Brain atrophy and white matter hyperintensity change in older adults and relationship to blood pressure

Pregnancy as a window of opportunity for dementia prevention: a narrative review

Dementia is a debilitating condition with a disproportionate impact on women. While sex differences in longevity contribute to the disparity, the role of the female sex as a biological variable in disease progression is not yet fully elucidated. Metabolic dysfunctions are drivers of dementia etiology, and cardiometabolic diseases are among the most influential modifiable risk factors. Pregnancy is a time of enhanced vulnerability for metabolic disorders. Many dementia risk factors, such as hypertension or blood glucose dysregulation, often emerge for the first time in pregnancy. While such cardiometabolic complications in pregnancy pose a risk to the health trajectory of a woman, increasing her odds of developing type 2 diabetes or chronic hypertension, it is not fully understood how this relates to her risk for dementia. Furthermore, structural and functional changes in the maternal brain have been reported during pregnancy suggesting it is a time of neuroplasticity for the mother. Therefore, pregnancy may be a window of opportunity to optimize metabolic health and support the maternal brain. Healthy dietary patterns are known to reduce the risk of cardiometabolic diseases and have been linked to dementia prevention, yet interventions targeting cognitive function in late life have largely been unsuccessful. Earlier interventions are needed to address the underlying metabolic dysfunctions and potentially reduce the risk of dementia, and pregnancy offers an ideal opportunity to intervene. This review discusses current evidence regarding maternal brain health and the potential window of opportunity in pregnancy to use diet to address neurological health disparities for women.

Leukoaraiosis: Epidemiology, Imaging, Risk Factors, and Management of Age-Related Cerebral White Matter Hyperintensities

Leukoaraiosis (LA) manifests as cerebral white matter hyperintensities on T2-weighted magnetic resonance imaging scans and corresponds to white matter lesions or abnormalities in brain tissue. Clinically, it is generally detected in the early 40s and is highly prevalent globally in individuals aged >60 years. From the imaging perspective, LA can present as several heterogeneous forms, including punctate and patchy lesions in deep or subcortical white matter; lesions with periventricular caps, a pencil-thin lining, and smooth halo; as well as irregular lesions, which are not always benign. Given its potential of having deleterious effects on normal brain function and the resulting increase in public health burden, considerable effort has been focused on investigating the associations between various risk factors and LA risk, and developing its associated clinical interventions. However, study results have been inconsistent, most likely due to potential differences in study designs, neuroimaging methods, and sample sizes as well as the inherent neuroimaging heterogeneity and multi-factorial nature of LA. In this article, we provided an overview of LA and summarized the current knowledge regarding its epidemiology, neuroimaging classification, pathological characteristics, risk factors, and potential intervention strategies.

Increase in blood pressure precedes distress behavior in nursing home residents with dementia

BACKGROUND

Distress behaviors in dementia (DBD) likely increase sympathetic nervous system activity. The aim of this study was to examine the associations among DBD, blood pressure (BP), and intensity of antihypertensive treatment, in nursing home (NH) residents with dementia.

METHODS

We identified long-stay Veterans Affairs NH residents with dementia in 2019-20 electronic health data. Each individual with a BP reading and a DBD incident according to a structured behavior note on a calendar day (DBD group) was compared with an individual with a BP reading but without a DBD incident on that same day (comparison group). In each group we calculated daily mean BP from 14 days before to 7 days after the DBD incident day. We then calculated the change in BP between the DBD incident day and, as baseline, the 7-day average of BP 1 week prior, and tested for differences between DBD and comparison groups in a generalized estimating equations multivariate model.

RESULTS

The DBD and comparison groups consisted of 707 and 2328 individuals, respectively. The DBD group was older (74 vs. 72 y), was more likely to have severe cognitive impairment (13% vs. 8%), and had worse physical function scores (15 vs. 13 on 28-point scale). In the DBD group, mean systolic BP on the DBD incident day was 1.6 mmHg higher than baseline (p < .001), a change that was not observed in the comparison group. After adjusting for covariates, residents in the DBD group, but not the comparison group, had increased likelihood of having systolic BP > = 160 mmHg on DBD incident days (OR 1.02; 95%CI 1.00-1.03). Systolic BP in the DBD group began to rise 7 days before the DBD incident day and this rise persisted 1 week after. There were no significant changes in mean number of antihypertensive medications over this time period in either group.

CONCLUSIONS

NH residents with dementia have higher BP when they experience DBD, and BP rises 7 days before the DBD incident. Clinicians should be aware of these findings when deciding intensity of BP treatment.

How often does white matter hyperintensity volume regress in cerebral small vessel disease?

BACKGROUND AND OBJECTIVES

It has been suggested that white matter hyperintensity lesions (WMHs), which typically progress over time, can also regress, and that this might be associated with favorable cognitive performance. We determined the prevalence of WMH regression in patients with cerebral small vessel disease (SVD) and examined which demographic, clinical, and radiological markers were associated with this regression.

METHODS

We used semi-automated lesion marking methods to quantify WMH volume at multiple timepoints in three cohorts with symptomatic SVD; two with moderate-to-severe symptomatic SVD (the SCANS observational cohort and the control arm of the PRESERVE interventional trial) and one with mild-to-moderate SVD (the RUN DMC observational cohort). Mixed-effects ordered logistic regression models were used to test which factors predicted participants to show WMH regression.

RESULTS

No participants (0/98) in SCANS, 6/42 (14.3%) participants in PRESERVE, and 6/276 (2.2%) in RUN DMC showed WMH regression. On multivariate analysis, only lower WMH volume (OR: 0.36, 95% CI: 0.23-0.56) and better white matter microstructural integrity assessed by fractional anisotropy using diffusion tensor imaging (OR: 1.55, 95% CI: 1.07-2.24) predicted participant classification as regressor versus stable or progressor.

DISCUSSION

Only a small proportion of participants demonstrated WMH regression across the three cohorts, when a blinded standardized assessment method was used. Subjects who showed regression had less severe imaging markers of disease at baseline. Our results show that lesion regression is uncommon in SVD and unlikely to be a major factor affecting the use of WMH quantification as an outcome for clinical trials.

Racial and Ethnic Differences in Amyloid PET Positivity in Individuals With Mild Cognitive Impairment or Dementia: A Secondary Analysis of the Imaging Dementia-Evidence for Amyloid Scanning (IDEAS) Cohort Study

Importance

Racial and ethnic groups with higher rates of clinical Alzheimer disease (AD) are underrepresented in studies of AD biomarkers, including amyloid positron emission tomography (PET).

Objective

To compare amyloid PET positivity among a diverse cohort of individuals with mild cognitive impairment (MCI) or dementia.

Design, Setting, and Participants

Secondary analysis of the Imaging Dementia-Evidence for Amyloid Scanning (IDEAS), a single-arm multisite cohort study of Medicare beneficiaries who met appropriate-use criteria for amyloid PET imaging between February 2016 and September 2017 with follow-up through January 2018. Data were analyzed between April 2020 and January 2022. This study used 2 approaches: the McNemar test to compare amyloid PET positivity proportions between matched racial and ethnic groups and multivariable logistic regression to assess the odds of having a positive amyloid PET scan. IDEAS enrolled participants at 595 US dementia specialist practices. A total of 21 949 were enrolled and 4842 (22%) were excluded from the present analysis due to protocol violations, not receiving an amyloid PET scan, not having a positive or negative scan, or because of small numbers in some subgroups.

