Ultrasonographic assessment of carotid wall characteristics and cognitive functions in a community sample of 59- to 71-year-olds. The EVA Study Group

Associations of carotid atherosclerosis with cognitive function and brain health: Findings from a UK tri-ethnic cohort study (Southall and Brent Revisited)

Background

Cognitive function has an important role in determining the quality of life of older adults. Cardiovascular disease (CVD) is common in older people and may compromise cognitive performance; however, the extent to which this is related to carotid atherosclerosis is unclear.

Aim

We investigated associations between carotid atherosclerosis and cognitive function and neuroimaging markers of brain health in a UK multi-ethnic community-based sample including older people of European, South Asian, and African-Caribbean ethnicity.

Methods

Carotid plaques and intima-media thickness (cIMT) were assessed using ultrasound in 985 people (mean age 73.2y, 56 % male). Associations of carotid atherosclerosis with cognitive function (memory, executive function, language and CSI-D, a global measure of cognitive state) and neuroimaging measures (total brain volume, hippocampal volume, white matter (WM) lesion volume and coalescence score) were analysed using regression analyses, with and without adjustment for potential confounders using two models: 1) adjustment for age, sex, and ethnicity; 2) model 1 plus education, physical activity category, body mass index, hypertension, diabetes, total and high density lipoprotein cholesterol, atrial fibrillation, smoking, previous CVD, alcohol consumption, and presence of chronic kidney disease.

Results

People with carotid plaque or higher cIMT had lower CSI-D score, poorer memory poorer executive function and higher WM lesion volume and coalescence. Language was poorer in people with plaque but was not correlated with cIMT. Associations with plaque were preserved after full adjustment (model 2) but relationships for cIMT were attenuated. Associations with other plaque characteristics were generally unconvincing after adjustment.

Conclusions

This multi-ethnic cohort study provides evidence that presence of carotid plaque, is associated with poorer cognitive function and brain health.

Enhanced Carotid Plaque Echolucency Is Associated with Reduced Cognitive Performance in Elderly Patients with Atherosclerotic Disease Independently on Metabolic Profile

Vulnerable carotid atherosclerotic plaques are related to an increased risk of cognitive impairment and dementia in advanced age. In this study, we investigated the relationship between the echogenicity of carotid plaques and cognitive performance in patients with asymptomatic carotid atherosclerotic plaques. We enrolled 113 patients aged 65 years or more (72.4 ± 5.9 years) who underwent carotid duplex ultrasound to evaluate plaque echogenicity by grey-scale median (GSM) and neuropsychological tests to assess cognitive function. The GSM values at baseline were inversely correlated with the number of seconds required to complete Trail Makin Test (TMT) A (rho: −0.442; p < 0.0001), TMT B (rho: −0.460; p < 0.0001) and TMT B-A (rho: −0.333; p < 0.0001) and directly correlated with Mini Mental State Examination (MMSE) and Verbal Fluency Test (VFT) score (rho: 0.217; p = 0.021 and rho: 0.375; p < 0.0001, respectively) and the composite cognitive z-score (rho: 0.464; p < 0.0001). After a mean period of 3.5 ± 0.5 years, 55 patients were reevaluated according to the same baseline study protocol. Patients with baseline GSM value higher than the median value of 29 did not show any significant variation in the z-score. Instead, those with GSM ≤ 29 showed a significant worsening of z-score (−1.2; p = 0.0258). In conclusion, this study demonstrates the existence of an inverse relationship between the echolucency of carotid plaques and cognitive function in elderly patients with atherosclerotic carotid disease. These data suggest that the assessment of plaque echogenicity if used appropriately, might aid in identifying subjects at increased risk for cognitive dysfunction.

Is carotid artery atherosclerosis associated with poor cognitive function assessed using the Mini-Mental State Examination? A systematic review and meta-analysis

OBJECTIVES

To determine associations between carotid atherosclerosis assessed by ultrasound and the Mini-Mental State Examination (MMSE), a measure of global cognitive function.

DESIGN

Systematic review and meta-analysis.

METHODS

MEDLINE and EMBASE databases were searched up to 1 May 2020 to identify studies assessed the associations between asymptomatic carotid atherosclerosis and the MMSE. Studies reporting OR for associations between carotid plaque or intima-media thickness (cIMT) and dichotomised MMSE were meta-analysed. Publication bias of included studies was assessed.

RESULTS

A total of 31 of 378 reviewed articles met the inclusion criteria; together they included 27 738 participants (age 35-95 years). Fifteen studies reported some evidence of a positive association between measures of atherosclerosis and poorer cognitive performance in either cross-sectional or longitudinal studies. The remaining 16 studies found no evidence of an association. Seven cross-sectional studies provided data suitable for meta-analysis. Meta-analysis of three studies that assessed carotid plaque (n=3549) showed an association between the presence of plaque and impaired MMSE with pooled estimate for the OR (95% CI) being 2.72 (0.85 to 4.59). An association between cIMT and impaired MMSE was reported in six studies (n=4443) with a pooled estimate for the OR (95% CI) being 1.13 (1.04 to 1.22). Heterogeneity across studies was moderate to small (carotid plaque with MMSE, I2=40.9%; cIMT with MMSE, I2=4.9%). There was evidence of publication bias for carotid plaque studies (p=0.02), but not cIMT studies (p=0.2).

CONCLUSIONS

There is some, limited cross-sectional evidence indicating an association between cIMT and poorer global cognitive function assessed with MMSE. Estimates of the association between plaques and poor cognition are too imprecise to draw firm conclusions and evidence from studies of longitudinal associations between carotid atherosclerosis and MMSE is limited.

PROSPERO REGISTRATION NUMBER

CRD42021240077.

Asymptomatic Carotid Disease and Cognitive Impairment: What Is the Evidence?

The development of cognitive dysfunction and dementia is a complex, multifactorial process. One of the contributors to various types of cognitive dysfunction is carotid atherosclerosis which can frequently be seen in asymptomatic individuals. There are a number of different manifestations of asymptomatic carotid atherosclerosis including arterial stiffness, carotid intima-media thickening, flow-limiting stenosis, and complex, atherosclerotic plaque. Each of these forms of atherosclerosis may contribute to cerebral parenchymal damage, contributing to cognitive dysfunction. In this review article, we will discuss each of these forms of carotid atherosclerosis, present the potential mechanistic underpinnings behind an association, and then review the scientific evidence supporting potential associations to cognitive dysfunction and dementia.

Subclinical Carotid Artery Atherosclerosis and Cognitive Function: A Mini-Review

Carotid artery atherosclerosis, the result of a multitude of vascular risk factors, is a promising marker for use in risk stratification. Recent evidence suggests that carotid artery atherosclerosis affects cognitive function and is an independent risk factor for the development of cognitive impairment. Both atherosclerosis and cognitive impairment develop over a prolonged period (years), and due to the aging population, markers to identify persons at risk are needed. Carotid artery atherosclerosis can easily be visualized using non-invasive ultrasound, potentially enabling early and intensified risk factor management to preserve cognitive function or delay further decline. However, the burden of atherosclerosis and temporal exposure required to pose a risk of cognitive impairment is unclear. This mini-review aims to explore the available evidence on the association between carotid atherosclerosis and cognition, and furthermore identify the remaining gaps in knowledge.

