuals can access to understand the link between cardiovascular health and cognitive decline. It is recognized that maximizing cardiovascular health has the potential to lessen the risk of vascular cognitive impairment and vascular dementia developing and progressing yet targeted health promoting material remains lacking. With the developments in understanding the causal links between poor cardiovascular health, vascular cognitive impairment, and vascular dementia progress now needs to be made in developing targeted health promotion material for individuals to access to share this knowledge to reduce the potential onset and subsequent burden of dementia.

Role of Citicoline in Patients With Mild Cognitive Impairment

The term mild cognitive impairment (MCI) defines an intermediate state between normal aging and dementia. Vascular cognitive impairment refers to a decline in cognitive function that is caused by or associated with vascular disease and comprises all the spectrum of cognitive impairments, from MCI of vascular origin to vascular dementia. One of the available treatments for cognitive impairment is cytidine diphosphate-choline (CDP-Choline), or citicoline. The objective of the present manuscript is to provide complete evidence about the efficacy of citicoline for MCI, especially of vascular origin, but also due to other neurodegenerative disorders. Citicoline is a pharmaceutical product constituted by the combination of 2 natural molecules (cytidine and choline) and is marketed as a food supplement. It has been proposed to provide neuroprotective effects through diverse mechanisms of action. Taking into account the available literature, citicoline has shown a consistent improvement in cognitive function in patients with MCI, especially of vascular origin. Moreover, it provides beneficial effects on vascular, Alzheimer, and mixed dementias, stroke sequelae, intracerebral hemorrhages, traumatic brain injuries, and neurodegenerative diseases. Long-term treatment with citicoline has also been demonstrated to be well-tolerated and has not been associated with severe adverse events. Citicoline is a safe, well-tolerated, and promising agent with evidenced neuroprotective properties.

Comparison of Diffusion Tensor Imaging Metrics in Normal-Appearing White Matter to Cerebrovascular Lesions and Correlation with Cerebrovascular Disease Risk Factors and Severity

Alterations in tissue microstructure in normal-appearing white matter (NAWM), specifically measured by diffusion tensor imaging (DTI) fractional anisotropy (FA), have been associated with cognitive outcomes following stroke. The purpose of this study was to comprehensively compare conventional DTI measures of tissue microstructure in NAWM to diverse vascular brain lesions in people with cerebrovascular disease (CVD) and to examine associations between FA in NAWM and cerebrovascular risk factors. DTI metrics including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were measured in cerebral tissues and cerebrovascular anomalies from 152 people with CVD participating in the Ontario Neurodegenerative Disease Research Initiative (ONDRI). Ten cerebral tissue types were segmented including NAWM, and vascular lesions including stroke, periventricular and deep white matter hyperintensities, periventricular and deep lacunar infarcts, and perivascular spaces (PVS) using T1-weighted, proton density-weighted, T2-weighted, and fluid attenuated inversion recovery MRI scans. Mean DTI metrics were measured in each tissue region using a previously developed DTI processing pipeline and compared between tissues using multivariate analysis of covariance. Associations between FA in NAWM and several CVD risk factors were also examined. DTI metrics in vascular lesions differed significantly from healthy tissue. Specifically, all tissue types had significantly different MD values, while FA was also found to be different in most tissue types. FA in NAWM was inversely related to hypertension and modified Rankin scale (mRS). This study demonstrated the differences between conventional DTI metrics, FA, MD, AD, and RD, in cerebral vascular lesions and healthy tissue types. Therefore, incorporating DTI to characterize the integrity of the tissue microstructure could help to define the extent and severity of various brain vascular anomalies. The association between FA within NAWM and clinical evaluation of hypertension and disability provides further evidence that white matter microstructural integrity is impacted by cerebrovascular function.

The Value of Brain Structural Magnetic Resonance Imaging Combined with APOE--ε4 Genotype in Early Diagnosis and Disease Progression of Senile Vascular Cognitive Impairment No Dementia

Objective

To explore the value of brain structure magnetic resonance imaging combined with APOE-ε4 genotype in the early diagnosis and disease progression of elderly patients with vascular cognitive impairment no dementia (VCIND).

