Cardiovascular risk factors and small vessel disease of the brain: Blood pressure, white matter lesions, and functional decline in older persons

Resistance to developing brain pathology due to vascular risk factors: the role of educational attainment

Brain pathology develops at different rates between individuals with similar burden of risk factors, possibly explained by brain resistance. We examined if education contributes to brain resistance by studying its influence on the association between vascular risk factors and brain pathology. In 4111 stroke-free and dementia-free community-dwelling participants (62.9 ± 10.7 years), we explored the association between vascular risk factors (hypertension and the Framingham Stroke Risk Profile [FRSP]) and imaging markers of brain pathology (markers of cerebral small vessel disease and brain volumetry), stratified by educational attainment level. Associations of hypertension and FSRP with markers of brain pathology were not significantly different between levels of educational attainment. Certain associations appeared weaker in those with higher compared to lower educational attainment, particularly for white matter hyperintensities (WMH). Supplementary residual analyses showed significant associations between higher educational attainment and stronger resistance to WMH among others. Our results suggest a role for educational attainment in resistance to vascular brain pathology. Yet, further research is needed to better characterize determinants of brain resistance.

Association of Blood Pressure, White Matter Lesions, and Regional Cerebral Blood Flow

Background

At present, the association between blood pressure, regional cerebral blood flow, and white matter lesions is not well understood.

Material/Methods

A total of 147 subjects aged from 40 to 80 years were assessed by the Fazekas score for white matter lesions, CT perfusion imaging for regional cerebral blood flow, and 24-h ambulatory blood pressure monitoring for blood pressure level and rhythm. Logistic regression analysis was used to obtain the odds ratio and 95% confidence interval between Fazekas scores and relevant factors. The relationship between blood pressure index and regional cerebral blood flow was analyzed through cubic curve estimation.

Results

Fazekas score was negatively correlated with regional cerebral blood flow (r=−0.801; r=−0.831, P<0.001). For subcortical lesion, the regional cerebral blood flow of Fazekas grade 0 was 1.976 times that of Fazekas grade 3 (OR=1.976, 95% CI=1.576–2.477), and for periventricular lesion, the regional cerebral blood flow of Fazekas grade 0 was 2.034 times that of Fazekas grade 3 (OR=2.034, 95% CI=1.602–2.583). Increased nighttime systolic blood pressure may be more dangerous (OR=1.112, 95% CI=1.059–1.169). The day-night systolic blood pressure ratio (OR=0.801, 95% CI 0.711–0.902) and the day-night diastolic blood pressure ratio (OR=0.876, 95% CI 0.807–0.950) were significantly correlated with Fazekas score.

Conclusions

The decrease of white matter regional cerebral blood flow caused by hypertension is probably one of the important causes of white matter lesions. Patients with white matter lesions should also pay attention to the rhythm of blood pressure when controlling hypertension, especially if their blood pressure is too high or too low at night.

Beware of white matter hyperintensities causing systematic errors in FreeSurfer gray matter segmentations!

Volumetric estimates of subcortical and cortical structures, extracted from T1-weighted MRIs, are widely used in many clinical and research applications. Here, we investigate the impact of the presence of white matter hyperintensities (WMHs) on FreeSurfer gray matter (GM) structure volumes and its possible bias on functional relationships. T1-weighted images from 1,077 participants (4,321 timepoints) from the Alzheimer's Disease Neuroimaging Initiative were processed with FreeSurfer version 6.0.0. WMHs were segmented using a previously validated algorithm on either T2-weighted or Fluid-attenuated inversion recovery images. Mixed-effects models were used to assess the relationships between overlapping WMHs and GM structure volumes and overall WMH burden, as well as to investigate whether such overlaps impact associations with age, diagnosis, and cognitive performance. Participants with higher WMH volumes had higher overlaps with GM volumes of bilateral caudate, cerebral cortex, putamen, thalamus, pallidum, and accumbens areas (p < .0001). When not corrected for WMHs, caudate volumes increased with age (p < .0001) and were not different between cognitively healthy individuals and age-matched probable Alzheimer's disease patients. After correcting for WMHs, caudate volumes decreased with age (p < .0001), and Alzheimer's disease patients had lower caudate volumes than cognitively healthy individuals (p < .01). Uncorrected caudate volume was not associated with ADAS13 scores, whereas corrected lower caudate volumes were significantly associated with poorer cognitive performance (p < .0001). Presence of WMHs leads to systematic inaccuracies in GM segmentations, particularly for the caudate, which can also change clinical associations. While specifically measured for the Freesurfer toolkit, this problem likely affects other algorithms.

White matter hyperintensities segmentation using the ensemble U-Net with multi-scale highlighting foregrounds

White matter hyperintensities (WMHs) are abnormal signals within the white matter region on the human brain MRI and have been associated with aging processes, cognitive decline, and dementia. In the current study, we proposed a U-Net with multi-scale highlighting foregrounds (HF) for WMHs segmentation. Our method, U-Net with HF, is designed to improve the detection of the WMH voxels with partial volume effects. We evaluated the segmentation performance of the proposed approach using the Challenge training dataset. Then we assessed the clinical utility of the WMH volumes that were automatically computed using our method and the Alzheimer’s Disease Neuroimaging Initiative database. We demonstrated that the U-Net with HF significantly improved the detection of the WMH voxels at the boundary of the WMHs or in small WMH clusters quantitatively and qualitatively. Up to date, the proposed method has achieved the best overall evaluation scores, the highest dice similarity index, and the best F1-score among 39 methods submitted on the WMH Segmentation Challenge that was initially hosted by MICCAI 2017 and is continuously accepting new challengers. The evaluation of the clinical utility showed that the WMH volume that was automatically computed using U-Net with HF was significantly associated with cognitive performance and improves the classification between cognitive normal and Alzheimer’s disease subjects and between patients with mild cognitive impairment and those with Alzheimer’s disease. The implementation of our proposed method is publicly available using Dockerhub (https://hub.docker.com/r/wmhchallenge/pgs).

Plasma lipids are associated with white matter microstructural changes and axonal degeneration

Dislipidemia is a risk factor for cognitive impairment. We studied the association between interindividual variability of plasma lipids and white matter (WM) microstructure, using diffusion tensor imaging (DTI) in 273 healthy adults. Special focus was placed on 7 regions of interest (ROI) which are structural components of cognitive neurocircuitry. We also investigated the effect of plasma lipids on cerebrospinal fluid (CSF) neurofilament light chain (NfL), an axonal degeneration marker. Low density lipoprotein (LDL) and triglyceride (TG) levels showed a negative association with axial diffusivity (AxD) in multiple regions. High density lipoproteins (HDL) showed a positive correlation. The association was independent of Apolipoprotein E (APOE) genotype, blood pressure or use of statins. LDL moderated the relation between NfL and AxD in the body of the corpus callosum (p = 0.041), right cingulum gyrus (p = 0.041), right fornix/stria terminalis (p = 0.025) and right superior longitudinal fasciculus (p = 0.020) and TG in the right inferior longitudinal fasciculus (p = 0.004) and left fornix/stria terminalis (p = 0.001). We conclude that plasma lipids are associated to WM microstructural changes and axonal degeneration and might represent a risk factor in the transition from healthy aging to disease.

White matter hyperintensities and cognition across different Alzheimer's biomarker profiles

BACKGROUND/OBJECTIVES

To examine the association between white matter hyperintensities (WMH) and cognitive domains such as memory and executive function (EF) across different clinical and biomarker categories of Alzheimer's disease (AD).

DESIGN

Cross-sectional study.

SETTING

Alzheimer's Disease Neuroimaging Initiative.

PARTICIPANTS

A total of 216 cognitively normal (CN) participants and 407 participants with mild cognitive impairment (MCI) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) at baseline.

MEASUREMENTS

Based on the 2018 research framework, participants were classified using AT(N) (amyloid-β deposition [A], pathologic tau [T], and neurodegeneration [(N)]) biomarkers into one of three categories: biomarker negative [A - T- (N)-], amyloid negative but other biomarker positive [A - T ± (N)+ or A - T + (N)±] or amyloid positive [A + T ± (N)±]. Linear regression models were then used to examine the association between WMH and memory composite scores and EF composite scores.