Exposures

In the IDEAS study, participants underwent a single amyloid PET scan.

Main Outcomes and Measures

The main outcomes were amyloid PET positivity proportions and odds.

Results

Data from 17 107 individuals (321 Asian, 635 Black, 829 Hispanic, and 15 322 White) with MCI or dementia and amyloid PET were analyzed between April 2020 and January 2022. The median (range) age of participants was 75 (65-105) years; 8769 participants (51.3%) were female and 8338 (48.7%) were male. In the optimal 1:1 matching analysis (n = 3154), White participants had a greater proportion of positive amyloid PET scans compared with Asian participants (181 of 313; 57.8%; 95% CI, 52.3-63.2 vs 142 of 313; 45.4%; 95% CI, 39.9-50.9, respectively; P = .001) and Hispanic participants (482 of 780; 61.8%; 95% CI, 58.3-65.1 vs 425 of 780; 54.5%; 95% CI, 51.0-58.0, respectively; P = .003) but not Black participants (359 of 615; 58.4%; 95% CI, 54.4-62.2 vs 333 of 615; 54.1%; 95% CI, 50.2-58.0, respectively; P = .13). In the adjusted model, the odds of having a positive amyloid PET scan were lower for Asian participants (odds ratio [OR], 0.47; 95% CI, 0.37-0.59; P < .001), Black participants (OR, 0.71; 95% CI, 0.60-0.84; P < .001), and Hispanic participants (OR, 0.68; 95% CI, 0.59-0.79; P < .001) compared with White participants.

Conclusions and Relevance

Racial and ethnic differences found in amyloid PET positivity among individuals with MCI and dementia in this study may indicate differences in underlying etiology of cognitive impairment and guide future treatment and prevention approaches.

Effects of Obesity, Blood Pressure, and Blood Metabolic Biomarkers on Grey Matter Brain Healthcare Quotient: A Large Cohort Study of a Magnetic Resonance Imaging Brain Screening System in Japan

This study investigated the relationship between grey matter (GM) volume and blood biomarkers, blood pressure, and obesity. We aimed to elucidate lifestyle factors that promote GM volume loss. A total of 1799 participants underwent the brain dock as a medical checkup. Data regarding blood pressure, obesity measurements, and standard blood biomarkers were obtained. Further, brain magnetic resonance imaging (MRI), including high-resolution T1-weighted imaging, was performed. We calculated the grey matter brain healthcare quotient (GM-BHQ), which represents GM volume as a deviation value. After adjusting for confounding variables, multiple regression analysis revealed that body mass index (BMI) (b = −0.28, p < 0.001), gamma-glutamyltransferase (γ-GTP) (b = −0.01, p = 0.16), and fasting blood glucose (b = −0.02, p = 0.049) were significantly correlated with GM-BHQ. Although the current cross-sectional study cannot determine a cause-and-effect relationship, elevated BMI, γ-GTP, and fasting blood glucose could promote GM volume loss.

Associations of Peripheral Neuropathy Defined by Monofilament Insensitivity with Mild Cognitive Impairment and Dementia in Older Adults

INTRODUCTION

The aim of this study was to assess the association of peripheral neuropathy (PN) as defined by monofilament insensitivity with mild cognitive impairment (MCI) and dementia in older adults with and without diabetes.

METHODS

We conducted a cross-sectional analysis of 3,362 Black and White participants in the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS) who underwent monofilament testing at visit 6 (2016-2017, age 71-94 years). Participants' cognitive status was classified by an adjudication committee as cognitively normal, MCI, or dementia after completing a comprehensive battery of neurocognitive assessments. We used logistic regression to evaluate the association of PN with MCI or dementia overall and stratified by diabetes status after adjusting for traditional dementia risk factors. We also compared age-adjusted brain MRI measures among a subset (N = 1,095) of participants with versus without PN.

RESULTS

Overall, the prevalence of MCI (21.9% vs. 16.7%) and dementia (7.8% vs. 3.9%) were higher among participants with versus without PN (both p < 0.05). After adjustment, PN was positively associated with MCI or dementia in the overall study population (OR 1.45, 95% CI 1.23, 1.73). Results were similar by diabetes status (diabetes: OR 1.38, 95% CI 1.03-1.87; no diabetes: OR 1.48, 95% CI 1.20-1.83; p-for-interaction = 0.46). Age-adjusted total and lobar brain volumes were significantly lower in participants with versus without PN (both, p < 0.05).

DISCUSSION/CONCLUSIONS

PN as defined by monofilament insensitivity was associated with cognitive status independent of vascular risk factors and regardless of diabetes status. Our findings support a connection between PN and cognitive impairment, even in the absence of diabetes.

Leisure Activity Variety and Brain Volume Among Community-Dwelling Older Adults: Analysis of the Neuron to Environmental Impact Across Generations Study Data

Background: Recent findings indicate that leisure activity (LA) delays cognitive decline and reduces the risk of dementia. However, the association between LA and brain volume remains unclear. This study aimed to examine the association between LA variety and brain volume with a focus on the hippocampus and gray matter. Methods: Data were obtained from the baseline survey of the Neuron to Environmental Impact across Generations study, which had targeted community-dwelling older adults living in Niigata, Japan. We divided LAs into 10 categories, and counted the number of categories of activities in which the participants engaged. We classified them as follows: 0 (i.e., no activity), 1, 2, or ≥ 3 types. Brain volume was assessed through magnetic resonance imaging, and hippocampal and gray matter volumes were ascertained. Results: The sample size was 482. Multiple linear regression analysis showed that hippocampal and gray matter volumes were significantly greater among participants with ≥ 3 types of LAs than among their no-activity counterparts. Hippocampal volume was significantly greater among those who engaged in one type of LA than among those who engaged in no such activity. Sex-stratified analysis revealed that hippocampal volumes were significantly greater among males who engaged in ≥ 3 types of LAs and one type of LA. However, no such association was found among females. Conclusion: The present findings suggest that engaging in a wide range of LAs is related to hippocampal and gray matter volumes. Furthermore, there was a sex difference in the association between LA variety and brain volume.

Rate of, and risk factors for, white matter hyperintensity growth: a systematic review and meta-analysis with implications for clinical trial design

BACKGROUND

White matter hyperintensities (WMHs) are a highly prevalent MRI marker of cerebral small vessel disease (SVD), which predict stroke and dementia risk, and are being increasingly used as a surrogate marker in clinical trials. However, the influence of study population selection on WMH progression rate has not been studied and the effect of individual patient factors for WMH growth are not fully understood.

METHODS

We performed a systematic review and meta-analysis of the literature on progression of WMHs in longitudinal studies to determine rates of WMH growth, and how these varied according to population characteristics and cardiovascular risk factors. We used these data to calculate necessary sample sizes for clinical trials using WMH as an endpoint.

RESULTS

WMH growth rate was highest in SVD (2.50cc/year), intermediate in unselected stroke patients (1.29cc/year) and lower in patients with non-stroke cardiovascular disease, and with cognitive impairment. Age was significantly associated with progression (correlation coefficient 0.15cc/year, 95% CI 0.02 to 0.28cc/year) as was baseline lesion volume (0.6cc/year, 95% CI 0.13 to 1.06 cc/year). Both hypertension (OR 1.72, 95% CI 1.19 to 2.46) and current smoking (OR 1.48, 95% CI 1.02 to 2.16) were associated with WMH growth. Sample sizes for a clinical trial varied greatly with patient population selection and baseline lesion volume; estimates are provided.

