Associations among vascular risk factors, carotid atherosclerosis, and cortical volume and thickness in older adults

Contributions of Cardiovascular Burden, Peripheral Inflammation, and Brain Integrity on Digital Clock Drawing Performance in Non-Demented Older Adults

BACKGROUND

Greater cardiovascular burden and peripheral inflammation are associated with dysexecutive neuropsychological profiles and a higher likelihood of conversion to vascular dementia. The digital clock drawing test (dCDT) is useful in identifying neuropsychological dysfunction related to vascular etiology. However, the specific cognitive implications of the combination of cardiovascular risk, peripheral inflammation, and brain integrity remain unknown.

OBJECTIVE

We aimed to examine the role of cardiovascular burden, inflammation, and MRI-defined brain integrity on dCDT latency and graphomotor metrics in older adults.

METHODS

184 non-demented older adults (age 69±6, 16±3 education years, 46% female, 94% white) completed dCDT, vascular assessment, blood draw, and brain MRI. dCDT variables of interest: total completion time (TCT), pre-first hand latency, digit misplacement, hour hand distance from center, and clock face area. Cardiovascular burden was calculated using the Framingham Stroke Risk Profile (FSRP-10). Peripheral inflammation markers included interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor-alpha, and high sensitivity C-reactive protein. Brain integrity included bilateral entorhinal cortex volume, lateral ventricular volume, and whole brain leukoaraiosis.

RESULTS

FSRP-10, peripheral inflammation, and brain integrity explained an additional 14.6% of the variance in command TCT, where FSRP-10 was the main predictor. FSRP-10, inflammatory markers, and brain integrity explained an additional 17.0% in command digit misplacement variance, with findings largely driven by FSRP-10.

CONCLUSION

Subtle graphomotor behavior operationalized using dCDT metrics (i.e., TCT and digit misplacement) is partly explained by cardiovascular burden, peripheral inflammation, and brain integrity and may indicate vulnerability to a disease process.

Can dementia risk be reduced by following the American Heart Association's Life's Simple 7? A systematic review and dose-response meta-analysis

This study aimed to quantify the relationships between the American Heart Association (AHA) Cardiovascular Health (CVH) metrics, namely AHA Life's Simple 7, and cognitive outcomes. We searched PubMed and Embase (January 1, 2010-August 24, 2022) and finally included 14 longitudinal studies (311654 participants with 8006 incident dementia cases). Random-effects meta-analysis and one-stage linear mixed-effects models were performed. Increased CVH score seemed to associate with decreased risk of incident dementia in a linear manner, but this relationship varied by the measurement age of CVH metrics. That is, midlife CVH tended to have a linear association with late-life dementia risk, whereas a J-shaped association was observed between the late-life CVH score and dementia. In addition, late-life dementia risk was reduced significantly if individuals maintained an ideal level of AHA's CVH guidelines of physical activity, fasting plasma glucose, total cholesterol, and smoking. However, our meta-analysis did not show a significant association between CVH score and global cognitive decline rate. Following AHA's CVH guidelines and maintaining CVH at an optimal level would substantially reduce the late-life dementia risk. More research is required to explore the link between a favorable CVH score and cognitive trajectories among cognitively asymptomatic older populations.

Integrating multiple brain imaging modalities does not boost prediction of subclinical atherosclerosis in midlife adults

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Brain measures from MRI do not improve Framingham Risk Score prediction of CA-IMT.

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Prediction stacking is a flexible approach to determine added predictive utility.

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Multimodal stacking can be applied to individual difference factors.

Background

Human neuroimaging evidence suggests that cardiovascular disease (CVD) risk may relate to functional and structural features of the brain. The present study tested whether combining functional and structural (multimodal) brain measures, derived from magnetic resonance imaging (MRI), would yield a multivariate brain biomarker that reliably predicts a subclinical marker of CVD risk, carotid-artery intima-media thickness (CA-IMT).

Methods

Neuroimaging, cardiovascular, and demographic data were assessed in 324 midlife and otherwise healthy adults who were free of (a) clinical CVD and (b) use of medications for chronic illnesses (aged 30–51 years, 49% female). We implemented a prediction stacking algorithm that combined multimodal brain imaging measures and Framingham Risk Scores (FRS) to predict CA-IMT. We included imaging measures that could be easily obtained in clinical settings: resting state functional connectivity and structural morphology measures from T1-weighted images.

Results

Our models reliably predicted CA-IMT using FRS, as well as for several individual MRI measures; however, none of the individual MRI measures outperformed FRS. Moreover, stacking functional and structural brain measures with FRS did not boost prediction accuracy above that of FRS alone.

Conclusions

Combining multimodal functional and structural brain measures through a stacking algorithm does not appear to yield a reliable brain biomarker of subclinical CVD, as reflected by CA-IMT.

Preliminary Study of Subclinical Brain Alterations in Patients With Asymptomatic Carotid Vulnerable Plaques Using Intravoxel Incoherent Motion Imaging by Voxelwise Comparison: A Study of Whole-Brain Imaging Measures

Objective

To preliminarily explore subclinical brain alterations in an asymptomatic carotid vulnerable plaque group based on intravoxel incoherent motion (IVIM) imaging through voxelwise comparison in the whole brain.

Materials and Methods

Forty-nine elderly participants underwent multi-b-value DWI, of whom 24 participants with asymptomatic carotid vulnerable plaques and <50% stenosis served as the test group, while the rest served as the healthy control group. After fitting the double-exponential model, slow ADC (Ds) and the fraction of fast ADC (f) values of the whole brain were obtained, which then were compared in a voxelwise manner by two-sample t-test. Multiple comparisons were corrected by the family-wise error (FWE) method with a corrected threshold of P < 0.05. Pearson correlations between IVIM parameters in altered brain regions and blood pressure, glucose, lipid, and homocysteine were calculated.

Results

For the test group, the Z-normalized Ds values were significantly higher in the left median cingulate and paracingulate gyrus (DCG.L), posterior cingulate gyrus (PCG. L), and left precuneus gyrus (PCUN.L) (cluster size = 156) and in the left middle frontal gyrus (MFG.L), orbital middle frontal gyrus (ORBmid.L), and superior frontal gyrus (SFG.L) (cluster size = 165); the Z-normalized Ds values were significantly lower in the right middle temporal gyrus (MTG.R) and inferior temporal gyrus (ITG.R) (cluster size = 116); and the Z-normalized f-values were significantly lower in the MTG.R and ITG.R (cluster size = 85) (p < 0.05, FWE correction). LDL-C was negatively correlated with the Z-normalized Ds values in the DCG.L, PCG.L, and PCUN.L (r = 0.601, p = 0.002). LDL-C was positively correlated with the Z-normalized f-value in the MTG.R and ITG.R (r = 0.405, p = 0.05). Systolic blood pressure was positively correlated with the Z-normalized Ds values in the MFG.L, ORBmid.L, and SFG.L (r = 0.433, p = 0.035).