Carotid Atherosclerosis and Cognitive Function in a General Population Aged 63-65 Years: Data from the Akershus Cardiac Examination (ACE) 1950 Study

BACKGROUND

Studies on the relationship between carotid atherosclerosis and cognitive function in subjects from the general population are few and results have been inconsistent.

OBJECTIVE

We aimed to investigate the association between carotid atherosclerotic burden and cognitive function in a cross-sectional analysis of a population-based cohort aged 63-65 years.

METHODS

All habitants born in 1950 from Akershus County, Norway were invited to participate. A linear regression model was used to assess the association between carotid atherosclerosis and cognitive function. We used carotid plaque score as a measure of carotid atherosclerotic burden and the Montreal Cognitive Assessment (MoCA) for global cognitive function.

RESULTS

We analyzed 3,413 individuals aged 63-65 with mean MoCA score 25.3±2.9 and 87% visible carotid plaques. We found a negative correlation between carotid plaque score and MoCA score (r = -0.14, p < 0.001), but this association was lost in multivariable analysis. In contrast, diameter or area of the thickest plaque was independently associated with MoCA score. Lower educational level, male sex, current smoking, and diabetes were also associated with lower MoCA score in multivariable analysis.

CONCLUSION

Carotid atherosclerotic burden was, unlike other measures of advanced carotid atherosclerosis, not independently associated with global cognitive function.

The Association of Physical Activity With Carotid Intima Media Thickening in a Healthy Older Population: Cooper Center Longitudinal Study

The purpose of this study was to examine the association between self-reported physical activity (PA) and mean common carotid artery intima-media thickness (CCA IMT) among older adults. The data are from 1,811 Cooper Center Longitudinal Study participants, who were aged ≥60 years, with no history of cardiovascular disease. A medical history questionnaire was used to assess PA. Carotid ultrasound was performed to measure CCA IMT and the presence of plaque and stenosis. Logistic regression models were constructed to estimate the association between PA and CCA IMT after adjustment for covariates. The participants were aged 69.2 ± 5.9 years, and the majority were male (73.3%) and White (96.7%). The odds ratio of abnormal thickening of CCA IMT was 0.72 (95% confidence interval [0.54, 0.96]) in physically active participants (≥500 metabolic equivalent·min/week) after adjustment for covariates. In the current study, meeting PA guidelines in older adulthood was associated with lower odds of abnormal thickening of CCA IMT.

Neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio: novel markers for the diagnosis and prognosis in patients with restenosis following CAS

Aim: In this study, we investigated the effect of neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio on restenosis status in patients undergoing carotid angioplasty stenting (CAS). Methodology & results: Clinical imageology and receiver operating characteristic analysis were utilized to study the prognostic significance of NLRs/platelet-to-lymphocyte ratios and their correlation with survival. NLR of restenosis (+) patients was evidently increased after the CAS procedures, while the NLR of restenosis (-) patients before the CAS procedures being the lowest. Area under the curve of pre-CAS NLR or/and post-CAS NLR were all evidently higher than 50%. Also, restenosis incidence was the highest in patients with both high pre-CAS and high post-CAS values. Conclusion: Therefore, NLR can be utilized as an independent prognostic indicator to predict the incidence of restenosis after CAS procedures.

Carotid circumferential wall stress is not associated with cognitive performance among individuals in late middle age: The Maastricht Study

BACKGROUND AND AIMS

Arterial remodelling aims at normalising circumferential wall stress (CWS). Greater CWS in the carotid artery has previously been associated with the prevalence and severity of cerebral small vessel disease, a major cause of ageing-related cognitive decline. Here we test the hypothesis that greater carotid CWS is associated with poorer cognitive performance.

METHODS

We studied 722 individuals (60 ± 8 years, 55% men, 42.5% highly educated, blood pressure 137 ± 19/77 ± 11 mmHg, n = 197 with type 2 diabetes) who completed a neuropsychological assessment and underwent vascular ultrasound to measure the intima-media thickness (IMT) and interadventitial diameter (IAD) of the left common carotid artery at a plaque-free site. From IMT and IAD, lumen diameter (LD) was calculated. These structural measures were then combined with local carotid pulse pressure and brachial mean arterial pressure to obtain a measure of pulsatile (CWS_pulsatile) and average (CWS_mean) mechanical load on the vessel wall. Cognitive domains assessed were memory, executive function and attention, and processing speed.

RESULTS

After adjustment for age, sex, and education, regression analyses showed that neither CWS_pulsatile nor CWS_mean were associated with measures of cognitive performance (p-values ≥0.31). This null association did not differ by age or educational level, and was observed in both individuals with and without carotid plaque, diabetes and/or hypertension. In addition, none of the individual measures of carotid structure (i.e. IMT, IAD, and LD) was related to cognitive performance.

CONCLUSIONS

The present cross-sectional study shows that carotid CWS is not associated with cognitive performance, at least not among relatively highly educated individuals in late middle age with adequately controlled cardiovascular risk factors.

Severe carotid artery stenosis evaluated by ultrasound is associated with post stroke vascular cognitive impairment

BACKGROUND

Acute ischemic stroke has been recognized as one key cause of vascular cognitive impairment (VCI). The purpose of this study was to evaluate the correlation between carotid artery stenosis and post VCI in acute ischemic stroke patients.

METHODS

In this study, B-mode ultrasound was applied to measure the degree of carotid artery stenosis. After 1 year, the stroke patients' cognitive function was assessed by the mini-mental state examination (MMSE) score. The relationship between the VCI and degree of carotid artery stenosis was evaluated by multivariate regression analysis.

RESULTS

VCI was observed in 136 (37.2%) of the 365 participants. High degree of carotid artery stenosis was significantly correlated with VCI (p < .01), and this correlation remained unchanged even adjustment for age, gender, education level, stroke features, and vascular risk factors.

CONCLUSIONS

These findings indicate that high-grade stenosis of carotid artery is positively correlated with post stroke VCI in patients with acute ischemic stroke. The evaluation of 1 year post stroke cognitive function may be a potential tool for screening stroke patients at risk of VCI.

Association between Carotid Intima-Media Thickness and Cognitive Impairment in a Chinese Stroke Population: A Cross-sectional Study

This study aimed to investigate the potential associations between carotid intima-media thickness and cognitive impairment among patients with acute ischemic stroke and to identify the clinical implications. We measured carotid intima-media thickness (IMT) and performed the Mini-Mental State Examination (MMSE) upon the admission of 1,826 acute ischemic stroke patients. The association between IMT and cognitive impairment evaluated by the MMSE was assessed with a multivariate regression analysis. Other clinical variables of interest were also assessed. After adjusting for potential confounders, participants in the highest IMT quartile had a higher likelihood of having cognitive impairments compared with the lowest IMT quartile (odds ratio: 3.01, 95% confidence interval: 2.07–4.37, p < 0.001). Stratified analyses indicated that this positive correlation was similar for the maxIMT and meanIMT of carotid artery measurements. A positive correlation was found between IMT and cognitive impairment in participants with acute ischemic stroke.