CONCLUSIONS

WMH progression varies markedly according to the characteristics of the population being studied and this will have a major impact on sample sizes required in a clinical trial. Our sample size estimates provide data for planning clinical trials using WMH as an outcome measure.

PROSPERO REGISTRATION NUMBER

CRD42020191781.

Cognitive Dysfunction in White Matter Disorders: New Perspectives in Treatment and Recovery

White matter disorders are increasingly appreciated as capable of disrupting cognitive function, and this impairment may be sufficiently severe to produce the syndrome of white matter dementia. Although recognizing this problem is important for diagnostic accuracy, the treatment of cognitive dysfunction and dementia in the white matter disorders has received relatively little attention. Similarly, few data are available regarding the potential for cognitive recovery in these disorders. Recent clinical and laboratory advances, however, indicate that effective treatment and meaningful recovery may be achievable goals for many patients with macrostructural or microstructural white matter pathology. One recent observation is that leukoaraiosis has been observed to regress with treatment of hypertension, often with concomitant improvement in cognition. Equally novel is emerging evidence that white matter exhibits substantial plasticity related to activity-dependent myelination and that this phenomenon may produce clinical benefit. These insights suggest that noninvasive and inexpensive interventions targeting white matter are warranted for a wide range of cognitively impaired patients. Moreover, given the well-established risk that vascular white matter pathology portends for developing dementia-including both vascular dementia and Alzheimer's disease-the application of these principles before dementia onset may also be efficacious for prevention. In view of the increasingly compelling case for early white matter involvement in the etiopathogenesis of late-life dementia and the continuing lack of disease-modifying therapy, progress in treating cognitive disturbances arising from white matter disorders offers the prospect that this approach may enhance the prevention of dementia as well as the treatment of cognitive dysfunction.

Prevalence of mild cognitive impairment in patients with hypertension: a systematic review and meta-analysis

Mild cognitive impairment (MCI) is common in patients with hypertension. Prevalence estimates of MCI in hypertensive patients are needed to guide both public health and clinical decision making. A literature search was conducted in four databases, including PubMed, Embase, Cochrane Library, and Web of Science, from their inception to February 2021. The methodological quality assessment used the risk of bias tool. The pooled prevalence of MCI in hypertensive patients was determined by a random-effects model. Heterogeneity was explored using sensitivity analysis, subgroup analysis, and random effects meta-regression. Of 2314 references, 11 studies (47,179 participants) were included in the meta-analysis. The overall pooled prevalence of MCI in patients with hypertension was 30% (95% CI, 25-35), with significant heterogeneity present (I² = 99.3%, p < 0.001). In subgroup analyses, Asian and European samples had a prevalence of 26% (95% CI, 20-31) and 40% (95% CI, 14-66), respectively; cross-sectional and cohort studies had a prevalence of 28% (95% CI, 24-32) and 38% (95% CI, -5-81); age older than 60 years had a prevalence of 28% (95% CI, 23-33); community-based and clinic-based samples had a prevalence of 17% (95% CI, 15-19) and 42% (95% CI, 23-62); and MCI diagnosis using the MoCA, NIA-AA, MMSE, and Peterson criteria had a prevalence of 64% (95% CI, 59-68), 18% (95% CI, 16-19), 19% (95% CI, 15-23), and 13% (95% CI, 9-17). Meta-regression analysis showed that different MCI diagnostic criteria could be the source of heterogeneity in the pooled results. MCI is common in patients with hypertension, with an overall prevalence of 30%. Earlier cognitive screening and management in hypertensive patients should be advocated.

The Contribution of Vascular Pathology Toward Cognitive Impairment in Older Individuals with Intermediate Braak Stage Tau Pathology

BACKGROUND

The pathological features of Alzheimer's disease (AD) are well described but little is known as to how both neurodegeneration and vascular changes might interact in causing cognitive impairment.

OBJECTIVE

The present study aims to investigate relationships between vascular and AD pathology in cognitively healthy and cognitively impaired individuals with a particular emphasis on those at intermediate Braak tau stages.

METHODS

We investigated the interplay between Braak tau stage and measures of vascular pathology as described by the vascular cognitive impairment neuropathology guidelines (VCING) in 185 brains from the Brains for Dementia Research programme and The University of Manchester Longitudinal Study of Cognition in Healthy Old Age. VCING asserts that at least one large (>10 mm) infarct, moderate/severe occipital leptomeningeal cerebral amyloid angiopathy, and moderate/severe arteriosclerosis in occipital white matter accurately predicts the contribution of cerebrovascular pathology to cognitive impairment.

RESULTS

We found that the extent of arteriosclerosis in the occipital white matter did not differ between cognitive groups at intermediate (III-IV) Braak stages whereas moderate/severe leptomeningeal occipital cerebral amyloid angiopathy was greater in cognitively impaired than normal individuals at Braak stage III-IV. This finding remained significant after controlling for effects of age, sex, CERAD score, Thal phase, presence/severity of primary age-related tauopathy, presence/severity of limbic-predominant age-related TDP43 encephalopathy and small vessel disease in basal ganglia.

CONCLUSION

Interventions targeting cerebral amyloid angiopathy may contribute to delay the onset of cognitive impairment in individuals with intermediate Alzheimer's type pathology.

MRI of healthy brain aging: A review

We present a review of the characterization of healthy brain aging using MRI with an emphasis on morphology, lesions, and quantitative MR parameters. A scope review found 6612 articles encompassing the keywords "Brain Aging" and "Magnetic Resonance"; papers involving functional MRI or not involving imaging of healthy human brain aging were discarded, leaving 2246 articles. We first consider some of the biogerontological mechanisms of aging, and the consequences of aging in terms of cognition and onset of disease. Morphological changes with aging are reviewed for the whole brain, cerebral cortex, white matter, subcortical gray matter, and other individual structures. In general, volume and cortical thickness decline with age, beginning in mid-life. Prevalent silent lesions such as white matter hyperintensities, microbleeds, and lacunar infarcts are also observed with increasing frequency. The literature regarding quantitative MR parameter changes includes T₁ , T₂ , T₂ *, magnetic susceptibility, spectroscopy, magnetization transfer, diffusion, and blood flow. We summarize the findings on how each of these parameters varies with aging. Finally, we examine how the aforementioned techniques have been used for age prediction. While relatively large in scope, we present a comprehensive review that should provide the reader with sound understanding of what MRI has been able to tell us about how the healthy brain ages.

The relation between antihypertensive treatment and progression of cerebral small vessel disease: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Cerebral small vessel disease is relevant to hypertension. We tried to figure out whether antihypertensive treatment is beneficial for this disease.

METHODS

We systematically searched PubMed, Embase, and Cochrane electronic databases for randomized controlled trials about white matter hyperintensities (WMH), brain atrophy, microbleeds, and lacunar infarcts with antihypertensive treatment and performed a meta-analysis.

