Rapid buildup of brain white matter hyperintensities over 4 years linked to ambulatory blood pressure, mobility, cognition, and depression in old persons

Association of Arterial Stiffness Index and Brain Structure in the UK Biobank: A 10-Year Retrospective Analysis

Arterial stiffening and changes in brain structure both occur with normal aging and can be exacerbated via acquired health conditions. While cross-sectional associations exist, the longitudinal relationship between arterial stiffness and brain structure remains unclear. In this study, we investigated 1) associations between baseline arterial stiffness index (ASI) and brain structure (global and regional grey matter volumes (GMV), white matter hyperintensities (WMH)) 10-years post-baseline (10.4±0.8 years) and 2) associations between the 10-year change in ASI from baseline and brain structure 10-years post-baseline in 650 healthy middle- to older-aged adults (53.4±7.5 years) from the UK Biobank. We observed significant associations between baseline ASI and GMV (p<0.001) and WMH (p=0.0036) 10-years post-baseline. No significant associations between 10-year change in ASI and brain structure (global GMV p=0.24; WMH volume p=0.87) were observed. There were significant associations of baseline ASI in 2 of 60 regional brain volumes analyzed (right posterior superior temporal gyrus p=0.001; left superior lateral occipital cortex p<0.001). Strong associations with baseline ASI, but not changes in ASI over 10-years, suggest arterial stiffness at the entry point of older adulthood is more impactful on brain structure 10-years later compared to age-related stiffening. Based on these associations, we suggest clinical monitoring and potential intervention for reducing arterial stiffness should occur in midlife to reduce vascular contributions to structural changes in the brain, supporting a healthy trajectory of brain aging. Our findings also support use of ASI as a surrogate for gold standard measures in showing overall relationships between arterial stiffness and brain structure.

Impact of long-term white matter hyperintensity changes on mobility and dexterity

White matter hyperintensities (WMH), a common feature of cerebral small vessel disease, are related to worse clinical outcomes after stroke. We assessed the impact of white matter hyperintensity changes over 1 year after minor stroke on change in mobility and dexterity, including differences between the dominant and non-dominant hands and objective in-person assessment versus patient-reported experience. We recruited participants with lacunar or minor cortical ischaemic stroke, performed medical and cognitive assessments and brain MRI at presentation and at 1 year. At both time points, we used the timed-up and go test and the 9-hole peg test to assess mobility and dexterity. At 1 year, participants completed the Stroke Impact Scale. We ran two linear mixed models to assess change in timed-up and go and 9-hole peg test, adjusted for age, sex, stroke severity (National Institutes of Health Stroke Scale), dependency (modified Rankin Score), vascular risk factor score, white matter hyperintensity volume (as % intracranial volume) and additionally for 9-hole peg test: Montreal cognitive assessment, hand (dominant/non-dominant), National Adult Reading Test (premorbid IQ), index lesion side. We performed ordinal logistic regression, corrected for age and sex, to assess relations between timed-up and go and Stroke Impact Scale mobility, and 9-hole peg test and Stroke Impact Scale hand function. We included 229 participants, mean age 65.9 (standard deviation = 11.13); 66% male. 215/229 attended 1-year follow-up. Over 1 year, timed-up and go time increased with aging (standardized β [standardized 95% Confidence Interval]: 0.124[0.011, 0.238]), increasing National Institutes of Health Stroke Scale (0.106[0.032, 0.180]), increasing modified Rankin Score (0.152[0.073, 0.231]) and increasing white matter hyperintensity volume (0.176[0.061, 0.291]). Men were faster than women (-0.306[0.011, 0.238]). Over 1 year, slower 9-hole peg test was related to use of non-dominant hand (0.290[0.155, 0.424]), aging (0.102[0.012, 0.192]), male sex (0.182[0.008, 0.356]), increasing National Institutes of Health Stroke Scale (0.160 [0.094, 0.226]), increasing modified Rankin Score (0.100[0.032, 0.169]), decreasing Montreal cognitive assessment score (-0.090[-0.167, -0.014]) and increasing white matter hyperintensity volume (0.104[0.015, 0.193]). One year post-stroke, Stroke Impact Scale mobility worsened per second increase on timed-up and go, odds ratio 0.67 [95% confidence interval 0.60, 0.75]. Stroke Impact Scale hand function worsened per second increase on the 9-hole peg test for the dominant hand (odds ratio 0.79 [0.71, 0.86]) and for the non-dominant hand (odds ratio 0.88 [0.83, 0.93]). Decline in mobility and dexterity is associated with white matter hyperintensity volume increase, independently of stroke severity. Mobility and dexterity declined more gradually for stable and regressing white matter hyperintensity volume. Dominant and non-dominant hands might be affected differently. In-person measures of dexterity and mobility are associated with self-reported experience 1-year post-stroke.

Association of white matter hyperintensity accumulation with domain-specific cognitive decline: a population-based cohort study

We investigated the association of load and accumulation of white matter hyperintensities (WMHs) with rate of cognitive decline. This population-based study included 510 dementia-free people (age ≥60 years) who had repeated measures of global and regional (lobar, deep, periventricular) WMHs up to 6 years (from 2001-2003 to 2007-2010) and repeated measures of cognitive function (episodic memory, semantic memory, category fluency, letter fluency, executive function, perceptual speed) up to 15 years (from 2001-2004 to 2016-2019). We found that greater baseline loads of global and regional WMHs were associated with faster decline in letter fluency, perceptual speed, and global cognition. Furthermore, faster accumulation of global, deep, and periventricular WMHs was related to accelerated cognitive decline, primarily in perceptual speed. These data show that WMHs are associated with decline in perceptual speed rather than episodic or semantic memory and that cognitive change is more vulnerable to WMH accumulations in deep and periventricular regions.

Reliable Cognitive Decline in Late-Life Major Depression

OBJECTIVE

Major depression in older adults increases the statistical likelihood of dementia. It is challenging to translate statistical evidence of cognitive decline at the group level into knowledge of individual cognitive outcomes. The objective of the current study is to investigate 2-year reliable cognitive change in late-life depression (LLD), which will enhance understanding of cognitive changes in LLD and provide a means to assess individual change.

METHODS

In a sample of non-depressed cognitively normal older adults or NDCN (n = 113), we used linear regression to predict tests of global cognition, processing speed-executive functioning, and memory administered 1 and 2 years later. Stepwise regression was used to select covariates among demographics and raw test scores (either baseline or year 1) and we cross-validated the final models using the predicted residual error sum of squares (PRESS). We then derived a z-change score from the difference between actual and predicted follow-up scores and investigated the proportion of LLD patients (n = 199) and NDCN adults who experienced reliable "decline" (a z-score < -1.645), "stability" (z-scores between + - 1.645), and "improvement" (z scores > +1.645).

RESULTS

A greater proportion LLD compared with NDCN experienced cognitive decline in processing speed/executive functioning and global cognition over 2 years. When compared to NDCN, a greater proportion of LLD also significantly improved on one test of processing speed over 2 years.

CONCLUSIONS

Older adults with LLD are at risk of meaningful cognitive decline over a relatively short period, particularly in the domain of executive functioning and processing speed. This study provides a series of reliable change equations for common neuropsychological tests that can be applied clinically.

