Magnetic resonance abnormalities and cardiovascular disease in older adults. The Cardiovascular Health Study

Measurement of brain activation during an upright stepping reaction task using functional near-infrared spectroscopy

Functional near-infrared spectroscopy (fNIRS) is a non-invasive brain imaging technology that uses light to measure changes in cortical hemoglobin concentrations. FNIRS measurements are recorded through fiber optic cables, which allow the participant to wear the fNIRS sensors while standing upright. Thus, fNIRS technology is well suited to study cortical brain activity during upright balance, stepping, and gait tasks. In this study, fNIRS was used to measure changes in brain activation from the frontal, motor, and premotor brain regions during an upright step task that required subjects to step laterally in response to visual cues that required executive function control. We hypothesized that cognitive processing during complex stepping cues would elicit brain activation of the frontal cortex in areas involved in cognition. Our results show increased prefrontal activation associated with the processing of the stepping cues. Moreover, these results demonstrate the potential to use fNIRS to investigate cognitive processing during cognitively demanding balance and gait studies.

Anatomic brain disease in hemodialysis patients: a cross-sectional study

BACKGROUND

Although dialysis patients are at high risk of stroke and have a high burden of cognitive impairment, there are few reports of anatomic brain findings in the hemodialysis population. Using magnetic resonance imaging of the brain, we compared the prevalence of brain abnormalities in hemodialysis patients with that in a control population without known kidney disease.

STUDY DESIGN

Cross-sectional cohort.

SETTING & PARTICIPANTS

45 maintenance hemodialysis patients and 67 controls without reported kidney disease, both without history of known stroke.

PREDICTOR

The primary predictor was dialysis status. Covariates included demographics (age, race, and sex), vascular risk factors (diabetes and hypertension), and cardiovascular disease (coronary artery disease and congestive heart failure).

OUTCOMES

Magnetic resonance imaging of the brain features, including severity of white matter disease and cerebral atrophy (sulcal prominence and ventricular atrophy), hippocampal size, and small-/large-vessel infarcts.

MEASUREMENTS

Semiquantitative scale (0-9 for white matter disease and cerebral atrophy, 0-3 for hippocampal size) and infarct prevalence.

RESULTS

Mean ages of hemodialysis patients and controls were 55 ± 17 (SD) and 53 ± 13 years, respectively. In comparison to controls, hemodialysis patients had more severe white matter disease (1.6 vs 0.7) and cerebral atrophy (sulcal prominence, 2.3 vs 0.6; ventricular enlargement, 2.3 vs 0.9; hippocampal size, 1.3 vs 1.0), with all P < 0.001. In multivariable analyses, hemodialysis status was associated independently with worse white matter disease and atrophy grades. Hemodialysis patients also had a higher prevalence of small- (17.8%) and large- (7.8%) vessel infarcts than controls (combined, 22% vs 0%; P < 0.001).

LIMITATIONS

The dialysis cohort likely is healthier than the overall US hemodialysis population, partly limiting generalizability.

CONCLUSIONS

Hemodialysis patients have more white matter disease and cerebral atrophy compared with controls without known kidney disease. Hemodialysis patients also have a high prevalence of unrecognized infarcts.

Cerebral white matter disease is associated with Alzheimer pathology in a prospective cohort

BACKGROUND

Although magnetic resonance imaging (MRI)-detected white matter disease has been correlated with cognitive decline in the elderly individuals, it is unclear whether white matter disease is primarily responsible for the cognitive deterioration or whether another process is common to both white matter disease and dementia.

METHODS

We examined the relationship between Alzheimer-type brain pathology at autopsy and MRI-detected cerebral white matter disease in 50 participants from the Baltimore Longitudinal Study of Aging Autopsy Program, a prospective study of aging that includes detailed cognitive assessments.

RESULTS

White matter disease was quantitated in pre- and postmortem MRI scans using the Cardiovascular Health Study (CHS) criteria in a blinded manner. We found that several measures of Alzheimer's disease (AD) pathology, including the Consortium to Establish a Registry for Alzheimer's Disease score, Braak score, and a composite AD pathology score, along with hypertension, were significantly associated with CHS white matter score using univariate and multivariate ordinal regression. In contrast, amyloid angiopathy was not independently associated with CHS score. Although a clinical diagnosis of dementia was associated with CHS score in univariate analysis, the association disappeared after accounting for AD pathology.

CONCLUSION

AD pathology at autopsy is associated with MRI-detected cerebral white matter disease. This relationship may explain, in part, the association between cerebral white matter disease and cognitive decline in the elderly individuals.

Genetics of age-related white matter lesions from linkage to genome wide association studies

White matter lesions are a frequent phenomenon in the elderly and contribute to the development of disability. The mechanisms underlying these brain lesions are still not fully understood with age and hypertension being the most well established risk factors. The heritability of white matter lesions is consistently high in different populations. Candidate gene studies strongly support the role of genes involved in the renin–angiotensin system, as well as Notch3 signaling. The recent genome wide association study by the CHARGE consortium identified a novel locus on chromosome 17q25 harboring several genes such as TRIM65 and TRIM47 which pinpoint to possible novel mechanisms leading to white matter lesions.

Effect of cardiac function on cognition and brain structural changes in dementia

Background and Purpose

Cardiovascular risk factors are considered to also be risk factors for dementia. Recent studies have shown that the prevalence of cognitive dysfunction is high in patients with cardiac diseases. However, few studies have investigated the influence of cardiac function on cognition and brain structural changes in dementia. The aims of this study were to determine the relationship between cardiac and cognitive function, and to characterize any structural changes in the brain that could be caused by cardiac function in patients with dementia.

Methods

Dementia patients (n=93) were recruited prospectively with checking for the presence of vascular risk factors such as hypertension. Cognitive function was measured by the Mini-Mental State Examination, modified Mini-Mental State test, and Korean version of the Dementia Rating Scale. Brain magnetic resonance imaging was conducted to evaluate the cerebral white-matter changes (WMC), ventricular dilation, and cortical and hippocampal atrophy. Cardiac function was evaluated using two-dimensional echocardiography. We divided the patients into two groups according to the presence (+) or absence (-) of WMC.

Results

In the entire cohort, the size of the left atrium (LA) was positively correlated with the degree of WMC, irrespective of age (p<0.05). The LA was larger in the WMC (+) group (n=42) than in the WMC (-) group. General cognitive function was significantly lower in the WMC (+) group than in the WMC (-) group. Subjects with an enlarged LA tended to exhibit lower cognitive function and more-severe cerebral WMC.

Conclusions

Cardiac dysfunction represented by LA enlargement could be related to cognitive decline and WMC of the brain resulting from impairment of the cerebral hemodynamic process in dementia.

Cerebral white matter hyperintensity in African Americans and European Americans with type 2 diabetes

Previous studies involving inner city populations detected higher cerebral white matter hyperintensity (WMH) scores in African Americans (AAs) compared with European Americans (EAs). This finding might be attributable to the higher prevalence of cardiovascular disease (CVD) risk factors and poorer access to healthcare in AAs. Despite racial differences in CVD risk factor profiles, AAs have paradoxically lower levels of subclinical CVD. We hypothesized that AAs with diabetes and good access to healthcare would have comparable or lower levels of WMH as EAs. Racial differences in the distribution of WMH were analyzed in 46 AAs and 156 EAs with type 2 diabetes enrolled in the Diabetes Heart Study (DHS)-Mind, and replicated in a sample of 113 AAs and 61 EAs patients who had clinically indicated cerebral magnetic resonance imaging. Wilcoxon 2-sample tests and linear models were used to compare the distribution of WMH in AAs and EAs and to test for association between WMH and race. The unadjusted mean WMH score from the Diabetes Heart Study-Mind was 1.9 in AAs and 2.3 in EAs (P = .3244). Among those with clinically indicated magnetic resonance imaging, the mean WMH score was 2.9 in AAs and 3.9 in EAs (P = .0503). Adjustment for age and sex produced no statistically significant differences in WMH score between AAs and EAs. These independent datasets reveal comparable WMH scores in AAs and EAs, suggesting that disparities in access to healthcare and environmental exposures likely underlie the previously reported excess burden of WMH in AAs.