Conclusion

This study was the first to detect subclinical brain alterations in asymptomatic carotid vulnerable plaque group through IVIM using whole-brain voxelwise comparisons, which were partially correlated with blood pressure and lipids. Thus, IVIM might be utilized as a noninvasive biomarker of microvascular and microstructural brain changes in the asymptomatic carotid vulnerable plaque group.

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

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

Brain imaging biomarkers of carotid artery disease

Extracranial carotid artery atherosclerotic disease is a major contributor to ischemic stroke. Carotid atherosclerotic disease can present with a spectrum of findings ranging from mild carotid intima-media thickness to high-risk vulnerable carotid plaque features and carotid stenosis. Before leading to clinically overt stroke or transient ischemic attack, there may be other markers of downstream ischemia secondary to carotid atherosclerotic disease. In this review article, we will review some of the imaging findings that may be seen downstream to carotid artery disease on various imaging modalities, including hemodynamic and perfusional abnormalities which may be seen on CT, MR, or using other advanced imaging techniques, white matter hyperintensities on brain imaging, silent or covert brain infarctions, cerebral microbleeds, and regional and generalized cerebral volume loss. Many of these imaging findings are seen routinely on brain magnetic resonance imaging in patients without overt clinical symptoms. Despite frequently being asymptomatic, many of these imaging findings are also strongly associated with increased risk of future stroke, cognitive impairment, and even mortality. We will review the existing evidence underpinning the associations between these frequently encountered imaging findings and carotid artery atherosclerotic disease. Future validation of these imaging findings could lead to them being powerful biomarkers of cerebrovascular health.

MRI-based biomarkers of accelerated aging and dementia risk in midlife: how close are we?

The global population is aging, leading to an increasing burden of age-related neurodegenerative disease. Efforts to intervene against age-related dementias in older adults have generally proven ineffective. These failures suggest that a lifetime of brain aging may be difficult to reverse once widespread deterioration has occurred. To test interventions in younger populations, biomarkers of brain aging are needed that index subtle signs of accelerated brain deterioration that are part of the putative pathway to dementia. Here I review potential MRI-based biomarkers that could connect midlife brain aging to later life dementia. I survey the literature with three questions in mind, 1) Does the biomarker index age-related changes across the lifespan? 2) Does the biomarker index cognitive ability and cognitive decline? 3) Is the biomarker sensitive to known risk factors for dementia? I find that while there is preliminary support for some midlife MRI-based biomarkers for accelerated aging, the longitudinal research that would best answer these questions is still in its infancy and needs to be further developed. I conclude with suggestions for future research.

The progression of carotid atherosclerosis and imaging markers of dementia

INTRODUCTION

We studied the association of carotid intima-media thickness (CIMT) with hippocampal volume (HV) in community dwelling individuals, testing the hypothesis that persons with carotid atherosclerosis progression would have lower HV.

METHODS

We studied 1376 Framingham Offspring participants with two carotid ultrasounds and brain magnetic resonance imaging (MRIs). We used multivariable linear regression analyses to relate CIMT progression and HV and total brain volume. Regression models were adjusted for demographics and vascular risk factors, time interval between imaging examinations, and baseline CIMT. We assessed effect modification by hypertension treatment (HRx).

RESULTS

Participants with higher ICA IMT progression had significantly lower HV after adjustment for vascular risk factors and baseline IMT (standardized beta ± standard error: -0.067 ± 0.027, P = .01). We observed weaker association between ICA IMT change and HV among subjects treated for hypertension (β = -0.047, P = .19 vs β = -0.096, P = .026).

DISCUSSION

Cumulative vascular risk factor exposure, reflected by CIMT progression, may increase the risk of neurodegeneration.

Cortical thickness and cognitive performance in asymptomatic unilateral carotid artery stenosis

Background

We investigated changes of cortical thickness and its association with cognitive performance in patients with high-grade carotid artery stenosis without ischemic brain lesions.

Methods

We studied 25 patients with unilateral carotid artery stenosis ≥50% and 25 age-matched controls. All subjects underwent T1-weighted MRI, and cortical thickness was measured in 33 regions of interest in each hemisphere, as well as in brain regions belonging to the vascular territory of the middle cerebral artery (MCA). General linear mixed models were fitted to the dependent variable cortical thickness. Cognitive assessment comprised the Stroop Test and Trail Making Test B.

Results

In the linear mixed model, presence of carotid stenosis had no effect on cortical thickness. There was a significant interaction of stenosis and region with a trend towards lower cortical thickness in the MCA region on the side of carotid stenosis. Patients with carotid stenosis performed significantly worse on the Stroop test than controls, but there was no correlation with cortical thickness.

Conclusion

In patients with carotid stenosis without ischemic brain lesions, neither a clear pattern of reduced cortical thickness nor an association of cortical thickness with cognitive function was observed. Our data do not support the hypothesized association of cortical thinning and cognitive impairment in carotid stenosis.

Electronic supplementary material

The online version of this article (10.1186/s12872-019-1127-y) contains supplementary material, which is available to authorized users.

Cortical Thickness and Cognitive Performance After Out-of-Hospital Cardiac Arrest

BACKGROUND

Cognitive impairment is common in long-term survivors of out-of-hospital cardiac arrest (OHCA) but corresponding neuroimaging data are lacking.

OBJECTIVES

This study explored the relationship among the cortical brain structure, cognitive performance, and clinical variables after OHCA.

METHODS

Three months after resuscitation, 13 OHCA survivors who had recovered from a coma to living independently and 19 healthy controls were assessed by cerebral magnetic resonance imaging and neuropsychological tests quantifying memory, fine-motor coordination, and attention/executive functions. Cortical thickness (Cth) and surface area (SA) were compared between groups and analyzed for relationships with cognitive performance as well as the clinical variables of coma duration and the time to return of spontaneous circulation (ROSC). All analyses were controlled for age and sex.