The Association Between 24-Hour Blood Pressure Profiles and Dementia

Midlife hypertension increases risk for dementia. Around one third of adults have diagnosed hypertension; however, many adults are undiagnosed, or remain hypertensive despite diagnosis or treatment. Since blood pressure (BP) follows a circadian rhythm, ambulatory BP monitoring allows for the assessment of BP over a 24-hour period and provides an important tool for improving the diagnosis and management of hypertension. The measurement of 24-hour BP profiles, especially nocturnal BP, demonstrate better predictive ability for cardiovascular disease and mortality than office measurement. However, few studies have examined 24-hour BP profiles with respect to dementia risk. This is an important topic since improvements in BP management could facilitate the primary prevention of vascular cognitive impairment and dementia. Therefore, this review discusses the evidence linking BP to dementia, with a focus on whether the implementation of 24-hour BP measurements can improve risk prediction and prevention strategies. Pathways linking nocturnal BP to dementia are also discussed as are risk reduction strategies. Overall, limited research suggests an association between 24-hour BP elevation and poorer cognition, cerebral small vessel disease, and dementia. However, most studies were cross-sectional. Further evidence is needed to substantiate 24-hour BP profiles, over and above office BP, as predictors of vascular cognitive impairment and incident dementia.

Quadratic relationship between systolic blood pressure and white matter lesions in individuals with hypertension

BACKGROUND

There is a well documented relationship between cardiovascular risk factors and the development of brain injury, which can lead to cognitive dysfunction. Hypertension (HTN) is a condition increasing the risk of silent and symptomatic ischemic brain lesions. Although benefits of hypertension treatment are indisputable, the target blood pressure value where the possibility of tissue damage is most reduced remains under debate.

METHOD

Our group performed a cross-sectional ( n  = 376) and longitudinal ( n  = 188) study of individuals without dementia or stroke (60% women n  = 228, age 68.5 ± 7.4 years; men n  = 148, age 70.7 ± 6.9 years). Participants were split into hypertensive ( n  = 169) and normotensive ( n  = 207) groups. MR images were obtained on a 3T system. Linear modeling was performed in hypertensive and normotensive cohorts to investigate the relationship between systolic (SBP) and diastolic (DBP) blood pressure, white matter lesion (WML), and brain volumes.

RESULTS

Participants in the hypertensive cohort showed a quadratic relationship between SBP and WML, with the lowest amounts of WML being measured in participants with readings at approximately 124 mmHg. Additionally, the hypertensive cohort also exhibited a quadratic relationship between DBP and mean hippocampal volume; participants with readings at approximately 77 mmHg showing the largest volumes. Longitudinally, all groups experienced WML growth, despite different BP trajectories, further suggesting that WML expansion may occur despite or because of BP reduction in individuals with compromised vascular system.

CONCLUSION

Overall, our study suggests that in the hypertensive group there is a valley of mid-range blood pressures displaying less pathology in the brain.

Dose-response association between plasma homocysteine and white matter lesions in patients with hypertension: a case-control study

White matter lesions (WMLs) are common MRI changes that are indicative of cerebral small vessel disease (CSVD). Elevated plasma homocysteine (Hcy) levels are related to an increased risk of vascular disease. We aimed to analyze the relationship between Hcy levels and WMLs in patients with hypertension. A total of 1961 patients with WMLs and 15,463 patients without WMLs were matched at a 1:1 ratio by age and sex. Hyperhomocysteinemia (HHcy) was defined as an abnormally high level (>15 µmol/l) of Hcy in a plasma sample. In total, 1888 (WML group) and 1888 (No-WMLs group) patients were enrolled, with 51.6% of the sample being male and a mean age of 63 years. Multivariate logistic regression analysis showed a significant association between a higher level of plasma Hcy and a higher prevalence of WMLs (OR 1.03 95% CI, 1.02-1.04) when the Hcy level was used as a continuous variable. Patients with Hcy levels of 15-20 µmol/l (OR 1.54, 95% CI 1.31-1.81) and >20 µmol/l (OR 1.51, 95% CI 1.26-1.82) also had a significantly higher risk of WMLs than patients with Hcy levels <15 µmol/l. Multivariable-adjusted spline regression models showed that the risk of WMLs started to increase only in patients with Hcy levels above 13.85 µmol/l (P < 0.001). In subgroup analyses of WMLs, there was no significant interaction between the Hcy group and subgroup heterogeneity for the prevalence of WMLs (P > 0.05). Our study found a dose-response association between plasma homocysteine levels, especially a Hcy level >13.85 µmol/l, and the prevalence of WMLs, implying that lowering Hcy levels might be a target for prevention.

Plasma aldosterone concentration is associated with white matter lesions in patients with primary aldosteronism

PURPOSE

Primary aldosteronism (PA) is the most frequent form of secondary hypertension. Hypertension is a risk factor for cognitive decline and dementia. White matter lesions (WMLs) are linked to vascular risk factors, which increase the risk of dementia. We aimed to analyze the association of PA-related parameters and WMLs in patients with PA.

METHODS

We conducted a retrospective analysis of all patients with PA in the Hypertension Center of the People's Hospital of Xinjiang Uygur Autonomous Region from January 1, 2011 to April 1, 2021. We analyzed the relationship between plasma aldosterone concentration (PAC), plasma renin activity (PRA), aldosterone-renin ratio (ARR), serum potassium, and WMLs.

RESULTS

We enrolled 138 patients with WMLs and matched these to controls without WMLs at a 1:4 ratio. Among the analytic sample (N = 711) with ages ranging from 30 to 64 years, 69% were male. In the logistic regression analysis, PAC, PRA and serum potassium were treated as continuous variables. The results showed that PAC (OR 1.04, 95% CI 1.01, 1.06, P = 0.008) was positively associated with the risk of WMLs, and serum potassium (OR 0.26, 95% CI 0.16, 0.44, P < 0.001) was inversely associated with the risk of WMLs. PRA (OR 0.86, 95% CI 0.68, 1.08, P = 0.384) was not associated with the risk of WMLs after adjusting for confounders. The results of restricted cubic splines showed the dose-response association between increasing PAC, ARR, decreasing serum potassium, and the risk of WMLs. We also divided PAC, ARR and serum potassium into two groups according to the result of restricted cubic splines. After adjusting for confounders, patients who were in Q2 (≥23.12 ng/dl) of PAC (OR 2.07, 95% CI 1.36, 3.15), Q2 (≥56.81 (ng/dl per ng/ml*h) of ARR (OR 1.82, 95% CI 1.22, 2.72) and Q2 (≤3.58 mmol/l) of serum potassium (OR 2.99, 95% CI 1.95, 4.50) had a significantly higher risk of WMLs than their counterparts. In stratified analyses, there was no evidence of subgroup heterogeneity regarding the change in the risk of WMLs (P > 0.05 for interaction for all).

CONCLUSION

Our results suggested that the PAC and serum potassium were related to the risk of WMLs in patients with PA. In particular, PAC ≥23.12 ng/dl significantly increased the risk of WMLs in patients with PA.

Physical Activity in Early- and Mid-Adulthood Are Independently Associated With Longitudinal Memory Trajectories in Later Life

BACKGROUND

Physical activity (PA) in later life may reduce dementia risk, but little is known regarding long-term cognitive effects of PA that occurred earlier in adulthood or mechanisms underlying associations. PA patterns at different ages may independently contribute to dementia risk, which would implicate multiple critical periods for intervention. The current study tested whether retrospective reports of PA in early and mid-adulthood were independently associated with later-life longitudinal memory outcomes and whether associations were mediated by late-life cardiometabolic diseases.

METHOD

Participants comprised 5200 Health and Retirement Study Life History Mail Survey respondents. Latent growth curves estimated independent associations between retrospectively reported PA in early adulthood (age 18-29) and mid-adulthood (age 40-49) and 16-year episodic memory trajectories. Indirect pathways involving the maintenance of PA from early- to mid-adulthood and the influence of PA on later-life cardiometabolic diseases (hypertension, diabetes, and heart disease) were also estimated.