Incidence and predictors of cognitive decline in patients with left ventricular assist devices

BACKGROUND

After left ventricular assist device (LVAD) placement for advanced heart failure, increased cerebral perfusion should result in improved cognitive function. However, stroke (a well-known LVAD complication) and subclinical cerebral ischemia may result in transient or permanent cognitive decline. We sought to describe the incidence and predictors of cognitive decline after LVAD using a valid, sensitive assessment tool.

METHODS AND RESULTS

Among 4419 patients in the Interagency Registry for Mechanically Assisted Circulatory Support who underwent LVAD implantation between May 2012 and December 2013, cognitive function was assessed in 1173 patients with the Trail Making B Test before LVAD and at 3, 6, and 12 months. The test detects several forms of cognitive impairment, including subclinical stroke. Cognitive decline was defined as a clinically important increase during follow-up using a moderate Cohen d effect size of 0.5×baseline SD (32 s). The cumulative incidence of cognitive decline in the year after LVAD implantation, treating death and transplantation as competing risks, was 29.2%. In adjusted analysis, older age (≥70 versus <50 years; hazard ratio, 2.24; 95% confidence interval 1.46-3.44; P(trend)<0.001) and destination therapy (hazard ratio, 1.42; 95% confidence interval, 1.05-1.92) were significantly associated with greater risk of cognitive decline.

CONCLUSIONS

Cognitive decline occurs commonly in patients in the year after LVAD and is associated with older age and destination therapy. These results could have important implications for patient selection and improved communication of risks before LVAD implantation. Additional studies are needed to explore the association between cognitive decline and subsequent stroke, health status, and mortality in patients after LVAD.

Subclinical atherosclerotic calcification and cognitive functioning in middle-aged adults: the CARDIA study

OBJECTIVE

Cardiovascular risk factors in middle-age are associated with cognitive impairment and dementia in older age. Less is known about the burden of calcified subclinical atherosclerosis and cognition, especially in midlife. We examined the association of coronary artery and abdominal aortic calcified plaque (CAC and AAC, respectively) with cognitive functioning in middle-aged adults.

METHODS

This cross-sectional study included 2510 black and white adults (age: 43-55 years) without heart disease or stroke who completed a year 25 follow-up exam (2010-11) as part of the Coronary Artery Risk Development in Young Adults Study. CAC and AAC were measured with non-contrast computed tomography. Cognition was assessed with the Digit Symbol Substitution Test (DSST) (psychomotor speed), Stroop Test (executive function), and Rey Auditory Verbal Learning Test (RAVLT) (verbal memory).

RESULTS

A greater amount of CAC and AAC was associated with worse performance on each test of cognitive function after adjustment for age, sex, race, education, and study center. Associations were attenuated, but remained significant for the DSST and RAVLT following additional adjustment for vascular risk factors, including adiposity, smoking, alcohol use, dyslipidemia, hypertension, and diabetes. Compared to participants without CAC or AAC, those with both CAC and AAC, but not CAC or AAC alone was associated with lower DSST scores (p < 0.05).

CONCLUSIONS

In this community-based sample, greater subclinical atherosclerotic calcification was associated with worse psychomotor speed and memory in midlife. These findings underscore the importance of a life course approach to the study of cognitive impairment with aging.

Asymptomatic cervicocerebral atherosclerosis, intracranial vascular resistance and cognition: the AsIA-neuropsychology study

BACKGROUND AND PURPOSE

Carotid atherosclerosis has emerged as a relevant contributor to cognitive impairment and dementia whereas the role of intracranial stenosis and vascular resistance in cognition remains unknown. This study aims to assess the association of asymptomatic cervicocerebral atherosclerosis and intracranial vascular resistance with cognitive performance in a large dementia-free population.

METHODS

The Barcelona-AsIA (Asymptomatic Intracranial Atherosclerosis) Neuropsychology Study included 747 Caucasian subjects older than 50 with a moderate-high vascular risk (assessed by REGICOR score) and without history of neither symptomatic vascular disease nor dementia. Extracranial and transcranial color-coded duplex ultrasound examination was performed to assess carotid intima-media thickness (IMT), presence of carotid plaques (ECAD group), intracranial stenosis (ICAD group), and middle cerebral artery pulsatility index (MCA-PI) as a measure of intracranial vascular resistance. Neuropsychological assessment included tests in three cognitive domains: visuospatial skills and speed, verbal memory and verbal fluency.

RESULTS

In univariate analyses, carotid IMT, ECAD and MCA-PI were associated with lower performance in almost all cognitive domains, and ICAD was associated with poor performance in some visuospatial and verbal cognitive tests. After adjustment for age, sex, vascular risk score, years of education and depressive symptoms, ECAD remained associated with poor performance in the three cognitive domains and elevated MCA-PI with worse performance in visuospatial skills and speed.

CONCLUSIONS

Carotid plaques and increased intracranial vascular resistance are independently associated with low cognitive functioning in Caucasian stroke and dementia-free subjects. We failed to find an independent association of intracranial large vessel stenosis with cognitive performance.

Can lifestyle modification improve neurocognition? Rationale and design of the ENLIGHTEN clinical trial

BACKGROUND

Risk factors for cardiovascular disease (CVD) not only increase the risk for clinical CVD events, but also are associated with a cascade of neurophysiologic and neuroanatomic changes that increase the risk of cognitive impairment and dementia. Although epidemiological studies have shown that exercise and diet are associated with lower CVD risk and reduced incidence of dementia, no randomized controlled trial (RCT) has examined the independent effects of exercise and diet on neurocognitive function among individuals at risk for dementia. The ENLIGHTEN trial is a RCT of patients with CVD risk factors who also are characterized by subjective cognitive complaints and objective evidence of neurocognitive impairment without dementia (CIND) STUDY DESIGN: A 2 by 2 design will examine the independent and combined effects of diet and exercise on neurocognition. 160 participants diagnosed with CIND will be randomly assigned to 6 months of aerobic exercise, the DASH diet, or a combination of both exercise and diet; a (control) group will receive health education but otherwise will maintain their usual dietary and activity habits. Participants will complete comprehensive assessments of neurocognitive functioning along with biomarkers of CVD risk including measures of blood pressure, glucose, endothelial function, and arterial stiffness.

CONCLUSION

The ENLIGHTEN trial will (a) evaluate the effectiveness of aerobic exercise and the DASH diet in improving neurocognitive functioning in CIND patients with CVD risk factors; (b) examine possible mechanisms by which exercise and diet improve neurocognition; and (c) consider potential moderators of treatment, including subclinical CVD.

Utilizing imaging tools in lipidology: examining the potential of MRI for monitoring cholesterol therapy

Lipid abnormalities play important roles in the development of atherosclerosis. Lipid therapies result in alterations in atherosclerotic plaques including halting of progression of the plaque, lipid transport out of the plaque and reducing inflammatory activity, which lead to plaque morphologies that are less prone to disruption, the main cause of clinical events. In order to investigate and monitor plaque morphological changes during lipid therapy in vivo we need an imaging method that can provide accurate assessment of plaque tissue components and activity. MRI of atherosclerosis has been validated as a reliable assessment of the size of the vessel lumen, but also the size of the plaque, its tissue composition and plaque activity, including inflammation. The purpose of this review is to summarize the state of evidence for the direct assessment of atherosclerotic plaque and its change by MRI, and to establish the proven role of MRI of atherosclerosis in pharmaceutical trials with lipid therapy.