Methods

The first stroke patients admitted to our hospital from March 2017 to December 2018 were collected, including 130 cases of vascular cognitive impairment no dementia (VCIND group) and 50 cases of the control group (NC group). The basic information of all subjects was recorded, and APOE-ε4 alleles of all subjects were detected. The neuropsychological test scale evaluated the cognitive psychology of the subjects, and they were scanned by multi-parameter MRI. After follow-up, VCIND patients were divided into the dementia group and the nondementia group. MRI scans were again performed, and the risk factors of VCIND patients developing dementia were analyzed.

Results

Compared with the NC group, patients in the VCIND group had shorter years of education, more patients with hypertension, higher levels of homocysteine (Hcy), and lower cognitive ability. Patients with White Matter Volume (WMV), White Matter Hyperintensity (WMH), Lacunar Infarction (LI), elevated Fazekas scores, and APOE-ε4 gene carriers are more likely to develop VCIND. After 12 months of follow-up, compared with the nondementia group, the number of WMV, WMH, Fazekas scores, and APOE-ε4 gene carriers in the dementia group was significantly increased. In addition, the progression-free survival rate of APOE-ε4 gene carriers was significantly lower than that of nonAPOE-ε4 gene carriers.

Conclusion

Years of education, hypertension, high levels of Hcy, elevated WMV, WMH, LI, and Fazekas scores, and carrying the APOE-ε4 gene are risk factors for VCIND in stroke patients. Craniocerebral structural MRI combined with APOE-ε4 genotype has a diagnostic role in the early diagnosis and disease progression of elderly patients with VCIND.

Long-term psychological consequences of stroke (OX-CHRONIC): A longitudinal study of cognition in relation to mood and fatigue after stroke: Protocol

Background

The long-term psychological consequences of stroke and how cognitive problems change over time after the first-year following stroke remain unclear. Particularly, trajectories of domain-specific and domain-general cognitive functions and how cognition interacts with mood, fatigue and quality of life are not well described.

Aims

To determine the prevalence, trajectories and wider impact of domain-specific cognitive impairment in long-term stroke survivors, in relation to mood, fatigue and quality of life.

Methods

Participants who previously took part in the Oxford Cognitive Screening study, completed the 6-month follow-up with cognitive, mood, fatigue and quality of life assessments and agreed to be contacted for future research will be recruited into OX-CHRONIC. The eligible cohort is between 2- and 9-years post-stroke. Cognition will be assessed with a detailed neuropsychological battery, alongside questionnaire measures of mood, fatigue, activities of daily life and quality of life measures at two timepoints, 1 year apart. Additionally, medical records will be accessed to extract further clinical information about the stroke and patients may opt-in to wear an activity monitor for 1 week to provide fine-grained measures of sleep and activity. The study protocol and study materials were approved by the national ethics committee (REC Ref: 19/SC/0520).

Planned outputs

OX-CHRONIC will provide detailed data on the evolving cognitive profiles of stroke survivors over several years post-stroke. Estimates of long-term prevalence as well as the effect of changes in cognitive profiles on mood, fatigue and quality of life will be examined. This study is funded by a Priority Programme Grant from the Stroke Association (SA PPA 18/100032).

Cerebrovascular and Neurodegenerative Pathologies in Long-Term Stable Mild Cognitive Impairment

BACKGROUND

Mild cognitive impairment (MCI) is considered by some to be a prodromal phase of a progressive disease (i.e., neurodegeneration) resulting in dementia; however, a substantial portion of individuals (ranging from 5-30%) remain cognitively stable over the long term (sMCI). The etiology of sMCI is unclear but may be linked to cerebrovascular disease (CVD), as evidence from longitudinal studies suggest a significant proportion of individuals with vasculopathy remain stable over time.

OBJECTIVE

To quantify the presence of neurodegenerative and vascular pathologies in individuals with long-term (>5-year) sMCI, in a preliminary test of the hypothesis that CVD may be a contributor to non-degenerative cognitive impairment. We expect frequent vasculopathy at autopsy in sMCI relative to neurodegenerative disease, and relative to individuals who convert to dementia.