RESULTS

PA in early- and mid-adulthood independently predicted higher initial memory level and slower memory decline in later life, respectively. Early-adulthood PA was indirectly associated with later-life memory level through higher mid-adulthood PA and lower rates of later-life hypertension, as well as with subsequent memory decline through higher mid-adulthood PA.

CONCLUSIONS

The current findings highlight the importance of PA throughout adulthood, such that initiating and/or maintaining exercise in early- or mid-adulthood may be protective for later-life cognitive health, and hypertension appears to represent a key mediator of these effects.

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.

Positive Association Between Plasma Aldosterone Concentration and White Matter Lesions in Patients With Hypertension

BACKGROUND AND OBJECTIVE

White matter lesions (WMLs) are imaging changes in MRI of cerebral small vessel disease associated with vascular risk factors, increasing the risk of dementia, depression, and stroke. Aldosterone (ALD) or activation of mineralocorticoid receptor (MR) causes cerebrovascular injury in a mouse model. We aimed to analyze the relationship between ALD and WMLs in a population with hypertension.

METHODS

We conducted a retrospective review of all patients screened for causes of secondary hypertension. We enrolled 547 patients with WMLs and matched these to controls without WMLs at a 1:1 ratio. White matter lesion load was assessed by using a modified Scheltens' scale.

RESULTS

Among the analytic sample (N = 1,094) with ages ranging from 30 to 64 years, 62.2% were male. We divided plasma ALD concentration (PAC), plasma renin activity (PRA), and ALD-renin ratio (ARR) into the third tertile (Q3), second tertile (Q2), and first tertile (Q1). We also analyzed them simultaneously as continuous variables. Multivariate logistic regression analysis showed that participants in Q3 (>17.26 ng/dl) of PAC (OR 1.59, 95% CI 1.15, 2.19), Q3 (<0.80 ng/dl) of PRA (OR 2.50, 95% CI 1.81, 3.44), and Q3 (>18.59 ng/dl per ng/ml*h) of ARR (OR 2.90, 95% CI 2.10, 4.01) had a significantly higher risk of WMLs than those in Q1 (<12.48) of PAC, Q1 (>2.19) of PRA, and Q1 (<6.96) of ARR. In linear regression analysis, we separately analyzed the correlation between the modified Scheltens' scale score and log(PAC) (β = 2.36; 95% CI 1.30, 3.41; p < 0.001), log(PRA) (β = -1.76; 95% CI -2.09, -1.43; p < 0.001), and log(ARR) (β = 1.86; 95% CI 1.55, 2.17; p < 0.001), which were all significantly correlated with white matter lesion load, after adjusting for confounding factors. Simple mediation analyses showed that systolic blood pressure (SBP) or diastolic blood pressure (DBP) mediated -3.83% or -2.66% of the association between PAC and white matter lesion load, respectively. In stratified analyses, there was no evidence of subgroup heterogeneity concerning the change in the risk of WMLs (p > 0.05 for interaction for all).

CONCLUSION

Higher PAC, especially in PAC >17.26 ng/dl, increased the risk of WMLs. PAC was positively associated with white matter lesion load independent of SBP or DBP.

Medium-term effects of SARS-CoV-2 infection on multiple vital organs, exercise capacity, cognition, quality of life and mental health, post-hospital discharge

BACKGROUND

The medium-term effects of Coronavirus disease (COVID-19) on organ health, exercise capacity, cognition, quality of life and mental health are poorly understood.

METHODS

Fifty-eight COVID-19 patients post-hospital discharge and 30 age, sex, body mass index comorbidity-matched controls were enrolled for multiorgan (brain, lungs, heart, liver and kidneys) magnetic resonance imaging (MRI), spirometry, six-minute walk test, cardiopulmonary exercise test (CPET), quality of life, cognitive and mental health assessments.

FINDINGS

At 2-3 months from disease-onset, 64% of patients experienced breathlessness and 55% reported fatigue. On MRI, abnormalities were seen in lungs (60%), heart (26%), liver (10%) and kidneys (29%). Patients exhibited changes in the thalamus, posterior thalamic radiations and sagittal stratum on brain MRI and demonstrated impaired cognitive performance, specifically in the executive and visuospatial domains. Exercise tolerance (maximal oxygen consumption and ventilatory efficiency on CPET) and six-minute walk distance were significantly reduced. The extent of extra-pulmonary MRI abnormalities and exercise intolerance correlated with serum markers of inflammation and acute illness severity. Patients had a higher burden of self-reported symptoms of depression and experienced significant impairment in all domains of quality of life compared to controls (p<0.0001 to 0.044).

INTERPRETATION

A significant proportion of patients discharged from hospital reported symptoms of breathlessness, fatigue, depression and had limited exercise capacity. Persistent lung and extra-pulmonary organ MRI findings are common in patients and linked to inflammation and severity of acute illness.

FUNDING

NIHR Oxford and Oxford Health Biomedical Research Centres, British Heart Foundation Centre for Research Excellence, UKRI, Wellcome Trust, British Heart Foundation.

Higher inflammation and cerebral white matter injury associated with cognitive deficit in asthmatic patients with depression

OBJECTIVE

Depression is a common co-morbidity in asthma, worsening asthma control and impairing quality of life. Previous studies have reported a higher risk of cognitive deficit in depression, yet little research has focused on the level of cognition in asthmatic patients with depression. Evidence shows that inflammation may play an important role in both asthma and depression. Cerebral white matter injury, possibly induced by inflammation, has been associated with depression. This study assesses cognitive function in patients with asthma and a depression comorbidity, compared to patients with asthma only or depression only.

METHODS

Four groups were studied: Asthma comorbid Depression group (A + D, n = 26), Depression group (D, n = 25), Asthma group (A, n = 33) and Normal controls (N, n = 28). Cognitive function was evaluated using Montreal Cognitive Assessment (MoCA). Inflammatory cytokines were measured, including interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), high-mobility group box 1(HMGB1) and Netrin-1. Cerebral white matter injury was assessed by serum myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG), and their correlations with cognitive performance were calculated.

RESULTS

A + D group showed the highest incidence of cognitive deficit, with the cognitive domain particularly affected. Compared to N group, serum levels of IL-6, HMGB1, Netrin-1, MBP and MOG were significantly elevated in A + D group. MOG level negatively correlated with the MoCA score.

CONCLUSION

Patients with comorbidities presented with more severe cognitive deficits and higher levels of inflammatory cytokines. Cerebral white matter injury may account for the cognitive deficit in patients and MOG could be a potential biomarker for this process.

Prediction of Alzheimer's disease biomarker status defined by the 'ATN framework' among cognitively healthy individuals: results from the EPAD longitudinal cohort study

BACKGROUND

The Amyloid/Tau/Neurodegeneration (ATN) framework has been proposed as a means of evidencing the biological state of Alzheimer's disease (AD). Predicting ATN status in pre-dementia individuals therefore provides an important opportunity for targeted recruitment into AD interventional studies. We investigated the extent to which ATN-defined biomarker status can be predicted by known AD risk factors as well as vascular-related composite risk scores.

METHODS

One thousand ten cognitively healthy older adults were allocated to one of five ATN-defined biomarker categories. Multinomial logistic regression tested risk factors including age, sex, education, APOE4, family history of dementia, cognitive function, vascular risk indices (high systolic blood pressure, body mass index (BMI), high cholesterol, physical inactivity, ever smoked, blood pressure medication, diabetes, prior cardiovascular disease, atrial fibrillation and white matter lesion (WML) volume), and three vascular-related composite scores, to predict five ATN subgroups; ROC curve models estimated their added value in predicting pathology.

RESULTS

Age, APOE4, family history, BMI, MMSE and white matter lesions (WML) volume differed between ATN biomarker groups. Prediction of Alzheimer's disease pathology (versus normal AD biomarkers) improved by 7% after adding family history, BMI, MMSE and WML to a ROC curve that included age, sex and APOE4. Risk composite scores did not add value.