The effect of carotid occlusion in cognition before endarterectomy

The role of carotid stenosis on cognition remains to be determined. To study whether people with stenosis of the carotid artery have increased cognitive impairments, we studied 53 patients with moderate or severe carotid stenosis (with no symptoms of stroke or dementia) and 53 controls. We describe which cognitive functions were impaired in the patients and whether there were differences based on the side, the severity of the stenosis or the presence of neurological symptoms. Using the Repeatable Battery for the Assessment of Neuropsychological Status, we found that the patients with carotid stenosis had lower cognitive performances in attention, verbal memory, visuospatial capacity and verbal fluency. Patients with lesser degrees of stenosis than healthy control patients had better scores in learning and memory. The results from this study suggest that patients with severe carotid stenosis have a lower cognitive status than healthy control patients, which is associated with the degree of total carotid stenosis.

Is there a bidirectional relationship between depressive symptoms and cognitive ability in older people? A prospective study using the English Longitudinal Study of Ageing

BACKGROUND

Cross-sectional surveys of older people commonly find associations between higher levels of depressive symptoms and poorer cognitive performance, but the direction of effect is unclear. We examined whether there was a bidirectional relationship between depressive symptoms and general cognitive ability in non-demented older people, and explored the role of physical health, smoking, exercise, social class and education as potential confounders of this association and as possible determinants of the rate of change of cognitive decline and depressive symptoms.

METHOD

The English Longitudinal Study of Ageing consists of people aged 50 years and over. Cognitive function and self-reported depressive symptoms were measured in 2002-2003, 2004-2005, 2006-2007 and 2008-2009. We fitted linear piecewise models with fixed knot positions to allow different slopes for different age groups. Analyses are based on 8611 people.

RESULTS

Mean cognitive function declined with age; there was no trend in the trajectory of depressive symptoms. Better cognitive function was associated with less depression up to the age of 80 years. Greater depression was associated with a slightly faster rate of cognitive decline but only in people aged 60-80 years. There were no consistent associations across age groups between sex, smoking, education, social class, exercise or number of chronic physical illnesses and the rate of change of cognitive decline or depressive symptoms.

CONCLUSIONS

In this longitudinal study of older people, there was no consistent evidence that being more depressed led to an acceleration in cognitive decline and no support for the hypothesis that there might be reciprocal dynamic influences between cognitive ability and depressive symptoms.

Vascular risk factors in Alzheimer's disease - preliminary report

BACKGROUND

The vascular risk factors are associated with an increased risk for vascular cognitive decline (VCD), but also with Alzheimer disease (AD).

OBJECTIVE

To investigate vascular risk factors in relation to AD and VCD, with a non-invasive neurosonological methods in a clinical settings.

RESULTS

A total of 296 patients with AD and 237 patients with VCD were included in the study. Hypertension, hyperlipidemia, diabetes mellitus, stroke, and white matter changes (p<0.001) were significantly more prevalent in VCD, although they were also present in AD patients. No statistically significant differences were obtained between groups regarding coronary disease, atrial fibrillation, average degree of carotid artery stenosis and carotid intima-media thickness (cITM). However, the patients with AD had carotid artery stenosis ">50%" (p=0.007) and present plaques (p<0.001) more frequently compared to vascular group. The significant associations between robust cognitive measure and vascular factors, diabetes mellitus, carotid stenosis, cITM, and type of plaques were identified only in VCD, but not in AD group.

CONCLUSIONS

The vascular risk factors were more prevalent in VCD group, although they were also present in AD. With few treatment options available in AD, it may be important not to neglect the vascular risk factors.

Carotid atherosclerosis and cognitive function in midlife: the Beaver Dam Offspring Study

BACKGROUND

Atherosclerosis may be associated with cognitive function; however the studies are few, especially among midlife adults.

METHODS

Participants in the beaver dam offspring study who had cognitive test data and gradable carotid artery ultrasound scans were included (n=2794, mean age: 49 years). Atherosclerosis was measured by carotid intima-media thickness (IMT) and the presence of plaque. Cognitive function was measured by the trail making test (TMT), grooved pegboard test (GPT) and mini-mental state examination (MMSE). Generalized cognitive function was defined by a summary score calculated from the TMT and GPT. Linear regression was used to evaluate the associations between carotid atherosclerosis and cognitive function tests.

RESULTS

Larger IMT was associated with lower GPT, MMSE and the summary score adjusting for multiple factors, the coefficients were: 13.8s (p<0.0001), -0.6 (p=0.007), and 0.47 (p=0.01), respectively for 1mm increase in IMT. Plaque scores were significantly associated with TMT-B, GPT, MMSE, and the summary score adjusting for age, sex and education. The associations remained statistically significant after further adjustments except for the association with TMT-B, which was attenuated and no longer significant.

CONCLUSIONS

Our results show the significant associations between markers of carotid atherosclerosis and cognitive function in a cohort of persons aged 21-84 years. Longitudinal studies are needed to further examine these associations.

Association of vascular health and neurocognitive performance in overweight adults with high blood pressure

The relationship between vascular health--including flow-mediated dilation (FMD) and intima medial thickness (IMT)--and neurocognitive performance was examined in a sample of 124 sedentary, middle-aged adults with high blood pressure (systolic blood pressure, SBP, 130-159 mmHg or diastolic blood pressure, DBP, 85-99 mmHg) who were overweight or obese (body mass index 25.0-39.99 kg/m²). Patients completed a neuropsychological test battery, including measures of executive function and psychomotor speed, and measures of IMT and FMD were obtained. Hierarchical multiple regression analyses were used to investigate the association between vascular measures and neurocognitive performance after controlling for demographic factors and cerebrovascular risk factors. Higher levels of FMD predicted better executive function (b = 0.90, p = .045). Greater IMT tended to be associated with slower psychomotor speed (b = -0.82, p = .084), with the effect attenuated after controlling for FMD. Impaired FMD is associated with worse neurocognitive functioning among overweight adults with high blood pressure.

Subclinical atherosclerosis is related to lower neuronal viability in middle-aged adults: a 1H MRS study

BACKGROUND

Increased carotid artery intima-media thickness (IMT) is a noninvasive marker of systemic arterial disease, associated with atherosclerosis, abnormal arterial mechanics, myocardial infarction, and stroke. In the elderly, clinically elevated IMT is related to diminished attention-executive function. In this context, previous work involving paper-and-pencil measures of cognition has demonstrated that a threshold of pathology (i.e., IMT>or=0.9 mm) is needed before IMT consistently relates to poor neuropsychological test performance. Given the critical role of arterial health in the development of cognitive dysfunction, the goal of this study was to investigate early markers of brain vulnerability by examining subclinical levels of IMT in relation to a sensitive marker of neuronal integrity, cerebral N-acetyl-aspartate/creatine (NAA/Cr) ratio, in midlife.