METHODS

In this retrospective study, using data from the National Alzheimer's Coordinating Center, individuals with sMCI (n = 28) were compared to those with MCI who declined over a 5 to 9-year period (dMCI; n = 139) on measures of neurodegenerative pathology (i.e., Aβ plaques, neurofibrillary tangles, TDP-43, and cerebral amyloid angiopathy) and CVD (infarcts, lacunes, microinfarcts, hemorrhages, and microbleeds).

RESULTS

Alzheimer's disease pathology (Aβ plaques, neurofibrillary tangles, and cerebral amyloid angiopathy) was significantly higher in the dMCI group than the sMCI group. Microinfarcts were the only vasculopathy associated with group membership; these were more frequent in sMCI.

CONCLUSION

The most frequent neuropathology in this sample of long-term sMCI was microinfarcts, tentatively suggesting that silent small vessel disease may characterize non-worsening cognitive impairment.

Cerebral microinfarcts affect brain structural network topology in cognitively impaired patients

Cerebral microinfarcts (CMIs), a novel cerebrovascular marker, are prevalent in Alzheimer's disease (AD) and associated with cognitive impairment. Nonetheless, the underlying mechanism of how CMIs influence cognition remains uncertain. We hypothesized that cortical-CMIs disrupted structural connectivity in the higher-order cognitive networks, leading to cognitive impairment. We analyzed diffusion-MRI data of 92 AD (26 with cortical-CMIs) and 110 cognitive impairment no dementia patients (CIND, 28 with cortical-CMIs). We compared structural network topology between groups with and without cortical-CMIs in AD/CIND, and tested whether structural connectivity mediated the association between cortical-CMIs and cognition. Cortical-CMIs correlated with impaired structural network topology (i.e. lower efficiency/degree centrality in the executive control/dorsal attention networks in CIND, and lower clustering coefficient in the default mode/dorsal attention networks in AD), which mediated the association of cortical-CMIs with visuoconstruction dysfunction. Our findings provide the first in vivo human evidence that cortical-CMIs impair cognition in elderly via disrupting structural connectivity.

Function-based dementia severity assessment for vascular cognitive impairment

BACKGROUND/PURPOSES

Unimpaired activities of daily living (ADL) is essential for the diagnosis of normal cognition and mild cognitive impairment. However, diagnosis according to this concept is difficult to apply to patients comorbid with motor dysfunction. We aim to use a novel ADL questionnaire for operationally diagnosing unimpaired ADL in vascular cognitive impairment with no dementia (VCIND).

METHODS AND PARTICIPANTS

This was a retrospective cohort study with both cross-sectional and long-term follow-up analysis. Patients with cerebrovascular disease with normal cognition (CVDNC), VCIND, and vascular dementia (VaD) were analyzed. Cutoff scores for differentiating different stages of cognitive impairment were compared between the new History-based Artificial Intelligent ADL questionnaire (HAI-ADL) and other tools.

RESULTS

A total of 596 individuals were analyzed, including 40 CVDNC, 167 VCIND, 218 mild, 119 moderate, and 52 severe-dementia patients. The cutoff scores for determining unimpaired ADL in VCIND were 8.5, 3.5, 5, 100, and 60 in HAI-ADL, CDR-SB, IADL, BI, and CASI, respectively. HAI-ADL had the highest correlations with CDR-SB and the CDR staging system compared to other tools. Four models of progression rates from CVDNC/VCIND to VaD revealed it was much higher in the group with HAI-ADL > 8.5 compared to those with HAI-ADL≦8.5 with odds ratios of 3.75, 3.66, 3.31, and 2.77, respectively.

CONCLUSION

Our study showed that HAI-ADL provides an operational determinates unimpaired ADL which is necessary for the diagnosis of VCIND. The predictive value for progression to dementia was proved by a long-term follow-up analysis of the research cohort.

Impact of different methods defining post-stroke neurocognitive disorder: The Nor-COAST study

INTRODUCTION

Post-stroke neurocognitive disorder (NCD) is common; prevalence varies between studies, partially related to lack of consensus on how to identify cases. The aim was to compare the prevalence of post-stroke NCD using only cognitive assessment (model A), DSM-5 criteria (model B), and the Global Deterioration Scale (model C) and to determine agreement among the three models.