RESULTS

Higher WMH burden was associated with worse EF in both CN and MCI subgroups while a significant association between WMH and memory was only found in the MCI subgroup. Furthermore, WMH was associated with EF in the group with A - T ± (N)+ or A - T + (N)± biomarker category, but not for A - T - (N)- (normal biomarker) and A + T ± (N) ± (AD pathology). The association between higher WMH and worse memory was independent of amyloid levels in individuals with MCI with evidence of AD pathology.

CONCLUSION

Vascular disease, as indexed by WMH, independent of AD pathology affects cognitive function in both CN and MCI subgroups. Future studies using the AT(N) research framework should consider white matter lesions as a key biomarker contributing to the clinical presentation of AD.

PHACTR1 genetic variability is not critical in small vessel ischemic disease patients and PcomA recruitment in C57BL/6J mice

Recently, several genome-wide association studies identified PHACTR1 as key locus for five diverse vascular disorders: coronary artery disease, migraine, fibromuscular dysplasia, cervical artery dissection and hypertension. Although these represent significant risk factors or comorbidities for ischemic stroke, PHACTR1 role in brain small vessel ischemic disease and ischemic stroke most important survival mechanism, such as the recruitment of brain collateral arteries like posterior communicating arteries (PcomAs), remains unknown. Therefore, we applied exome and genome sequencing in a multi-ethnic cohort of 180 early-onset independent familial and apparently sporadic brain small vessel ischemic disease and CADASIL-like Caucasian patients from US, Portugal, Finland, Serbia and Turkey and in 2 C57BL/6J stroke mouse models (bilateral common carotid artery stenosis [BCCAS] and middle cerebral artery occlusion [MCAO]), characterized by different degrees of PcomAs patency. We report 3 very rare coding variants in the small vessel ischemic disease-CADASIL-like cohort (p.Glu198Gln, p.Arg204Gly, p.Val251Leu) and a stop-gain mutation (p.Gln273*) in one MCAO mouse. These coding variants do not cluster in PHACTR1 known pathogenic domains and are not likely to play a critical role in small vessel ischemic disease or brain collateral circulation. We also exclude the possibility that copy number variants (CNVs) or a variant enrichment in Phactr1 may be associated with PcomA recruitment in BCCAS mice or linked to diverse vascular traits (cerebral blood flow pre-surgery, PcomA size, leptomeningeal microcollateral length and junction density during brain hypoperfusion) in C57BL/6J mice, respectively. Genetic variability in PHACTR1 is not likely to be a common susceptibility factor influencing small vessel ischemic disease in patients and PcomA recruitment in C57BL/6J mice. Nonetheless, rare variants in PHACTR1 RPEL domains may influence the stroke outcome and are worth investigating in a larger cohort of small vessel ischemic disease patients, different ischemic stroke subtypes and with functional studies.

White matter hyperintensities mediate the impact of amyloid ß on future freezing of gait in Parkinson's disease

BACKGROUND

Freezing of gait (FOG) is a common symptom in Parkinson's Disease (PD) patients. Previous studies have reported relationships between FOG, substantia nigra (SN) degeneration, dopamine transporter (DAT) concentration, as well as amyloid β deposition. However, there is a paucity of research on the concurrent impact of white matter damage.

OBJECTIVES

To assess the inter-relationships between these different co-morbidities, their impact on future FOG and whether they act independently of each other.

METHODS

We used baseline MRI and longitudinal gait data from 423 de novo PD patients from the Parkinson's Progression Markers Initiative (PPMI). We used deformation based morphometry (DBM) from T1-weighted MRI to measure SN atrophy, and segmentation of white matter hyperintensities (WMH) as a measure of WM pathological load. Putamen and caudate DAT levels from SPECT as well as cerebrospinal fluid (CSF) amyloid β were obtained directly from the PPMI. Following correlation analyses, we investigated whether WMH burden mediates the impact of amyloid β on future FOG.

RESULTS

SN DBM, WMH load, putamen and caudate DAT activity and CSF amyloid β levels were significantly different between PD patients with and without future FOG (p < 0.008). Mediation analysis demonstrated an effect of CSF amyloid β levels on future FOG via WMH load, independent of SN atrophy and striatal DAT activity levels.

CONCLUSIONS

Amyloid β might impact future FOG in PD patients through an increase in WMH burden, in a pathway independent of Lewy body pathology.

Relationship of Four Blood Pressure Indexes to Subclinical Cerebrovascular Diseases Assessed by Brain MRI in General Japanese Men

Aim: The relationship of blood pressure (BP) indexes (systolic blood pressure [SBP], diastolic blood pressure [DBP], pulse pressure [PP], mean arterial pressure [MAP]) to subclinical cerebrovascular diseases (SCVDs) remains unclear. This study aimed to elucidate the relationship of four BP indexes measured at two visits on SCVDs assessed by magnetic resonance imaging (MRI) in general Japanese men.

Methods: In general Japanese men aged 40–79 years ( N =616), office BP indexes were measured at two visits (Visits 1 [2006–2008] and 2 [2010–2014]). MRI images obtained on the third visit (2012–2015) were examined for prevalent SCVDs: lacunar infarction, periventricular hyperintensity (PVH), deep subcortical white matter hyperintensity (DSWMH), microbleeds, and intracranial artery stenosis (ICAS). Using a multivariable logistic regression analysis, we computed and estimated the odds ratio of each prevalent SCVD for one standard deviation higher BP indexes. The same analyses were performed using home BP.

Results: All four office BP indexes at both visits associated with lacunar infarction. Visit 1 and 2 DBP and Visit 1 MAP associated with PVH and DSWMH, and Visit 1 SBP associated with DSWMH. All Visit 2 BP indexes appear to show stronger association with microbleeds than Visit 1 indexes, and Visit 1 and 2 SBP, PP, and MAP showed similar associations with ICAS. Additional analyses using home BP indexes revealed similar relationships; however, the significance of some relationships decreased.

Conclusion: In general Japanese men, BP indexes were associated with most of SCVDs, and BP indexes measured at different periods associated with different SCVDs assessed by MRI.

Longitudinal Association between White Matter Hyperintensities and White Matter Beta-Amyloid Deposition in Cognitively Unimpaired Elderly

BACKGROUND

White matter (WM) beta-amyloid uptake has been used as a reference region to calculate the cortical standard uptake value ratio (SUVr). However, white matter hyperintensities (WMH) may have an influence on WM beta-amyloid uptake. Our study aimed to investigate the associations between WMH and WM beta-amyloid deposition in cognitively unimpaired elderly.

METHODS

Data from 83 cognitively unimpaired individuals in the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset were analyzed. All participants had complete baseline and four-year follow-up information about WMH volume, WM 18F-AV-45 SUVr, and cognitive function, including ADNI-Memory (ADNI-Mem) and ADNI-Executive function (ADNI-EF) scores. Cross-sectional and longitudinal linear regression analyses were used to determine the associations between WMH and WM SUVr and cognitive measures.

RESULTS

Lower WM 18F-AV-45 SUVr at baseline was associated with younger age (β=0.01, P=0.037) and larger WMH volume (β=-0.049, P=0.048). The longitudinal analysis found an annual increase in WM 18F-AV-45 SUVr was associated with an annual decrease in WMH volume (β=-0.016, P=0.041). An annual decrease in the ADNI-Mem score was associated with an annual increase in WMH volume (β=-0.070, P=0.001), an annual decrease in WM 18F-AV-45 SUVr (β=0.559, P=0.030), and fewer years of education (β=0.011, P=0.044). There was no significant association between WM 18F-AV-45 SUVr and ADNI-EF (P>0.05).

CONCLUSION

Reduced beta-amyloid deposition in WM was associated with higher WMH load and memory decline in cognitively unimpaired elderly. WMH volume should be considered when WM 18F-AV-45 SUVr is used as a reference for evaluating cortical 18F-AV-45 SUVr.

Brain Reserve in a Case of Cognitive Resilience to Severe Leukoaraiosis

OBJECTIVE

Leukoaraiosis, or white matter rarefaction, is a common imaging finding in aging and is presumed to reflect vascular disease. When severe in presentation, potential congenital or acquired etiologies are investigated, prompting referral for neuropsychological evaluation in addition to neuroimaging. T2-weighted imaging is the most common magnetic resonance imaging (MRI) approach to identifying white matter disease. However, more advanced diffusion MRI techniques may provide additional insight into mechanisms that influence the abnormal T2 signal, especially when clinical presentations are discrepant with imaging findings.