White matter predictors of cognitive functioning in older adults

Few studies have applied multiple imaging modalities to examine cognitive correlates of white matter. We examined the utility of T2-weighted magnetic resonance imaging (MRI) -derived white matter hyperintensities (WMH) and diffusion tensor imaging-derived fractional anisotropy (FA) to predict cognitive functioning among older adults. Quantitative MRI and neuropsychological evaluations were performed in 112 older participants from an ongoing study of the genetics of Alzheimer's disease (AD) in African Americans. Regional WMH volumes and FA were measured in multiple regions of interest. We examined the association of regional WMH and an FA summary score with cognitive test performance. Differences in WMH and FA were compared across diagnostic groups (i.e., normal controls, mild cognitive impairment, and probable AD). Increased WMH volume in frontal lobes was associated with poorer delayed memory performance. FA did not emerge as a significant predictor of cognition. White matter hyperintensity volume in the frontal and parietal lobes was increased in MCI participants and more so in AD patients relative to controls. These results highlight the importance of regionally distributed small vessel cerebrovascular disease in memory performance and AD among African American older adults. White matter microstructural changes, quantified with diffusion tensor imaging, appear to play a lesser role in our sample.

White matter lesions and brain gray matter volume in cognitively normal elders

Cerebral white matter lesions (WMLs) reflect small vessel disease, are common in elderly individuals, and are associated with cognitive impairment. We sought to determine the relationships between WMLs, age, gray matter (GM) volume, and cognition in the Cardiovascular Health Study (CHS). From the Cardiovascular Health Study we selected 740 cognitively normal controls with a 1.5 T magnetic resonance imaging (MRI) scan of the brain and a detailed diagnostic evaluation. WML severity was determined using a standardized visual rating system. GM volumes were analyzed using voxel-based morphometry implemented in the Statistical Parametric Mapping software. WMLs were inversely correlated with GM volume, with the greatest volume loss in the frontal cortex. Age-related atrophy was observed in the hippocampus and posterior cingulate cortex. Regression analyses revealed links among age, APOE*4 allele, hypertension, WMLs, GM volume, and digit symbol substitution test scores. Both advancing age and hypertension predict higher WML load, which is itself associated with GM atrophy. Longitudinal data are needed to confirm the temporal sequence of events leading to a decline in cognitive function.

Severity of leukoaraiosis in large vessel atherosclerotic disease

BACKGROUND AND PURPOSE

The severity of white matter hyperintensity, or leukoaraiosis, is a marker of cerebrovascular disease. In stroke, WMH burden is strongly linked to lacunar infarction; however, impaired cerebral perfusion due to extracranial or intracranial atherosclerosis may also contribute to WMH burden. We sought to determine whether WMH burden is associated with extracranial or intracranial stenosis in patients with AIS.

MATERIALS AND METHODS

Patients with AIS with admission head/neck CTA and brain MR imaging were included in this analysis. "Extracranial stenosis" was defined as >50% stenosis in the extracranial ICA, and "intracranial," as >50% stenosis in either the middle, anterior, or posterior cerebral arteries on CTA, on either side. WMHV was determined by using a validated semiautomated protocol. Multiple regression was used to assess the relationship between WMHV and extracranial/intracranial atherosclerosis.

RESULTS

Of 201 subjects, 51 (25.4%) had extracranial and 63 (31.5%) had intracranial stenosis. Mean age was 62 ± 15 years; 36% were women. Mean WMHV was 12.87 cm(3) in the extracranial and 8.59 cm(3) in the intracranial stenosis groups. In univariate analysis, age (P < .0001), SBP and DBP (P = .004), and HTN (P = .0003) were associated with WMHV. Extracranial stenosis was associated with greater WMHV after adjustment for intracranial stenosis (P = .04). In multivariate analysis including extracranial stenosis, only age (P < .0001) and HTN (P = .03) demonstrated independent effects on WMHV.

CONCLUSIONS

In our cohort of patients with AIS, age and HTN were the strongest determinants of the WMHV severity. Future studies are warranted to unravel further association between WMHV and cerebral vessel atherosclerosis.

Do brain image databanks support understanding of normal ageing brain structure? A systematic review

OBJECTIVE

To document accessible magnetic resonance (MR) brain images, metadata and statistical results from normal older subjects that may be used to improve diagnoses of dementia.

METHODS

We systematically reviewed published brain image databanks (print literature and Internet) concerned with normal ageing brain structure.

RESULTS

From nine eligible databanks, there appeared to be 944 normal subjects aged ≥60 years. However, many subjects were in more than one databank and not all were fully representative of normal ageing clinical characteristics. Therefore, there were approximately 343 subjects aged ≥60 years with metadata representative of normal ageing, but only 98 subjects were openly accessible. No databank had the range of MR image sequences, e.g. T2*, fluid-attenuated inversion recovery (FLAIR), required to effectively characterise the features of brain ageing. No databank supported random subject retrieval; therefore, manual selection bias and errors may occur in studies that use these subjects as controls. Finally, no databank stored results from statistical analyses of its brain image and metadata that may be validated with analyses of further data.

CONCLUSION

Brain image databanks require open access, more subjects, metadata, MR image sequences, searchability and statistical results to improve understanding of normal ageing brain structure and diagnoses of dementia.

KEY POINTS

• We reviewed databanks with structural MR brain images of normal older people. • Among these nine databanks, 98 normal subjects ≥60 years were openly accessible. • None had all the required sequences, random subject retrieval or statistical results. • More access, subjects, sequences, metadata, searchability and results are needed. • These may improve understanding of normal brain ageing and diagnoses of dementia.

Slower gait, slower information processing and smaller prefrontal area in older adults

BACKGROUND

Slower gait in older adults is related to smaller volume of the prefrontal area (PFAv). The pathways underlying this association have not yet been explored. Understanding slowing gait could help improve function in older age. We examine whether the association between smaller PFAv and slower gait is explained by lower performance on numerous neuropsychological tests.

HYPOTHESIS

We hypothesise that slower information processing explains this association, while tests of language or memory will not.

METHODS

Data on brain imaging, neuropsychological tests (information processing speed, visuospatial attention, memory, language, mood) and time to walk 15 feet were obtained in 214 adults (73.3 years, 62% women) free from stroke and dementia. Covariates included central (white matter hyperintensities, vision) and peripheral contributors of gait (vibration sense, muscle strength, arthritis, body mass index), demographics (age, race, gender, education), as well as markers of prevalent vascular diseases (cardiovascular disease, diabetes and ankle arm index).

RESULTS

In linear regression models, smaller PFAv was associated with slower time to walk independent of covariates. This association was no longer significant after adding information processing speed to the model. None of the other neuropsychological tests significantly attenuated this association.

CONCLUSIONS

We conclude that smaller PFAv may contribute to slower gait through slower information processing. Future longitudinal studies are warranted to examine the casual relationship between focal brain atrophy with slowing in information processing and gait.

Neuropsychological functioning in migraine: clinical and research implications

AIM

We review the research literature examining neuropsychological performance in migraine. Findings were organized by neuropsychological construct assessed and results were reported using effect size conventions. Factors considered in explaining results included sample characteristics, migraine factors, and control for non-migraine variables.

FINDINGS

There is weak evidence for deficits in processing speed, attention, verbal memory, verbal skills, working memory, sustained attention, and inhibition in migraine relative to healthy controls. There are mixed results regarding deficits in visual memory, motor dexterity, visuospatial/constructional skills, visual reasoning, and mental flexibility in migraine relative to healthy controls. Mixed findings do not seem to be consistently related to study characteristics or presence of aura; other important migraine factors (such as migraine severity or presence of neuroradiological findings) remain understudied. Relative to non-healthy control groups, however, there is weak evidence for an effect of migraine in any cognitive domain. Longitudinal studies provide little evidence that neuropsychological functioning worsens over time in migraine or that migraine is a risk factor for Alzheimer's disease.