CONCLUSIONS

ATN-defined Alzheimer's disease biomarker status prediction among cognitively healthy individuals is possible through a combination of constitutional and cardiovascular risk factors but established dementia composite risk scores do not appear to add value in this context.

Abnormal blood pressure circadian rhythms are relevant to cerebral infarction and Leukoaraiosis in hypertensive patients

BACKGROUND

To investigate the relationships between blood pressure (BP) circadian rhythms and acute cerebral infarction (ACI), silent cerebral infarction (SCI) and the severity of leukoaraiosis in hypertensive patients.

METHODS

A retrospective case-control study was performed among hypertensive patients with 24-h ambulatory blood pressure monitoring (ABPM) and cranial magnetic resonance imaging (MRI).

RESULTS

A total of 1267 patients were enrolled. Lower nocturnal blood pressure (BP) decreases were observed in ACI patients than in controls (3.3% vs 8.2%, P<0.001). Reverse-dipper pattern (RD) and non-dipper pattern (ND) were found to be independent risk factors for ACI. In ACI patients, both RD and ND BP circadian rhythms were revealed to be independent risk factors for moderate-severe leukoaraiosis. In addition, in SCI patients, RD (OR = 1.7, 95% CI, 0.9-3.0; P = 0.047) or extreme-dipper pattern (ED) (OR = 2.9, 95% CI, 1.2-7.0; P = 0.015) were found to be independent risk factors for moderate-severe leukoaraiosis. Moreover, the greater the severity of leukoaraiosis was, the higher the ratio of abnormal BP circadian rhythms.

CONCLUSION

RD and ND BP circadian rhythms might not only be relevant to the onset of ACI but also correlate with the severity of leukoaraiosis. Thus, when modulating BP with antihypertensive drugs, the BP circadian rhythms, and not merely the BP level, should warrant more attention.

Relationship Between Mood, Thinking, and Walking: A Systematic Review Examining Depressive Symptoms, Executive Function, and Gait

Prior literature has proposed that the coexistence of late-life depression, executive dysfunction and impaired gait speed may constitute a specific phenotype in older adults with a possible shared brain mechanism. All three conditions are independently associated with negative health outcomes including impaired function, risk of falling, and reduced quality of life. However, the existence, etiology, and implications of having all three conditions as a unitary triad remain unclear. This systematic review examined the literature to assess the consistency of this triad and to explore the possible role of frontal-subcortical circuitry in its etiology. English language literature that assessed mood, executive function, and gait speed using a validated tool in human participants over age 65 were included for this review. Following the PRISMA guidelines, 15 studies including 11,213 participants met criteria for inclusion in this study. The triad's existence was supported by 12 of the 15 studies (80%), including 4 longitudinal studies involving 368 participants. A prevalence of 17% was reported in one population study. The three included intervention studies provided mixed results regarding the benefit of pharmacologic and exercise interventions. Two studies assessed the association between presence of white matter hyperintensities and the triad, with one study finding a significant longitudinal relationship with periventricular white matter hyperintensities. Vascular risk factors were also commonly associated with this triad. Taken together, the relationship between this triad, the vascular depression hypothesis, and frontal-subcortical pathology is suggested. Further longitudinal research is needed to further clarify the etiology and clinical relevance of this concomitant prescence oflate-life depression, executive dysfunction and impaired gait speed.

Effects of Intensive Versus Standard Ambulatory Blood Pressure Control on Cerebrovascular Outcomes in Older People (INFINITY)

BACKGROUND

Subcortical microvascular disease represented by brain white matter hyperintensity on magnetic resonance imaging is associated with functional decline in older people with hypertension. The effects of 2 levels of 24-hour average systolic blood pressure (BP) on mobility, white matter disease progression, and cognitive function over 3 years were studied.

METHODS

This trial was a prospective, randomized, blinded end-points study in patients ≥75 years of age with systolic hypertension and magnetic resonance imaging evidence of white matter hyperintensity lesions. Patients were randomized to a 24-hour mean systolic BP of ≤130 mm Hg (intensive treatment) versus ≤145 mm Hg (standard treatment) with antihypertensive therapies. Primary study outcomes were changes in mobility (gait speed) and accrual of white matter hyperintensity volume after 3 years. Changes in cognitive function (executive processing) and adverse events were also evaluated.

RESULTS

In 199 randomized patients, the mean age of the cohort was 80.5 years, and 54% were women; the average 24-hour systolic BP was 149 mm Hg. Goal BPs were achieved after a median treatment period of 3 to 4 months; at that time, the mean 24-hour systolic BP was 127.7 mm Hg in the intensive treatment group and 144.0 mm Hg in the standard treatment group for an average difference of 16.3 mm Hg. Changes in gait speed were not different between treatment groups (0.40±2.0 versus 0.42±2.7 s in the intensive treatment and standard treatment groups, respectively; P=0.91), whereas changes from baseline in white matter hyperintensity volumes were smaller (0.29%) in the intensive treatment group compared with the standard treatment group (0.48%; P=0.03). Cognitive outcomes also were not different between the treatment groups. Major adverse cardiovascular events were higher in the standard treatment group compared with the intensive treatment group (17 versus 4 patients; P=0.01). Falls, with or without injury, and syncope were comparable in the treatment groups.

CONCLUSIONS

Intensive lowering of ambulatory BP reduction in older patients with hypertension did not result in differences in mobility outcomes but was associated with a reduction in accrual of subcortical white matter disease. Over periods >3 years, a reduction in the accumulation of white matter disease may be a factor in conserving function.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01650402.

Association of Blood Pressure Variability and Intima-Media Thickness With White Matter Hyperintensities in Hypertensive Patients

Background and Purpose: Ambulatory blood pressure variability (ABPV), ABP, and carotid intima-media thickness (IMT) are closely associated with white matter hyperintensities (WMH), and few studies focused on establishing effective models based on ABP, ABPV, and IMT to predict the WMH burden. We aimed to evaluate the value of a predictive model based on the metrics of ABP, ABPV, and IMT, which were independently associated with the WMH burden.

Methods: We retrospectively enrolled 140 hypertensive inpatients for physical examinations in Shanghai East Hospital, Tongji University School of Medicine between February 2018 and January 2019. The basic clinical information of all subjects was recorded, and we also collected the metrics of ABP, ABPV, and IMT. Patients with Fazekas scale grade ≥2 were classified into heavy burden of WMH group. Then, we analyzed the association between all characteristics and the WMH burden. Multivariate analysis was performed to assess whether the metrics of ABP, ABPV, and IMT were independently associated with WMH, and we used receiver operating characteristic (ROC) to evaluate the value of predictive model based on the metrics of ABP, ABPV, and IMT.

Results: Higher WMH grade was associated with increasing age, diabetes mellitus, higher total cholesterol (TC), higher low-density lipoprotein (LDL), higher IMT, higher 24-h systolic blood pressure (SBP), higher daytime SBP, higher nocturnal SBP, 24-h and daytime standard deviation (SD) of SBP, and 24-h SBP weight SD; 24-h SBP, 24-h SBP-SD, and IMT were independently related to the burden of WMH even after adjusting for the clinical variables. In addition, we also established a model that has a higher predictive capacity using 24-h SBP, 24-h SBP-SD, and IMT in the ROC analysis to assess the WMH burden in hypertensive patients.

Conclusions: Higher 24-h SBP, higher 24-h SBP-SD, and larger IMT were independently associated with a greater burden of WMH among elderly primary hypertension Asian patients. Establishing a model based on these factors might provide a new approach for enhancing the accuracy of diagnosis of WMH using metrics in 24-h ABPM and carotid ultrasound.