METHOD

We present a case of a 74-year-old woman with severe leukoaraoisis. She was examined by a neurologist, neuropsychologist, and rheumatologist, and completed conventional (T1, T2-FLAIR) MRI, diffusion tensor imaging (DTI), and advanced single-shell, high b-value diffusion MRI (i.e., fiber ball imaging [FBI]).

RESULTS

The patient was found to have few neurological signs, no significant cognitive impairment, a negative workup for leukoencephalopathy, and a positive antibody for Sjogren's disease for which her degree of leukoaraiosis would be highly atypical. Tractography results indicate intact axonal architecture that was better resolved using FBI rather than DTI.

CONCLUSIONS

This case illustrates exceptional cognitive resilience in the face of severe leukoaraiosis and the potential for advanced diffusion MRI to identify brain reserve.

Interplay of White Matter Hyperintensities, Cerebral Networks, and Cognitive Function in an Adult Population: Diffusion-Tensor Imaging in the Maastricht Study

Background Lesions of cerebral small vessel disease, such as white matter hyperintensities (WMHs) in individuals with cardiometabolic risk factors, interfere with the trajectories of the white matter and eventually contribute to cognitive decline. However, there is no consensus yet about the precise underlying topological mechanism. Purpose To examine whether WMH and cognitive function are associated and whether any such association is mediated or explained by structural connectivity measures in an adult population. In addition, to investigate underlying local abnormalities in white matter by assessing the tract-specific WMH volumes and their tract-specific association with cognitive function. Materials and Methods In the prospective type 2 diabetes-enriched population-based Maastricht Study, structural and diffusion-tensor MRI was performed (December 2013 to February 2017). Total and tract-specific WMH volumes; network measures; cognition scores; and demographic, cardiovascular, and lifestyle characteristics were determined. Multivariable linear regression and mediation analyses were used to investigate the association of WMH volume, tract-specific WMH volumes, and network measures with cognitive function. Associations were adjusted for age, sex, education, diabetes status, and cardiovascular risk factors. Results A total of 5083 participants (mean age, 59 years ± 9 [standard deviation]; 2592 men; 1027 with diabetes) were evaluated. Larger WMH volumes were associated with stronger local (standardized β coefficient, 0.065; P < .001), but not global, network efficiency and lower information processing speed (standardized β coefficient, -0.073; P < .001). Moreover, lower local efficiency (standardized β coefficient, -0.084; P < .001) was associated with lower information processing speed. In particular, the relationship between WMHs and information processing speed was mediated (percentage mediated, 7.2% [95% CI: 3.5, 10.9]; P < .05) by the local network efficiency. Finally, WMH load was larger in the white matter tracts important for information processing speed. Conclusion White matter hyperintensity volume, local network efficiency, and information processing speed scores are interrelated, and local network properties explain lower cognitive performance due to white matter network alterations. © RSNA, 2020 Online supplemental material is available for this article.

CHA2DS2-VASc score, cerebral small vessel disease, and frailty in older patients with atrial fibrillation

The CHA₂DS₂-VASc score is a validated predictor of ischemic stroke in atrial fibrillation (AF) patients. However, data are limited on whether the CHA₂DS₂-VASc score is associated with subclinical brain structural changes or physical frailty among older AF patients. We assessed the relationship between CHA₂DS₂-VASc scores and brain structural changes or physical frailty in AF patients without history of stroke. Overall, 117 patients completed a comprehensive geriatric assessment for physical frailty. In brain magnetic resonance imaging sub-study (n = 49), brain volume and white matter hyperintensity lesion burden were automatically quantified using the LESIONQUANT software program. Patients with high risk of CHA₂DS₂-VASc scores (≥ 2 in men or ≥ 3 in women) tended to be older and had more comorbidities, higher frailty index, and slower gait speed. Total white matter hyperintensity lesion burden was higher in those with high risk of CHA₂DS₂-VASc score than in those with intermediate risk (score of 1 in men or 2 in women) of CHA₂DS₂-VASc score (1.67 [interquartile range: 0.70–3.45] vs. 0.64 [0.19–1.44], p = 0.036). Cognitive function was associated with brain volume, but gait speed was related with white matter hyperintensity lesion burden. In conclusion, we showed a positive relationship between CHA₂DS₂-VASc scores, white matter hyperintensity lesion burden, and physical frailty in older AF patients. Subclinical brain changes associated with high CHA₂DS₂-VASc scores may predict physical frailty risk.

The temporal relationships between white matter hyperintensities, neurodegeneration, amyloid beta, and cognition

Introduction

Cognitive decline in Alzheimer's disease is associated with amyloid beta (Aβ) accumulation, neurodegeneration, and cerebral small vessel disease, but the temporal relationships among these factors is not well established.

Methods

Data included white matter hyperintensity (WMH) load, gray matter (GM) atrophy and Alzheimer's Disease Assessment Scale‐Cognitive‐Plus (ADAS13) scores for 720 participants and cerebrospinal fluid amyloid (Aβ1–42) for 461 participants from the Alzheimer's Disease Neuroimaging Initiative. Linear regressions were used to assess the relationships among baseline WMH, GM, and Aβ1–42 to changes in WMH, GM, Aβ1–42, and cognition at 1‐year follow‐up.

Results

Baseline WMHs and Aβ1–42 predicted WMH increase and GM atrophy. Baseline WMHs and Aβ1–42 predicted worsening cognition. Only baseline Aβ1–42 predicted change in Aβ1–42.

Discussion

Baseline WMHs lead to greater future GM atrophy and cognitive decline, suggesting that WM damage precedes neurodegeneration and cognitive decline. Baseline Aβ1–42 predicted WMH increase, suggesting a potential role of amyloid in WM damage.

Microstructural Predictors of Cognitive Impairment in Cerebral Small Vessel Disease and the Conditions of Their Formation

Introduction: Cerebral small vessel disease (CSVD) is the leading cause of vascular and mixed degenerative cognitive impairment (CI). The variability in the rate of progression of CSVD justifies the search for sensitive predictors of CI. Materials: A total of 74 patients (48 women, average age 60.6 ± 6.9 years) with CSVD and CI of varying severity were examined using 3T MRI. The results of diffusion tensor imaging with a region of interest (ROI) analysis were used to construct a predictive model of CI using binary logistic regression, while phase-contrast magnetic resonance imaging and voxel-based morphometry were used to clarify the conditions for the formation of CI predictors. Results: According to the constructed model, the predictors of CI are axial diffusivity (AD) of the posterior frontal periventricular normal-appearing white matter (pvNAWM), right middle cingulum bundle (CB), and mid-posterior corpus callosum (CC). These predictors showed a significant correlation with the volume of white matter hyperintensity; arterial and venous blood flow, pulsatility index, and aqueduct cerebrospinal fluid (CSF) flow; and surface area of the aqueduct, volume of the lateral ventricles and CSF, and gray matter volume. Conclusion: Disturbances in the AD of pvNAWM, CB, and CC, associated with axonal damage, are a predominant factor in the development of CI in CSVD. The relationship between AD predictors and both blood flow and CSF flow indicates a disturbance in their relationship, while their location near the floor of the lateral ventricle and their link with indicators of internal atrophy, CSF volume, and aqueduct CSF flow suggest the importance of transependymal CSF transudation when these regions are damaged.

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.

Cognitive Impairment Evaluation and Management

Clinicians should use a systematic approach to evaluating patients presenting with a concern for cognitive impairment. This approach includes interviewing a knowledgeable informant and performing a thorough mental status examination in order to determine the presence of functional impairments and the domains of cognition that are impaired. The results of this interview and examination determine the next steps of the diagnostic work-up. The pattern of cognitive impairment shapes the differential diagnosis. Treatment should address symptoms, and environmental, psychological, and behavioral interventions are essential.