METHODS

A total of 40 participants aged 50+/-6 years, underwent neuropsychological assessment, proton magnetic resonance spectroscopy ((1)H MRS) examination of occipitoparietal grey matter and B-mode ultrasound of the common carotid artery. IMT was defined as the distance between the luminal-endothelial interface and the junction between the media and the adventitia. The relation between IMT and cerebral metabolite ratios was modeled using a single multivariate multiple regression analysis adjusted for age and current systolic blood pressure.

RESULTS

Increased IMT was associated with significantly lower NAA/Cr ratios (IMT beta=-0.62, p=0.001), independent of age and systolic blood pressure (F(3,36)=4.928, p=0.006).

CONCLUSIONS

Our study extends previous findings by demonstrating a significant relationship between IMT and NAA concentration, suggesting compromised neuronal viability even at IMT levels below thresholds for clinical end-organ damage.

Carotid artery ultrasound and echocardiography testing to lower the prevalence of Alzheimer's disease

The use of two clinic office techniques, carotid artery ultrasound and echocardiography (CAUSE), to detect deficient brain blood flow delivery in the healthy, cognitively normal, older individual is proposed. Evidence indicates that persistent heart-to-brain blood flow deficit involving low cardiac output or low ejection fraction and carotid artery narrowing can promote cognitive impairment and that such impairment may lead to Alzheimer's disease (AD) or vascular dementia (VaD). A number of independent epidemiologic studies reported cardiovascular and cerebrovascular disease to be risk factors to AD and VaD. The clinical rationale for CAUSE is to detect and prevent progression of cognitive dysfunction in elderly persons and is based on the general understanding that mild cognitive impairment is a preclinical threshold to AD or VaD with high conversion rates to either dementia. The use of CAUSE is anticipated to prevent or attenuate, by appropriate clinical management, mild cognitive impairment arising from persistent brain hypoperfusion, a condition implicated in the promotion of cognitive impairment in the elderly and a common preclinical feature seen in AD and VaD. As detection of lowered cerebral perfusion from cardiac and carotid artery pathology is achieved using these cost-effective, noninvasive, and relatively accurate ultrasound procedures, a significant reduction in the number of new AD and VaD cases would be anticipated after appropriate patient treatment. In this context, a brief summary is presented outlining recent medical and surgical treatments that may improve cerebral blood flow insufficiency. The merit of CAUSE in screening and treating mentally healthy elderly persons who are identified as being at risk of cognitive decline is that it could blunt the soaring socioeconomic impact that will hammer the health care system of many nations by the mounting dementia prevalence rate expected in the next 25 years. A 5- year delay in the onset of AD could reduce the prevalence of AD by 50%. We are making preparations to test the merit of CAUSE in a clinical study of a cognitively healthy elderly population.

Carotid intimal medial thickness predicts cognitive decline among adults without clinical vascular disease

BACKGROUND AND PURPOSE

Though clinical cardiovascular and cerebrovascular diseases are established risk factors for cognitive decline and dementia, less is known about the relations between vascular health and cognition among individuals without these diseases. Carotid intimal medial thickness (IMT), a measure of subclinical vascular disease, is associated with concurrent decrements in cognitive function, but relatively little research has examined longitudinal relations between carotid IMT and prospective cognitive decline.

METHODS

We examined relations of carotid IMT to prospective trajectories of cognitive function among 538 (aged 20 to 93, 39% male, 66% white) participants in the Baltimore Longitudinal Study of Aging (BLSA) free of known cardiovascular, cerebrovascular, and neurological disease. Participants underwent initial carotid ultrasonography and repeat neuropsychological testing on up to 8 occasions over up to 11 years of follow-up. Mixed-effects regression analyses were adjusted for age, gender, race, education, mean arterial pressure, body mass index, total cholesterol, smoking, depressive symptoms, and cardiovascular medication use.

RESULTS

Individuals with greater carotid IMT displayed accelerated decline in performance over time on multiple tests of verbal and nonverbal memory, as well as a test of semantic association fluency and executive function.

CONCLUSIONS

Carotid IMT predicts accelerated cognitive decline, particularly in the domain of memory, among community-dwelling individuals free of vascular and neurological disease.

Chronic ischemia and neurocognition

Cognitive impairment from a major stroke as a consequence of carotid disease is an acknowledged clinical outcome; however, cognitive impairment without major stroke is open to discussion. The three recognized mechanisms for cognitive dysfunction from internal carotid artery are microembolization, white-matter disease, and hypoperfusion. The last has been most difficult to characterize physiologically. In this article, the authors review evidence supporting the existence of chronic ischemia in the brain and its direct impact on cognitive functions. By incorporating the pathophysiology of chronic ischemia into the algorithm of the management of carotid artery disease, we may be able to extend the goals of carotid artery revascularization beyond merely preventing stroke to include preventing or reversing cognitive decline.

Socioeconomic status moderates the association between carotid intima-media thickness and cognition in midlife: evidence from the Whitehall II study

BACKGROUND

Common carotid artery intima-media thickness (IMT) is a measure of generalized atherosclerosis and has been shown to be associated with cognitive function. We examine two questions: does socioeconomic status (SES) moderate this association and is IMT more strongly associated with specific aspects of cognitive function?

METHODS

Data are drawn from the Phase 7 (2003-2004) of the Whitehall II study (N=3896). In cross-sectional analyses the association between IMT and six measures of cognition (short-term verbal memory, inductive reasoning, vocabulary, semantic and phonemic fluency and a measure of global cognitive status) was examined in analyses adjusted for previous history of coronary heart disease, health behaviours and other vascular risk measures such as blood pressure, cholesterol and body mass index.

RESULTS

The overall association between IMT and the six measures of cognition was restricted to the low SES group (p=0.02). Within this group, IMT was significantly associated with inductive reasoning (p=0.001), vocabulary (p=0.002), phonemic (p=0.006) and semantic fluency (p=0.02). The covariates examined explained about a quarter of the association between IMT and cognition in the low SES group. The associations with the measure of inductive reasoning (p=0.02), vocabulary (p=0.02) and phonemic fluency (p=0.04) remained after adjustment for all covariates.

CONCLUSIONS

SES is an important modifier of the association between IMT and cognition, an inverse association between the two was observed only in the low SES group. It is possible that high cognitive reserve among the high SES individuals prevents the functional manifestations of atherosclerosis. Verbal memory was not one of the cognitive domains associated with IMT.

Carotid Intima-Media Thickness and Cognitive Function in Elderly Women: A Population-Based Study

OBJECTIVE

Several vascular risk factors have been linked to cognitive decline. However, little is known about the association between the atherosclerotic process and cognitive impairment. We investigated whether carotid intima-media thickness (IMT) predicts the risk of cognitive impairment and whether the putative impairment is specific for some cognitive domains.

METHODS

A 12-year population-based follow-up study was performed for a total of 91 women, aged 60-70 years at baseline. Ultrasonographically assessed carotid artery IMT and the Mini-Mental State Examination test were performed at baseline and 12-year follow-up. A detailed cognitive evaluation for memory and cognitive speed was performed in 2003. The mean of left and right carotid bifurcation IMT was used in the analyses for association with the risk for poor cognitive speed and memory.