The association between frailty and MRI features of cerebral small vessel disease

Frailty is a common syndrome in older individuals that is associated with poor cognitive outcome. The underlying brain correlates of frailty are unclear. The aim of this study was to investigate the association between frailty and MRI features of cerebral small vessel disease in a group of non-demented older individuals. We included 170 participants who were classified as frail (n = 30), pre-frail (n = 85) or non-frail (n = 55). The association of frailty and white matter hyperintensity volume and shape features, lacunar infarcts and cerebral perfusion was investigated by regression analyses adjusted for age and sex. Frail and pre-frail participants were older, more often female and showed higher white matter hyperintensity volume (0.69 [95%-CI 0.08 to 1.31], p = 0.03 respectively 0.43 [95%-CI: 0.04 to 0.82], p = 0.03) compared to non-frail participants. Frail participants showed a non-significant trend, and pre-frail participants showed a more complex shape of white matter hyperintensities (concavity index: 0.04 [95%-CI: 0.03 to 0.08], p = 0.03; fractal dimensions: 0.07 [95%-CI: 0.00 to 0.15], p = 0.05) compared to non-frail participants. No between group differences were found in gray matter perfusion or in the presence of lacunar infarcts. In conclusion, increased white matter hyperintensity volume and a more complex white matter hyperintensity shape may be structural brain correlates of the frailty phenotype.

The neural correlates of discrete gait characteristics in ageing: A structured review

Gait is complex, described by diverse characteristics underpinned by widespread central nervous system networks including motor and cognitive functions. Despite this, neural substrates of discrete gait characteristics are poorly understood, limiting understanding of gait impairment in ageing and disease. This structured review aims to map gait characteristics, defined from a pre-specified model reflecting independent gait domains, to brain imaging parameters in older adults. Fifty-two studies of 38,029 yielded were reviewed. Studies showed inconsistent approaches when mapping gait assessment to neural substrates, limiting conclusions. Gait impairments typically associated with brain deterioration, specifically grey matter atrophy and white matter integrity loss. Gait velocity, a global measure of gait control, was most frequently associated with these imaging markers within frontal and basal ganglia regions, and its decline predicted from white matter volume and integrity measurements. Fewer studies assessed additional gait measures or functional imaging parameters. Future studies mapping regional neuroanatomical and functional correlates of gait are needed, including those which take a multi-process network perspective to better understand mobility in health and disease.

Review of diffusion MRI studies in chronic white matter diseases

Diffusion MRI studies characterizing the changes in white matter (WM) due to vascular cognitive impairment, which includes all forms of small vessel disease are reviewed. We reviewed the usefulness of diffusion methods in discriminating the affected WM regions and its relation to cognitive impairment. These studies were categorized based on the diffusion MRI techniques used. The most common method was the diffusion tensor imaging, whereas other methods included diffusion weighted imaging, diffusion kurtosis imaging, intravoxel incoherent motion, and studies based on diffusion tractography. The diffusion measures showed correlation with cognitive scores and disease progression, with mean diffusivity being the most robust parameter. Future studies should focus on incorporating multi-compartment and higher order diffusion models, which can handle the presence of multiple and crossing fibers inside a voxel.

Relationships among clinic, home, and ambulatory blood pressures with small vessel disease of the brain and functional status in older people with hypertension

BACKGROUND

Subcortical small vessel disease, represented as white matter hyperintensity (WMH) on magnetic resonance images (MRI) is associated with functional decline in older people with hypertension. We evaluated the relationships of clinic and out-of-office blood pressures (BP) with WMH and functional status in older persons.

METHODS

Using cross-sectional data from 199 older study participants enrolled in the INFINITY trial, we analyzed the clinic, 24-hour ambulatory, and home BPs and their relationships with WMH burden and mobility and cognitive outcomes.

RESULTS

Volume of WMH was associated with clinic and 24-hour ambulatory systolic BP but not home systolic BP. The mobility measure, supine-to-sit time, had a significant association with 24-hour systolic BP and pulse pressure but not with diastolic BP or values obtained by home BP. Cognitive measures of processing speed (Trails Making Test Part A and the Stroop Word Test) were significantly associated with 24-hour systolic BP, but not clinic and home BPs.

CONCLUSION

These data demonstrate that ambulatory BP measurements in older people are more strongly associated with WMH and certain measures of functional status compared to home BP measurements. Hence, home BP may not be a useful substitute for ambulatory BP for assessing subcortical small vessel disease and its consequences. Further longitudinal analyses comparing clinic and various types of out-of-office BP measures with small vessel brain disease are needed. Clinicaltrials.gov identifier: NCT01650402.

A population neuroscience approach to the study of cerebral small vessel disease in midlife and late life: an invited review

Aging in later life engenders numerous changes to the cerebral microvasculature. Such changes can remain clinically silent but are associated with greater risk for negative health outcomes over time. Knowledge is limited about the pathogenesis, prevention, and treatment of potentially detrimental changes in the cerebral microvasculature that occur with advancing age. In this review, we summarize literature on aging of the cerebral microvasculature, and we propose a conceptual framework to fill existing research gaps and advance future work on this heterogeneous phenomenon. We propose that the major gaps in this area are attributable to an incomplete characterization of cerebrovascular pathology, the populations being studied, and the temporality of exposure to risk factors. Specifically, currently available measures of age-related cerebral microvasculature changes are indirect, primarily related to parenchymal damage rather than direct quantification of small vessel damage, limiting the understanding of cerebral small vessel disease (cSVD) itself. Moreover, studies seldom account for variability in the health-related conditions or interactions with risk factors, which are likely determinants of cSVD pathogenesis. Finally, study designs are predominantly cross-sectional and/or have relied on single time point measures, leaving no clear evidence of time trajectories of risk factors or of change in cerebral microvasculature. We argue that more resources should be invested in 1) developing methodological approaches and basic science models to better understand the pathogenic and etiological nature of age-related brain microvascular diseases and 2) implementing state-of-the-science population study designs that account for the temporal evolution of cerebral microvascular changes in diverse populations across the lifespan.

State of the Science of Neural Systems in Late-Life Depression: Impact on Clinical Presentation and Treatment Outcome

Major depression in older adults, or late-life depression (LLD), is a common and debilitating psychiatric disorder that increases the risk of morbidity and mortality. Although the effects of LLD make it important to achieve a diagnosis and start treatment quickly, individuals with LLD are often inadequately or unsuccessfully treated. The latest treatment developments suggest that interventions targeting executive dysfunction and neuroticism, constructs associated with poor response to antidepressants in older adults, are successful in treating LLD. Specific behavioral interventions (computerized cognitive training, mindfulness meditation, aerobic exercise) appear to decrease depressive symptoms and ameliorate executive dysfunction and neuroticism, but we do not fully understand the mechanisms by which these treatments work. We review recent research on neural network changes underlying executive dysfunction and neuroticism in LLD and their association with clinical outcomes (e.g., treatment response, cognitive functioning).