RESULTS

Analyses of SA revealed no significant differences. Compared with controls, survivors had significantly reduced memory and fine-motor coordination and significantly thinner cortex in large clusters in the frontal, parietal, and inferior temporal cortices, with additional regions in the left occipital lobe and the left temporal lobe. Widespread thinner cortical regions were significantly associated with decreased memory performance in survivors when compared with those in controls and were significantly associated with an increased time to ROSC and increased coma duration in the OHCA group. Increased coma duration, but not increased time to ROSC, was significantly correlated with cognitive test performance.

CONCLUSIONS

The results suggest that widespread Cth reductions correspond to the cognitive impairments observed after OHCA. Neuroimaging studies of long-term OHCA survivors are warranted to guide the development of diagnostics and treatment options.

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

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

Resilience to cognitive impairment in the oldest-old: design of the EMIF-AD 90+ study

BACKGROUND

The oldest-old (subjects aged 90 years and older) population represents the fastest growing segment of society and shows a high dementia prevalence rate of up to 40%. Only a few studies have investigated protective factors for cognitive impairment in the oldest-old. The EMIF-AD 90+ Study aims to identify factors associated with resilience to cognitive impairment in the oldest-old. In this paper we reviewed previous studies on cognitive resilience in the oldest-old and described the design of the EMIF-AD 90+ Study.

METHODS

The EMIF-AD 90+ Study aimed to enroll 80 cognitively normal subjects and 40 subjects with cognitive impairment aged 90 years or older. Cognitive impairment was operationalized as amnestic mild cognitive impairment (aMCI), or possible or probable Alzheimer's Disease (AD). The study was part of the European Medical Information Framework for AD (EMIF-AD) and was conducted at the Amsterdam University Medical Centers (UMC) and at the University of Manchester. We will test whether cognitive resilience is associated with cognitive reserve, vascular comorbidities, mood, sleep, sensory system capacity, physical performance and capacity, genetic risk factors, hallmarks of ageing, and markers of neurodegeneration. Markers of neurodegeneration included an amyloid positron emission tomography, amyloid β and tau in cerebrospinal fluid/blood and neurophysiological measures.

DISCUSSION

The EMIF-AD 90+ Study will extend our knowledge on resilience to cognitive impairment in the oldest-old by extensive phenotyping of the subjects and the measurement of a wide range of potential protective factors, hallmarks of aging and markers of neurodegeneration.

TRIAL REGISTRATION

Nederlands Trial Register NTR5867 . Registered 20 May 2016.

Association between carotid atheroma and cerebral cortex structure at age 73 years

OBJECTIVE

To examine the relationship between carotid atherosclerosis and cerebral cortical thickness and investigate whether cortical thickness mediates the association between carotid atheroma and relative cognitive decline.

METHODS

We assessed 554 community-dwelling subjects (male/female: 296/258) from the Lothian Birth Cohort 1936 who underwent brain magnetic resonance imaging and carotid Doppler ultrasound studies at age 73 years. The relationship between carotid atherosclerosis markers (internal carotid artery stenosis, intima-media thickness, velocity, pulsatility, and resistivity indexes) and vertex-wide cerebral cortical thickness was examined cross-sectionally, controlling for gender, extensive vascular risk factors (VRFs), and intelligence quotient at age 11 (IQ-11). We also determined the association between carotid stenosis and a composite measure of fluid intelligence at age 73 years. A mediation model was applied to examine whether cortical thickness mediated the relationship between carotid stenosis and cognitive function.

RESULTS

A widespread negative association was identified between carotid stenosis (median = 15%) and cerebral cortical thickness at age 73 years, independent of the side of carotid stenosis, other carotid measures, VRFs, and IQ-11. This association increased in an almost dose-response relationship from mild to severe degrees of carotid stenosis, across the anterior and posterior circulation territories. A negative association was also noted between carotid stenosis and fluid intelligence (standardized beta coefficient = -0.151, p = 0.001), which appeared partly (approximately 22%) mediated by carotid stenosis-related thinning of the cerebral cortex.

INTERPRETATION

The findings suggest that carotid stenosis represents a marker of processes that accelerate aging of the cerebral cortex and cognition that is in part independent of measurable VRFs. Cortical thinning within the anterior and posterior circulation territories partially mediated the relationship between carotid atheroma and fluid intelligence. Ann Neurol 2018;84:576-587.

Seizure-Related Cortical Volume Alterations in Alzheimer's Disease: A Preliminary Study

Background and Purpose

Alzheimer’s disease (AD) leads to cognitive dysfunction and neuronal loss, both of which can be exacerbated by seizures. For the treatment and diagnosis of AD, it is imperative to identify the cortical characteristics of comorbidities of AD such as seizures. The present study investigated the alterations in cortical volumes in patients with comorbid AD and seizures.

Methods

In this retrospective study, magnetic resonance T1-weighted brain images were collected from six patients with early AD or amnestic mild cognitive impairment without seizures (AD-No Seizure, age: 66.17 ± 4.92 years) and six individuals with seizures (AD-Seizure, age: 80.33 ± 4.63 years). The gray matter volumes estimated from the T1 images were compared between the groups using nuisance variables (e.g., age). Subsequently, a correlation analysis was performed to investigate the relationship between cortical structure and global cognitive function.

Results

AD-Seizure group showed volumetric alterations compared with AD-No Seizure group. In the volumetrically altered regions, correlation analysis revealed that the AD-Seizure group showed a positive correlation between the mini-mental state examination (MMSE) score and cortical volume, with smaller volumes than the AD-No Seizure group in the right parahippocampal gyrus, left angular gyrus, and middle temporal gyrus. The AD-No Seizure group showed negative correlations with MMSE score in the volume of right inferior frontal gyrus and cerebellar culmen and a positive correlation with the volume of the left middle frontal gyrus.

Conclusions

Our findings revealed that smaller temporal region volumes are predictive of cognitive dysfunction in AD patients with seizures. Given that these temporal areas overlap with regions showing abnormal brain activities in AD patients with seizures, these results suggest synergistic effects of AD and seizures on cortical volume and cognitive function.

The EMIF-AD PreclinAD study: study design and baseline cohort overview

Background

Amyloid pathology is the pathological hallmark in Alzheimer’s disease (AD) and can precede clinical dementia by decades. So far it remains unclear how amyloid pathology leads to cognitive impairment and dementia. To design AD prevention trials it is key to include cognitively normal subjects at high risk for amyloid pathology and to find predictors of cognitive decline in these subjects. These goals can be accomplished by targeting twins, with additional benefits to identify genetic and environmental pathways for amyloid pathology, other AD biomarkers, and cognitive decline.