RESULTS

We identified 7 trials on white matter hyperintensities and brain atrophy with antihypertensive treatment. Pooled analysis showed antihypertensive treatment performed positively in the progression of WMH (standardized mean difference, -0.22; 95% CI, -0.36 to -0.07, I^2 = 52%). And in the subgroup meta-analysis, only lower SBP controlled level (110-129 mm Hg) had effect on the progression of WMH (standardized mean difference, -0.37; 95% CI, -0.54 to -0.29, I^2 =0). The meta-regression showed larger difference of SBP in treatment groups having a smaller WMH progression. Antihypertensive treatment is not significant in the progression of brain atrophy (standardized mean difference, -0.02; 95% CI, -0.26 to 0.30, I^2 = 85%). Only 1 trial reported the new patients of lacunar infarcts in the follow-up, no association with antihypertensive treatment (odds ratio, 2.2; 95% CI, 0.4-12.1; P = .36).

CONCLUSIONS

Antihypertensive treatment is beneficial for cerebral small vessel disease on white matter hyperintensities progression, but no impact on brain atrophy. And lower SBP level is more effective on the progression of WMH. There is not enough evidence to prove the relationship between antihypertensive treatment and lacunar stroke, microbleeds.

Role of White Matter Hyperintensities and Related Risk Factors in Vascular Cognitive Impairment: A Review

White matter hyperintensities (WMHs) of presumed vascular origin are one of the imaging markers of cerebral small-vessel disease, which is prevalent in older individuals and closely associated with the occurrence and development of cognitive impairment. The heterogeneous nature of the imaging manifestations of WMHs creates difficulties for early detection and diagnosis of vascular cognitive impairment (VCI) associated with WMHs. Because the underlying pathological processes and biomarkers of WMHs and their development in cognitive impairment remain uncertain, progress in prevention and treatment is lagging. For this reason, this paper reviews the status of research on the features of WMHs related to VCI, as well as mediators associated with both WMHs and VCI, and summarizes potential treatment strategies for the prevention and intervention in WMHs associated with VCI.

Higher Handgrip Strength Is Linked to Better Cognitive Performance in Chinese Adults with Hypertension

Objective: There is growing evidence that in adults, higher levels of handgrip strength (HGS) are linked to better cognitive performance. However, the relationship between HGS and cognitive performance has not been sufficiently investigated in special cohorts, such as individuals with hypertension who have an intrinsically higher risk of cognitive decline. Thus, the purpose of this study was to examine the relationship between HGS and cognitive performance in adults with hypertension using data from the Global Ageing and Adult Health Survey (SAGE). Methods: A total of 4486 Chinese adults with hypertension from the SAGE were included in this study. Absolute handgrip strength (aHGS in kilograms) was measured using a handheld electronic dynamometer, and cognitive performance was assessed in the domains of short-term memory, delayed memory, and language ability. Multiple linear regression models were fitted to examine the association between relative handgrip strength (rHGS; aHGS divided by body mass index) and measures of cognitive performance. Results: Overall, higher levels of rHGS were associated with higher scores in short-term memory (β = 0.20) and language (β = 0.63) compared with the lowest tertiles of rHGS. In male participants, higher HGS was associated with higher scores in short-term memory (β = 0.31), language (β = 0.64), and delayed memory (β = 0.22). There were no associations between rHGS and cognitive performance measures in females. Conclusion: We observed that a higher level of rHGS was associated with better cognitive performance among hypertensive male individuals. Further studies are needed to investigate the neurobiological mechanisms, including sex-specific differences driving the relationship between measures of HGS and cognitive performance in individuals with hypertension.

ESO Guideline on covert cerebral small vessel disease

'Covert' cerebral small vessel disease (ccSVD) is common on neuroimaging in persons without overt neurological manifestations, and increases the risk of future stroke, cognitive impairment, dependency, and death. These European Stroke Organisation (ESO) guidelines provide evidence-based recommendations to assist with clinical decisions about management of ccSVD, specifically white matter hyperintensities and lacunes, to prevent adverse clinical outcomes. The guidelines were developed according to ESO standard operating procedures and Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. We prioritised the clinical outcomes of stroke, cognitive decline or dementia, dependency, death, mobility and mood disorders, and interventions of blood pressure lowering, antiplatelet drugs, lipid lowering, lifestyle modifications, glucose lowering and conventional treatments for dementia. We systematically reviewed the literature, assessed the evidence, formulated evidence-based recommendations where feasible, and expert consensus statements. We found little direct evidence, mostly of low quality. We recommend patients with ccSVD and hypertension to have their blood pressure well controlled; lower blood pressure targets may reduce ccSVD progression. We do not recommend antiplatelet drugs such as aspirin in ccSVD. We found little evidence on lipid lowering in ccSVD. Smoking cessation is a health priority. We recommend regular exercise which may benefit cognition, and a healthy diet, good sleep habits, avoiding obesity and stress for general health reasons. In ccSVD, we found no evidence for glucose control in the absence of diabetes or for conventional Alzheimer dementia treatments. Randomised controlled trials with clinical endpoints are a priority for ccSVD.

Changes in brain functional connectivity and cognition related to white matter lesion burden in hypertensive patients from SPRINT

PURPOSE

Hypertension is a risk factor for cognitive impairment; however, the mechanisms leading to cognitive changes remain unclear. In this cross-sectional study, we evaluate the impact of white matter lesion (WML) burden on brain functional connectivity (FC) and cognition in a large cohort of hypertensive patients from the Systolic Blood Pressure Intervention Trial (SPRINT) at baseline.

METHODS

Functional networks were identified from baseline resting state functional MRI scans of 660 SPRINT participants using independent component analysis. WML volumes were calculated from structural MRI. Correlation analyses were carried out between mean FC of each functional network and global WML as well as WML within atlas-defined white matter regions. For networks of interest, voxel-wise-adjusted correlation analyses between FC and regional WML volume were performed. Multiple variable linear regression models were built for cognitive test performance as a function of network FC, followed by mediation analysis.

RESULTS

Mean FC of the default mode network (DMN) was negatively correlated with global WML volume, and regional WML volume within the precuneus. Voxel-wise correlation analyses revealed that regional WML was negatively correlated with FC of the DMN's left lateral temporal region. FC in this region of the DMN was positively correlated to performance on the Montreal Cognitive Assessment and demonstrated significant mediation effects. Additional networks also demonstrated global and regional WML correlations; however, they did not demonstrate an association with cognition.

CONCLUSION

In hypertensive patients, greater WML volume is associated with lower FC of the DMN, which in turn is related to poorer cognitive test performance.

TRIAL REGISTRATION

NCT01206062.

A 10-year longitudinal study of deep white matter lesions on magnetic resonance imaging

PURPOSE

Deep white matter lesions (DWMLs), T2 high-intensity areas in the subcortical white matter on magnetic resonance imaging (MRI), are a clinical phenotype of cerebral small vessel disease. Factors such as age and hypertension have been reported to significantly contribute to the presence and severity of DWMLs in cross-sectional studies. We herein report a 10-year longitudinal study on DWMLs in elderly Japanese subjects to reveal the clinical variables contributing to the progression of DWMLs.

METHODS

A total of 469 Japanese subjects were invited to participate in the study. Of the participants at baseline, 259 subjects completed the revisit MRI study 10 years later. In those 259 subjects, we evaluated the correlation between the progression of DWMLs and clinical variables, such as the gender, age, and overt vascular risk factors. To clarify the role of hypertension, 200 subjects with grade 1 DWMLs at baseline were categorized into three groups according to their status of hypertension and its treatment.