Spatial distribution and cognitive impact of cerebrovascular risk-related white matter hyperintensities

OBJECTIVES

White matter hyperintensities (WMHs) are considered macroscale markers of cerebrovascular burden and are associated with increased risk of vascular cognitive impairment and dementia. However, the spatial location of WMHs has typically been considered in broad categories of periventricular versus deep white matter. The spatial distribution of WHMs associated with individual cerebrovascular risk factors (CVR), controlling for frequently comorbid risk factors, has not been systematically investigated at the population level in a healthy ageing cohort. Furthermore, there is an inconsistent relationship between total white matter hyperintensity load and cognition, which may be due to the confounding of several simultaneous risk factors in models based on smaller cohorts.

METHODS

We examined trends in individual CVR factors on total WMH burden in 13,680 individuals (aged 45-80) using data from the UK Biobank. We estimated the spatial distribution of white matter hyperintensities associated with each risk factor and their contribution to explaining total WMH load using voxel-wise probit regression and univariate linear regression. Finally, we explored the impact of CVR-related WMHs on speed of processing using regression and mediation analysis.

RESULTS

Contrary to the assumed dominance of hypertension as the biggest predictor of WMH burden, we show associations with a number of risk factors including diabetes, heavy smoking, APOE ε4/ε4 status and high waist-to-hip ratio of similar, or greater magnitude to hypertension. The spatial distribution of WMHs varied considerably with individual cerebrovascular risk factors. There were independent effects of visceral adiposity, as measured by waist-to-hip ratio, and carriage of the APOE ε4 allele in terms of the unique spatial distribution of CVR-related WMHs. Importantly, the relationship between total WMH load and speed of processing was mediated by waist-to-hip ratio suggesting cognitive consequences to WMHs associated with excessive visceral fat deposition.

CONCLUSION

Waist-to-hip ratio, diabetes, heavy smoking, hypercholesterolemia and homozygous APOE ε4 status are important risk factors, beyond hypertension, associated with WMH total burden and warrant careful control across ageing. The spatial distribution associated with different risk factors may provide important clues as to the pathogenesis and cognitive consequences of WMHs. High waist-to-hip ratio is a key risk factor associated with slowing in speed of processing. With global obesity levels rising, focused management of visceral adiposity may present a useful strategy for the mitigation of cognitive decline in ageing.

Deep White Matter Lesions Are Associated with Early Recognition of Dementia in Alzheimer's Disease

Neuroimages of cerebral amyloid-β (Aβ) accumulation and small vessel disease (SVD) were examined in patients with various types of cognitive disorders using 11C-labeled Pittsburgh Compound B-positron emission tomography (PiB-PET) and magnetic resonance imaging (MRI). The mean cortical standardized uptake value ratio (mcSUVR) was applied for a quantitative analysis of PiB-PET data. The severity of white matter lesions (WML) and enlarged perivascular spaces (EPVS) on MRI were assessed to evaluate complicating cerebral SVD using semiquantitative scales. In homozygous apolipoprotein E ɛ3/ɛ3 carriers, the incidence of more severe WML and EPVS was higher in PiB-positive than PiB-negative patients, indicating that WML and EPVS might be associated with enhanced Aβ accumulation. An association study between PiB-PET and MRI findings revealed that higher WML grades significantly correlate with lower mcSUVRs, especially in the frontal area, indicating that more severe ischemic MRI findings are associated with milder Aβ accumulation among patients with Alzheimer's disease. In these patients SVD may accelerate the occurrence of cognitive decline and facilitate early recognition of dementia.

High-frequency versus theta burst transcranial magnetic stimulation for the treatment of poststroke cognitive impairment in humans

Background

Because the reliability of repetitive transcranial magnetic stimulation (rTMS) in treating poststroke cognitive impairment has not been convincingly demonstrated, we systematically examined the effectiveness of this regimen with 2 protocols.

Methods

We randomly allocated 41 patients with poststroke cognitive impairment to receive 5 Hz rTMS (n = 11), intermittent theta burst stimulation (iTBS; n = 15) or sham stimulation (n = 15). Each group received 10 stimulation sessions over the left dorsolateral prefrontal cortex. We performed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the Beck Depression Inventory at baseline and after the intervention.

Results

The 5 Hz rTMS group showed significantly greater improvement than the sham group in RBANS total score (p = 0.006), attention (p = 0.001) and delayed memory (p < 0.001). The iTBS group showed significantly greater improvement than the sham group in RBANS total score (p = 0.005) and delayed memory (p = 0.007). The 5 Hz rTMS group exhibited a superior modulating effect in attention compared to the iTBS group (p = 0.016). Patients without comorbid hypertension (p = 0.008) were predisposed to favourable therapeutic outcomes.

Limitations

Although we included only patients with left hemispheric stroke, heterogeneity associated with cortical and subcortical implications existed. We did not investigate the remote effects of rTMS.

Conclusion

Our results demonstrated that both 5 Hz rTMS and iTBS were effective for poststroke cognitive impairment in terms of global cognition, attention and memory function; the domain of attention was susceptible to 5 Hz modulation. Treatment with 5 Hz rTMS may slow cognitive decline, representing both a pivotal process in poststroke cognitive impairment and an aspect of neuroplasticity that contributes to disease-modifying strategies.

Clinical trial registration

NCT02006615; clinicaltrials.gov/ct2/show/NCT02006615.

The relation between APOE genotype and cerebral microbleeds in cognitively unimpaired middle- and old-aged individuals

Positive associations between cerebral microbleeds (CMBs) and APOE-ε4 (apolipoprotein E) genotype have been reported in Alzheimer's disease, but show conflicting results. We investigated the effect of APOE genotype on CMBs in a cohort of cognitively unimpaired middle- and old-aged individuals enriched for APOE-ε4 genotype. Participants from ALFA (Alzheimer and Families) cohort were included and their magnetic resonance scans assessed (n = 564, 50% APOE-ε4 carriers). Quantitative magnetic resonance analyses included visual ratings, atrophy measures, and white matter hyperintensity (WMH) segmentations. The prevalence of CMBs was 17%, increased with age (p < 0.05), and followed an increasing trend paralleling APOE-ε4 dose. The number of CMBs was significantly higher in APOE-ε4 homozygotes compared to heterozygotes and non-carriers (p < 0.05). This association was driven by lobar CMBs (p < 0.05). CMBs co-localized with WMH (p < 0.05). No associations between CMBs and APOE-ε2, gray matter volumes, and cognitive performance were found. Our results suggest that cerebral vessels of APOE-ε4 homozygous are more fragile, especially in lobar locations. Co-occurrence of CMBs and WMH suggests that such changes localize in areas with increased vascular vulnerability.

White matter hyperintensities mediate the association of nocturnal blood pressure with cognition

OBJECTIVE

To test the hypotheses that hypertension and nocturnal blood pressure are related to white matter hyperintensity (WMH) volume, an MRI marker of small vessel cerebrovascular disease, and that WMH burden statistically mediates the association of hypertension and dipping status with memory functioning, we examined the relationship of hypertension and dipping status on WMH volume and neuropsychological test scores in middle-aged and older adults.

METHODS

Participants from the community-based Maracaibo Aging Study received ambulatory 24-hour blood pressure monitoring, structural MRI, and neuropsychological assessment. Four hundred thirty-five participants (mean ± SD age 59 ± 13 years, 71% women) with available ambulatory blood pressure, MRI, and neuropsychological data were included in the analyses. Ambulatory blood pressure was used to define hypertension and dipping status (i.e., dipper, nondipper, and reverse dipper based on night/day blood pressure ratio <0.9, 0.9-1, and >1, respectively). Outcome measures included regional WMH and memory functioning derived from a neuropsychological test battery.

RESULTS

The majority of the participants (59%) were hypertensive. Ten percent were reverse dippers, and 40% were nondippers. Reverse dipping in the presence of hypertension was associated with particularly elevated periventricular WMH volume (F 2,423 = 3.78, p = 0.024) and with lowered memory scores (F 2,423 = 3.911, p = 0.021). Periventricular WMH volume mediated the effect of dipping status and hypertension on memory (β = -4.1, 95% confidence interval -8.7 to -0.2, p < 0.05).

CONCLUSION

Reverse dipping in the presence of hypertension is associated with small vessel cerebrovascular disease, which, in turn, mediates memory functioning. These results point toward reverse dipping as a marker of poor nocturnal blood pressure control, particularly among hypertensive individuals, with potentially pernicious effects on cerebrovascular health and associated cognitive function.