Methods

From December 2014 to October 2017 we enrolled cognitively normal participants aged 60 years and older from the ongoing Manchester and Newcastle Age and Cognitive Performance Research Cohort and the Netherlands Twins Register. In Manchester we included single individuals, and in Amsterdam monozygotic twin pairs. At baseline, participants completed neuropsychological tests and questionnaires, and underwent physical examination, blood sampling, ultrasound of the carotid arteries, structural and resting state functional brain magnetic resonance imaging, and dynamic amyloid positron emission tomography (PET) scanning with [¹⁸F]flutemetamol. In addition, the twin cohort underwent lumbar puncture for cerebrospinal fluid collection, buccal cell collection, magnetoencephalography, optical coherence tomography, and retinal imaging.

Results

We included 285 participants, who were on average 74.8 ± 9.7 years old, 64% female. Fifty-eight participants (22%) had an abnormal amyloid PET scan.

Conclusions

A rich baseline dataset of cognitively normal elderly individuals has been established to estimate risk factors and biomarkers for amyloid pathology and future cognitive decline.

Electronic supplementary material

The online version of this article (10.1186/s13195-018-0406-7) contains supplementary material, which is available to authorized users.

Type-2 diabetes mellitus reduces cortical thickness and decreases oxidative metabolism in sensorimotor regions after stroke

Individuals with type-2 diabetes mellitus experience poor motor outcomes after ischemic stroke. Recent research suggests that type-2 diabetes adversely impacts neuronal integrity and function, yet little work has considered how these neuronal changes affect sensorimotor outcomes after stroke. Here, we considered how type-2 diabetes impacted the structural and metabolic function of the sensorimotor cortex after stroke using volumetric magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). We hypothesized that the combination of chronic stroke and type-2 diabetes would negatively impact the integrity of sensorimotor cortex as compared to individuals with chronic stroke alone. Compared to stroke alone, individuals with stroke and diabetes had lower cortical thickness bilaterally in the primary somatosensory cortex, and primary and secondary motor cortices. Individuals with stroke and diabetes also showed reduced creatine levels bilaterally in the sensorimotor cortex. Contralesional primary and secondary motor cortex thicknesses were negatively related to sensorimotor outcomes in the paretic upper-limb in the stroke and diabetes group such that those with thinner primary and secondary motor cortices had better motor function. These data suggest that type-2 diabetes alters cerebral energy metabolism, and is associated with thinning of sensorimotor cortex after stroke. These factors may influence motor outcomes after stroke.

Changes in Blood Factors and Ultrasound Findings in Mild Cognitive Impairment and Dementia

The present study aimed to assess the changes in blood factors and ultrasound measures of atherosclerosis burden patient with mild cognitive impairment (MCI) and dementia. Peripheral blood samples and ultrasonography findings were obtained for 53 enrolled participants. Flow cytometry was used to evaluate levels of activated platelets and platelet-leukocyte aggregates (PLAs). The number of platelets expressing p-selectin was correlated with intima media thickness (IMT) and plaque number in both the MCI and dementia groups. The number of platelets expressing p-selectin glycoprotein ligand (PSGL) was strongly correlated with IMT in patients with MCI, whereas the number of platelets expressing PGSL was correlated with plaque number rather than IMT in patients with dementia. PLAs was associated with both IMT and plaque number in patients with MCI but not in those with dementia. Our findings demonstrate that alterations in IMT and plaque number are associated with an increased risk of cognitive decline as well as conversion from MCI to dementia and that blood factor analysis may aid to detect the severity of cognitive decline.

Does left ventricular hypertrophy affect cognition and brain structural integrity in type 2 diabetes? Study design and rationale of the Diabetes and Dementia (D2) study

BACKGROUND

Cognitive impairment is common in type 2 diabetes mellitus, and there is a strong association between type 2 diabetes and Alzheimer's disease. However, we do not know which type 2 diabetes patients will dement or which biomarkers predict cognitive decline. Left ventricular hypertrophy (LVH) is potentially such a marker. LVH is highly prevalent in type 2 diabetes and is a strong, independent predictor of cardiovascular events. To date, no studies have investigated the association between LVH and cognitive decline in type 2 diabetes. The Diabetes and Dementia (D2) study is designed to establish whether patients with type 2 diabetes and LVH have increased rates of brain atrophy and cognitive decline.

METHODS

The D2 study is a single centre, observational, longitudinal case control study that will follow 168 adult patients aged >50 years with type 2 diabetes: 50% with LVH (case) and 50% without LVH (control). It will assess change in cardiovascular risk, brain imaging and neuropsychological testing between two time-points, baseline (0 months) and 24 months. The primary outcome is brain volume change at 24 months. The co-primary outcome is the presence of cognitive decline at 24 months. The secondary outcome is change in left ventricular mass associated with brain atrophy and cognitive decline at 24 months.

DISCUSSION

The D2 study will test the hypothesis that patients with type 2 diabetes and LVH will exhibit greater brain atrophy than those without LVH. An understanding of whether LVH contributes to cognitive decline, and in which patients, will allow us to identify patients at particular risk.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ( ACTRN12616000546459 ), date registered, 28/04/2016.

A T1 and DTI fused 3D corpus callosum analysis in MCI subjects with high and low cardiovascular risk profile

Understanding the extent to which vascular disease and its risk factors are associated with prodromal dementia, notably Alzheimer's disease (AD), may enhance predictive accuracy as well as guide early interventions. One promising avenue to determine this relationship consists of looking for reliable and sensitive in-vivo imaging methods capable of characterizing the subtle brain alterations before the clinical manifestations. However, little is known from the imaging perspective about how risk factors such as vascular disease influence AD progression. Here, for the first time, we apply an innovative T1 and DTI fusion analysis of 3D corpus callosum (CC) on mild cognitive impairment (MCI) populations with different levels of vascular profile, aiming to de-couple the vascular factor in the prodromal AD stage. Our new fusion method successfully increases the detection power for differentiating MCI subjects with high from low vascular risk profiles, as well as from healthy controls. MCI subjects with high and low vascular risk profiles showed differed alteration patterns in the anterior CC, which may help to elucidate the inter-wired relationship between MCI and vascular risk factors.