Longitudinal microstructural changes of cerebral white matter and their association with mobility performance in older persons

Mobility impairment in older persons is associated with brain white matter hyperintensities (WMH), a common finding in magnetic resonance images and one established imaging biomarker of small vessel disease. The contribution of possible microstructural abnormalities within normal-appearing white matter (NAWM) to mobility, however, remains unclear. We used diffusion tensor imaging (DTI) measures, i.e. fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), to assess microstructural changes within supratentorial NAWM and WMH sub-compartments, and to investigate their association with changes in mobility performance, i.e. Tinetti assessment and the 2.5-meters walk time test. We analyzed baseline (N = 86, age ≥75 years) and 4-year (N = 41) follow-up data. Results from cross-sectional analysis on baseline data showed significant correlation between WMH volume and NAWM-FA (r = -0.33, p = 0.002), NAWM-AD (r = 0.32, p = 0.003) and NAWM-RD (r = 0.39, p = 0.0002). Our longitudinal analysis showed that after 4-years, FA and AD decreased and RD increased within NAWM. In regional tract-based analysis decrease in NAWM-FA and increase in NAWM-RD within the genu of the corpus callosum correlated with slower walk time independent of age, gender and WMH burden. In conclusion, global DTI indices of microstructural integrity indicate that significant changes occur in the supratentorial NAWM over four years. The observed changes likely reflect white matter deterioration resulting from aging as well as accrual of cerebrovascular injury associated with small vessel disease. The observed association between mobility scores and regional measures of NAWM microstructural integrity within the corpus callosum suggests that subtle changes within this structure may contribute to mobility impairment.

Binswanger's disease: biomarkers in the inflammatory form of vascular cognitive impairment and dementia

Vascular cognitive impairment and dementia (VCID) is a major public health concern because of the increased incidence of vascular disease in the aging population and the impact of vascular disease on Alzheimer's disease. VCID is a heterogeneous group of diseases for which there are no proven treatments. Biomarkers can be used to select more homogeneous populations. Small vessel disease is the most prevalent form of VCID and is the optimal form for treatment trials because there is a progressive course with characteristic pathological changes. Subcortical ischemic vascular disease of the Binswanger type (SIVD-BD) has a characteristic set of features that can be used both to identify patients and to follow treatment. SIVD-BD patients have clinical, neuropsychological, cerebrospinal fluid (CSF) and imaging features that can be used as biomarkers. No one feature is diagnostic, but a multimodal approach defines the SIVD-BD spectrum disorder. The most important features are large white matter lesions with axonal damage, blood-brain barrier disruption as shown by magnetic resonance imaging and CSF, and neuropsychological evidence of executive dysfunction. We have used these features to create a Binswanger Disease Scale and a probability of SIVD-BD, using a machine-learning algorithm. The patients discussed in this review are derived from published studies. Biomarkers not only aid in early diagnosis before the disease process has progressed too far for treatment, but also can indicate response to treatment. Refining the use of biomarkers will allow dementia treatment to enter the era of precision medicine. This article is part of the Special Issue "Vascular Dementia".

In Vivo Brain Plaque and Tangle Burden Mediates the Association Between Diastolic Blood Pressure and Cognitive Functioning in Nondemented Adults

OBJECTIVE

Growing evidence supports an association between increased blood pressure and: (a) poor cognitive performance in older adults, and (b) various biomarkers of increased Alzheimer's disease (AD) neuropathology. The objective of this study was to determine whether systolic blood pressure (SBP) and diastolic blood pressure (DBP) were significantly associated with cognitive functioning in non-demented adults, and to examine in vivo AD pathology as a possible mediator of this association.

METHODS

Positron emission tomography (PET) scans with 2-(1-{6-[(2-[F-18]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile (FDDNP) provide in vivo measurements of plaque and tangle burden. A total of 101 non-demented older subjects with blood pressure data and FDDNP-PET scans were drawn from a larger study of predictors of cognitive decline. A neuropsychological test battery was used to compute "global cognitive scores" (averaged across five key domains), which served as an index of general cognitive functioning.

RESULTS

Higher DBP (but not SBP) was significantly associated with lower cognitive scores, controlling for age, sex, antihypertensive medication use, and ApoE genotype (η2 = 0.06). However, this relationship was no longer significant after introducing FDDNP-PET binding as an additional covariate in the statistical models. In vivo plaque and tangle burden accounted for over 30% of the observed association between higher DBP and poorer cognitive performance.

CONCLUSIONS

By suggesting a mediation of the relationship between DBP and cognitive functioning by FDDNP-PET binding, this study advances our understanding of some potential predictors of cognitive decline in non-demented adults, and underscores the importance of devising early multimodal interventions to more effectively combat degenerative brain disorders.

Prediction of Cognitive Decline from White Matter Hyperintensity and Single-Photon Emission Computed Tomography in Alzheimer's Disease

BACKGROUND

While several studies support an association of white matter hyperintensity (WMH) volume and regional cerebral blood flow (rCBF) with cognitive decline in Alzheimer's disease (AD), no reports have simultaneously considered the effects of both factors on cognitive decline.

OBJECTIVE

The purpose of the present study was to compare WMH volume and rCBF in relation to cognitive function by developing a new software program to fuse magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) data.

METHOD

We used MRI, SPECT, and neuropsychological data from 182 serial outpatients treated at the memory clinic of our hospital.

RESULTS

Twenty-nine AD patients fulfilled the inclusion criteria (18 females, mean age: 73.1 ± 7.9 years, mean Mini-Mental State Examination: 23.1 ± 3.0). Analysis of variance revealed that posterior deep WMH (DWMH) volume was significantly larger than both anterior periventricular hyperintensity (PVH) and DWMH, and posterior PVH volumes. Multivariate regression analysis showed that increased volumes of the anterior PVH and the posterior DWMH and decreased rCBF of the parietal cortex negatively affected cognitive function. The other areas had no significant negative effects on cognitive function.

CONCLUSION

Our findings show that the volume of the posterior WMH was significantly larger than that of other areas, and the increased posterior WMH volume and decreased rCBF of the parietal cortex negatively affected cognitive function. Therefore, the posterior WMH volume and the parietal rCBF are key parameters of cognitive decline in AD patients.

Disease progression and regression in sporadic small vessel disease-insights from neuroimaging

Cerebral small vessel disease (SVD) is considered the most important vascular contributor to the development of dementia. Comprehensive characterization of the time course of disease progression will result in better understanding of aetiology and clinical consequences of SVD. SVD progression has been studied extensively over the years, usually describing change in SVD markers over time using neuroimaging at two time points. As a consequence, SVD is usually seen as a rather linear, continuously progressive process. This assumption of continuous progression of SVD markers was recently challenged by several studies that showed regression of SVD markers. Here, we provide a review on disease progression in sporadic SVD, thereby taking into account both progression and regression of SVD markers with emphasis on white matter hyperintensities (WMH), lacunes and microbleeds. We will elaborate on temporal dynamics of SVD progression and discuss the view of SVD progression as a dynamic process, rather than the traditional view of SVD as a continuous progressive process, that might better fit evidence from longitudinal neuroimaging studies. We will discuss possible mechanisms and clinical implications of a dynamic time course of SVD, with both progression and regression of SVD markers.

Physical Inactivity Predicts Slow Gait Speed in an Elderly Multi-Ethnic Cohort Study: The Northern Manhattan Study

INTRODUCTION

Gait speed is associated with multiple adverse outcomes of aging. We hypothesized that physical inactivity would be prospectively inversely associated with gait speed independently of white matter hyperintensity volume and silent brain infarcts on MRI.

METHODS

Participants in the Northern Manhattan Study MRI sub-study had physical activity assessed when they were enrolled into the study. A mean of 5 years after the MRI, participants had gait speed measured via a timed 5-meter walk test. Physical inactivity was defined as reporting no leisure-time physical activity. Multi-variable logistic and quantile regression was performed to examine the associations between physical inactivity and future gait speed adjusted for confounders.

RESULTS

Among 711 participants with MRI and gait speed measures (62% women, 71% Hispanic, mean age 74.1 ± 8.4), the mean gait speed was 1.02 ± 0.26 m/s. Physical inactivity was associated with a greater odds of gait speed in the lowest quartile (<0.85 m/s, adjusted OR 1.90, 95% CI 1.17-3.08), and in quantile regression with 0.06 m/s slower gait speed at the lowest 20 percentile (p = 0.005).