RESULTS

Increased IMT at baseline was an independent predictor for poor memory (beta = -5.004, 95% confidence interval = -7.74 to -2.27; p = 0.001) and cognitive speed (beta = 2.562, 95% confidence interval = 1.19-4.94; p = 0.035) at 12-year follow-up after adjustment for age, education, depression, plasma LDL cholesterol, systolic blood pressure, cardiovascular disease, hormone replacement therapy, smoking, alcohol consumption and physical activity. The risk for poor memory (p = 0.023 for linear trend) and cognitive speed (p = 0.070 for linear trend) increased with increasing IMT tertiles.

CONCLUSIONS

Carotid IMT predicts an increased risk for cognitive impairment, particularly poor memory and cognitive speed, in elderly women.

Cerebrovascular risk factors, vascular disease, and neuropsychological outcomes in adults with major depression

OBJECTIVE

To investigate the relationship of cerebrovascular risk factors (CVRFs), endothelial function, carotid artery intima medial thickness (IMT), and neuropsychological performance in a sample of 198 middle-aged and older individuals with major depressive disorder (MDD). Neuropsychological deficits are common among adults with MDD, particularly among those with CVRFs and potentially persons with subclinical vascular disease.

METHODS

CVRFs were indexed by the Framingham Stroke Risk Profile (FSRP) and serum cholesterol levels obtained by medical history and physical examination. Patients completed a neuropsychological test battery including measures of executive functioning, working memory, and verbal recall. Vascular function was indexed by carotid artery IMT and brachial artery flow mediated dilation (FMD). Hierarchical multiple regression analyses were used to investigate the association between CVRFs, vascular disease, and neurocognitive performance.

RESULTS

Greater FSRP scores were associated with poorer executive functioning (b = -0.86; p = .041) and working memory (b = -0.90; p = .024). Lower high-density lipoprotein levels also were associated with poorer executive functioning (b = 1.03; p = .035). Higher IMT (b = -0.83; p = .028) and lower FMD (b = 1.29; p = .032) were associated with poorer executive functioning after controlling for CVRFs. Lower FMD was also associated with poorer working memory (b = 1.58; p = .015).

CONCLUSIONS

Greater CVRFs were associated with poorer neuropsychological performance. Vascular dysfunction also was associated with neuropsychological decrements independent of traditional CVRFs.

Carotid artery intima-media thickness and cognition in cardiovascular disease

BACKGROUND

Increased carotid artery intima-media thickness (IMT) is a non-invasive marker of systemic arterial disease. Increased IMT has been associated with atherosclerosis, abnormal arterial mechanics, myocardial infarction, and stroke. Given evidence of a relationship between cardiovascular health and attention-executive-psychomotor functioning, the purpose of this study was to examine IMT in relation to neuropsychological test performance in patients with a variety of cardiovascular diagnoses.

METHODS

One hundred and nine participants, ages 55 to 85, underwent neuropsychological assessment and B-mode ultrasound of the left common carotid artery. IMT was calculated using an automated algorithm based on a validated edge-detection technique. The relationship between IMT and measures of language, memory, visual-spatial abilities and attention-executive-psychomotor functioning was modeled using hierarchical linear regression analyses adjusted for age, education, sex, cardiovascular risk, current systolic blood pressure, and history of coronary artery disease (CAD).

RESULTS

Increased IMT was associated with significantly lower performance in the attention-executive-psychomotor domain (IMT beta=-0.26, p<.01), independent of age, education, sex, cardiovascular risk, current systolic blood pressure, and CAD (F(10,100)=3.61, p<.001). IMT was not significantly related to language, memory, or visual-spatial abilities.

CONCLUSIONS

Our findings suggest that, in patients with cardiovascular disease, IMT may be associated with the integrity of frontal subcortical networks responsible for attention-executive-psychomotor performance. Future studies are needed to clarify the mechanisms by which IMT affects cognition and examine potential interactions between increased IMT and other measures of cardiovascular health such as blood pressure variability, cardiac systolic performance, and systemic perfusion.

Effect of contrast enhancement on the measurement of carotid arterial lumen and wall volume using MRI

PURPOSE

To investigate whether gadolinium (Gd)-based contrast enhancement (CE) affects high-resolution magnetic resonance imaging (MRI) measurements of carotid arterial wall volume.

MATERIALS AND METHODS

The common carotid artery (CCA), bifurcation, and internal carotid artery (ICA) of 50 consecutive patients were imaged using 1.5T MRI. T1-weighted (T1W) images were obtained before and after Gd administration. Pre- and post-CE measurements were compared among different arterial locations of the CCA, bifurcation, and ICA, and among different atherosclerotic lesion types.

RESULTS

In comparison to pre-CE T1W images, post-CE images showed an increase in the apparent wall volume measurement of 28.2% (108.7 mm3 vs. 84.7 mm3, P < 0.001). The post-CE measurement increases in wall volume for the CCA, bifurcation, and ICA were 26.7%, 29.2%, and 28.0%, respectively.

CONCLUSION

Gd CE causes a significant increase in the apparent volume of the carotid wall throughout multiple carotid artery locations, which may be associated with improved visibility or neovascularization.

Executive cognitive dysfunction without stroke after long-term mechanical circulatory support

Among patients who receive heart transplantation (HTx) after long-term mechanical circulatory support (MCS), some show executive cognitive dysfunction without a history of stroke. Fifty HTx patients (19 patients on MCS for longer than 3 months before HTx and 31 patients without MCS as control group) were enrolled in the study. All subjects were men aged between 20 and 59 years without a history of stroke. Patients with MCS were divided into two groups: the AH-Thr group (n = 11), in which thrombus was detected in the left ventricular assist device (LVAD) and quickly removed (mean 3.3 times); and the AH group (n = 8), in which there was no detectable thrombus in the LVAD. The Trail Making Test (TMT) and the Wisconsin Card Sorting Test (WCST) were administered. The AH-Thr group showed poorer cognitive performance both in the TMT part B, with longer completion time (p < 0.05 versus the other two groups), and in the WCST, with more perseverative errors (p < 0.001 versus the other two groups). These data indicate that patients in the AH-Thr group showed executive cognitive dysfunction in set-shifting ability, suggesting frontal lobe damage. The conditions that facilitate thrombus formation in the LVAD may induce executive cognitive dysfunction without stroke.

Lipid metabolism in cognitive decline and dementia

This review will focus on the current knowledge on circulating serum and plasma risk factors of cognitive decline of degenerative (Alzheimer's disease, AD) or vascular origin (vascular dementia, VaD) linked to cholesterol homeostasis and lipoprotein disturbances, i.e. total cholesterol (TC), 24S-hydroxy-cholesterol, lipoprotein(a) (Lp(a)), or apolipoprotein E (APOE). These measures linked to lipoprotein metabolism appear to be altered in AD, VaD, or predementia syndrome relative to controls, but with contrasting results. At present, several studies have demonstrated the dependence of APOE serum levels upon the APOE genotype, nonetheless serum APOE levels seems not to be a credible risk factor or a biochemical marker for AD instead of APOE genotyping. In fact, there was no consistent association of serum or plasma apoE protein levels with the disease when controlled for APOE genotype. In addition, there are some evidence that higher Lp(a) levels could be linked with AD, although there are studies suggesting an increased presence of low molecular weight apo(a) in AD, VaD, and frontotemporal dementia, that are associated with elevated Lp(a) levels. In fact, the apo(a) gene is highly polymorphic in length due to variation in the numbers of a sequence encoding the apo(a) kringle 4 domain, and plasma levels of Lp(a) are inversely correlated with apo(a) size. Furthermore, although serum/plasma levels of TC and 24S-hydroxycholesterol are not credible diagnostic markers for AD and cognitive decline, the current evidence suggests that they may be modifiable risk/protective factors. The prevailing wisdom is that high TC is a risk factor for dementia. However, the relationship between TC and dementia may vary considerably depending on when cholesterol is measured over the life course or, alternatively, in relation to the underlying course of the disease. Several observational studies have suggested that statins, which are effective in lowering cholesterol, may reduce the risk of dementia, but the results of these reports are inconclusive. Thus, more studies with long-term follow-up and serial assessments of TC are needed to further clarify the causal relationship between cholesterol and dementia.