METHODS

In the Norwegian Cognitive Impairment After Stroke study, 599 patients were assessed 3 months after suffering a stroke.

RESULTS

The prevalence of mild NCD varied from 174 (29%) in model B to 83 (14%) in model C; prevalence of major NCD varied from 249 (42%) in model A to 68 (11%) in model C. Cohen's kappa and Cohen's quadratic weighted kappa showed fair to very good agreement among models; the poorest agreement was found for identification of mild NCD.

DISCUSSION

The findings indicate a need for international harmonization to classify post-stroke NCD.

Apolipoprotein E ε4 allele is associated with vascular cognitive impairment no dementia in Chinese population

BACKGROUND

The association between apolipoprotein E (APOE) ε4 allele and vascular cognitive impairment no dementia (VCIND) is still controversial.

OBJECTIVE

To examine the relationship between the APOE ε4 allele and patients with VCIND after cerebral infarction.

METHODS

This study included first-ever cerebral infarction patients 3-12 months after the attack at the Xuanwu Hospital between June 2012 and December 2014. Patients were divided into VCIND group and normal cognition group (NC group).The APOE ε4 carriers (including ε2/ε4, ε3/ε4 and ε4/ε4 genotypes) and ε4 allele frequency were analyzed in relation to cognition grouping after cerebral infarction. MRI features of infarctions and some known risk factors for VCIND，as confounding factors, were also analyzed for correlation with VCIND at the same time.

RESULTS

Participants (n = 707) were divided into the VCIND (n = 361) and NC (n = 346) groups. The percentage of APOE ε4 carriers was higher in the VCIND group (23.6%) than in the NC group (12.7%, P < .001).The APOE ε4 allele frequency was higher in the VCIND group (12.5%) than in the NC group (6.7%, P = .001). Regardless of other confounding factors, such as male gender (OR = 1.963, 95%CI: 1.394-2.763, P < .001), age (OR = 1.034, 95%CI: 1.017-1.052, P < .001), education (OR = 0.834, 95%CI: 0.795-0.875, P < .001), hypertension (OR = 2.044, 95%CI: 1.460-2.861, P < .001), hyperlipidemia (OR = 0.682, 95%CI: 0.482-0.965, P = .031), infarction lesion diameter (OR = 1.044, 95%CI: 1.017-1.072, P = .001) and white matter lesions (OR = 1.330, 95%CI: 1.126-1.571, P = .001), the APOE ε4 allele was independently associated with VCIND (OR = 2.244, 95%CI: 1.454-3.463, P < .001).

CONCLUSION

These results confirms the hypothesis that the APOE ε4 allele is a risk factor associated with VCIND after cerebral infarction.

Hierarchical Clustering Analyses of Plasma Proteins in Subjects With Cardiovascular Risk Factors Identify Informative Subsets Based on Differential Levels of Angiogenic and Inflammatory Biomarkers

Agglomerative hierarchical clustering analysis (HCA) is a commonly used unsupervised machine learning approach for identifying informative natural clusters of observations. HCA is performed by calculating a pairwise dissimilarity matrix and then clustering similar observations until all observations are grouped within a cluster. Verifying the empirical clusters produced by HCA is complex and not well studied in biomedical applications. Here, we demonstrate the comparability of a novel HCA technique with one that was used in previous biomedical applications while applying both techniques to plasma angiogenic (FGF, FLT, PIGF, Tie-2, VEGF, VEGF-D) and inflammatory (MMP1, MMP3, MMP9, IL8, TNFα) protein data to identify informative subsets of individuals. Study subjects were diagnosed with mild cognitive impairment due to cerebrovascular disease (MCI-CVD). Through comparison of the two HCA techniques, we were able to identify subsets of individuals, based on differences in VEGF (p < 0.001), MMP1 (p < 0.001), and IL8 (p < 0.001) levels. These profiles provide novel insights into angiogenic and inflammatory pathologies that may contribute to VCID.

[Mild cognitive impairment: what's next?]