RESULTS

Of the 200 subjects with grade 1 DWMLs, 47 subjects (23.5%) showed progression of DWMLs (progression group). In the progression group, the percentage of subjects with hypertension and the systolic blood pressure values were higher than in the non-progression group. In addition, subjects ≥ 60 years old at baseline tended to show deterioration of DWMLs in the group with hypertension without antihypertensive treatment.

CONCLUSION

The results of this 10-year longitudinal study imply a positive correlation between long-standing hypertension and the progression of DWMLs.

Higher Blood Pressure is Associated with Greater White Matter Lesions and Brain Atrophy: A Systematic Review with Meta-Analysis

BACKGROUND

To summarise and quantify the evidence on the association between Blood pressure (BP), white matter lesions (WMLs), and brain volumes.

METHOD

Electronic databases PubMed, Scopus, and Clarivate were searched in February 2020 using an established methodology and pre-determined search terms. Studies were eligible for inclusion if they reported on the association between BP and WMLs or brain volume in cognitively healthy individuals, while adjusting for age and intra-cranial volume.

RESULTS

Searches yielded 7509 articles, of which 52 (26 longitudinal and 33 cross-sectional), were eligible and had a combined sample size of 343,794 individuals. Analyses found that 93.7% of studies reported that higher BP was associated with poorer cerebral health (higher WMLs and lower brain volumes). Meta-analysis of compatible results indicated a dose-dependent relationship with every one standard deviation increase in systolic BP (SBP) above 120 mmHg being associated with a 11.2% (95% CI 2.3, 19.9, p = 0.0128) increase in WMLs and -0.13% (95% CI -0.25, -0.023, p = 0.0183) smaller hippocampal volume.

CONCLUSION

The association between BP and brain volumes appears across the full range of BP measurements and is not limited to hypertensive individuals. Higher BP in community-residing individuals is associated with poorer cerebral health.

Cerebral alterations in West African HIV and non-HIV adults aged ≥50: An MRI study

Objectives:

To cross-sectionally describe brain alterations in PLHIV aged above 50 years old, receiving antiretroviral treatment (ART) and living in Senegal compared to HIV-negative subjects.

Methods:

Twenty PLHIV and 26 HIV-negative subjects with comparable socio-demographic and clinical characteristics underwent an MRI exam (3D-T1 and FLAIR sequences). Global atrophy and White Matter Hyperintensities (WMH) were evaluated. After assessing the feasibility and acceptability of MRI scans in this population, we described atrophy and WHM prevalence and associated factors using logistic regressions.

Results:

Overall, 43.5% of the study sample were aged ≥60 years, 58.7% were women, and 28.3% had hypertension. The overall prevalence of atrophy and WMH was 19.6% [95% CI: 8.1–31.1] and 30.4% [95% CI: 17.1–43.7]. HIV status had no significant effect on atrophy or WMH. Unemployment and hypertension were significantly associated with atrophy, whereas women were less likely to present atrophy. Aged ≥60 years was the only factor associated with WMH.

Conclusions:

A high prevalence of atrophy and WMH was observed in West African adults aged over 50 years without a clear HIV impact. As brain MRI studies are critical to better understand cognitive and emotional outcomes, we encourage those studies in older PLHIV in West Africa.

Interaction of Age and Self-reported Physical Sports Activity on White Matter Hyperintensity Volume in Healthy Older Adults

Cerebral white matter (WM) lesion load, as measured by white matter hyperintensity (WMH) volume with magnetic resonance imaging (MRI), has been associated with increasing age and cardiovascular risk factors, like hypertension. Physical sports activity (PSA) may play an important role in maintaining WM in the context of healthy aging. In 196 healthy older adults, we investigated whether participants reporting high levels of PSA (n = 36) had reduced total and regional WMH volumes compared to those reporting low levels of PSA (n = 160). Age group [young-old (YO) = 50-69 years; old-old (OO) = 70-89 years], PSA group, and age by PSA group interaction effects were tested, with sex, hypertension, and body mass index (BMI) as covariates. We found significant main effects for age group and age by PSA group interactions for total, frontal, temporal, and parietal WMH volumes. There were no main effects of PSA group on WMH volumes. The OO group with low PSA had greater total, frontal, temporal, and parietal WMH volumes than the YO with low PSA and OO with high PSA groups. WMH volumes for the YO and OO groups with high PSA were comparable. These findings indicate an age group difference in those with low PSA, with greater WMH volumes in older adults, which was not observed in those with high PSA. The results suggest that engaging in high levels of PSA may be an important lifestyle factor that can help to diminish WMH lesion load in old age, potentially reducing the impact of brain aging.

Common Brain Structural Alterations Associated with Cardiovascular Disease Risk Factors and Alzheimer's Dementia: Future Directions and Implications

Recent reports suggest declines in the age-specific risk of Alzheimer's dementia in higher income Western countries. At the same time, investigators believe that worldwide trends of increasing mid-life modifiable risk factors [e.g., cardiovascular disease (CVD) risk factors] coupled with the growth of the world's oldest age groups may nonetheless lead to an increase in Alzheimer's dementia. Thus, understanding the overlap in neuroanatomical profiles associated with CVD risk factors and AD may offer more relevant targets for investigating ways to reduce the growing dementia epidemic than current targets specific to isolated AD-related neuropathology. We hypothesized that a core group of common brain structural alterations exist between CVD risk factors and Alzheimer's dementia. Two co-authors conducted independent literature reviews in PubMed using search terms for CVD risk factor burden (separate searches for 'cardiovascular disease risk factors', 'hypertension', and 'Type 2 diabetes') and 'aging' or 'Alzheimer's dementia' with either 'grey matter volumes' or 'white matter'. Of studies that reported regionally localized results, we found support for our hypothesis, determining 23 regions commonly associated with both CVD risk factors and Alzheimer's dementia. Within this context, we outline future directions for research as well as larger cerebrovascular implications for these commonalities. Overall, this review supports previous as well as more recent calls for the consideration that both vascular and neurodegenerative factors contribute to the pathogenesis of dementia.

Heat therapy: possible benefits for cognitive function and the aging brain

Alzheimer's disease (AD) is the most common neurodegenerative disease, yet there are no disease-modifying treatments available and there is no cure. It is becoming apparent that metabolic and vascular conditions such as type 2 diabetes (T2D) and hypertension promote the development and accumulation of Alzheimer's disease-related dementia pathologies. To this end, aerobic exercise, which is a common lifestyle intervention for both metabolic disease and hypertension, is shown to improve brain health during both healthy aging and dementia. However, noncompliance or other barriers to exercise response are common in exercise treatment paradigms. In addition, reduced intracellular proteostasis and mitochondrial function could contribute to the etiology of AD. Specifically, compromised chaperone systems [i.e., heat shock protein (HSP) systems] can contribute to protein aggregates (i.e., β-amyloid plaques and neurofibrillary tangles) and reduced mitochondrial quality control (i.e., mitophagy). Therefore, novel therapies that target whole body metabolism, the vasculature, and chaperone systems (like HSPs) are needed to effectively treat AD. This review focuses on the role of heat therapy in the treatment and prevention of AD. Heat therapy has been independently shown to reduce whole body insulin resistance, improve vascular function, activate interorgan cross talk via endocytic vesicles, and activate HSPs to improve mitochondrial function and proteostasis in a variety of tissues. Thus, heat therapy could offer immense clinical benefit to patients suffering from AD. Importantly, future studies in patients are needed to determine the safety and efficacy of heat therapy in preventing AD.