RESEARCH IMPLICATIONS

It remains possible that cognitive dysfunction is seen in only a subset of migraine sufferers, perhaps those with more severe illness or neurological involvement; however, more research is needed to examine this issue. Non-migraine differences among migraine sufferers, including medical and psychiatric comorbidities and variables associated with treatment seeking, may partially account for inconsistent findings and should be evaluated for in future research.

CLINICAL IMPLICATIONS

Clinicians should refer migraine patients for comprehensive neuropsychological evaluation only when there is sufficient evidence for concern. Such evaluations should include consideration of other psychological, neurological, and medical contributors to both migraine and cognitive status.

Neuropsychology, neuroimaging or motor phenotype in diagnosis of Parkinson's disease-dementia: which matters most?

Parkinson's disease (PD) is a neurodegenerative disorder affecting not only the motor system but also the cognitive and behavioral domains. Although there are many studies addressing the issue of cognition, a universally recognized method to diagnose patients with dementia is still lacking. The aim of this study was to determine which neuropsychological test is the most reliable in the diagnosis of dementia in PD and to establish if mini mental state examination (MMSE) is enough to detect this condition. We studied 200 consecutive PD patients through an extensive neuropsychological battery, clinical evaluation and brain magnetic resonance imaging over a period of 4 years. A logistic regression model was used to evaluate the interplay between possible risk factors and the accuracy of different neuropsychological tests. PD patients with dementia performed significantly worse in all the tests as compared to patients with PD alone: phonological verbal fluency, attentional matrices, Rey auditory verbal learning test and digit span were the most useful tools. Age and disease duration were correlated with cognitive impairment. No relevant differences were detected in phenotype, affected body side at onset, levodopa equivalent daily dose or neuroimaging findings (except for the occurrence of atrophy). Despite reasonable accuracy of MMSE (90%), its positive predictive value is only 74%. Using at least 3 neuropsychological tests, among those more significant detected with logistic regression analysis, the positive predictive value rises to 91%. In conclusion, the use of an extensive neuropsychological battery is still recommended in the diagnosis of dementia in PD.

White matter hyperintensities: from medical comorbidities to bipolar disorders and back

White matter hyperintensities (WMHs) are among the most replicated neuroimaging findings in studies of patients with bipolar disorders (BD). Despite the high rates of WMHs, their role and etiology in BD are not well understood. WMHs occur in multiple other conditions frequently co-morbid with BD. From the available studies it seems that WMHs are not a primary risk factor/endophenotype for BD. More likely, these lesions indicate the presence of medical co-morbidities with specific links to BD. Furthermore, the etiology of the WMHs in BD may represent different processes depending on age. In certain forms of BD, such as pediatric BD, WMHs may represent co-morbidity with developmental disorders. High frequency of migraine in BD and high prevalence of WMHs in migraine may suggest that a substantial proportion of WMHs in early adulthood to midlife BD subjects may be related to co-morbidity with migraine. Among elderly subjects with BD, or those with late-onset BD, WMHs are likely related to the presence of cardiovascular/metabolic disorders. With further research WMHs may enhance our knowledge about various pathological pathways involved in BD, help in decreasing the etiological heterogeneity of BD, and become useful as markers of severity or subtype of BD.

Subtypes of mild cognitive impairment among the elderly with major depressive disorder in remission

BACKGROUND

Cognitive impairment in remitted late-life depression varies and might be associated with greater risk of dementia in some individuals. This study aimed to classify the subtypes of mild cognitive impairment (MCI) in late-life major depressive disorder in remission and to examine their clinical correlates and structural magnetic resonance imaging (MRI) features.

METHODS

Elderly patients with major depressive disorder in remission and elderly comparisons were examined by a comprehensive battery of cognitive tasks. Proposed diagnostic criteria were used for MCI classification, and the degree of brain atrophy and white matter hyperintensity on MRI were evaluated.

RESULTS

We found information-processing speed and memory were independent cognitive domains associated with late-life remitted major depressive disorder. Of the study cohort, 52.3% met the definition of MCI, including 28.5% with amnestic MCI (aMCI) and 23.8% with nonamnestic MCI (naMCI). A clinical correlate of aMCI was the late-onset of disorder (OR = 4.76; 95% CI = 1.57, 14.40) and of naMCI was a higher score on the Framingham stroke risk scale (OR = 1.39; 95% CI = 1.12, 1.72). The odds ratio of highest quartile of ventricular atrophy for aMCI compared to the comparisons was 3.65 (95% CI = 1.22, 10.96).

CONCLUSIONS

The central cognitive impairments among the elderly with major depressive disorder in remission were memory and information-processing speed, and over half of the subjects met the MCI diagnostic criteria. Different risk factors existed for the subtypes of aMCI and naMCI. Later-age onset of first episode and ventricular atrophy were associated with aMCI, whereas vascular risk factor were associated with naMCI. We suggest there were different pathogeneses between aMCI and naMCI in late-life major depressive disorder.

Cerebral microangiopathy in treatment-resistant hypertension

Cerebral microangiopathy is a cause of cognitive impairment and indicates high risk for clinically overt cerebrovascular disease. It develops in patients with or without hypertension, and different pathologies may play a supporting role. In this pilot study, the authors aimed to elucidate risk factors contributing to the deleterious action of hypertension on cerebral small vessels. A cross-sectional study in 42 patients with treatment-resistant hypertension was performed. Microangiopathy was investigated by cerebral magnetic resonance imaging (MRI). Determinants were identified by clinical investigation, computed tomography, intima-media thickness and pulse wave velocity measurement, and urinary albumin excretion. Nineteen of 42 patients had cerebral microangiopathy (23 controls). Patients were different with respect to heart rate (60.5 ± 10.2 vs 69.7 ± 15.1 beats per minute; P = .029) and systolic blood pressure during nighttime (138 ± 13 mm Hg vs 126 ± 18 mm Hg; P = .019). In addition, there were significant differences in pulse wave velocity (10.7 ± 2.0 m/s vs 9.4 ± 1.4 m/s; P = .034), peripheral pulse pressure (70.8 ± 16.3 mm Hg vs 59.2 ± 13.6 mm Hg; P = .016), central pulse pressure (62.9 ± 15.8 mm Hg vs 50.3 ± 14.2 mm Hg; P = .012), and aortic augmentation pressure (15.9 ± 6.0 vs 11.8 ± 6.6; P = .040). Systolic blood pressure and signs of hypertensive vasculopathy such as peripheral and central pulse pressure and pulse wave velocity were associated with cerebral microangiopathy in patients with long-standing treatment-resistant hypertension.

White matter lesions on brain magnetic resonance imaging scan and 5-year cognitive decline: the Honolulu-Asia aging study

OBJECTIVES

To study white matter lesions (WMLs) and 5-year cognitive decline in elderly Japanese-American men.

DESIGN

Longitudinal cohort study.

SETTING

Population-based study in Honolulu, Hawaii.

PARTICIPANTS

Japanese-American men aged 74 to 95 from the Honolulu-Asia Aging Study (HAAS) who were free of prevalent dementia, underwent a protocol brain MRI scan at the fifth HAAS examination (1994-1996), and returned for cognitive testing 5 years later (N=267).

MEASUREMENTS

WMLs were dichotomized as present (grade 3-9, 38.2%) or absent (grade 1-2, 61.8%). Cognitive function was measured using the Cognitive Abilities Screening Instrument (CASI), and 5-year cognitive decline was defined as a drop in CASI score of 12 points or more (1 standard deviation).

RESULTS

Men with WMLs on MRI at baseline were significantly more likely to experience cognitive decline at 5 years than those without (22.4% vs 34.4%, P=.03). Using multiple logistic regression, adjusting for age, education, apolipoprotein (Apo)E4 allele, large or small infarcts on MRI, baseline CASI score, and hypertension, those with WMLs were significantly more likely to develop 5-year cognitive decline (odds ratio=2.00, 95% confidence interval=1.10-3.65, P=.02). This association was stronger in men who were cognitively intact and free of the ApoE4 genotype and clinical stroke at baseline.