Brain structural connectivity distinguishes patients at risk for cognitive decline after carotid interventions

While brain connectivity analyses have been demonstrated to identify ill patients for a number of diseases, their ability to predict cognitive impairment after brain injury is not well established. Traditional post brain injury models, such as stroke, are limited for this evaluation because pre-injury brain connectivity patterns are infrequently available. Patients with severe carotid stenosis, in contrast, often undergo non-emergent revascularization surgery, allowing the collection of pre and post-operative imaging, may experience brain insult due to perioperative thrombotic/embolic infarcts or hypoperfusion, and can suffer post-operative cognitive decline. We hypothesized that a distributed function such as memory would be more resilient in patients with brains demonstrating higher degrees of modularity. To test this hypothesis, we analyzed preoperative structural connectivity graphs (using T1 and DWI MRI) for 34 patients that underwent carotid intervention, and evaluated differences in graph metrics using the Brain Connectivity Toolbox. We found that patients with lower binary component number, binary community number and weighted community number prior to surgery were at greater risk for developing cognitive decline. These findings highlight the promise of brain connectivity analyses to predict cognitive decline following brain injury and serve as a clinical decision support tool. Hum Brain Mapp 37:2185-2194, 2016. © 2016 Wiley Periodicals, Inc.

Differential effects of ischemic vascular disease and Alzheimer's disease on brain atrophy and cognition

We previously reported that pathologic measures of arteriosclerosis (AS), cerebral infarction, and Alzheimer’s disease (AD) are independently correlated with cortical gray matter (CGM) atrophy measured by in vivo magnetic resonance imaging (MRI). Here, we use path analyses to model the associations between these three pathology measures and cognitive impairment, as mediated by CGM atrophy, after controlling for age and education. In this sample of 116 elderly persons followed longitudinally to autopsy (ischemic vascular disease (IVD) program project), differential patterns were observed between AS and atrophy/cognition versus AD and atrophy/cognition. The total effect of AD pathology on global cognition (β = -0.61, s.e. = 0.06) was four times stronger than that of AS (β = -0.15, s.e. = 0.08). The effect of AS on cognition appears to occur through cerebral infarction and CGM atrophy (β = -0.13, s.e. = 0.04). In contrast, the effects of AD pathology on global cognition (β = -0.50, s.e. = 0.07) occur through a direct pathway that is five times stronger than the indirect pathway acting through CGM atrophy (β = -0.09, s.e. = 0.03). The strength of this direct AD pathway was not significantly mitigated by adding hippocampal volume to the model. AD pathology affects cognition not only through brain atrophy, but also via an unmeasured pathway that could be related to synaptic dysfunction before the development of cortical atrophy.

Vascular Health and Genetic Risk Affect Mild Cognitive Impairment Status and 4-Year Stability: Evidence From the Victoria Longitudinal Study

OBJECTIVES

Mild cognitive impairment (MCI) is a high-risk condition for progression to Alzheimer's disease (AD). Vascular health is a key mechanism underlying age-related cognitive decline and neurodegeneration. AD-related genetic risk factors may be associated with preclinical cognitive status changes. We examine independent and cross-domain interactive effects of vascular and genetic markers for predicting MCI status and stability.

METHOD

We used cross-sectional and 2-wave longitudinal data from the Victoria Longitudinal Study, including indicators of vascular health (e.g., reported vascular diseases, measured lung capacity and pulse rate) and genetic risk factors-that is, apolipoprotein E (APOE; rs429358 and rs7412; the presence vs absence of ε4) and catechol-O-methyltransferase (COMT; rs4680; met/met vs val/val). We examined associations with objectively classified (a) cognitive status at baseline (not impaired congnitive (NIC) controls vs MCI) and (b) stability or transition of cognitive status across a 4-year interval (stable NIC-NIC vs chronic MCI-MCI or transitional NIC-MCI).

RESULTS

Using logistic regression, indicators of vascular health, both independently and interactively with APOE ε4, were associated with risk of MCI at baseline and/or associated with MCI conversion or MCI stability over the retest interval.

DISCUSSION

Several vascular health markers of aging predict MCI risk. Interactively, APOE ε4 may intensify the vascular health risk for MCI.

Cardiovascular Risk Factors Associated with Smaller Brain Volumes in Regions Identified as Early Predictors of Cognitive Decline

PURPOSE

To determine in a large multiethnic cohort the cardiovascular and genetic risk factors associated with smaller volume in the hippocampus, precuneus, and posterior cingulate, and their association with preclinical deficits in cognitive performance in patients younger and older than 50 years.

MATERIALS AND METHODS

The institutional review board approved the study and all participants provided written informed consent. Eligible for this study were 1629 participants (700 men and 929 women; mean age, 50.0 years ± 10.2 [standard deviation]) drawn from the population-based Dallas Heart Study who underwent laboratory and clinical analysis in an initial baseline visit and approximately 7 years later underwent brain magnetic resonance imaging with automated volumetry and cognitive assessment with the Montreal Cognitive Assessment (MoCA). Regression analysis showed associations between risk factors and segmental volumes, and associations between these volumes with cognitive performance in participants younger and older than 50 years.

RESULTS

Lower hippocampal volume was associated with previous alcohol consumption (standardized estimate, -0.04; P = .039) and smoking (standardized estimate, -0.04; P = .048). Several risk factors correlated with lower total brain, posterior cingulate, and precuneus volumes. Higher total (standardized estimate, 0.06; P = .050), high-density lipoprotein (standardized estimate, 0.07; P = .003), and low-density lipoprotein (standardized estimate, 0.04; P = .037) cholesterol levels were associated with larger posterior cingulate volume, and higher triglyceride levels (standardized estimate, 0.06; P = .004) were associated with larger precuneus volume. Total MoCA score was associated with posterior cingulate volume (standardized estimate, 0.13; P = .001) in younger individuals and with hippocampal (standardized estimate, 0.06; P < .05) and precuneus (standardized estimate, 0.08; P < .023) volumes in older adults.

CONCLUSION

Smaller volumes in specific brain regions considered to be early markers of dementia risk were associated with specific cardiovascular disease risk factors and cognitive deficits in a predominantly midlife multiethnic population-based sample. Additionally, the risk factors most associated with these brain volumes differed in participants younger and older than 50 years, as did the association between brain volume and MoCA score.