Age and Diastolic Blood Pressure Play an Important Role in the Progression of White Matter Lesions: A Meta-Analysis

INTRODUCTION

White matter lesions (WMLs) are currently considered as a cerebral microvascular disease, and hypertension is considered as its most important risk factor. This study analysis systematically evaluated the effects of systolic blood pressure (SBP) and diastolic blood pressure (DBP) on the progression of WMLs.

METHODS

We searched the MeSH terms: "white matter," "blood pressure," "hypertension," "Leukoencephalopathy," and "leukoaraiosis" on PubMed and Cochrane from January 2000 to August 2019. A total of 12 closely related literature were included for research.

RESULTS

The results of the meta-analysis showed that the increase of both SBP and DBP can promote the progression of WMLs (respectively, odds ratio [OR] = 2.90, 95% confidence interval [CI] 2.86-2.94; OR = 3.13, 95% CI 3.03-3.23). Subgroup analysis found that patients with hypertension aged younger than 70 years are at a greater risk of WML progression when their DBP increased (OR = 4.69, 95% CI 3.31-6.65).

CONCLUSION

The relationship between DBP and WMLs is closer than that of SBP. Also, the risk of WML progression in patients aged under 70 years was higher than that in patients aged over 70 years. Furthermore, when DBP is elevated in patients younger than 70 years of age, the risk of WML progression may be higher. Therefore, it is expected that more researchers will attach importance to the change in DBP and identify the range of blood pressure and strategies that control DBP, thus contributing to delay the progression of WMLs.

Associations of Blood Pressure and Carotid Flow Velocity with Brain Volume and Cerebral Small Vessel Disease in a Community-Based Population

Cerebral small vessel disease (CSVD) is a common finding on brain magnetic resonance imaging (MRI). We previously demonstrated that high blood pressure (BP) and low carotid flow velocity were associated with cerebrovascular disease. However, their associations with brain volume and CSVD remain to be determined. A total of 721 adults (≥ 50 years) from the community-based I-Lan Longitudinal Aging Study were included. Flow velocities at the common (CCA) and internal carotid artery (ICA), including peak systolic velocity (PSV) and end-diastolic velocity (EDV), were measured with Doppler ultrasound. We further detected the presence of CSVD including lacune, microbleed, and white matter hyperintensity (WMH) on brain MRI, which were used to construct a combined CSVD score. General linear regression and logistic regression analysis were exploited to evaluate the association between carotid flow velocity, BP, brain volume, and CSVD. The mean of white matter, gray matter, and WMH volume were 422.2 cm³, 546.9 cm³, and 2.61 cm³, respectively. The proportion of lacune and microbleed were 11.1% and 14.2%, respectively. The CSVD score were negatively associated with gray (r = - 0.121, p < .01) and white matter volume (r = 0.058, p = 0.12), but positively associated with systolic BP (beta = 1.02, p = 0.0017). EDV at common carotid artery associated positively with white matter volume (beta = 1.013, p = 0.0064) and negatively predicted the presence CSVD (odds ratio [OR] = 0.93, p = 0.0023). In the ordinal logistic regression analysis adjusting for age, sex, total intracranial volume education, low-density lipoprotein cholesterol, and fasting glucose, compared with hypertensive subjects with low EDV, normotensive subjects with low, middle, and high EDV had an odds ratio of 0.656 (0.327-1.318), 0.429 (0.261-0.705), and 0.272 (0.147-0.502) for CSVD score, respectively. High SBP and low carotid flow velocities were independently associated with brain volume and CSVD. These associations may be involved in the pathophysiology of cognitive function decline.

Immune responses to stroke: mechanisms, modulation, and therapeutic potential

Stroke is the second leading cause of death worldwide and a leading cause of disability. Most strokes are caused by occlusion of a major cerebral artery, and substantial advances have been made in elucidating how ischemia damages the brain. In particular, increasing evidence points to a double-edged role of the immune system in stroke pathophysiology. In the acute phase, innate immune cells invade brain and meninges and contribute to ischemic damage, but may also be protective. At the same time, danger signals released into the circulation by damaged brain cells lead to activation of systemic immunity, followed by profound immunodepression that promotes life-threatening infections. In the chronic phase, antigen presentation initiates an adaptive immune response targeted to the brain, which may underlie neuropsychiatric sequelae, a considerable cause of poststroke morbidity. Here, we briefly review these pathogenic processes and assess the potential therapeutic value of targeting immunity in human stroke.

High blood pressure predicts hippocampal atrophy rate in cognitively impaired elders

INTRODUCTION

Understanding relationships among blood pressure (BP), cognition, and brain volume could inform Alzheimer's disease (AD) management.

METHODS

We investigated Alzheimer's Disease Neuroimaging Initiative (ADNI) participants: 200 controls, 346 mild cognitive impairment (MCI), and 154 AD. National Alzheimer's Co-ordinating Center (NACC) participants were separately analyzed: 1098 controls, 2297 MCI, and 4845 AD. Relationships between cognition and BP were assessed in both cohorts and BP and atrophy rates in ADNI. Multivariate mixed linear-regression models were fitted with joint outcomes of BP (systolic, diastolic, and pulse pressure), cognition (Mini-Mental State Examination, Logical Memory, and Digit Symbol) and atrophy rate (whole-brain, hippocampus).

RESULTS

ADNI MCI and AD patients with greater baseline systolic BP had higher hippocampal atrophy rates ([r, P value]; 0.2, 0.005 and 0.2, 0.04, respectively). NACC AD patients with lower systolic BP had lower cognitive scores (0.1, 0.0003).

DISCUSSION

Higher late-life BP may be associated with faster decline in cognitively impaired elders.

Brain atrophy in cerebral small vessel diseases: Extent, consequences, technical limitations and perspectives: The HARNESS initiative

Brain atrophy is increasingly evaluated in cerebral small vessel diseases. We aim at systematically reviewing the available data regarding its extent, correlates and cognitive consequences. Given that in this context, brain atrophy measures might be biased, the first part of the review focuses on technical aspects. Thereafter, data from the literature are analyzed in light of these potential limitations, to better understand the relationships between brain atrophy and other MRI markers of cerebral small vessel diseases. In the last part, we review the links between brain atrophy and cognitive alterations in patients with cerebral small vessel diseases.

Pregnancy History, Hypertension, and Cognitive Impairment in Postmenopausal Women

Purpose of Review

Risks for developing cardiovascular disease and cognitive decline increase with age. In women, these risks may be influenced by pregnancy history. This review provides an integrated evaluation of associations of pregnancy history with hypertension, brain atrophy, and cognitive decline in postmenopausal women.

Recent Findings

Atrophy in the occipital lobes of the brain was evident in women who had current hypertension and a history of preeclampsia. Deficits in visual memory in women with a history of preeclampsia are consistent with these brain structural changes. The blood velocity response to chemical and sympathoexcitatory stimuli were altered in women with a history of preeclampsia linking impairments in cerebrovascular regulation to the structural and functional changes in the brain.

Summary

Having a history of preeclampsia should require close monitoring of blood pressure and initiation of anti-hypertensive treatment in perimenopausal women. Mechanisms by which preeclampsia affects cerebrovascular structure and function require additional study.