CONCLUSION

Presence of WMLs on MRI was significantly associated with higher odds of 5-year cognitive decline in older Japanese-American men. Presence of WMLs may help identify people at risk for developing dementia, who may benefit from early intervention.

Arterial stiffness and cognitive decline in well-functioning older adults

BACKGROUND

Stiffness of the central arteries in aging may contribute to cerebral microvascular disease independent of hypertension and other vascular risk factors. Few studies of older adults have evaluated the association of central arterial stiffness with longitudinal cognitive decline.

METHODS

We evaluated associations of aortic pulse wave velocity (centimeters per second), a measure of central arterial stiffness, with cognitive function and decline in 552 participants in the Health, Aging, and Body Composition (Health ABC) study Cognitive Vitality Substudy (mean age ± SD = 73.1 ± 2.7 years, 48% men and 42% black). Aortic pulse wave velocity was assessed at baseline via Doppler-recorded carotid and femoral pulse waveforms. Global cognitive function, verbal memory, psychomotor, and perceptual speed were evaluated over 6 years.

RESULTS

After adjustment for demographics, vascular risk factors, and chronic conditions, each 1 SD higher aortic pulse wave velocity (389 cm/s) was associated with poorer cognitive function: -0.11 SD for global function (SE = 0.04, p < .01), -0.09 SD for psychomotor speed (SE = 0.04, p = .03), and -0.12 SD for perceptual speed (SE = 0.04, p < .01). Higher aortic pulse wave velocity was also associated with greater decline in psychomotor speed, defined as greater than 1 SD more than the mean change (odds ratio = 1.42 [95% confidence interval = 1.06, 1.90]) but not with verbal memory or longitudinal decline in global function, verbal memory, or perceptual speed. Results were consistent with mixed models of decline in each cognitive test.

CONCLUSIONS

In well-functioning older adults, central arterial stiffness may contribute to cognitive decline independent of hypertension and other vascular risk factors.

Mapping the brain in type II diabetes: Voxel-based morphometry using DARTEL

PURPOSE

To investigate the pattern of brain volume changes of the brain in patients with type II diabetes mellitus using voxel-based morphometry.

MATERIAL AND METHODS

Institutional ethics approval and informed consent were obtained. VBM based on the high resolution three-dimensional T1-weighted fast spoiled gradient recalled echo MRI images was obtained from 16 type II diabetes patients (mean age 61.2 years) and 16 normal controls (mean age 59.6 years). All images were spatially preprocessed using Diffeomorphic Anatomical Registration using Exponentiated Lie algebra (DARTEL) algorithm, and the DARTEL templates were made from 100 normal subjects. Statistical parametric mapping was generated using analysis of covariance (ANCOVA).

RESULTS

An atrophy pattern of gray matter was seen in type II diabetes patients compared with controls that involved the right superior, middle, and inferior temporal gyri, right precentral gyrus, and left rolandic operculum region. The loss of white matter volume in type II diabetes mellitus was observed in right temporal lobe and left inferior frontal triangle region. ROI analysis revealed that the gray and white matter volume of right temporal lobe were significant lower in type II diabetes mellitus than that in controls (P<0.05).

CONCLUSION

This work demonstrated that type II diabetes mellitus patients mainly exhibited gray and white matter atrophy in right temporal lobe, and this finding supported that type II diabetes mellitus could lead to subtle diabetic brain structural changes in patients without dementia or macrovascular complications.

High blood pressure accelerates gait slowing in well-functioning older adults over 18-years of follow-up

OBJECTIVES

To examine whether the association between hypertension and decline in gait speed is significant in well-functioning older adults and whether other health-related factors, such as brain, kidney, and heart function, can explain it.

DESIGN

Longitudinal cohort study.

SETTING

Cardiovascular Health Study.

PARTICIPANTS

Of 2,733 potential participants with a brain magnetic resonance imaging (MRI) scan, measures of mobility and systolic blood pressure (BP), no self-reported disability in 1992 to 1994 (baseline), and with at least 1 follow-up gait speed measurement through 1997 to 1999, 643 (aged 73.6, 57% female, 15% black) who had received a second MRI in 1997 to 1999 and an additional gait speed measure in 2005 to 2006 were included.

MEASUREMENTS

Mixed models with random slopes and intercepts were adjusted for age, race, and sex. Main explanatory factors included white matter hyperintensity progression, baseline cystatin-C, and left cardiac ventricular mass. Incidence of stroke and dementia, BP trajectories, and intake of antihypertensive medications during follow-up were tested as other potential explanatory factors.

RESULTS

Higher systolic BP was associated with faster rate of gait speed decline in this selected group of 643 participants, and results were similar in the parent cohort (N = 2,733). Participants with high BP (n = 293) had a significantly faster rate of gait speed decline than those with baseline BP less than 140/90 mmHg and no history of hypertension (n = 350). Rates were similar for those with history of hypertension who were uncontrolled (n = 110) or controlled (n = 87) at baseline and for those who were newly diagnosed (n = 96) at baseline. Adjustment for explanatory factors or for other covariates (education, prevalent cardiovascular disease, physical activity, vision, mood, cognition, muscle strength, body mass index, osteoporosis) did not change the results.

CONCLUSION

High BP accelerates gait slowing in well-functioning older adults over a long period of time, even for those who control their BP or develop hypertension later in life. Health-related measurements did not explain these associations. Future studies to investigate the mechanisms linking hypertension to slowing gait in older adults are warranted.

Carotid artery wall thickness and leukoaraiosis: preliminary results using multidetector row CT angiography

BACKGROUND AND PURPOSE

LA is a condition caused by chronic cerebral ischemia and it represents an independent risk for stroke. The purpose of this work was to determine whether CAWT studied by using MDCTA is correlated with LA and its severity.

MATERIALS AND METHODS

Ninety-eight patients ≥60 years of age were retrospectively studied by using multidetector row CT. Supra-aortic vessel analysis and brain CT were performed in the same procedure. In each patient, CAWT was measured with an internal digital caliper, and the presence and severity of LA were assessed. Correlation coefficients by using Spearman statistics and ROC curves were calculated. A P value < .05 was considered statistically significant.

RESULTS

Measurements of the distal common CAWT ranged from 0.5 to 1.53 mm. A correlation between LA and increased CAWT was observed (Pearson correlation, 0.33; P < .001). On the basis of a threshold of 0.9 mm, an important statistical association between increased CAWT and LA (P < .0001) was found. With the same threshold, ROC curve analysis indicated a sensitivity of 55% and a specificity of 75% for LA.

CONCLUSIONS

The results of this study show a statistically significant correlation between increased CAWT and LA (and its severity).

Clinical, radiological and pathological correlates of leukoaraiosis

INTRODUCTION

Leukoaraiosis is characterized by an abnormal appearance of the brain white matter on imaging. Its pathogenesis is still a matter of investigation. The purpose of this study was to investigate the radiological, clinical and pathological correlates of leukoaraiosis.

METHODS

The study population consisted of 93 deceased patients. The pre-mortem T2W magnetic resonance images were evaluated for the presence and grading of leukoaraiosis. The clinical and pathological characteristics based on the clinical charts and autopsy reports were evaluated. Tissue specimens of the blocks of 19 brains that demonstrated severe leukoaraiosis and those of five control brains were excised and stained.

RESULTS

The variables found to be significantly associated with leukoaraiosis were age and a clinical history of Parkinson's disease. Other risk factors and pathological markers of atherosclerosis were not significantly correlated with leukoaraiosis. No significant difference was found between the scoring of the myelin integrity, glial fibrillary acidic protein, cluster of differentiation 68 and smooth muscle actin. There was a significant difference with respect to thickening of vessels walls.

CONCLUSIONS

Our pathological results indicate that structural vascular abnormalities characterized by vessel wall thickening are associated with leukoaraiosis, supporting the assertion that vascular changes and ischemia generate leukoaraiosis. The relations between parkinsonism and leukoaraiosis may be explicable through vascular effects on the circuitry of the basal ganglia.