Framingham risk score can predict cognitive decline progression in Alzheimer's disease

The role of vascular factors in influencing cognitive decline has been extensively investigated, and some difficulties in defining their weight in dementia pathogenesis have emerged. The aim of the study was to investigate the relevance of the Framingham cardiovascular risk profile (FCRP) in influencing cognitive deterioration in a population of Alzheimer's disease (AD) patients. Two hundred eighty-four consecutive AD patients were enrolled. For each patient, FCRP score was calculated. We did a 1-year follow-up to quantify the cognitive decline by recording changes in the Clinical Dementia Rating score. The FCRP score predicted cognitive deterioration with an area under the curve of 0.63 (95% confidence interval: 0.57-0.69; p < 0.0001). In the subpopulation of patients with a genetic increased predisposition to develop cognitive deterioration and with an advanced vascular impairment, the FCRP predictive value significantly increased with an area under the curve of 0.77 (95% confidence interval: 0.52-0.93; p < 0.05). Our findings show that FCRP can predict the progression of deterioration in AD patients. This was particularly evident in patients with major genetic and atherosclerotic risk factors.

Subclinical atherosclerosis and subsequent cognitive function

OBJECTIVE

To examine the relationship between measures of subclinical atherosclerosis and subsequent cognitive function.

METHOD

Participants from the Dallas Heart Study (DHS), a population-based multiethnic study of cardiovascular disease pathogenesis, were re-examined 8 years later (DHS-2) with the Montreal Cognitive Assessment (MoCA); N = 1904, mean age = 42.9, range 8-65. Associations of baseline measures of subclinical atherosclerosis (coronary artery calcium, abdominal aortic plaque, and abdominal aortic wall thickness) with MoCA scores measured at follow-up were examined in the group as a whole and in relation to age and ApoE4 status.

RESULTS

A significant linear trend of successively lower MoCA scores with increasing numbers of atherosclerotic indicators was observed (F(3, 1150) = 5.918, p = .001). CAC was weakly correlated with MoCA scores (p = .047) and MoCA scores were significantly different between participants with and without CAC (M = 22.35 vs 23.69, p = 0.038). With the exception of a small association between abdominal AWT and MoCA in subjects over age 50, abdominal AWT and abdominal aortic plaque did not correlate with MoCA total score (p ≥ .052). Cognitive scores and atherosclerosis measures were not impacted by ApoE4 status (p ≥ .455).

CONCLUSION

In this ethnically diverse population-based sample, subclinical atherosclerosis was minimally associated with later cognitive function in middle-aged adults.

The synergistic effects of anxiety and cerebral hypoperfusion on cognitive dysfunction in older adults with cardiovascular disease

OBJECTIVES

Anxiety is a risk factor for cardiovascular disease (CVD) and is associated with neurocognitive outcomes. The effect of anxiety on brain perfusion in a CVD population has yet to be examined, and no study has investigated the interactive effects of anxiety and cerebral perfusion on cognition.

METHODS

A total of 55 older adults with CVD completed the Beck Anxiety Inventory (BAI) and underwent arterial spin labeling to quantify cortical perfusion and thickness. Participants were administered the Mini-Mental State Examination (MMSE) and the Repeatable Battery for the Assessment of Neuropsychological Status.

RESULTS

Reduced perfusion predicted poorer cognition and decreased cortical thickness. Higher anxiety score predicted worse memory performance and decreased frontal perfusion. Frontal lobe hypoperfusion combined with increased BAI scores exacerbated poorer MMSE performance.

CONCLUSIONS

Higher anxiety may exacerbate the effects of cerebral hypoperfusion on cognitive impairment. Longitudinal studies are needed to confirm our findings and determine whether anxiety treatment improves neurocognitive outcomes in CVD.

Cardiovascular risk factors and future risk of Alzheimer's disease

Alzheimer's disease (AD) is the most common neurodegenerative disorder in elderly people, but there are still no curative options. Senile plaques and neurofibrillary tangles are considered hallmarks of AD, but cerebrovascular pathology is also common. In this review, we summarize findings on cardiovascular disease (CVD) and risk factors in the etiology of AD. Firstly, we discuss the association of clinical CVD (such as stroke and heart disease) and AD. Secondly, we summarize the relation between imaging makers of pre-clinical vascular disease and AD. Lastly, we discuss the association of cardiovascular risk factors and AD. We discuss both established cardiovascular risk factors and emerging putative risk factors, which exert their effect partly via CVD.

Cortical surface anatomy in pediatric patients with generalized anxiety disorder

BACKGROUND

It is established that pediatric patients with generalized anxiety disorder (GAD) exhibit functional abnormalities and altered gray matter volumes in neural structures that subserve emotional processing, yet there are no data regarding the surface anatomy of the cerebral cortex in youth with GAD.

METHODS

Using an automated surface-based approach (FreeSurfer), cortical thickness was assessed node-by-node over the entire cerebral cortex in adolescents with GAD and no co-occurring major depressive disorder (n=13) and healthy subjects (n=19).

RESULTS

Compared with healthy adolescents, youth with GAD exhibited increased cortical thickness in the right inferolateral and ventromedial prefrontal cortex (i.e., inferior frontal gyrus), the left inferior and middle temporal cortex as well as the right lateral occipital cortex. No relationships were observed between cortical thickness and the severity of anxiety symptoms in the significant regions that were identified in the vertex-wise analysis.

CONCLUSIONS

These findings suggest that, in adolescents with GAD, abnormalities in cortical thickness are present in an ensemble of regions responsible for fear learning, fear extinction, reflective functioning (e.g., mentalization), and regulation of the amygdala.

Reduced cortical thickness associated with visceral fat and BMI

Structural brain imaging studies have shown that obesity is associated with widespread reductions in gray matter (GM) volume. Although the body mass index (BMI) is an easily accessible anthropometric measure, substantial health problems are more related to specific body fat compartments, like visceral adipose tissue (VAT). We investigated cortical thickness measures in a group of 72 healthy subjects (BMI range 20–35 kg/m², age range 19–50 years). Multiple regression analyses were performed using VAT and BMI as predictors and age, gender, total surface area and education as confounds. BMI and VAT were independently associated with reductions in cortical thickness in clusters comprising the left lateral occipital area, the left inferior temporal cortex, and the left precentral and inferior parietal area, while the right insula, the left fusiform gyrus and the right inferior temporal area showed a negative correlation with VAT only. In addition, we could show significant reductions in cortical thickness with increasing VAT adjusted for BMI in the left temporal cortex. We were able to detect widespread cortical thinning in a young to middle-aged population related to BMI and VAT; these findings show close resemblance to studies focusing on GM volume differences in diabetic patients. This may point to the influence of VAT related adverse effects, like low-grade inflammation, as a potentially harmful factor on brain integrity already in individuals at risk of developing diabetes, metabolic syndromes and arteriosclerosis.