Diagnostic tools for the study of vascular cognitive dysfunction in hypertension and antihypertensive drug research

Arterial hypertension is one of the main risk factors for cerebrovascular diseases, and antihypertensive treatment has significantly reduced their associated mortality. However, morbidity has not been reduced to a similar extent and a still increasing number of patients suffers from recurring strokes and from the disabling consequences of cerebrovascular diseases and develops progressive cognitive impairment. It is still debated to what extent antihypertensive treatment may prevent the development of cognitive dysfunction, due to the lack of a focused approach to vascular cognitive impairment, to the lack of a systematic study of the early phases of dementia, and to the use of diagnostic tests that are not sensitive and specific for a slow onset clinical condition, such as dementia. The aim of the present expert consensus report is to enlist the diagnostic tools that are currently available to assess mild cognitive impairment (MCI) and early dementia and that are sensitive and specific enough to be used in observational, longitudinal, and interventional clinical research studies, aiming to investigate the impact of antihypertensive drugs on vascular dementia (VD).

Inhibitory avoidance memory retention in the elevated T-maze is impaired after perivascular manipulation of the common carotid arteries

Perivascular manipulation promoted by the positioning of a silicone collar around the common carotid arteries causes local inflammation and has been suggested as an animal model of atherosclerosis. This manipulation induces biochemical and morphological changes that are similar to those observed in the early stage of atherosclerosis in humans. Based on evidences showing that atherosclerosis is associated with cognitive deficits in humans, we presently investigated the temporal consequences of the bilateral positioning of silicone collars around the common carotid arteries (n = 15) on inhibitory avoidance memory retention in male Wistar rats tested in the elevated T-maze. The effects of this procedure were compared to those observed in sham-operated animals (n = 15) and to those observed in animals submitted to permanent bilateral occlusion of the common carotid arteries (n = 16). Additionally we studied the effects of the pretreatment with the non-selective anti-inflammatory drug indomethacin (n = 13) or the selective COX-2 inhibitor celecoxib (n = 12) and compared the effects to those of the pretreatment with vehicle (n = 11). The results showed that the silicone collar implants induced deficits in memory retention when animals were tested 2 and 4, but not 15 or 30, days after surgery. Permanent bilateral occlusion of the common carotid arteries impaired avoidance retention up to 30 days after surgery. Pretreatment with indomethacin (2 mg/kg/day) or celecoxib (5 mg/kg/day) post surgery and up to 3 days thereafter did not prevent memory deficits caused by silicone collar implants. Our data suggest that the prostanoids that participate in the inflammatory process triggered by the placement of the silicone collar do not seem responsible for the deficit in memory retention observed during the first days after collar placement.

Hepatic steatosis is associated with an increased risk of carotid atherosclerosis

AIM: Although an association between hepatic steatosis and vascular risk factors has been described, direct relationships between fatty liver and atherosclerosis have not yet been investigated. The aim of the present study has been to investigate those relationships.

METHODS: The Study of Health in Pomerania examined a random population sample aged between 20 and 79 years. A study population of 4222 subjects without hepatitis B and C infections and without liver cirrhosis was available for the present analysis. Hepatic steatosis was defined sonographically and intima-media thickness (IMT) as well as plaque prevalence were estimated by carotid ultrasound.

RESULTS: The prevalence rate of hepatic steatosis was 29.9%. Among subjects aged ≥45 years, an association between hepatic steatosis and IMT of the carotid arteries was found in bivariate analysis, but not after adjustment for atherosclerotic risk factors. Individuals with fatty liver had more often carotid plaques than persons without fatty liver (plaque prevalence rate 76.8% vs 66.6%; P<0.001). This association persisted after adjustment for confounding factors and was predominantly present in subjects with no to mild alcohol consumption.

CONCLUSION: There is an independent association between hepatic steatosis and carotid atherosclerotic plaques. Metabolic changes due to nonalcoholic fatty liver disease may explain this relationship.

Common carotid artery intima media thickness and post-stroke cognitive impairment

BACKGROUND AND PURPOSE

Acute stroke and other forms of cerebrovascular disease are well-recognized causes of cognitive impairment. Common carotid artery intima media thickness (CCA-IMT) has been associated with certain forms of cerebrovascular disease, but its association with cognitive impairment of vascular origin has not been elucidated. The purpose of this study was to investigate whether CCA-IMT is associated with cognitive impairment 1 year after an acute ischemic stroke.

METHODS

A total of 171 consecutive patients with the first ever stroke (mean age 66+/-11.5, 41% female) underwent carotid ultrasonography during hospitalization. Demographic data, vascular risk factors and presenting stroke features were also recorded. One year later, patients' cognitive performance and depression were assessed using the Mini-Mental State Examination (MMSE), and the Montgomery Asberg Depression Rating Scale (MADRS).

RESULTS

Cognitive impairment (MMSE score<24) was found in 67 (39%) of the 171 patients. CCA-IMT was significantly associated with cognitive impairment, and this association remained unchanged (OR 1.94; 95% CI 1.19-3.18) after adjustment for demographic data, vascular risk factors, stroke features, other carotid ultrasonography measurements and depression. Older age, low education level, large hemispheric lesions, hyperdense carotid plaques and depression were also independently associated with post-stroke cognitive impairment.

CONCLUSIONS

In this study, CCA-IMT was independently associated with cognitive impairment 1 year after an acute ischemic stroke, and thus, it might help with the screening of stroke patients at risk of cognitive impairment.

Peripheral arterial disease and cognitive function

OBJECTIVE

Peripheral arterial disease (PAD) is associated with comorbid atherosclerosis of the coronary and carotid arteries and is a significant risk factor for stroke. However, cognitive function in PAD patients before clinically evident stroke remains poorly characterized. Here we hypothesized that, on neuropsychological testing, PAD patients would perform more poorly than healthy control subjects, and persons with mild cardiovascular disease (essential hypertension), but better than stroke patients, thus reflecting a continuum of cognitive impairment associated with increased severity of vascular disease.

METHOD

The cognitive performance of 38 PAD patients (mean ankle-brachial index=0.67, Fontaine Class II) was contrasted with that of 23 healthy normotensive controls, 20 essential hypertensives, and 26 anterior ischemic stroke patients on twelve neuropsychological tests.