High normal fasting blood glucose is associated with dementia in Chinese elderly

BACKGROUND

Diabetes is a risk factor for mild cognitive impairment (MCI) and dementia. However, the association between high normal fasting blood glucose (FBG) and dementia has not been studied.

METHODS

Polytomous logistic regression was used to assess the association of dementia and MCI with FBG in an age- and sex-matched sample of 32 dementia patients, 27 amnestic MCI (aMCI) patients, and 31 normal controls (NC). Analyses were repeated for those with normal FBG. Correlations between FBG and cognitive test scores were obtained.

RESULTS

Controlling for age, gender, education, body mass index, Hachinski Ischemic Score, magnetic resonance imaging (MRI) stroke, and normalized brain, hippocampal, and white matter hyperintensity MRI volumes; higher FBG was associated with dementia versus aMCI status (OR = 3.13; 95% CI, 1.28-7.69). This association remained (OR = 7.75; 95% CI, 1.10-55.56) when analyses were restricted to subjects with normal FBG. When dementia patients were compared with NC adjusting for age, gender, and education, a significant association with FBG also was seen (OR = 1.83; 95% CI, 1.09-3.08), but it was lost when vascular covariates were added to the model. FBG was not associated with aMCI status versus NC. Higher FBG was correlated with poorer performance on the Trailmaking Test Part B (P = .003). The percentage of dementia patients with high normal FBG (90%) was significantly higher than that of aMCI patients with high normal FBG (32.9%) (χ(2) = 13.9, P < .001).

CONCLUSIONS

Higher FBG was associated with dementia (vs. aMCI) independent of vascular risk factors and MRI indicators of vascular disease, and remained a significant risk factor when analyses were restricted to subjects with normal FBG. The results of this cross-sectional study suggest that a high normal level of FBG may be a risk factor for dementia.

Diastolic blood pressure levels and ischemic stroke incidence in older adults with white matter lesions

BACKGROUND

The optimal blood pressure level to minimize the risk of ischemic stroke (IS) in older adults is undetermined. Cerebral white matter lesions (WML), prevalent in older adults, may be a marker for vulnerability to IS. We aimed at determining the relationship between diastolic blood pressure (DBP) levels and IS in the presence of WML.

METHODS

The Cardiovascular Health Study population (N = 3,345, age ≥ 65 years, N = 3,345) was followed between 1989 and 2002 for IS incidence. Survival analysis included quintiles of DBP analyzed within WML levels controlling for age and cardiovascular disease.

RESULTS

DBP had no effect on IS incidence in low WML levels but had a marginally significant J-curve relationship with IS in high WML levels: the adjusted hazard ratio for IS in the lowest (<63 mmHg) and highest (≥ 80) DBP quintiles compared with the third (nadir, 69-73 mmHg) was 1.64 (95% confidence interval: 0.93-2.9) and 1.83 (95% confidence interval: 1.06-3.15), respectively.

CONCLUSIONS

In older adults with low-grade WML, low DBP may not pose a risk for IS. However, in high-grade WML, IS risk may increase in DBP less than 69 mmHg but is highest more than 80 mmHg. People with high-grade WML may be at risk of IS in high and low DBP.

Elevated anti-heat shock protein 60 antibody titer is related to white matter hyperintensities

BACKGROUND

There are many reports that the antibody against heat shock protein 60 (Hsp60) is present in most patients with coronary artery disease and atherosclerosis, and that its titer correlates with disease severity. However, few reports have described the association between anti-Hsp60 antibody and cerebrovascular disease.

METHODS

We determined the anti-Hsp60 antibody titer in patients with neurologic diseases and healthy subjects using enzyme-linked immunosorbent assay (ELISA) and evaluated their findings of brain magnetic resonance imaging (MRI) of the white matter. White matter hyperintensities (WMHs) on T2-weighted and fluid-attenuated inversion recovery (FLAIR) images were classified into 2 categories: periventricular hyperintensity (PVH) and deep white matter hyperintensity (DWMH). The lesions in each category were then divided into 4 grades (grades 0-3) according to the Fazekas rating scale.

RESULTS

There were no significant differences in the titer between patients with neurologic diseases and healthy subjects. The mean grade of DWMHs (mean ± SD, 1.56 ± 0.70) was significantly higher in 18 subjects in the high-titer group (≥39.8 ng/mL; mean titer + 2 SD in sera from 23 healthy subjects) than in 86 subjects (mean ± SD, 0.09 ± 0.76) in the normal-titer group (<39.8 ng/mL; P < .003). The mean grade of PVHs (mean ± SD, 1.50 ± 0.71) was also significantly higher in the high-titer group than in the normal-titer group (mean ± SD, 1.17 ± 0.62; P < .02).

CONCLUSIONS

A significant correlation was noted between anti-Hsp60 antibody titer and the severity of WMHs on brain MR images. We suggest that an elevated titer of the anti-Hsp60 antibody could be a risk factor for cerebral small-vessel disease.

Promotion of the mind through exercise (PROMoTE): a proof-of-concept randomized controlled trial of aerobic exercise training in older adults with vascular cognitive impairment

Background

Sub-cortical vascular ischaemia is the second most common etiology contributing to cognitive impairment in older adults, and is frequently under-diagnosed and under-treated. Although evidence is mounting that exercise has benefits for cognitive function among seniors, very few randomized controlled trials of exercise have been conducted in populations at high-risk for progression to dementia. Aerobic-based exercise training may be of specific benefit in delaying the progression of cognitive decline among seniors with vascular cognitive impairment by reducing key vascular risk factors associated with metabolic syndrome. Thus, we aim to carry out a proof-of-concept single-blinded randomized controlled trial primarily designed to provide preliminary evidence of efficacy aerobic-based exercise training program on cognitive and everyday function among older adults with mild sub-cortical ischaemic vascular cognitive impairment.

Methods/Design

A proof-of-concept single-blinded randomized trial comparing a six-month, thrice-weekly, aerobic-based exercise training group with usual care on cognitive and everyday function. Seventy older adults who meet the diagnostic criteria for sub-cortical ischaemic vascular cognitive impairment as outlined by Erkinjuntti and colleagues will be recruited from a memory clinic of a metropolitan hospital. The aerobic-based exercise training will last for 6 months. Participants will be followed for an additional six months after the cessation of exercise training.

Discussion

This research will be an important first step in quantifying the effect of an exercise intervention on cognitive and daily function among seniors with sub-cortical ischaemic vascular cognitive impairment, a recognized risk state for progression to dementia. Exercise has the potential to be an effective, inexpensive, and accessible intervention strategy with minimal adverse effects. Reducing the rate of cognitive decline among seniors with sub-cortical ischaemic vascular cognitive impairment could preserve independent functioning and health related quality of life in this population. This, in turn, could lead to reduced health care resource utilization costs and avoidance of early institutional care.

Trial Registration

ClinicalTrials.gov Protocol Registration System: NCT01027858.

Secondhand smoke, vascular disease, and dementia incidence: findings from the cardiovascular health cognition study

Recent studies have found that smoking is associated with an increased risk of dementia, but the effects of secondhand smoke (SHS) on dementia risk are not known to have previously been studied. The authors used Cox proportional hazards marginal structural models to examine the association between self-reported lifetime household SHS exposure and risk of incident dementia over 6 years among 970 US participants in the Cardiovascular Health Cognition Study (performed from 1991 to 1999) who were never smokers and were free of clinical cardiovascular disease (CVD), dementia, and mild cognitive impairment at baseline. In addition, because prior studies have found that SHS is associated with increased risk of CVD and that CVD is associated with increased risk of dementia, the authors tested for interactions between SHS and measures of clinical and subclinical CVD on dementia risk. Moderate (16-25 years) and high (>25 years) SHS exposure levels were not independently associated with dementia risk; however, subjects with >25 years of SHS exposure and >25% carotid artery stenosis had a 3-fold increase (hazard ratio = 3.00, 95% confidence interval: 1.03, 9.72) in dementia risk compared with subjects with no/low (0-15 years) SHS exposure and < or =25% carotid artery stenosis. High lifetime SHS exposure may increase the risk of dementia in elderly with undiagnosed CVD.