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We investigated cortical thickness in healthy adults.

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Body mass index (BMI) and visceral adipose tissue (VAT) were used as predictors.

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BMI and VAT were independently associated with cortical thickness.

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Cortical thinning was observed in the temporal cortex with increasing VAT.

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Our findings show close resemblance to GM volume differences in diabetic patients.

Preventing vascular effects on brain injury and cognition late in life: knowns and unknowns

For some researchers, the relationship between prevalent cardiovascular risk factors and late-life cognitive decline is not worthy of further study. It is already known that effective treatment of vascular risk factors lowers risk of such major outcomes as stroke and heart attack, the argument goes; thus, any new information about the relationship between vascular risk factors and another major outcome--late-life cognitive decline--is unlikely to have an impact on clinical practice. The purpose of this review is to probe the logic of this argument by focusing on what is known, and what is not known, about the relationship between vascular risk factors and late-life cognitive decline. The unknowns are substantial: in particular, there is relatively little evidence that current vascular risk factor treatment protocols are adequate to prevent late-life cognitive decline or the clinically silent brain injury that precedes it. In addition, there is relatively little understanding of which factors lead to differential vulnerability or resilience to the effects of vascular risk factors on silent brain injury. Differential effects of different classes of treatments are similarly unclear. Finally, there is limited understanding of the impact of clinically-silent neurodegenerative disease processes on cerebrovascular processes. Further study of the relationships among vascular risk factors, brain injury, and late-life cognitive decline could have a major impact on development of new vascular therapies and on clinical management of vascular risk factors, and there are promising avenues for future research in this direction.

Vascular risk and Aβ interact to reduce cortical thickness in AD vulnerable brain regions

OBJECTIVE

The objective of this study was to define whether vascular risk factors interact with β-amyloid (Aβ) in producing changes in brain structure that could underlie the increased risk of Alzheimer disease (AD).

METHODS

Sixty-six cognitively normal and mildly impaired older individuals with a wide range of vascular risk factors were included in this study. The presence of Aβ was assessed using [(11)C]Pittsburgh compound B-PET imaging, and cortical thickness was measured using 3-tesla MRI. Vascular risk was measured with the Framingham Coronary Risk Profile Index.

RESULTS

Individuals with high levels of vascular risk factors have thinner frontotemporal cortex independent of Aβ. These frontotemporal regions are also affected in individuals with Aβ deposition, but the latter show additional thinning in parietal cortices. Aβ and vascular risk were found to interact in posterior (especially in parietal) brain regions, where Aβ has its greatest effect. In this way, the negative effect of Aβ in posterior regions is increased by the presence of vascular risk.

CONCLUSION

Aβ and vascular risk interact to enhance cortical thinning in posterior brain regions that are particularly vulnerable to AD. These findings give insight concerning the mechanisms whereby vascular risk increases the likelihood of developing AD and supports the therapeutic intervention of controlling vascular risk for the prevention of AD.

The pattern of brain gray matter impairments in patients with subcortical vascular dementia

Though subcortical ischemic vascular dementia (SIVD) is known to initially affect subcortical regions, numerous brain imaging studies have also documented the widespread cortical alternations. Here we collected brain structural magnetic resonance imaging data from 34 SIVD patients and 35 healthy controls. Voxel-based morphometry (VBM), cortical thickness (and surface area) analysis and deep gray matter volume measurements were performed. VBM analysis showed gray matter volume reduction in lateral and medial temporal lobes, as well as orbitofrontal cortex in SIVD patients. The surface-based analyses revealed more subtle structural differences in the perisylvian area, medial temporal lobe, anterior and posterior cingulate, as well as prefrontal areas. Furthermore, analyses of deep gray matter demonstrated significant atrophy of the hippocampus, amygdala, nucleus accumbens and other nuclei. Finally, we found that thinning in the hippocampus and anterior cingulate cortex, as well as the volume decline in thalamus, caudate nucleus and amygdala was correlated with the cognitive impairment in patients. In conclusion, our study showed the structural abnormalities of the hippocampus and its associated outflow areas, as well as cortices implicated in cholinergic circuits in SIVD. These findings may bring new insights into the dysfunction of brain gray matter in SIVD.

Susceptibility to focal and global brain ischemia of Alzheimer mice displaying aβ deposits: effect of immunoglobulin

Cerebral ischemia is a risk factor for Alzheimer's disease (AD). Moreover, recent evidence indicates that it is a two-way street as the incidence rate of stroke is significantly higher in AD patients than those without the disease. Here we investigated the interaction of ischemic brain insults and AD in 9-month-old ApdE9 mice, which show full-blown accumulation of Aβ deposits and microgliosis in the brain. Permanent occlusion of the middle cerebral artery (pMCAo) resulted in 36% larger infarct in ApdE9 mice compared to their wild-type (wt) controls. This was not due to differences in endothelium-dependent vascular reactivity. Treatment with human intravenous immunoglobulin (IVIG) reduced the infarct volumes and abolished the increased vulnerability of ApdE9 mice to pMCAo induced brain ischemia. When the mice were exposed to global brain ischemia (GI), an insult of hippocampal cells, ApdE9 mice showed increased neuronal loss in CA2 and CA3 subregions compared to their wt controls. GI was associated with increased microgliosis, astrogliosis, infiltration of blood-derived monocytic cells, and neurogenesis without clear differences between the genotypes. IVIG treatment prevented the GI-induced neuron loss in hippocampal CA1 and CA3 regions in ApdE9 mice. IVIG treatment increased microgliosis in wt but not in ApdE9 mice. Finally, GI induced 60% reduction in the hippocampal Aβ burden in ApdE9 mice, which was not affected by IVIG treatment. The results indicate that the AD pathology with Aβ deposits and microgliosis increases ischemic vulnerability in various brain areas. Moreover, IVIG treatment may be beneficial especially in patients suffering from both acute ischemic insult and AD.