Investigating APOE, APP-Aβ metabolism genes and Alzheimer's disease GWAS hits in brain small vessel ischemic disease

Alzheimer’s disease and small vessel ischemic disease frequently co-exist in the aging brain. However, pathogenic links between these 2 disorders are yet to be identified. Therefore we used Taqman genotyping, exome and RNA sequencing to investigate Alzheimer’s disease known pathogenic variants and pathways: APOE ε4 allele, APP-Aβ metabolism and late-onset Alzheimer’s disease main genome-wide association loci (APOE, BIN1, CD33, MS4A6A, CD2AP, PICALM, CLU, CR1, EPHA1, ABCA7) in 96 early-onset small vessel ischemic disease Caucasian patients and 368 elderly neuropathologically proven controls (HEX database) and in a mouse model of cerebral hypoperfusion. Only a minority of patients (29%) carried APOE ε4 allele. We did not detect any pathogenic mutation in APP, PSEN1 and PSEN2 and report a burden of truncating mutations in APP-Aß degradation genes. The single-variant association test identified 3 common variants with a likely protective effect on small vessel ischemic disease (0.54>OR > 0.32, adj. p-value <0.05) (EPHA1 p.M900V and p.V160A and CD33 p.A14V). Moreover, 5/17 APP-Aß catabolism genes were significantly upregulated (LogFC > 1, adj. p-val<0.05) together with Apoe, Ms4a cluster and Cd33 during brain hypoperfusion and their overexpression correlated with the ischemic lesion size. Finally, the detection of Aβ oligomers in the hypoperfused hippocampus supported the link between brain ischemia and Alzheimer’s disease pathology.

Patients with the Subcortical Small Vessel Type of Dementia Have Disturbed Cardiometabolic Risk Profile

BACKGROUND

Population-based studies have shown that cardiometabolic status is associated with the amount of white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI). However, little is known of cardiometabolic risk factors in the subcortical small vessel type of dementia (SSVD), in which WMHs are one of the most prominent manifestations.

OBJECTIVE

To determine whether the profile of cardiometabolic risk factors differed between SSVD, Alzheimer's disease (AD), mixed dementia (combined AD and SSVD), and healthy controls.

METHODS

This was a mono-center, cross-sectional study of SSVD (n = 40), AD (n = 113), mixed dementia (n = 62), and healthy controls (n = 94). In the statistical analyses, we adjusted for covariates using ANCOVA and binary logistic regression.

RESULTS

The prevalence of hypertension was increased in SSVD and mixed dementia (p < 0.001 and p < 0.05 versus controls, respectively). Diabetes was more prevalent in SSVD patients, and body mass index was lower in AD and mixed dementia, compared to the controls (all p < 0.05). Serum total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) were reduced in the SSVD group (both p < 0.05 versus control). These differences remained after adjustment for covariates. In the SSVD group, Trail Making Test A score correlated positively with systolic blood pressure, mean arterial pressure, and pulse pressure.

CONCLUSION

All dementia groups had an altered cardiometabolic risk profile compared to the controls. The SSVD patients showed increased prevalence of hypertension and diabetes, and in line with previous population-based data, TC and LDL-C in serum were reduced.

Education moderates the effects of large central artery aging on cognitive performance in middle-aged and older adults

Central artery aging, including elevated aortic stiffness, central blood pressure (BP), and pulse pressure (PP), is a novel risk factor for the development of age-associated cognitive dysfunction. Individuals with higher educational attainment may develop greater brain pathology prior to the onset of cognitive decline. However, whether education moderates relations between central artery aging and cognitive performance is unknown. We hypothesized that years of formal education would moderate the relation between central artery aging and cognitive performance in middle-aged/older (MA/O) adults (n = 113, age 67.3 ± 0.7 years). Significant interactions between education*central systolic BP (β = .21, p = .02) and education*central PP (β = .22, p = .01) demonstrated weaker associations between central BP and PP with processing speed performance in those with higher education. Similarly, education moderated the relation between aortic stiffness (carotid-femoral pulse wave velocity, cfPWV) and executive function performance (β = .21, p = .02). To test if the relation between central arterial aging and cognitive performance was captured by a predetermined education threshold, MA/O adults were secondarily categorized as ≤high school (HS) (i.e., ≤12 years, n = 36) or >HS (≥13 years, n = 77). Higher central systolic BP was associated with slower processing speed (≤HS: r = -.59, p < .001 vs. >HS: r = -.25, p = .03) and weaker executive function (r = -.39, p = .03 vs. r = -.32, p = .006). Higher cfPWV was selectively correlated with weaker executive function performance (r = -.39, p = .03) in ≤HS only and this association significantly differed between education groups. Educational attainment appears to moderate the adverse effects of central artery aging on cognitive performance among MA/O adults.

Small Vessel Disease

Small vessel disease (SVD) refers to conditions where damage to arterioles and capillaries is predominant, leading to reduced, or interrupted perfusion of the affected organ. Data suggest that when this condition is evident in any organ, it is already systemic in its occurrence and consequences. SVD affects primarily organs that receive significant portions of cardiac output such as the brain, the kidney, and the retina. Thus, SVD is a major etiologic cause in debilitating conditions such as renal failure, blindness, lacunar infarcts, and dementia. The factors that lead to this devastating condition include all the known vascular risk factors when they are not strictly controlled, but lifestyles that include sedentary existence, obesity, and poor sleep patterns are also recognized drivers of SVD. In addition, depression is now recognized as a vascular risk factor. Inflammation is a mediator of SVD, but it is not known which factor(s) predominate in its etiology. This article emphasizes the need for more investigations to define this link further and suggests clinical and societal responses that might reduce the major impacts of this condition on populations.

Is there a relation between sudden sensorineural hearing loss and white matter lesions?

PURPOSE

Sudden sensorineural hearing loss (SSNHL) has similarities to conditions with vascular etiologies such as myocardial infarction and cerebral stroke. Thus, it could be considered as an early sign of a vascular disease and not only a specific local condition. Chronic hypoperfusion in the brain districts leads to a chronic ischemic damage, called cerebral small vessel disease (CSVD), detectable with brain magnetic resonance imaging (MRI).

METHODS

The authors used CSVD to establish the presence of vascular risk factors in individuals with SSNHL and used the Fazekas score scale to classify them.

RESULTS

Our study showed that individuals with SSNHL aged between 48 and 60 years have 26% more probability to have a Fazekas score higher than 1 compared to the general population. Individuals younger than 28 years showed a statistically significant negative correlation to have a Fazekas score higher than 0. The higher is the Fazekas score, the less is the probability of hearing recovery. The medium hearing-recovery probability is 46%. This decreases by 16% for every increase of score in the Fazekas scale. In the present study, the recovery probability decreased from 80% in individuals younger than 48 years with a score of 0 to 14% in individuals with a Fazekas scores of 3 and 4.

CONCLUSIONS

The authors assessed a higher prevalence of CSVD compared to the general population in patients aged between 48 and 60 years with SSNHL. Moreover, they assessed that the presence of CSVD is related to a decreased probability of recovery, as it has already been demonstrated for stroke.

Poor awareness of IADL deficits is associated with reduced regional brain volume in older adults with cognitive impairment

Performance of instrumental activities of daily living (IADLs) can become compromised in older adults with mild cognitive impairment (MCI). Patients' level of insight into their everyday functioning varies both amongst individuals and across domains assessed, with some individuals exhibiting complete unawareness of deficits. The current cross-sectional study examined the neuroanatomical substrates of self-awareness in order to help explain the variability in this phenomenon in older adults across a continuum of cognitive impairment. Eighty-five participants (ages 54-88, mean age = 73 years, 57% female, 89% Caucasian) diagnosed with MCI or mild probable dementia underwent structural magnetic resonance imaging. Level of self-awareness was assessed by calculating the discrepancy between objective and subjective performance across six IADLs (Financial Management, Driving, Grocery Shopping, Nutrition Evaluation, Medication Management, and Telephone Use). Over-estimation of current abilities occurred in 13-31% of the sample depending on which IADL was evaluated. Poor awareness was significantly related to reduced volume in the bilateral medial prefrontal cortex, middle and posterior cingulate cortex, right insular cortex, and cerebellum. No associations were found with total white matter lesion load. These findings were broadly consistent across all functional domains assessed, supporting the theory that cortical midline and cerebellar structures are involved in self-referential processing across a variety of different cognitive and behavioral skills. Longitudinal studies are needed to confirm this association.