A noninvasive imaging approach to assess plaque severity: the carotid atherosclerosis score

BACKGROUND AND PURPOSE

The presence of IPH and/or FCR in the carotid atherosclerotic plaque indicates a high-risk lesion. The aim of this multicenter cross-sectional study was to establish the characteristics of lesions that may precede IPH and/or FCR. We further sought to construct a CAS that stratifies carotid disease severity.

MATERIALS AND METHODS

Three hundred forty-four individuals from 4 imaging centers with 16%-99% carotid stenosis by duplex sonography underwent carotid MR imaging. In approximately 60% of the study sample (training group), multivariate analysis was used to determine factors associated with IPH and FCR. Statistically significant parameters identified during multivariate analysis were used to construct CAS. CAS was then applied to the remaining arteries (40%, test group), and the accuracy of classification for determining the presence versus absence of IPH or, separately, FCR was determined by ROC analysis and calculation of the AUC.

RESULTS

The maximum proportion of the arterial wall occupied by the LRNC was the strongest predictor of IPH (P < .001) and FCR (P < .001) during multivariate analysis of the training group. The subsequently derived CAS applied to the test group was an accurate classifier of IPH (AUC = 0.91) and FCR (AUC = 0.93). Compared with MRA stenosis, CAS was a stronger classifier of both IPH and FCR.

CONCLUSIONS

LRNC quantification may be an effective complementary strategy to stenosis for classifying carotid atherosclerotic disease severity. CAS forms the foundation for a simple imaging-based risk-stratification system in the carotid artery to classify severity of atherosclerotic disease.

Initial experience in using continuous arterial spin-labeled MR imaging for early detection of Alzheimer disease

BACKGROUND AND PURPOSE

MR imaging of the brain has significant potential in the early detection of neurodegenerative disorders such as AD. The purpose of this work was to determine if perfusion MR imaging can be used to separate AD from normal cognition in individual subjects. We investigated the diagnostic utility of perfusion MR imaging for early detection of AD compared with structural imaging.

MATERIALS AND METHODS

Data were analyzed from 32 participants in the institutional review board-approved CHS-CS: 19 cognitively healthy individuals and 13 with clinically adjudicated AD. All subjects underwent structural T1-weighted SGPR and CASL MR imaging. Four readers with varying experience separately rated each CASL and SPGR scan finding as normal or abnormal on the basis of standardized qualitative diagnostic criteria for observed perfusion abnormalities on CASL or volume loss on SPGR and rated the confidence in their evaluation.

RESULTS

Inter-rater reliability was superior in CASL (kappa = 0.7 in experienced readers) compared with SPGR (kappa = 0.17). CASL MR imaging had the highest sensitivity (85%) and accuracy (70%). Frontal lobe CASL findings increased sensitivity to 88% and accuracy to 79%. Fifty-seven percent of false-positive readings with CASL were in controls with cognitive decline or instability within 5 years. Three of the 4 readers revealed a statistically significant relationship between confidence and correct classification when using CASL.

CONCLUSIONS

Readers were able to separate individuals with mild AD from those with normal cognition with high sensitivity by using CASL but not volumetric MR imaging. This initial experience suggests that CASL MR imaging may be a useful technique for detecting AD.

Blood pressure and white-matter disease progression in a biethnic cohort: Atherosclerosis Risk in Communities (ARIC) study

BACKGROUND AND PURPOSE

Blood pressure (BP) is a predictor of concurrent and subsequently measured white-matter hyperintensity (WMH), but longitudinal studies of WMH changes and data in black participants are lacking. We hypothesized that WMH progression would be (1) strongly related to BP in blacks and whites and (2) predicted more strongly by earlier (midlife) or cumulative BP measurements than by measures at older ages.

METHODS

Participants were 983 individuals (49% black) from the Atherosclerosis Risk in Communities (ARIC) Study who underwent cerebral magnetic resonance imaging in 1993-1995 and 2004-2006. Associations between BP (measured at each of 5 visits, in addition to a time-averaged cumulative BP) and progression of WMHs were analyzed and compared.

RESULTS

Cumulative systolic BP (SBP) was the strongest BP predictor of WMH progression in adjusted models. Higher cumulative SBP (by 20 mm Hg) was associated with greater progression of WMHs and was similar in blacks (2.5 cm(3), P<0.0001) and whites (2.6 cm(3), P<0.0001). Higher cumulative SBP (per 20 mm Hg) was also associated with being in the top quintile of WMH progression (adjusted odds ratio=2.0; 95% CI, 1.6 to 2.6). Earlier SBP measurements were stronger predictors of WMH progression than were later SBP measurements, but in blacks only.

CONCLUSIONS

In this population-based cohort, cumulative SBP was a stronger predictor of WMH progression than SBP from individual visits, in both blacks and whites. Earlier BPs were stronger predictors than BPs measured at later time points in blacks only.

White matter hyperintensities and cognition: testing the reserve hypothesis

OBJECTIVE

White matter hyperintensities (WMH), visualized on T2-weighted MRI, are thought to reflect small-vessel vascular disease. Much like other markers of brain disease, the association between WMH and cognition is imperfect. The concept of reserve may account for this imperfect relationship. The purpose of this study was to test the reserve hypothesis in the association between WMH severity and cognition. We hypothesized that individuals with higher amounts of reserve would be able to tolerate greater amounts of pathology than those with lower reserve.

METHODS

Neurologically healthy older adults (n=717) from a community-based study received structural MRI, neuropsychological assessment, and evaluation of reserve. WMH volume was quantified algorithmically. We derived latent constructs representing four neuropsychological domains, a measure of cognitive reserve, and a measure of brain reserve. Measures of cognitive and brain reserve consisted of psychosocial (e.g., education) and anthropometric (e.g., craniometry) variables, respectively.

RESULTS

Increased WMH volume was associated with poorer cognition and higher cognitive and brain reserve were associated with better cognition. Controlling for speed/executive function or for language function, those with higher estimates of cognitive reserve had significantly greater degrees of WMH volume, particularly among women. Controlling for cognitive functioning across all domains, individuals with higher estimates of brain reserve had significantly greater WMH volume.

CONCLUSIONS

For any given level of cognitive function, those with higher reserve had more pathology in the form of WMH, suggesting that they are better able to cope with pathology than those with lower reserve. Both brain reserve and cognitive reserve appear to mitigate the impact of pathology on cognition.

Blood pressure and progression of cerebral atrophy in patients with vascular disease

BACKGROUND

Cerebral atrophy on brain magnetic resonance imaging (MRI) has been associated with vascular risk factors including hypertension. Progression of cerebral atrophy and its risk factors have not been studied in vascular disease patients. This study aimed to assess the progression of cerebral atrophy and to evaluate possible associations with blood pressure (BP) in patients with pre-existing vascular disease.

METHODS

A total of 331 patients with manifest vascular disease from the Second Manifestations of ARTerial Disease (SMART) Study underwent baseline and follow-up MRI scanning (mean follow-up 4.1 +/- 0.3 years). The annual change in brain and ventricular volume was calculated with an automated quantitative volumetric method. Associations between BP and change in brain and ventricular volumes and between BP and the occurrence of lacunar infarcts were analyzed.

RESULTS

At baseline mean age was 58 +/- 9 years and mean BP was 138/80 mm Hg. Mean annual decrease in brain tissue volume was 6.5 +/- 3.8 ml and mean annual increase in ventricular volume was 1.0 +/- 1.0 ml. There was no association observed between BP and annual change in brain or ventricular volume, but a clear association was found between BP and incident lacunar infarcts (odds ratio 1.57; 1.11-2.22 per s.d. increase in systolic BP (SBP)).

CONCLUSIONS

The magnitude of changes in brain tissue and ventricular volume in patients with vascular disease was comparable to the physiological changes described in normal people at a much higher age. Progression of cerebral atrophy in this population may be associated with advanced physiological aging, but is probably not caused by elevated BP.