Hypertension and Cognitive Decline: Implications of Obstructive Sleep Apnea

Hypertension and dementia are highly prevalent in the general population. Hypertension has been shown to be a risk factor for Alzheimer's dementia and vascular dementia. Sleep apnea, another common disorder, is strongly associated with hypertension and recent evidence suggests that it may also be linked with cognitive decline and dementia. It is possible that sleep apnea is the final common pathway linking hypertension to the development of dementia. This hypothesis merits further exploration as sleep apnea is readily treatable and such therapy could foreseeably delay or prevent the onset of dementia. At present, there is a paucity of therapeutic modalities that can prevent or arrest cognitive decline. In this review, we describe the associations between hypertension, dementia and sleep apnea, the pathophysiologic mechanisms underlying these associations, and the literature examining the impact of treatment of hypertension and sleep apnea on cognition. Potential areas of future investigation that may help advance our understanding of the magnitude and direction of the interaction between these conditions and the effects of treatment of high blood pressure and sleep apnea on cognition are highlighted.

Age-dependent association of white matter abnormality with cognition after TIA or minor stroke

OBJECTIVE

To investigate if the association between MRI-detectable white matter hyperintensity (WMH) and cognitive status reported in previous studies persists at older ages (>80 years), when some white matter abnormality is almost universally reported in clinical practice.

METHODS

Consecutive eligible patients from a population-based cohort of all TIA/nondisabling stroke (Oxford Vascular Study) underwent multimodal MRI, including fluid-attenuated inversion recovery and diffusion-weighted imaging, allowing automated measurement of WMH volume, mean diffusivity (MD), and fractional anisotropy (FA) in normal-appearing white matter using FSL tools. These measures were related to cognitive status (Montreal Cognitive Assessment) at age ≤80 vs >80 years.

RESULTS

Of 566 patients (mean [range] age 66.7 [20-102] years), 107 were aged >80 years. WMH volumes and MD/FA were strongly associated with cognitive status in patients aged ≤80 years (all p < 0.001 for WMH, MD, and FA) but not in patients aged >80 years (not significant for WMH, MD, and FA), with age interactions for WMH volume (p _interaction = 0.016) and MD (p _interaction = 0.037). Voxel-wise analyses also showed that lower Montreal Cognitive Assessment scores were associated with frontal WMH in patients ≤80 years, but not >80 years.

CONCLUSION

MRI markers of white matter damage are strongly related to cognition in patients with TIA/minor stroke at younger ages, but not at age >80 years. Clinicians and patients should not overinterpret the significance of these abnormalities at older ages.

Asymptomatic Cerebral Small Vessel Disease: Insights from Population-Based Studies

Cerebral small vessel disease (CSVD) is a common group of neurological conditions that confer a significant burden of morbidity and mortality worldwide. In most cases, CSVD is only recognized in its advanced stages once its symptomatic sequelae develop. However, its significance in asymptomatic healthy populations remains poorly defined. In population-based studies of presumed healthy elderly individuals, CSVD neuroimaging markers including white matter hyperintensities, lacunes, cerebral microbleeds, enlarged perivascular spaces, cortical superficial siderosis, and cerebral microinfarcts are frequently detected. While the presence of these imaging markers may reflect unique mechanisms at play, there are likely shared pathways underlying CSVD. Herein, we aim to assess the etiology and significance of these individual biomarkers by focusing in asymptomatic populations at an epidemiological level. By primarily examining population-based studies, we explore the risk factors that are involved in the formation and progression of these biomarkers. Through a critical semi-systematic review, we aim to characterize “asymptomatic” CSVD, review screening modalities, and draw associations from observational studies in clinical populations. Lastly, we highlight areas of research (including therapeutic approaches) in which further investigation is needed to better understand asymptomatic CSVD.

Cardiovascular disease risk factors, tract-based structural connectomics, and cognition in older adults

Cardiovascular disease risk factors (CVD-RFs) are associated with decreased gray and white matter integrity and cognitive impairment in older adults. Less is known regarding the interplay between CVD-RFs, brain structural connectome integrity, and cognition. We examined whether CVD-RFs were associated with measures of tract-based structural connectivity in 94 non-demented/non-depressed older adults and if alterations in connectivity mediated associations between CVD-RFs and cognition. Participants (age = 68.2 years; 52.1% female; 46.8% Black) underwent CVD-RF assessment, MRI, and cognitive evaluation. Framingham 10-year stroke risk (FSRP-10) quantified CVD-RFs. Graph theory analysis integrated T1-derived gray matter regions of interest (ROIs; 23 a-priori ROIs associated with CVD-RFs and dementia), and diffusion MRI-derived white matter tractography into connectivity matrices analyzed for local efficiency and nodal strength. A principal component analysis resulted in three rotated factor scores reflecting executive function (EF; FAS, Trail Making Test (TMT) B-A, Letter-Number Sequencing, Matrix Reasoning); attention/information processing (AIP; TMT-A, TMT-Motor, Digit Symbol); and memory (CVLT-II Trials 1-5 Total, Delayed Free Recall, Recognition Discriminability). Linear regressions between FSRP-10 and connectome ROIs adjusting for word reading, intracranial volume, and white matter hyperintensities revealed negative associations with nodal strength in eight ROIs (p-values<.05) and negative associations with efficiency in two ROIs, and a positive association in one ROI (p-values<.05). There was mediation of bilateral hippocampal strength on FSRP-10 and AIP, and left rostral middle frontal gyrus strength on FSRP-10 and AIP and EF. Stroke risk plays differential roles in connectivity and cognition, suggesting the importance of multi-modal neuroimaging biomarkers in understanding age-related CVD-RF burden and brain-behavior.

Metabolic syndrome alters relationships between cardiometabolic variables, cognition and white matter hyperintensity load

Cardiometabolic risk factors influence white matter hyperintensity (WMH) development: in metabolic syndrome (MetS), higher WMH load is often reported but the relationships between specific cardiometabolic variables, WMH load and cognitive performance are uncertain. We investigated these in a Brazilian sample (aged 50–85) with (N = 61) and without (N = 103) MetS. Stepwise regression models identified effects of cardiometabolic and demographic variables on WMH load (from FLAIR MRI) and verbal recall performance. WMH volume was greater in MetS, but verbal recall performance was not impaired. Age showed the strongest relationship with WMH load. Across all participants, systolic blood pressure (SBP) and fasting blood glucose were also contributors, and WMH volume was negatively associated with verbal recall performance. In non-MetS, higher HbA1c, SBP, and number of MetS components were linked to poorer recall performance while higher triglyceride levels appeared to be protective. In MetS only, these relationships were absent but education exerted a strongly protective effect on recall performance. Thus, results support MetS as a construct: the clustering of cardiometabolic variables in MetS alters their individual relationships with cognition; instead, MetS is characterised by a greater reliance on cognitive reserve mechanisms. In non-MetS, strategies to control HbA1c and SBP should be prioritised as these have the largest impact on cognition.

Effect of Antihypertensive Medication on Cerebral Small Vessel Disease

Background and Purpose—

Hypertension is an important risk factor for cerebral small vessel disease. We aimed to study the effect of antihypertensive medication (AHM) on the progression of cerebral small vessel disease.