Assessment of risk factors for coronary artery disease in military personnel: A study from Iran

Introduction:

Cardiovascular diseases are the most significant cause of mortality. Although the risk factors of this disease are well known, the strength of these factors varies in different populations and needs to be investigated.

Aim:

The aim of this study is to estimate the amount of the effect of each classic risk factor on CAD (coronary artery disease) among Aja personnel.

Materials and Methods:

This matched case-control study was conducted on 1000 male Aja personnel admitted selecting Aja hospitals in Tehran in 2017. The samples were selected using purposive-graded sampling method. The 250 military patients hospitalized for CAD were considered as a case group. Each case was individually matched for age and service force with tree military patients without CAD. Data were gathered using standard demographic information and history of risk factors questionnaire and analyzed using SPSS 23 and statistical tests. Odds ratio measured trough Cochran–Mantel–Haenszel test and used to estimate the amount of the effect of each classic risk factors on CAD.

Results:

Data analysis indicated that the risk factors including diabetes, hyperlipidemia, smoking, hypertension, and positive family history of CAD enhance the probability of CAD as much as 79.2%, 77.3%, 67.7%, 64.1%, and 56.6%, respectively.

Conclusion:

Diabetes and other modifiable risk factors have the greatest impact on CAD among the concerned Aja personnel. Hence, the authorities can consider the independent amount of the effect of each risk factor and modify them in order to prevent the disease more effectively and purposefully among the personnel.

Cognitive Functioning in Older People. Results of the First Wave of Cognition of Older People, Education, Recreational Activities, Nutrition, Comorbidities, Functional Capacity Studies (COPERNICUS)

Background: Cognitive reserve is a way of explaining why some individuals with a high degree of brain pathology are without clinical manifestations. In this study, factors related to systemic diseases, body composition, aerobic capacity, past and current behavior were examined and included as predictors of cognitive function.

Materials and Methods: 407 subjects (60–88 years old) underwent physical examination and cognitive function assessment [Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), and Trail Making Test Part B (TMT B)]. Predictors of cognitive functioning were evaluated: occupational status (OS), diet, mental and touristic activities were assessed using an ad hoc questionnaire. Aerobic capacity was measured using a six-minute walk test (6MWT).

Results: With each year of age there is a decrease in MMSE score by 0.18 points. Varicose veins on lower extremities and low OS were also significantly associated with MMSE result. For every year of having hypertension, low OS and not being abroad in the last 3 years, there was 0.17, 0.30, and 0.16 less points, respectively, and 0.15 more point per one additional meter walked in 6MWT in the MoCA score. With each year of age and for low OS there was there were 0.31 and 0.21 s more to complete TMT B, respectively.

Conclusion: Education, OS, presence of systemic diseases and social and tourist activities, aerobic capacity and body composition could be considered as factors contributing to cognitive functioning in older people. However, the relationship of above mentioned factors with education level and cognitive function may be not fully orthogonal.

Postmortem brain MRI is related to cognitive decline, independent of cerebral vessel disease in older adults

The purpose of this study was to determine whether metrics of brain tissue integrity derived from postmortem magnetic resonance imaging (MRI) are associated with late-life cognitive decline, independent of cerebral vessel disease. Using data from 554 older adults, we used voxelwise regression to identify regions where the postmortem MRI transverse relaxation rate constant R2 was associated with the rate of decline in global cognition. We then used linear mixed models to investigate the association between a composite R2 measure and cognitive decline, controlling for neuropathology including 3 indices of vessel disease: atherosclerosis, arteriolosclerosis, and cerebral amyloid angiopathy. This composite R2 measure was associated with the rate of decline (0.049 unit annually per R2 unit, p < 0.0001) and accounted for 6.1% of its variance, beyond contributions from vessel disease indices and other prominent age-related neuropathologies. Thus, postmortem brain R2 reflects disease processes underlying cognitive decline that are not captured by vessel disease indices or other standard neuropathologic indices and may provide a measure of brain tissue integrity that is complementary to histopathologic evaluation.

Impact of atrial fibrillation on the rate of mild cognitive impairment in the elderly

Mild cognitive impairment (MCI) in patients with cardiovascular risks is a transitional state to vascular dementia but which still has a possibility of being managed. The objectives of this study were to assess the impact of atrial fibrillation (AF) on cognitive performances in the elderly in comparison with similar cardiovascular risks. One hundred unselected patients were included in AF+ and AF- groups. Patients with prodromal Alzheimer disease as shown by semantic cueing test, and those suffering from major cognitive decline according to DSM 5 criteria were evaluated separately from those patients analysed for vascular cognitive impairment. MCI was distinguished with the help of the Montreal cognitive assessment and the mood status was studied with the geriatric depression scale. AF+ patients predominantly had paroxysmal type of AF with a mean duration of 6.3 years, with 77% of the patients being on anticoagulation. AF- patients had arterial hypertension. Prevalence of MCI was significantly higher among AF- patients, possibly due to lower rates of BP control. These study results show less impact of AF itself on cognitive performances in comparison with uncontrolled hypertension.

Hypertension and Cerebral Microangiopathy (Cerebral Small Vessel Disease): Genetic and Epigenetic Aspects of Their Relationship

Hypertension (HT) and its cerebral complications are extremely vexing medical and social problems. Despite the obvious association between hypertension and the clinical and neuroimaging features of cerebral microangiopathy (CMA) (also known as cerebral small vessel disease), the causal links between them remain ambiguous. Besides, antihypertensive therapy as the only way to manage these patients does not always prevent brain damage. Knowledge about the key factors and mechanisms involved in HT and CMA development is important for predicting the risk of cerebral complications and developing new approaches to their prevention and treatment. At present, genome-wide association studies and other approaches are used to investigate the common hereditary mechanisms of HT and CMA development, which will explain a large number of CMA cases not associated with hypertension, lack of a correlation between HT severity and the degree of cerebral injury, and failure of antihypertensive therapy to prevent CMA progression. Epigenetic markers likely play a modulating role in the development of these diseases.

Neuroimaging Signatures of Cerebral Small Vessel Disease at Blood Pressure Cutoff Levels of 130/80 and 140/90 mmHg: A Population-Based Study in Community-Dwellers Aged ≥ 60 Years

INTRODUCTION

Recent guidelines suggest that a blood pressure cutoff of 130/80 mmHg should be used to define arterial hypertension. This contrasts with the previously accepted cutoff of 140/90 mmHg.

AIM

Using the Atahualpa Project cohort, we aimed to assess the cutoff that better correlates with signatures of cerebral small vessel disease (SVD), which are related to arterial hypertension.

METHODS

Of 437 Atahualpa residents aged ≥ 60 years, 363 (83%) underwent brain MRI and blood pressure determinations. Using logistic regression models, we evaluated the association between SVD and the two different cutoffs, after adjusting for demographics and cardiovascular risk factors. Using receiver operator characteristics curve analysis, we calculated sensitivity, specificity, and the area under the curve for the predictive value of the two cutoffs for detecting signatures of SVD.

RESULTS

A comparison between the old and new cutoffs showed no differences in the ability to predict subjects with white matter hyperintensities, deep cerebral microbleeds or basal ganglia perivascular spaces. However, the new cutoff improved the identification of individuals with lacunar infarctions, which went from no association using the old cutoff (p = 0.097) to a significant association using the new cutoff (p = 0.036). The new cutoff was more sensitive but less specific than the old cutoff for identifying signatures of cerebral SVD. Areas under the curve were non-significantly higher for the old than for the new cutoffs for all the lesions of interest.

CONCLUSIONS

The new blood pressure cutoff is consistently more sensitive but less specific than the old cutoff for detecting signatures of cerebral SVD. The most striking effect of the new cutoff is the improvement in the identification of lacunar infarctions.