Clinical correlates of cerebral white matter hyperintensities in cognitively normal older adults

Many research studies have demonstrated asymptomatic white matter hyperintensities (WMHs) in older adults, which are postulated to be ischemic in origin. We hypothesized that certain clinical predictors, measured in a population of healthy older adults, would have a positive relationship with WMH scoring on magnetic resonance imaging (MRI). As part of a longitudinal study of cognitive aging we have performed MRI on healthy older adults. In a group of 46 volunteers (25 females; median age 73, range 63-84 years), we have calculated of the Hachinski score and Framingham Stroke Risk Profile (FSRP). Volunteers also provided self-reported health information using the Cornell Medical Index (CMI). These were compared against the total Age Related White Matter Changes (ARWMC) score. The mean total ARWMC score was 7.4 + or - 5.27 (+ or - S.D.) and only 3 (6.5%) individuals had no evidence of WMH. Regression analysis of individual variables identified self-report of cardiovascular disease from the CMI, section C as the only significant predictor of ARWMC. A multivariate linear regression model also identified FSRP at 1 year as a second independently significant predictor. The multivariate model accounted for 19% of the variance in total ARWMC score. The only 6.5% of individuals who had no WMH is in keeping with previous studies. The important finding was the positive relationship with self-reported cardiovascular disease, which is a possible biomarker of sub-clinical cerebrovascular disease (CVD).

Metabolic risks, white matter hyperintensities, and arterial stiffness in high-functioning healthy adults

BACKGROUND

Arterial stiffness, an age-related feature and measured noninvasively by pulse wave velocity (PWV), is associated with a variety of cardiovascular diseases. Although white matter lesion (WML), representing cerebrovascular micro-angiopathy, is typically considered as a preclinical cardiovascular disease, little is know about the association between PWV and WML. The aim of this study is to examine the association between PWV and WML.

METHOD

We examined the extent of white matter lesion on cranial magnetic resonance imaging of 93 participants (mean 72.46 years) from the annual Health Examination for the Elderly Program in the National Taiwan University Hospital. Two subtypes of WML including periventricular hyperintensity (PVH) and deep white matter hyperintensity (DWMH) were graded according to Fazekas et al. The brachial-ankle PWV (baPWV) and heart-ankle PWV (haPWV) were measured using an automatic waveform analyzer.

RESULTS

PVH and DWHM were found in 71 (76%) and 58 (62%) participants. Various degree of WML was observed in 80 (86%) participants. Hypertension, use of anti-hypertensive medications, and elevated blood pressure were identified as risk factors of WML. The baPWV and haPWV were correlated with many metabolic risks, including systolic blood pressure, pulse pressure, and serum triglycerides. The baPWV and haPWV were greater in participants with higher grades of WML in the multivariate analyses. The receiver operating characteristics analyses demonstrated that area under curves for haPWV to identify moderate-to-severe PVH and DWMH were 0.78 (95% confidence interval [CI] 0.66-0.91) and 0.72 (95% CI 0.59-0.85), respectively.

CONCLUSION

Greater PWV is associated with higher grades of WML among high-functioning older adults. Our findings support the notion that measurement of arterial stiffness is useful in clinical practice for detection of preclinical cerebrovascular disease.

Long-term function in an older cohort--the cardiovascular health study all stars study

OBJECTIVES

To evaluate shared and unique risk factors for maintaining physical and cognitive function into the ninth decade and beyond.

DESIGN

Longitudinal cohort study.

SETTING

Four U.S. communities.

PARTICIPANTS

One thousand six hundred seventy-seven participants in the Cardiovascular Health Study All Stars Study, assessed in 2005/06. Median age was 85 (range 77-102), 66.5% were women, and 16.6% were black.

MEASUREMENTS

Intact function was defined as no difficulty with any activities of daily living and a score of 80 or higher on the Modified Mini-Mental State Examination. Baseline characteristics assessed in 1992/93 included demographics, behavioral health factors, chronic disease history, subclinical disease markers, cardiovascular risk factors, and inflammatory markers. Multinomial logistic regression was used to compare risk for physical disability, cognitive impairment,and combined impairments with no functional impairment.

RESULTS

Of the 1,677 participants evaluated in both domains, 891 (53%) were functionally intact. Continuous measures of function, including the Digit Symbol Substitution Test and gait speed, showed that all groups, including the most functional, had declined over time. The functional group had less decline but also tended to have higher starting values. Functional individuals had a higher baseline health profile than those with either or cognitive impairment or both impairments combined. Women and individuals with greater weight had higher rates of physical impairment but not cognitive impairment. Risk factors common to both types of impairment included cardiovascular disease and hypertension.

CONCLUSION

Intact function was found in only approximately half of these older adults in the ninth decade and beyond. High baseline function and low vascular disease risk characterized functional aging.

Aging of cerebral white matter: a review of MRI findings

BACKGROUND

Cerebral aging is a complex and heterogeneous process that is associated with a high degree of inter-individual variability. Structural magnetic resonance imaging (MRI) can be used to identify and quantify non-disease-related aging of the cerebral white matter.

METHODS

The present article reviews the findings from several MRI techniques, including morphometric approaches, study of white matter hyperintensities, diffusion tensor imaging, and magnetization transfer imaging, that have been used to examine aging of the cerebral white matter. Furthermore, the relationship of MRI indices of white matter integrity to age-related cognitive declines is reported.

RESULTS

A general pattern of age-related preservation and decline emerges indicating that the prefrontal white matter is most susceptible to the influence of age. Studies that combine MRI with cognitive measures suggest that such age-related reductions in white matter integrity may produce a disconnection state that underlies some of the age-related performance declines in age-sensitive cognitive domains.

CONCLUSIONS

White matter aging may contribute to a disconnection state that is associated with declines in episodic memory, executive functions, and information processing speed.

The rebirth of neuroscience in psychosomatic medicine, Part I: historical context, methods, and relevant basic science

Neuroscience was an integral part of psychosomatic medicine at its inception in the early 20th century. Since the mid-20th century, however, psychosomatic research has largely ignored the brain. The field of neuroscience has burgeoned in recent years largely because a variety of powerful new methods have become available. Many of these methods allow for the noninvasive study of the living human brain and thus are potentially available for integration into psychosomatic medicine research at this time. In this first paper we examine various methods available for human neuroscientific investigation and discuss their relative strengths and weaknesses. We next review some basic functional neuroanatomy involving structures that are increasingly being identified as relevant for psychosomatic processes. We then discuss, and provide examples of, how the brain influences end organs through "information transfer systems," including the autonomic, neuroendocrine, and immune systems. The evidence currently available suggests that neuroscience holds great promise for advancing the goal of understanding the mechanisms by which psychosocial variables influence physical disease outcomes. An increased focus on such mechanistic research in psychosomatic medicine is needed to further its acceptance into the field of medicine.

Pathways linking late-life depression to persistent cognitive impairment and dementia

There is a strong association between late-life depression, cognitive impairment, cerebrovascular disease, and poor cognitive outcomes, including progressive dementia, especially Alzheimer's disease. While neuroimaging evidence suggests that cerebrovascular disease plays a prominent role, it seems that depression alone may also confer substantial risk for developing Alzheimer's disease. The relationships between the prominent cerebrovascular changes, other structural abnormalities, specific forms of cognitive dysfunction, and increased risk for developing Alzheimer's disease among those with late-life depression have been difficult to reconcile. The varied findings suggest that there are likely multiple pathways to poor cognitive outcomes. We present a framework outlining multiple, non-mutually exclusive etiologic links between depression, cognitive impairment, and progressive decline, including dementia. Importantly, the model is both testable and falsifiable. Going forward, using models such as this to inform research should accelerate knowledge acquisition on the depression/dementia relationship that may be useful for dementia prevention, monitoring the impact of depression treatment on clinical status and course of illness.

Magnetic resonance imaging in occupational chronic solvent encephalopathy

PURPOSE

The aim of this study was to characterize the magnetic resonance imaging (MRI) findings in chronic solvent encephalopathy (CSE) patients and to study whether the findings are associated with solvent exposure indices.