CONCLUSIONS

Physical inactivity is associated with slower gait speed independently of osteoarthritis, grip strength, and subclinical ischemic brain injury. Modifying sedentary behavior poses a target for interventions aimed at reducing decline in mobility.

Brain structural connectivity in late-life major depressive disorder

Disrupted brain connectivity might explain both the pathogenesis and consequences of late-life major depressive disorder (LLD). However, it remains difficult to ascertain whether and how specific circuits are affected. We reviewed literature regarding brain connectivity in LLD, and we specifically focused on the role of structural pathology. LLD is associated with greater levels of cerebrovascular disease, and greater levels of cerebrovascular disease are associated with both depression development and treatment responsiveness. Cerebrovascular disease is most often measured as white matter hyperintensity (WMH) burden, and histopathology studies suggest WMH reflect myelin damage and fluid accumulation (among other underlying pathology). WMHs appear as confluent caps around the ventricles (periventricular), as well as isolated lesions in the deep white matter. The underlying tissue damage and implications for brain connectivity may differ by WMH location or severity. WMHs are associated with lower white matter microstructural integrity (measured with diffusion tensor imaging) and altered brain function (measured with functional MRI). LLD is also associated with lower white matter microstructural integrity and grey matter loss which may also alter the network properties and function of the brain. Damage to brain structure reflected by WMH, reduced white matter microstructural integrity, and atrophy may affect brain function, and are therefore likely pathophysiological mechanisms of LLD. Additional research is needed to fully characterize the developmental course and pathology underlying these imaging markers, and to understand how structural damage explains LLD's various clinical manifestations.

Dynamic Progression of White Matter Hyperintensities in Alzheimer's Disease and Normal Aging: Results from the Sunnybrook Dementia Study

Although white matter hyperintensities (WMH), markers of cerebral small vessel disease (SVD), are believed to generally increase over time, some studies have shown sharp decreases after therapeutic intervention, suggesting that WMH progression may be more dynamic than previously thought. Our primary goal was to examine dynamic progression of WMH in a real-world sample of Alzheimer’s disease (AD) patients and normal elderly (NC), with varying degrees of SVD. WMH volumes from serial magnetic resonance imaging (MRI; mean = 1.8 years) were measured from NC (n = 44) and AD patients (n = 113) with high and low SVD burden. Dynamic progression for each individual was measured using spatial overlap images to assess shrinkage, growth, and stable WMH volumes. Significant group differences were found for shrinkage (p < 0.001), growth (p < 0.001) and stable (p < 0.001) WMH, where the AD high SVD group showed the largest changes relative to low SVD and NC. Our results suggest spatial progression measured at the individual patient level may be more sensitive to the dynamic nature of WMH.

Midlife exercise blood pressure, heart rate, and fitness relate to brain volume 2 decades later

OBJECTIVE

To determine whether poor cardiovascular (CV) fitness and exaggerated exercise blood pressure (BP) and heart rate (HR) were associated with worse brain morphology in later life.

METHODS

Framingham Offspring participants (n = 1,094, 53.9% female) free from dementia and CV disease (CVD) underwent an exercise treadmill test at a mean age of 40 ± 9 years. A second treadmill test and MRI scans of the brain were administered 2 decades later at mean age of 58 ± 8 years.

RESULTS

Poor CV fitness and greater diastolic BP and HR response to exercise at baseline were associated with a smaller total cerebral brain volume (TCBV) almost 2 decades later (all p < 0.05) in multivariable adjusted models; the effect of 1 SD lower fitness was equivalent to approximately 1 additional year of brain aging in individuals free of CVD. In participants with prehypertension or hypertension at baseline, exercise systolic BP was also associated with smaller TCBV (p < 0.05).

CONCLUSION

Our results suggest that lower CV fitness and exaggerated exercise BP and HR responses in middle-aged adults are associated with smaller brain volume nearly 2 decades later. Promotion of midlife CV fitness may be an important step towards ensuring healthy brain aging.

Consensus statement for diagnosis of subcortical small vessel disease

Vascular cognitive impairment (VCI) is the diagnostic term used to describe a heterogeneous group of sporadic and hereditary diseases of the large and small blood vessels. Subcortical small vessel disease (SVD) leads to lacunar infarcts and progressive damage to the white matter. Patients with progressive damage to the white matter, referred to as Binswanger's disease (BD), constitute a spectrum from pure vascular disease to a mixture with neurodegenerative changes. Binswanger's disease patients are a relatively homogeneous subgroup with hypoxic hypoperfusion, lacunar infarcts, and inflammation that act synergistically to disrupt the blood-brain barrier (BBB) and break down myelin. Identification of this subgroup can be facilitated by multimodal disease markers obtained from clinical, cerebrospinal fluid, neuropsychological, and imaging studies. This consensus statement identifies a potential set of biomarkers based on underlying pathologic changes that could facilitate diagnosis and aid patient selection for future collaborative treatment trials.

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

Several potential vascular risk factors exist for the development and accumulation of subcortical white matter disease in older people. We have reported that in older people followed for up to 4 years white matter hyperintensity (WMH) lesions on magnetic resonance imaging nearly doubled in volume and were associated with alterations in mobility and cognitive function. Herein we review the genetic, metabolic, and vascular risk factors that have been evaluated in association with the development and pathogenesis of WMH in older persons. Our research efforts have focused on systemic hypertension, particularly in the out-of-office setting as 24-hour ambulatory blood pressure (BP) has proven to be a stronger indicator of the progression of WMH in older people and the associated functional decline than doctor’s office BP. Based on relations between 24-hour systolic BP levels, the accrual of WMH, and functional decline, we have designed the INFINITY trial, the first interventional study to use ambulatory BP to guide antihypertensive therapy to address this problem in the geriatric population.

Late-life Depression Modifies the Association Between Cerebral White Matter Hyperintensities and Functional Decline Among Older Adults

OBJECTIVE

Vascular lesions seen through brain imaging as hyperintensities are associated with both depression and functional impairment in older adults. Our objective was to determine if the relationship between the volume of cerebral white matter hyperintensities (WMHs) and functional decline differed in the presence of late life depression.

DESIGN

Secondary analysis of data collected through the Neurocognitive Outcomes of Depression Study. Analysis techniques included general linear mixed models examining trajectories of functional change predicted by lesion volume at baseline.

PARTICIPANTS

381 participants (244 patients diagnosed with major depression and 137 never depressed comparison participants) ages 60 years and older followed for up to 16 years.

MEASUREMENTS

WMH volume was measured through analysis of brain magnetic resonance imaging data. Functional limitations included difficulties with basic activities of daily living tasks, instrumental activities of daily living tasks, and mobility.

RESULTS

Those participants who were both depressed and had a higher volume of WMHs at baseline were most at risk for functional decline across all measures of function. Among the never depressed, those with a higher WMH volume at baseline had a more accelerated rate of functional decline than those with lower WMH volume, and those who were depressed with lower volume of WMH started with more limitations than the never depressed but appeared to progress at a rate similar to those who were never depressed with lower WMH.

CONCLUSION

Older patients with both cerebrovascular risk factors and depression are at an increased risk for functional decline, and may benefit from the treatment of both conditions.