Update on Vascular Cognitive Impairment Associated with Subcortical Small-Vessel Disease

Subcortical small-vessel disease (SSVD) is a disorder well characterized from the clinical, imaging, and neuropathological viewpoints. SSVD is considered the most prevalent ischemic brain disorder, increasing in frequency with age. Vascular risk factors include hypertension, diabetes, hyperlipidemia, elevated homocysteine, and obstructive sleep apnea. Ischemic white matter lesions are the hallmark of SSVD; other pathological lesions include arteriolosclerosis, dilatation of perivascular spaces, venous collagenosis, cerebral amyloid angiopathy, microbleeds, microinfarcts, lacunes, and large infarcts. The pathogenesis of SSVD is incompletely understood but includes endothelial changes and blood-brain barrier alterations involving metalloproteinases, vascular endothelial growth factors, angiotensin II, mindin/spondin, and the mammalian target of rapamycin pathway. Metabolic and genetic conditions may also play a role but hitherto there are few conclusive studies. Clinical diagnosis of SSVD includes early executive dysfunction manifested by impaired capacity to use complex information, to formulate strategies, and to exercise self-control. In comparison with Alzheimer's disease (AD), patients with SSVD show less pronounced episodic memory deficits. Brain imaging has advanced substantially the diagnostic tools for SSVD. With the exception of cortical microinfarcts, all other lesions are well visualized with MRI. Diagnostic biomarkers that separate AD from SSVD include reduction of cerebrospinal fluid amyloid-β (Aβ)42 and of the ratio Aβ42/Aβ40 often with increased total tau levels. However, better markers of small-vessel function of intracerebral blood vessels are needed. The treatment of SSVD remains unsatisfactory other than control of vascular risk factors. There is an urgent need of finding targets to slow down and potentially halt the progression of this prevalent, but often unrecognized, disorder.

A population study of Norwegian psychiatric patients referred for clinical brain scanning

BACKGROUND

Patients with psychiatric conditions are often referred for a brain scan during the course of their diagnostic workup.

AIMS

The aim of our study is to determine frequency and type of organic brain pathology, the relationship to age, gender and psychiatric diagnosis.

METHOD

We investigated magnetic resonance imaging and computed tomography brain scans from consecutively referred patients over a 10-year period (January 2002-December 2011). The reasons for referral, estimated psychiatric diagnosis, and the pathology discovered for each patient were registered.

RESULTS

A total of 34% of patients demonstrated organic brain pathology, of which 32.8% were considered clinically relevant. This represents a higher frequency of relevant pathology than reported in healthy subjects. Age (P < 0.001) and diagnosis (P = 0.016) were the most important determinants for frequency of pathological findings.

CONCLUSIONS

Brain imaging in clinical psychiatry resulted in approximately 30% positive findings mainly associated with increasing pathologies with age, but also with diagnosis.

DECLARATION OF INTEREST

Both T.O.D. and M.K.B. have received honorary from Novartis for scientific lectures about multiple sclerosis. M.K.B. also received honoraria from Biogen for scientific lectures. The other authors have no conflicts of interest.

Peroxisome proliferator-activated receptor γ (PPARγ): A master gatekeeper in CNS injury and repair

Peroxisome proliferator-activated receptor γ (PPARγ) is a widely expressed ligand-modulated transcription factor that governs the expression of genes involved in inflammation, redox equilibrium, trophic factor production, insulin sensitivity, and the metabolism of lipids and glucose. Synthetic PPARγ agonists (e.g. thiazolidinediones) are used to treat Type II diabetes and have the potential to limit the risk of developing brain injuries such as stroke by mitigating the influence of comorbidities. If brain injury develops, PPARγ serves as a master gatekeeper of cytoprotective stress responses, improving the chances of cellular survival and recovery of homeostatic equilibrium. In the acute injury phase, PPARγ directly restricts tissue damage by inhibiting the NFκB pathway to mitigate inflammation and stimulating the Nrf2/ARE axis to neutralize oxidative stress. During the chronic phase of acute brain injuries, PPARγ activation in injured cells culminates in the repair of gray and white matter, preservation of the blood-brain barrier, reconstruction of the neurovascular unit, resolution of inflammation, and long-term functional recovery. Thus, PPARγ lies at the apex of cell fate decisions and exerts profound effects on the chronic progression of acute injury conditions. Here, we review the therapeutic potential of PPARγ in stroke and brain trauma and highlight the novel role of PPARγ in long-term tissue repair. We describe its structure and function and identify the genes that it targets. PPARγ regulation of inflammation, metabolism, cell fate (proliferation/differentiation/maturation/survival), and many other processes also has relevance to other neurological diseases. Therefore, PPARγ is an attractive target for therapies against a number of progressive neurological disorders.

Prevalence, risk factors and consequences of cerebral small vessel diseases: data from three Asian countries

BACKGROUND

Cerebral small vessel disease (SVD) has been suggested to be more common in Asians compared with Caucasians. However, data from population-based studies in Asia are lacking. We report on the prevalence, risk factors and consequences of SVD from contemporary studies in three Asian countries using 3-Tesla MRI for the evaluation of SVD.

METHODS

Clinical, cognitive and 3-Tesla brain MRI assessments were performed among participants of three studies from Singapore, Hong Kong and Korea. SVD markers include white matter hyperintensities (WMHs) using the modified Fazekas scale, lacunes and microbleeds. Cognition was assessed using the Mini Mental Status Examination (MMSE) and Montreal Cognitive Assessment (MoCA). Adjustments were made for age, sex and cardiovascular risk factors.

RESULTS

A total of 1797 subjects were available for analysis (mean age: 70.1±6.3 years and 57% women). The prevalence of confluent WMH was 36.6%, lacunes, 24.6% and microbleeds, 26.9%. Presence of all three SVD markers showed a steeper increase with increasing age rising from 1.9% in the lowest to 46.2% in the highest 5-year age strata. The major risk factors for the increased severity of SVD markers were advancing age and hypertension. Moreover, increasing severity of SVD markers was independently associated with worse performance on MMSE and MoCA.

CONCLUSION

Elderly Asians have a high burden of SVD which was associated with cognitive dysfunction. This suggests that SVD markers should be a potential target for treatment in clinical trials so as to delay progression of cerebrovascular disease and potentially cognitive decline.

Biochemical markers in vascular cognitive impairment associated with subcortical small vessel disease - A consensus report

Background

Vascular cognitive impairment (VCI) is a heterogeneous entity with multiple aetiologies, all linked to underlying vascular disease. Among these, VCI related to subcortical small vessel disease (SSVD) is emerging as a major homogeneous subtype. Its progressive course raises the need for biomarker identification and/or development for adequate therapeutic interventions to be tested. In order to shed light in the current status on biochemical markers for VCI-SSVD, experts in field reviewed the recent evidence and literature data.

Method

The group conducted a comprehensive search on Medline, PubMed and Embase databases for studies published until 15.01.2017. The proposal on current status of biochemical markers in VCI-SSVD was reviewed by all co-authors and the draft was repeatedly circulated and discussed before it was finalized.

Results

This review identifies a large number of biochemical markers derived from CSF and blood. There is a considerable overlap of VCI-SSVD clinical symptoms with those of Alzheimer’s disease (AD). Although most of the published studies are small and their findings remain to be replicated in larger cohorts, several biomarkers have shown promise in separating VCI-SSVD from AD. These promising biomarkers are closely linked to underlying SSVD pathophysiology, namely disruption of blood-CSF and blood–brain barriers (BCB-BBB) and breakdown of white matter myelinated fibres and extracellular matrix, as well as blood and brain inflammation. The leading biomarker candidates are: elevated CSF/blood albumin ratio, which reflects BCB/BBB disruption; altered CSF matrix metalloproteinases, reflecting extracellular matrix breakdown; CSF neurofilment as a marker of axonal damage, and possibly blood inflammatory cytokines and adhesion molecules. The suggested SSVD biomarker deviations contrasts the characteristic CSF profile in AD, i.e. depletion of amyloid beta peptide and increased phosphorylated and total tau.

Conclusions

Combining SSVD and AD biomarkers may provide a powerful tool to identify with greater precision appropriate patients for clinical trials of more homogeneous dementia populations. Thereby, biomarkers might promote therapeutic progress not only in VCI-SSVD, but also in AD.