METHODS

The brain MRI scans of 71 CSE patients were independently re-evaluated and rated by two experienced neuroradiologists. All the work tasks were analyzed and the chemical composition of lifetime exposure was categorized.

RESULTS

The MRI scans of 27/71 CSE patients (38%) were classified as abnormal. Brain atrophy in any brain area was found in 17/71 CSE patients (24%). Abnormal white matter hyperintensities (WMH) were found in 20/71 CSE patients (28%). Cerebral and cerebellar brain atrophy was associated with the duration of exposure in years, and vermian atrophy was associated with alcohol consumption. Periventricular and brainstem WMH were related to age.

CONCLUSIONS

Slight brain atrophy is associated with CSE and there is a correlation between brain atrophy and the duration of exposure in years. However, all the MRI findings in CSE are non-specific and thus MRI is useful mainly in the differential diagnosis of CSE.

Prevalence of CT-detected cerebral abnormalities in an elderly Swedish population sample

OBJECTIVE

To measure the prevalence of computed tomography (CT)-detected cerebral lesions in a population-based sample of elderly persons living in Göteborg, Sweden.

METHODS

Cerebral CT-scans were performed in the case of 466 women (mean age 74.3 +/- 5.1 years) and 191 70-year-old men. A single rater assessed white matter lesions (WML) using four different scales, lacunar lesions, large infarcts, cortical atrophy, and basal ganglia calcifications.

RESULTS

White matter lesions frequency assessed by different scales ranged between 54.5% and 68.5%. Lacunar lesions were detected in 46.7% (30.1% had lacunes >5 mm) and cerebral infarcts in 3.0% of participants. Overall, 72.8% of participants evidenced cerebral vascular abnormalities. Severe cortical atrophy was more common in temporal (6.4%) and frontal (6.7%) lobes, than in parietal (1.7%) and occipital (1.1%) lobes. Basal ganglia calcifications were found in 38.7% of participants. WML, lacunar lesions, large infarcts, and degree of cortical atrophy correlated positively with age. More lacunes, basal ganglia calcifications, and occipital lobe atrophy were associated with male gender.

CONCLUSIONS

Vascular and other brain lesions are very common on CT-scan in an elderly population, but large vascular lesions are rare. This study provides the first reference for the prevalence of CT-detected abnormalities in an elderly Swedish population.

Rate of progression in Alzheimer's disease correlates with coated-platelet levels--a longitudinal study

Coated-platelets represent a subset of platelets produced by activation with both collagen and thrombin that retain full-length amyloid precursor protein on their surface. In our initial cross-sectional study, coated-platelet levels correlated inversely with disease severity in Alzheimer's disease (AD). Higher levels were observed in the early stage compared with the advanced stage of the disease. In this longitudinal study, we investigated for the first time the relationship between initial coated-platelet levels and disease progression in individuals with AD. Coated-platelet levels were assayed in 25 patients with AD who where then clinically monitored for 2 years. A significant linear correlation (r = 0.47, P = 0.017) was detected between the initial coated-platelet levels and disease progression measured in the Mini-Mental State Examination score. The most severe decline was noted in individuals with the highest initial coated-platelet production. These findings support our previous observations from cross-sectional studies and suggest the need for additional study of coated-platelets as a link to the sequence of events leading to the development of AD.

Longitudinal cerebral blood flow and amyloid deposition: an emerging pattern?

Although cerebral amyloid deposition may precede cognitive impairment by decades, the relationship between amyloid deposition and longitudinal change in neuronal function has not, to our knowledge, been studied. The aim of this article was to determine whether individuals without dementia with high and low amyloid burden show different patterns of longitudinal regional cerebral blood flow (rCBF) changes in the years preceding measurement of amyloid deposition.

METHODS

Twenty-eight participants without dementia (mean age+/-SD, 82.5+/-4.8 y; 6 mildly impaired) from the Baltimore Longitudinal Study of Aging underwent yearly resting-state (15)O-H(2)O PET scans for up to 8 y. (11)C-PIB images of amyloid deposition were acquired on average 10.8+/-0.8 y after the first CBF scan. (11)C-PIB distribution volume ratios of regions of interest were estimated by fitting a reference-tissue model to the measured time-activity curves. On the basis of mean cortical distribution volume ratios, participants were divided into groups with high or low (11)C-PIB retention. Differences in longitudinal rCBF changes between high- and low-(11)C-PIB groups were investigated by voxel-based analysis.

RESULTS

Longitudinal rCBF changes differed significantly between high- (n=10) and low- (n=18) (11)C-PIB groups (P

CONCLUSION

In this group of older adults without dementia, those with high (11)C-PIB show greater longitudinal declines in rCBF in certain areas, representing regions with greater decrements in neuronal function. Greater longitudinal increases in rCBF are also observed in those with higher amyloid load and may represent an attempt to preserve neuronal function in these regions.

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Key Words

• pib
• cbf
• longitudinal
• positron emission tomography
• aging

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MESH Headings

• Aged
• Aged, 80 and over
• Blood Flow Velocity
• Brain/blood supply
• Brain/diagnostic imaging
• Cerebral Amyloid Angiopathy/diagnostic imaging
• Cerebrovascular Circulation
• Female
• Humans
• Longitudinal Studies
• Male
• Radionuclide Imaging

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Grants

• K24 DA000412 NIDA NIH HHS
• Z01 AG000191 Intramural NIH HHS
• K24 DA00412 NIDA NIH HHS
• N01-AG-3-2124 NIA NIH HHS

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Affiliation(s)

Jitka Sojkova National Institute on Aging, National Institutes of Health, Bethesda, Maryland, USA
Lori Beason-Held
Yun Zhou
Yang An
Michael A Kraut
Weigo Ye
Luigi Ferrucci
Chester A Mathis
William E Klunk
Dean F Wong
Susan M Resnick

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Collaborators Collapse

Brain morphology in older African Americans, Caribbean Hispanics, and whites from northern Manhattan

BACKGROUND

Aging is accompanied by a decrease in brain volume and by an increase in cerebrovascular disease.

OBJECTIVE

To examine the effects of age, sex, race/ethnicity, and vascular disease history on measures of brain morphology, including relative brain volume, ventricular volume, hippocampus and entorhinal cortex volumes, and white matter hyperintensity (WMH) burden, in a large community-based cohort of racially/ethnically diverse older adults without dementia.

DESIGN

The associations of age, sex, race/ethnicity, and self-reported vascular disease history with brain morphology were examined in a cross-sectional study using multiple linear regression analyses. Sex x race/ethnicity interactions were also considered.

SETTING

The Washington Heights-Inwood Columbia Aging Project, a community-based epidemiological study of older adults from 3 racial/ethnic groups (white, Hispanic, and African American) from northern Manhattan.

PARTICIPANTS

Beginning in 2003, high-resolution quantitative magnetic resonance (MR) images were acquired in 769 participants without dementia.

MAIN OUTCOME MEASURES

Relative brain volume (total brain volume/intracranial volume), ventricular volume, and hippocampus and entorhinal cortex volumes were derived manually on high-resolution MR images. White matter hyperintensities were quantified semiautomatically on fluid-attenuated inversion recovery-T2-weighted MR images.

RESULTS

Older age was associated with decreased relative brain volume and with increased ventricular and WMH volumes. Hispanic and African American participants had larger relative brain volumes and more severe WMH burden than white participants, but the associations of these variables with age were similar across racial/ethnic groups. Compared with men, women had larger relative brain volumes. Vascular disease was associated with smaller relative brain volume and with higher WMH burden, particularly among African Americans.

CONCLUSIONS

Older age and vascular disease, particularly among African Americans, are associated with increased brain atrophy and WMH burden. African American and Hispanic subjects have larger relative brain volumes and more WMH than white subjects. Racial/ethnic group differences in WMH severity seem to be partially attributable to differences in vascular disease. Future work will focus on the determinants and cognitive correlates of these differences.