Brain volumetric changes and cognitive ageing during the eighth decade of life

Later‐life changes in brain tissue volumes—decreases in the volume of healthy grey and white matter and increases in the volume of white matter hyperintensities (WMH)—are strong candidates to explain some of the variation in ageing‐related cognitive decline. We assessed fluid intelligence, memory, processing speed, and brain volumes (from structural MRI) at mean age 73 years, and at mean age 76 in a narrow‐age sample of older individuals (n = 657 with brain volumetric data at the initial wave, n = 465 at follow‐up). We used latent variable modeling to extract error‐free cognitive levels and slopes. Initial levels of cognitive ability were predictive of subsequent brain tissue volume changes. Initial brain volumes were not predictive of subsequent cognitive changes. Brain volume changes, especially increases in WMH, were associated with declines in each of the cognitive abilities. All statistically significant results were modest in size (absolute r‐values ranged from 0.114 to 0.334). These results build a comprehensive picture of macrostructural brain volume changes and declines in important cognitive faculties during the eighth decade of life. Hum Brain Mapp 36:4910–4925, 2015. © 2015 The Authors. Human Brain Mapping Published by Wiley Periodicals, Inc

Know your tools--concordance of different methods for measuring brain volume change after ischemic stroke

INTRODUCTION

Longitudinal brain volume changes have been investigated in a number of cerebral disorders as a surrogate marker of clinical outcome. In stroke, unique methodological challenges are posed by dynamic structural changes occurring after onset, particularly those relating to the infarct lesion. We aimed to evaluate agreement between different analysis methods for the measurement of post-stroke brain volume change, and to explore technical challenges inherent to these methods.

METHODS

Fifteen patients with anterior circulation stroke underwent magnetic resonance imaging within 1 week of onset and at 1 and 3 months. Whole-brain as well as grey- and white-matter volume were estimated separately using both an intensity-based and a surface watershed-based algorithm. In the case of the intensity-based algorithm, the analysis was also performed with and without exclusion of the infarct lesion. Due to the effects of peri-infarct edema at the baseline scan, longitudinal volume change was measured as percentage change between the 1 and 3-month scans. Intra-class and concordance correlation coefficients were used to assess agreement between the different analysis methods. Reduced major axis regression was used to inspect the nature of bias between measurements.

RESULTS

Overall agreement between methods was modest with strong disagreement between some techniques. Measurements were variably impacted by procedures performed to account for infarct lesions.

CONCLUSIONS

Improvements in volumetric methods and consensus between methodologies employed in different studies are necessary in order to increase the validity of conclusions derived from post-stroke cerebral volumetric studies. Readers should be aware of the potential impact of different methods on study conclusions.

Binswanger's disease: toward a diagnosis agreement and therapeutic approach

Binswanger's disease (BD) is a progressive form of cerebral small vessel disease affecting the white matter and other subcortical structures. Clinical and imaging characteristics, neuropsychological profile and cerebrospinal fluid analysis aid in making the diagnosis. BD shares features of other small vessel diseases and degenerative neurological conditions, which makes diagnosis difficult. However, with recent developments in MRI methods and serum/cerebrospinal fluid biomarkers, we have gained a greater understanding of the complex pathophysiology of the disease that will guide us to a more certain diagnosis. There is growing evidence that the white matter injury in BD is related to endothelial dysfunction with a secondary inflammatory response leading to breakdown of the neurovascular unit. This review summarizes current and future research directions, including pathophysiological mechanisms and potential therapeutic approaches.

Thalamic fractional anisotropy predicts accrual of cerebral white matter damage in older subjects with small-vessel disease

White matter hyperintensities (WMHs) and lacunes are magnetic resonance imaging hallmarks of cerebral small-vessel disease, which increase the risk of stroke, cognitive, and mobility impairment. Although most studies of cerebral small-vessel disease have focused on white matter abnormalities, the gray matter (GM) is also affected, as evidenced by frequently observed lacunes in subcortical GM. Diffusion tensor imaging (DTI) is sensitive to subtle neurodegenerative changes in deep GM structures. We explored the relationship between baseline DTI characteristics of the thalamus, caudate, and putamen, and the volume and subsequent accrual of WMHs over a 4-year period in 56 community-dwelling older (⩾75 years) individuals. Baseline thalamic fractional anisotropy (FA) was an independent predictor of WMH accrual. WMH accrual also correlated with baseline lacune count and baseline WMH volume, the latter showing the strongest predictive power, explaining 27.3% of the variance. The addition of baseline thalamic FA in multivariate modeling increased this value by 70%, which explains 46.5% of the variance in WMH accrual rate. Thalamic FA might serve as a novel predictor of cerebral small-vessel disease progression in clinical settings and trials. Furthermore, our findings point to the possibility of a causal relationship between thalamic damage and the accrual of WMHs.

Lacunar stroke, deep white matter disease and depression: a meta-analysis

BACKGROUND

Lacunar stroke is a small (<2 cm) infarction that accounts for approximately 20% of all strokes. While a third of all stroke patients experience depressive symptoms, the prevalence of depression in the lacunar stroke patient population is unclear. This meta-analysis aimed to synthesize the evidence on the effect of lacunar stroke and deep white matter disease on depressive symptoms.

METHODS

A systematic search of electronic databases was conducted, resulting in the inclusion of 12 studies. Analyses were performed on the effects of lacunar stroke, volume and location of lacunes on depression prevalence, and the effect on depression severity. The effects estimates were calculated in random-effects models.

RESULTS

None of the analyses produced statistically significant results. Lacunar stroke patients had a non-significantly higher prevalence of depression compared to patients with non-lacunar cerebrovascular diseases (OR = 1.46, 95% CI: 0.88-2.43, p = 0.15). Neither thalamic (OR = 1.37 (0.85-2.20), p = 0.19), deep white matter (RR = 1.16 (0.85-1.57), p = 0.35), multiple lacunes (OR = 1.34 (0.81-2.22), p = 0.25), or the volume of lacunes (MD = -4.71 (-351.59-342.18), p = 0.98) had an effect on depression prevalence. Lastly, lacunar stroke did not influence depressive symptom severity (MD = 0.96 (-1.57-3.48), p = 0.46).

CONCLUSIONS

The pooled group of patients with lacunar stroke and deep white matter disease appear to have a similar prevalence of depression compared to those with other types of cerebrovascular diseases. However, the small number of studies, heterogeneous comparison groups, and high statistical heterogeneity between studies posed an obstacle to the meta-analysis. To determine appropriate screening and treatment approaches, future research will need to separate lacunar stroke and deep white matter disease patients, and include larger sample sizes and healthy control groups to determine their distinct contributions to depression.

Infarct hemisphere and noninfarcted brain volumes affect locomotor performance following stroke

OBJECTIVE

Brain damage within the right middle cerebral artery (MCA) territory is particularly disruptive to mediolateral postural stabilization. The objective of this cross-sectional study was to test the hypothesis that chronic right MCA infarcts (as compared to left) are associated with slower and more bilaterally asymmetrical gait. We further hypothesized that in those with chronic right MCA infarct, locomotor performance is more dependent on gray matter (GM) volumes within noninfarcted regions of the brain that are involved in motor control yet lie outside of the MCA territory.

METHODS

Gait speed was assessed in 19 subjects with right MCA infarct, 20 with left MCA infarct, and 108 controls. Bilateral plantar pressure and temporal symmetry ratios were calculated in a subset of the cohort. GM volumes within 5 regions outside of the MCA territory (superior parietal lobe, precuneus, caudate, putamen, and cerebellum) were quantified from anatomic MRIs.

RESULTS

Right and left infarct groups had similar poststroke duration (7.6 ± 6.0 years), infarct size, and functional independence. The right infarct group demonstrated slower gait speed and greater asymmetry compared to the left infarct group and controls (p < 0.05). In the right infarct group only, those with larger GM volumes within the cerebellum (r(2) = 0.32, p = 0.02) and caudate (r(2) = 0.56, p < 0.001) exhibited faster gait speed.

CONCLUSION

Individuals with chronic lesions within the right MCA territory, as compared to the left MCA territory, exhibit slower, more asymmetrical gait. For these individuals, larger GM volumes within regions outside of the infarcted vascular territory may help preserve locomotor control.