Methods—

We performed a systematic literature search of electronic databases up to January 30, 2017, for randomized controlled trials on the effect of AHM on ≥1 cerebral small vessel disease magnetic resonance imaging markers (ie, white matter hyperintensities, lacunes, microbleeds, enlarged perivascular spaces, acute small subcortical infarcts, and brain atrophy) after ≥1 year. We performed a random-effects meta-analysis using standardized mean difference.

Results—

We included 4 trials, including patients with stroke, with diabetes mellitus, and people ≥70 years of age. Patients in the AHM group had less progression of white matter hyperintensity during 28 to 47 months (standardized mean difference, −0.19; 95% confidence interval, −0.32 to −0.06; I 2 =20%; n=1369). Two trials reported on progression of brain atrophy with conflicting results. None of the trials reported on other cerebral small vessel disease markers.

Conclusions—

AHM has a protective effect on the progression of white matter hyperintensities, but no effect on brain atrophy. There are no trials on the effect of AHM on lacunes, microbleeds, enlarged perivascular spaces, or acute small subcortical infarcts.

MRI progression of cerebral small vessel disease and cognitive decline in patients with hypertension

OBJECTIVE

Hypertension is associated with cognitive deficits, probably because it is a major risk factor for the development of white matter hyperintensities (WMH), lacunes, and cerebral microbleeds, which are MRI markers of cerebral small vessel disease. Studies into associations between presence or progression of these MRI markers and cognitive decline in hypertensive patients are rare. We investigated the association of baseline presence and progression of MRI markers of cerebral small vessel disease with cognitive decline over 4 years in patients with hypertension.

METHODS

In this longitudinal study, hypertensive patients underwent neuropsychological assessments and brain MRI at baseline and after 4 years. Presence and progression of periventricular and subcortical WMH, lacunes, and cerebral microbleeds were visually rated.

RESULTS

In total, 128 hypertensive patients (90 patients with essential hypertension and 38 hypertensive lacunar stroke patients), mean age: 58.6 ± 12.2 years, were included. Progression of periventricular WMH was associated with cognitive decline in simple regression analysis (P = 0.001) and in multivariable analysis with correction for baseline WMH presence and potential confounders (P = 0.004). In this multivariable analysis, R of progression of periventricular WMH was 5.6%, whereas R of baseline presence of periventricular WMH was 0.6%. We did not find significant associations between baseline presence or progression of the other MRI markers and cognitive decline.

CONCLUSION

In patients with hypertension, progression of periventricular WMH over 4 years is associated with cognitive decline, whereas we could not show an association between baseline periventricular WMH and cognitive decline. These results emphasize the importance of preventing progression of WMH in hypertensive patients.

Defining the Relationship Between Hypertension, Cognitive Decline, and Dementia: a Review

Hypertension is a highly prevalent condition which has been established as a risk factor for cardiovascular and cerebrovascular disease. Although the understanding of the relationship between cardiocirculatory dysfunction and brain health has improved significantly over the last several decades, it is still unclear whether hypertension constitutes a potentially treatable risk factor for cognitive decline and dementia. While it is clear that hypertension can affect brain structure and function, recent findings suggest that the associations between blood pressure and brain health are complex and, in many cases, dependent on factors such as age, hypertension chronicity, and antihypertensive medication use. Whereas large epidemiological studies have demonstrated a consistent association between high midlife BP and late-life cognitive decline and incident dementia, associations between late-life blood pressure and cognition have been less consistent. Recent evidence suggests that hypertension may promote alterations in brain structure and function through a process of cerebral vessel remodeling, which can lead to disruptions in cerebral autoregulation, reductions in cerebral perfusion, and limit the brain's ability to clear potentially harmful proteins such as β-amyloid. The purpose of the current review is to synthesize recent findings from epidemiological, neuroimaging, physiological, genetic, and translational research to provide an overview of what is currently known about the association between blood pressure and cognitive function across the lifespan. In doing so, the current review also discusses the results of recent randomized controlled trials of antihypertensive therapy to reduce cognitive decline, highlights several methodological limitations, and provides recommendations for future clinical trial design.

Location Sensitive Deep Convolutional Neural Networks for Segmentation of White Matter Hyperintensities

The anatomical location of imaging features is of crucial importance for accurate diagnosis in many medical tasks. Convolutional neural networks (CNN) have had huge successes in computer vision, but they lack the natural ability to incorporate the anatomical location in their decision making process, hindering success in some medical image analysis tasks. In this paper, to integrate the anatomical location information into the network, we propose several deep CNN architectures that consider multi-scale patches or take explicit location features while training. We apply and compare the proposed architectures for segmentation of white matter hyperintensities in brain MR images on a large dataset. As a result, we observe that the CNNs that incorporate location information substantially outperform a conventional segmentation method with handcrafted features as well as CNNs that do not integrate location information. On a test set of 50 scans, the best configuration of our networks obtained a Dice score of 0.792, compared to 0.805 for an independent human observer. Performance levels of the machine and the independent human observer were not statistically significantly different (p-value = 0.06).

Longitudinal association of hypertension and diabetes mellitus with cognitive functioning in a general 70-year-old population: the SONIC study

Both hypertension and diabetes in middle-aged individuals have been suggested to be predictive indicators of cognitive decline. However, the association of hypertension, diabetes and their combination with cognitive functioning is still controversial in older people. The purpose of this study was to investigate the association between cognitive decline and hypertension, diabetes, and their combination in 70-year-old people based on a 3-year longitudinal analysis. Four hundred and fifty-four people aged 70 (±1) years who participated in the Japanese longitudinal cohort study of Septuagenarians, Octogenarians and Nonagenarians Investigation with Centenarians (SONIC) were recruited randomly from a general population and were monitored for 3 years. The data, including most of the demographics, cognitive functioning measured by the Montreal Cognitive Assessment Japanese version (MoCA-J), blood pressure, blood chemistry and other medical histories, were collected at baseline and during the follow-up. The prevalence of hypertension noted in the follow-up survey was significantly higher than than noted at baseline. The mean MoCA-J score at follow-up was not significantly different from the score obtained at baseline. However, the participants with diabetes, especially combined with hypertension at baseline, had significantly lower MoCA-J scores than those without lifestyle-related diseases. The combination of hypertension and diabetes was still a significant risk factor for cognitive decline, considering the MoCA-J scores obtained during the follow-up after adjustments at baseline, relative to sex, body mass index, dyslipidemia, smoking, excessive alcohol intake, antihypertensive treatment and education level (β=-0.14; P<0.01). Our findings indicate that diabetes and the combination of hypertension and diabetes are clear risk factors for future cognitive decline in elderly individuals who are 70 years of age.

Age-induced differences in brain neural activation elicited by visual emotional stimuli: A high-density EEG study

Identifying the brain sources of neural activation during processing of emotional information remains a very challenging task. In this work, we investigated the response to different emotional stimuli and the effect of age on the neuronal activation. Two negative emotion conditions, i.e., 'anger' and 'fear' faces were presented to 22 adult female participants (11 young and 11 elderly) while acquiring high-density electroencephalogram (EEG) data of 256 channels. Brain source localization was utilized to study the modulations in the early N170 event-related-potential component. The results revealed alterations in the amplitude of N170 and the localization of areas with maximum neural activation. Furthermore, age-induced differences are shown in the topographic maps and the neural activation for both emotional stimuli. Overall, aging appeared to affect the limbic area and its implication to emotional processing. These findings can serve as a step toward the understanding of the way the brain functions and evolves with age which is a significant element in the design of assistive environments.