[Not Available]

Zusammenfassung. Unser Gehirn verändert sich mit zunehmendem Alter. Dieser physiologische Prozess kann mithilfe von Magnetresonanztomografie (MRT) beschrieben werden. Im Laufe des Lebens kommt es zu Atrophie (Schrumpfen von Hirnstrukturen) sowie Auftreten von charakteristischen MRT-Signal-Hyperintensitäten in der weissen Substanz. Eine besonders starke oder frühe Ausprägung dieser Veränderungen kann pathologisch sein. Die Abgrenzung zwischen gesundem Altern und Prozessen mit Krankheitswert ist dabei nicht einfach. In diesem Mini-Review sollen normale Alterungsprozesse des Gehirns beschrieben und krankhafte Veränderungen aufgezeigt werden, die weiterer Abklärung und Behandlung bedürfen.

Association between Low-density lipoprotein cholesterol and occipital periventricular hyperintensities in a group of Chinese patients: an observational study

BACKGROUND

While occipital periventricular hyperintensities (OPVHs) are among the most common mild white matter hyperintensities, the clinical factors associated with OPVHs remain unclear. In this study, we investigated the role of clinical factors in development of pure OPVHs.

METHODS

This study included 97 patients with OPVHs and 73 healthy controls. Univariate analysis of clinical factors in OPVH patients and controls was followed by binomial logistic regression analysis to identify clinical factors significantly associated with OPVHs.

RESULT

Univariate analysis indicated that age, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and apolipoprotein-B (Apo-B) levels differed significantly between the OPVH patients and controls (p < 0.05). Age and gender were correlated with OPVH scores (p < 0.05), while LDL-C, triglycerides, Apo-B and TC were anti-correlated with OPVHs scores (p < 0.05). Multivariate analysis indicated that LDL-C is negatively correlated with OPVHs (p < 0.05), and age is positively correlated with OPVHs (p < 0.001).

CONCLUSION

In summary, LDL-C was negatively and age was positively associated with OPVHs among Chinese patients in a hospital.

Is biological aging accelerated in drug addiction?

Drug-addiction may trigger early onset of age-related disease, due to drug-induced multi-system toxicity and perilous lifestyle, which remains mostly undetected and untreated. We present the literature on pathophysiological processes that may hasten aging and its relevance to addiction, including: oxidative stress and cellular aging, inflammation in periphery and brain, decline in brain volume and function, and early onset of cardiac, cerebrovascular, kidney, and liver disease. Timely detection of accelerated aging in addiction is crucial for the prevention of premature morbidity and mortality.

APOE ε4 status is associated with white matter hyperintensities volume accumulation rate independent of AD diagnosis

To assess the relationship between carriage of APOE ε4 allele and evolution of white matter hyperintensities (WMHs) volume, we longitudinally studied 339 subjects from the Alzheimer's Disease Neuroimaging Initiative cohort with diagnoses ranging from normal controls to probable Alzheimer's disease (AD). A purpose-built longitudinal automatic method was used to segment WMH using constraints derived from an atlas-based model selection applied to a time-averaged image. Linear mixed models were used to evaluate the differences in rate of change across diagnosis and genetic groups. After adjustment for covariates (age, sex, and total intracranial volume), homozygous APOE ε4ε4 subjects had a significantly higher rate of WMH accumulation (22.5% per year 95% CI [14.4, 31.2] for a standardized population having typical values of covariates) compared with the heterozygous (ε4ε3) subjects (10.0% per year [6.7, 13.4]) and homozygous ε3ε3 (6.6% per year [4.1, 9.3]) subjects. Rates of accumulation increased with diagnostic severity; controls accumulated 5.8% per year 95% CI: [2.2, 9.6] for the standardized population, early mild cognitive impairment 6.6% per year [3.9, 9.4], late mild cognitive impairment 12.5% per year [8.2, 17.0] and AD subjects 14.7% per year [6.0, 24.0]. Following adjustment for APOE status, these differences became nonstatistically significant suggesting that APOE ε4 genotype is the major driver of accumulation of WMH volume rather than diagnosis of AD.

White Matter Hyperintensity Associations with Cerebral Blood Flow in Elderly Subjects Stratified by Cerebrovascular Risk

OBJECTIVE

This study aims to add clarity to the relationship between deep and periventricular brain white matter hyperintensities (WMHs), cerebral blood flow (CBF), and cerebrovascular risk in older persons.

METHODS

Deep white matter hyperintensity (dWMH) and periventricular white matter hyperintensity (pWMH) and regional gray matter (GM) and white matter (WM) blood flow from arterial spin labeling were quantified from magnetic resonance imaging scans of 26 cognitively normal elderly subjects stratified by cerebrovascular disease (CVD) risk. Fluid-attenuated inversion recovery images were acquired using a high-resolution 3-dimensional (3-D) sequence that reduced partial volume effects seen with slice-based techniques.

RESULTS

dWMHs but not pWMHs were increased in patients at high risk of CVD; pWMHs but not dWMHs were associated with decreased regional cortical (GM) blood flow. We also found that blood flow in WM is decreased in regions of both pWMH and dWMH, with a greater degree of decrease in pWMH areas.

CONCLUSIONS

WMHs are usefully divided into dWMH and pWMH regions because they demonstrate differential effects. 3-D regional WMH volume is a potentially valuable marker for CVD based on associations with cortical CBF and WM CBF.

Cumulative systolic blood pressure exposure in relation to cognitive function in middle-aged and elderly adults: A prospective, population-based study

The association between systolic blood pressure (SBP) and cognitive function is controversial in elderly adults. In addition, few studies focused on the cumulative effect of SBP. We aimed to investigate the association between cumulative SBP exposure and cognitive function among middle-aged and elderly adults.The analysis was based on the Asymptomatic Polyvascular Abnormalities Community (APAC) study. The primary predictor was the cumulative SBP calculated by consecutive SBP values measured through baseline (2006-2007) up to the fourth examination (2012-2013). The cognitive function was estimated by mini-mental state examination (MMSE) in the fourth examination. Linear regression and logistic regression analyses were used to investigate the association between cumulative SBP and cognitive function.Among 2211 participants (41.4% female, aged 40-94 years), 167 (7.55%) were diagnosed with cognitive impairment (MMSE score < 24). Higher cumulative exposure to SBP (per SD increment) was independently associated with poor cognitive performance after controlling for multiple factors (P < 0.001). We observed nondifferential association between men and women. However, higher cumulative SBP in the adults aged ≥60 years had a stronger association with poor cognitive performance compared with that in adults aged 40 to 60 years.Greater exposure to cumulative SBP is associated with worse cognitive performance among middle-aged and elderly adults. This association is similar between men and women, but stronger in elderly adults.

Regional Gray Matter Atrophy Coexistent with Occipital Periventricular White Matter Hyper Intensities

White matter hyperintensities (WMHs) and brain atrophy often coexist in the elderly. Additionally, WMH is often observed as occipital periventricular hyperintensities (OPVHs) with low-grade periventricular (PV) white matter (WM) lesions and is usually confined within an anatomical structure. However, the effects of OPVHs on gray matter (GM) atrophy remain largely unknown. In this study, we investigated GM atrophy in OPVHs patients and explored the relationship between such atrophy and clinical risk factors. T1-weighted and T2-weighted Magnetic resonance imaging (MRI) were acquired, and voxel-based morphometry (VBM) analysis was applied. The clinical (demographic and cardiovascular) risk factors of the OPVHs patients and healthy controls were then compared. Lastly, scatter plots and correlation analysis were applied to explore the relationship between the MRI results and clinical risk factors in the OPVHs patients. OPVHs patients had significantly reduced GM in the right supramarginal gyrus, right angular gyrus, right middle temporal gyrus, right anterior cingulum and left insula compared to healthy controls. Additionally, OPVHs patients had GM atrophy in the left precentral gyrus and left insula cortex, and such atrophy is associated with a reduction in low-density lipoprotein cholesterol (LDL-C) and apolipoprotein-B (Apo-B).

William B. White Explains the Changes In the Way We Look at Blood Pressure: Which Numbers Matter Most-and Why Can They Be Deceptive?

Dr. White, known worldwide as an expert in the use of 24-hour ambulatory blood pressure monitoring (ABPM), discusses hypertension, the importance of accurate measurement, and the utility of ABPM for effective diagnoses and treatment.