The concept of mild cognitive impairment is one of the promising directions for studying the predementia stages of different diseases. The feasibility of studying this phenomenon is due not only to a high risk of dementia, but also the potential reversibility of cognitive decline in old age. Long-term follow-up of patients shows different trajectories of cognitive decline in aging. The study of risk factors for the progression of moderate cognitive impairment provided an opportunity to highlight new horizons of prevention of dementia of various etiologies. Despite the insufficient effectiveness of drug therapy in patients with moderate cognitive impairment, exploring the opportunities for possible treatment of their subtypes seems promising from the point of view of improving clinical symptoms and a possible reduction in the rate of disease progression.

Systematic review and meta-analysis of the prevalence of cognitive impairment no dementia in the first year post-stroke

Introduction

Increasing attention is being paid to interventions for cognitive impairment (CI) post-stroke, including for CI that does not meet dementia criteria. The aim of this paper was to conduct a systematic review and meta-analysis of the prevalence of cognitive impairment no dementia (CIND) within one year post-stroke.

Patients and methods

Pubmed, EMBASE and PsychInfo were searched for papers published in English in 1995-2017. Included studies were population or hospital-based cohort studies for first-ever/recurrent stroke, assessing CIND using standardised criteria at 1-12 months post-stroke. Abstracts were screened, followed by full text review of potentially relevant articles. Data were extracted using a standard form, and study quality was appraised using the Crowe Critical Appraisal Tool. A pooled prevalence of CIND with 95% confidence intervals (CI) was estimated using random-effects meta-analysis. Heterogeneity was measured using the I² statistic.

Results

A total of 7000 abstracts were screened, followed by 1028 full text articles. Twenty-three articles were included in the systematic review, and 21 in the meta-analysis. The pooled CIND prevalence was 38% [95% CI = 32-43%] (I²=92.5%, p < 0.01). Study quality emerged as one source of heterogeneity. The five studies with the highest quality scores had no heterogeneity (I²=0%, p = 0.99), with a similar pooled prevalence (39%, 95%CI = 35-42%). Other sources of heterogeneity were stroke type, inclusion of pre-stroke CI, and age at assessment time.Discussion and conclusion: Meta-analysis of available studies indicates that in the first year post-stroke, 4 in 10 patients display a level of cognitive impairment that does not meet the criteria for dementia.

Vascular Mild Cognitive Impairment: Identifying Disease in Community-Dwelling Older Adults, Reducing Risk Factors, and Providing Support. The Osaki-Tajiri and Kurihara Projects

Vascular mild cognitive impairment (MCI) is a critical disease. Its prognosis includes not only onset of vascular dementia, but also death by cardiovascular disease. The vascular risk factors for vascular MCI are treatable, and appropriate treatment can prevent or delay the progression to dementia. Therefore, this group is an excellent candidate for secondary prevention. However, community-dwelling older adults with vascular MCI are often undetected and are not clinically identified until they develop frank dementia. Furthermore, older adults with undetected vascular MCI often have decreased ability to follow their medication regimens and this poor medication adherence worsens their vascular comorbidities. This vicious cycle needs to be prevented through community-based interventions. There is evidence that treatment of hypertension or diabetes mellitus could lead to a reduced incidence of vascular MCI and dementia. In this review article, we first explain the background and etiology of vascular MCI. We then summarize phenotype of subcortical vascular dementia which is often unrecognized or "hidden" in the community. Then we introduce the Osaki-Tajiri and Kurihara Projects which have been conducted in Northern Japan, as an example of prevention projects aimed to identify early-stage vascular MCI in the community, reduce the risk factors and facilitate their treatment. Early identification of vascular MCI in the community could lead to a large reduction in the dementia burden worldwide. The outreach efforts presented here could be useful in developing secondary prevention strategies targeted to vascular MCI.

Risk Prediction Models for Post-Stroke Dementia

A strong association exists between stroke and dementia with both diseases linked to ageing. Survival rates from stroke are improving which would equate to an ever-expanding population of patients at risk of future dementia. Early or timelier identification of dementia has become a priority in many countries, including the UK. Although screening for dementia is not advocated, targeting at risk populations could be used to reduce an individual's risk via intervention (i.e., personalised medicine), where available. One approach to improving identification of high-risk dementia individuals is using risk prediction models. Such models could be applied to stroke survivors. Dementia risk prediction models specific to stroke survivors have recently been developed and will be discussed here.