Neuroprotective pathways: lifestyle activity, brain pathology, and cognition in cognitively normal older adults

This study used path analysis to examine effects of cognitive activity and physical activity on cognitive functioning in older adults, through pathways involving beta-amyloid (Aβ) burden, cerebrovascular lesions, and neural injury within the brain regions affected in Alzheimer's disease (AD). Ninety-two cognitively normal older adults (75.2 ± 5.6 years) reported lifetime cognitive activity and current physical activity using validated questionnaires. For each participant, we evaluated cortical Aβ burden (using [(11)C] labeled Pittsburgh-Compound-B positron emission tomography), cerebrovascular lesions (using magnetic resonance imaging-defined white matter lesion [WML]), and neural integrity within AD regions (using a multimodal neuroimaging biomarker). Path models (adjusted for age, gender, and education) indicated that higher lifetime cognitive activity and higher current physical activity was associated with fewer WMLs. Lower WML volumes were in turn related to higher neural integrity and higher global cognitive functioning. As shown previously, higher lifetime cognitive activity was associated with lower [(11)C] labeled Pittsburgh-Compound-B retention, which itself moderated the impact of neural integrity on cognitive functioning. Lifestyle activity may thus promote cognitive health in aging by protecting against cerebrovascular pathology and Aβ pathology thought to be relevant to AD development.

Cortical thickness mediates the effect of β-amyloid on episodic memory

OBJECTIVE

To investigate the associations among β-amyloid (Aβ), cortical thickness, and episodic memory in a cohort of cognitively normal to mildly impaired individuals at increased risk of vascular disease.

METHODS

In 67 subjects specifically recruited to span a continuum of cognitive function and vascular risk, we measured brain Aβ deposition using [(11)C] Pittsburgh compound B-PET imaging and cortical thickness using MRI. Episodic memory was tested using a standardized composite score of verbal memory, and vascular risk was quantified using the Framingham Coronary Risk Profile index.

RESULTS

Increased Aβ was associated with cortical thinning, notably in frontoparietal regions. This relationship was strongest in persons with high Aβ deposition. Increased Aβ was also associated with lower episodic memory performance. Cortical thickness was found to mediate the relationship between Aβ and memory performance. While age had a marginal effect on these associations, the relationship between Aβ and cortical thickness was eliminated after controlling for vascular risk except when examined in only Pittsburgh compound B-positive subjects, in whom Aβ remained associated with thinner cortex in precuneus and occipital lobe. In addition, only the precuneus was found to mediate the relationship between Aβ and memory after controlling for vascular risk.

CONCLUSION

These results suggest strong links among Aβ, cortical thickness, and memory. They highlight that, in individuals without dementia, vascular risk also contributes to cortical thickness and influences the relationships among Aβ, cortical thickness, and memory.

Predictors for cortical gray matter volume in stroke patients with confluent white matter changes

BACKGROUND AND PURPOSE

Our previous study found that cortical gray matter (cGM) volume predicted vascular cognitive impairment independent of age-related white matter changes (WMC). We aimed to investigate predictors for cGM volume in ischemic stroke patients with confluent WMC.

METHODS

One-hundred post-stroke patients with confluent WMC were recruited into the study. All volumetric measures were standardized by intracranial volume as volume ratio. Univariate analyses and multivariate linear regression models were used to test relationship of cGM volume with basic demography, vascular risk factors, APOE status, WMC volume (periventricular and deep WMC), infarct measures (volume, number and location) and microbleed (number, presence and location).

RESULTS

After controlling for significant variables in the univariate analyses, multivariate linear regression models found that old age (β=-0.288, p=0.001), low triglyceride (β=0.194, p=0.027), periventricular WMC (PVWMC) (β=-0.392, p<0.001) and presence of thalamic microbleed (β=-0.197, p=0.041) were independently predictive of less cGM volume ratio.

CONCLUSIONS

Age, PVWMC and left thalamic microbleed predict less cGM volume.

Carotid ultrasound examination as an aging and disability marker

AIM

To explore the usefulness of carotid ultrasound examination as a marker of aging and predictor of disability among older people.

METHODS

Carotid ultrasound, measuring carotid intima media thickness (CIMT) and recording the presence of plaques, was carried out in 152 adults aged 29-59 years (47 women) and in 107 older adults aged 61-88 years (86 women). In all, clinical routine laboratory parameters and lymphocyte telomere length as T/S ratio were measured. Among older adults, 12-min walk, timed up and go, hand grip and quadriceps strength were determined.

RESULTS

CIMT was significantly higher among older people and T/S ratio was significantly higher in young women. Carotid plaques were found in one adult and 17 older people. A multiple regression analysis accepted age, systolic blood pressure and T/S ratios as independent predictors of CIMT (R(2) = 0.51). Among older people, a logistic regression accepted age and the presence of carotid plaques as significant predictors of a 12-min walk speed below 1 m/s.

CONCLUSIONS

An abnormal 12-min walk as an indicator of functional decline among older people is associated with the presence of carotid artery plaques. CIMT is independently associated with age.

Cardio-metabolic risk factors and cortical thickness in a neurologically healthy male population: Results from the psychological, social and biological determinants of ill health (pSoBid) study

INTRODUCTION

Cardio-metabolic risk factors have been associated with poor physical and mental health. Epidemiological studies have shown peripheral risk markers to be associated with poor cognitive functioning in normal healthy population and in disease. The aim of the study was to explore the relationship between cardio-metabolic risk factors and cortical thickness in a neurologically healthy middle aged population-based sample.

METHODS

T1-weighted MRI was used to create models of the cortex for calculation of regional cortical thickness in 40 adult males (average age = 50.96 years), selected from the pSoBid study. The relationship between cardio-vascular risk markers and cortical thickness across the whole brain, was examined using the general linear model. The relationship with various covariates of interest was explored.

RESULTS

Lipid fractions with greater triglyceride content (TAG, VLDL and LDL) were associated with greater cortical thickness pertaining to a number of regions in the brain. Greater C reactive protein (CRP) and intercellular adhesion molecule (ICAM-1) levels were associated with cortical thinning pertaining to perisylvian regions in the left hemisphere. Smoking status and education status were significant covariates in the model.

CONCLUSIONS

This exploratory study adds to a small body of existing literature increasingly showing a relationship between cardio-metabolic risk markers and regional cortical thickness involving a number of regions in the brain in a neurologically normal middle aged sample. A focused investigation of factors determining the inter-individual variations in regional cortical thickness in the adult brain could provide further clarity in our understanding of the relationship between cardio-metabolic factors and cortical structures.