RESULTS

PAD patients performed significantly more poorly than hypertensives and normotensives, but better than stroke patients, on seven tests of nonverbal memory, concentration, executive function, perceptuo-motor speed, and manual dexterity. Hypertensives displayed poorer performance than normotensives on tests of nonverbal memory and manual dexterity. These findings were independent of age, education, and depression scores. Higher diastolic blood pressure and plasma glucose levels predicted poorer performance of select cognitive tests by PAD patients. Eight to 67% of PAD patients displayed impaired performance (< 5(th) percentile of normotensive controls) on the seven aforementioned cognitive tests.

CONCLUSIONS

PAD patients exhibit diminished performance across a variety of domains of cognitive function. Findings also suggest a continuum of cognitive impairment associated with increasingly severe manifestations of cardiovascular disease, thus emphasizing the need for enhanced preventative measures to avert functional declines.

Atherosclerosis and cognitive impairment are linked in the elderly. The Leiden 85-plus Study

Post-mortem analyses suggest that atherosclerosis more often contributes to late-onset dementia than hitherto expected. We set out to further unravel the relation between atherosclerosis and cognitive impairment. We therefore tested the hypothesis that the number of cardiovascular pathologies is positively associated with cognitive impairment in elderly subjects, and that the smaller number of cardiovascular pathologies in women explains the better cognitive function of elderly women. Within the Leiden 85-plus Study, we assessed the atherosclerotic burden by counting the number of cardiovascular pathologies in the medical histories of a population-based sample of 599 subjects aged 85 years (response 87%). Significantly more men than women had a history of cardiovascular pathologies (67% compared to 59%, P<0.001). In addition, cognitive function was assessed. All subjects completed the Mini-Mental State Examination (MMSE). Cognitive speed and memory were determined with specific neuro-psychological tests in those with a MMSE-score above 18 points. There was a highly significant dose-response relationship between the number of cardiovascular pathologies and cognitive impairment for both men and women. The median MMSE-score was 26 points in subjects without cardiovascular disease and decreased to 25 points for subjects who had two or more cardiovascular pathologies (P for trend =0.003). Similar associations were found for cognitive speed but not for memory. Our data confirm that in old age atherosclerosis significantly contributes to cognitive impairment. Since treatments for atherosclerosis appear to be particularly effective in elderly people, we consider our finding of utmost clinical importance in possibly preventing cognitive impairment and late-onset dementia.

Achieving and maintaining cognitive vitality with aging

Cognitive vitality is essential to quality of life and survival in old age. With normal aging, cognitive changes such as slowed speed of processing are common, but there is substantial interindividual variability, and cognitive decline is clearly not inevitable. In this review, we focus on recent research investigating the association of various lifestyle factors and medical comorbidities with cognitive aging. Most of these factors are potentially modifiable or manageable, and some are protective. For example, animal and human studies suggest that lifelong learning, mental and physical exercise, continuing social engagement, stress reduction, and proper nutrition may be important factors in promoting cognitive vitality in aging. Manageable medical comorbidities, such as diabetes, hypertension, and hyperlipidemia, also contribute to cognitive decline in older persons. Other comorbidities such as smoking and excess alcohol intake may contribute to cognitive decline, and avoiding these activities may promote cognitive vitality in aging. Various therapeutics, including cognitive enhancers and protective agents such as antioxidants and anti-inflammatories, may eventually prove useful as adjuncts for the prevention and treatment of cognitive decline with aging. The data presented in this review should interest physicians who provide preventive care management to middle-aged and older individuals who seek to maintain cognitive vitality with aging.

Cerebrovascular disease and cognitive dysfunction

As the general population ages, the progressive cognitive decline that occurs with aging and dementia is having a significant socioeconomic impact on society. Vascular dementia associated with cerebral vascular disease is now the third most common cause of dementia. Recent evidence has revealed a new and significant etiopathogenetic role of cerebrovascular pathology, as well as newly determined risk factors for the development of neurocognitive deficits and other forms of dementia including Alzheimer's disease. In this article, we summarize the experimental and clinical data linking cerebrovascular pathology to neurocognitive decline and dementia.

Intima-media thickness: a new tool for diagnosis and treatment of cardiovascular risk

Increased intima-media thickness (IMT) is a non-invasive marker of early arterial wall alteration, which is easily assessed in the carotid artery by B-mode ultrasound, and more and more widely used in clinical research. Methods of IMT measurement can be categorized by two approaches: (i) measurement at multiple extracranial carotid sites in near and far walls and (ii) computerized measurement restricted to the far wall of the distal common carotid artery. Because IMT reflects global cardiovascular risk, its normal value might be better defined in terms of increased risk rather than in terms of statistical distribution within a healthy population. The available epidemiological data indicate that increased IMT (at or above 1 mm) represents a risk of myocardial infarction and/or cerebrovascular disease. Close relationships have been shown between: (i) most traditional cardiovascular risk factors; (ii) certain emerging risk factors such as lipoproteins, psychosocial status, plasma viscosity, or hyperhomocysteinemia; and (iii) various cardiovascular or organ damages such as white matter lesion of the brain, left ventricular hypertrophy, microalbuminuria or decreased ankle to brachial systolic pressure index. Thus, IMT gives a comprehensive picture of the alterations caused by multiple risk factors over time on arterial walls. Prospective primary and secondary prevention studies have also shown that increased IMT is a powerful predictor of coronary and cerebrovascular complications (risk ratio from 2 to 6) with a higher predictive value when IMT is measured at multiple extracranial carotid sites than solely in the distal common carotid artery. Therapeutic double-blind trials have shown that lipid-lowering drugs, such as resin and overall statines, and to a lesser extent antihypertensive drugs, such as calcium antagonists, may have a beneficial effect on IMT progression in asymptomatic or in coronary patients. However, methodological standardization of IMT measurement still needs to be implemented before routine measurement of IMT can be proposed in clinical practice as a diagnostic tool for stratifying cardiovascular risk in primary prevention and for aggressive treatment decision. It can be anticipated however, that the presence of increased carotid IMT in one individual with intermediate cardiovascular risk would lead to his classification into the high-risk category and thus influence the aggressiveness of risk factor modifications.

Effect of the angiotensin I-converting enzyme I/D polymorphism on cognitive decline. The EVA Study Group

Several clinical, epidemiological, and pathological observations suggest that vascular risk factors are associated with cognitive performances. The renin-angiotensin system components, major determinants of the cardiovascular system, are expressed in the brain. To estimate their potential impact on cognitive performances, we studied the association between cognitive functioning and an insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme (ACE) gene. In a sample of 1168 highly performing subjects (59-71 years), DD homozygotes had the lowest cognitive scores as evaluated by the Mini-Mental State Examination. Cognitive decline at 4-year follow-up (defined as the loss of at least 3 points in Mini-Mental State Examination score) was more prevalent in these subjects, the odds ratio being equal to 1.53 (95% CI: 1.04-2.24) with subjects ID as reference class. Moreover, the combined effect of the presence of at least one APOE epsilon4 allele and ACE DD homozygosity was a risk factor for cognitive decline. This report reinforces the hypothesis of an influence of cardiovascular risk factors on cognitive performances.