Age-related white matter changes and cognitive impairment

Associations of cognitive reserve and psychological resilience with cognitive functioning in subjects with cerebral white matter hyperintensities

BACKGROUND AND PURPOSE

Cerebral small vessel disease is characterized by progressive white matter hyperintensities (WMH) and cognitive decline. However, variability exists in how individuals maintain cognitive capabilities despite significant neuropathology. The relationships between individual cognitive reserve, psychological resilience and cognitive functioning were examined in subjects with varying degrees of WMH.

METHODS

In the Helsinki Small Vessel Disease Study, 152 subjects (aged 65-75 years) underwent a comprehensive neuropsychological assessment, evaluation of subjective cognitive complaints and brain magnetic resonance imaging with volumetric WMH evaluation. Cognitive reserve was determined by education (years) and the modified Cognitive Reserve Scale (mCRS). Psychological resilience was evaluated with the Resilience Scale 14.

RESULTS

The mCRS total score correlated significantly with years of education (r = 0.23, p < 0.01), but it was not related to age, sex or WMH volume. Together, mCRS score and education were associated with performance in a wide range of cognitive domains including processing speed, executive functions, working memory, verbal memory, visuospatial perception and verbal reasoning. Independently of education, the mCRS score had incremental predictive value on delayed verbal recall and subjective cognitive complaints. Psychological resilience was not significantly related to age, education, sex, WMH severity or cognitive test scores, but it was associated with subjective cognitive complaints.

CONCLUSIONS

Cognitive reserve has strong and consistent associations with cognitive functioning in subjects with WMH. Education is widely associated with objective cognitive functioning, whereas lifetime engagement in cognitively stimulating leisure activities (mCRS) has independent predictive value on memory performance and subjective cognitive complaints. Psychological resilience is strongly associated with subjective, but not objective, cognitive functioning.

Therapeutic perspective on vascular cognitive impairment

Dementia is one of the greatest public health concerns for the modern aging world. Over the last decade, most researchers developing new therapeutic strategies for dementia have focused on amyloid-β. In contrast, numerous recent studies have indicated that vascular risk factors are associated with various forms of dementia, and that in fact most forms of dementia can be considered an extension of vascular disease. Accordingly, it is sensible to pursue treatment approaches that focus on the blood vessels. Blood-brain barrier (BBB) disruptions in the white matter of patients with vascular cognitive impairment (VCI) have been observed using imaging analysis, and might be potential targets for novel VCI treatment. Tight junctions between cerebral endothelial cells play an important role in the function of the BBB, and recent studies have demonstrated the essential role of microRNAs in regulating tight junctions. Further elucidation of the mechanisms of tight junction-disruption in dementia are likely to lead to promising novel treatments. In this article, we summarize current knowledge regarding microRNAs and vascular cognitive impairment and the possibility of utilizing microRNAs as biomarkers for BBB dysfunction, and seek to envision future therapeutic strategies.

Bispectral Index Monitoring During Anesthesia Promotes Early Postoperative Recovery of Cognitive Function and Reduces Acute Delirium in Elderly Patients with Colon Carcinoma: A Prospective Controlled Study using the Attention Network Test

Background

Bispectral index (BIS) monitoring can reduce the duration of anesthesia. This study aimed to evaluate the effects of BIS monitoring during surgery for resection of colon carcinoma in elderly patients using the Attention Network Test (ANT) to study alerting, orienting, and executive functions, and the Confusion Assessment Method (CAM).

Material/Methods

Eighty-one patients (65–75 years) underwent radical surgery for colon carcinoma with general intravenous anesthesia, propofol (6–8 mg/kg/h), vecuronium (0.03–0.05 mg/kg/min), and remifentanil (0.1–0.2 μg/kg/min). The BIS group (n=41) underwent adjustment of anesthesia to maintain a BIS value between 40–60; the non-BIS group (N=40) underwent standard intraoperative hemodynamic monitoring. Primary endpoints were alerting, orienting, and executive functions assessed pre-operatively and on postoperative days 1 and 5 using the ANT; the secondary endpoint was delirium during the first five postoperative days, assessed using the CAM.

Results

Propofol and remifentanil doses were significantly lower in the BIS group compared with the non-BIS group (P<0.001). Alerting, orienting, and executive functions showed no differences between the two groups pre-operatively but were impaired in both groups on postoperative day 1 compared with pre-operative levels (P<0.001). On postoperative day 5, alerting (P=0.607) and orienting (P=0.851) functions recovered in the BIS group but remained impaired in the non-BIS group (P<0.001). Delirium was significantly lower in the BIS group compared with the non-BIS group (17.5% vs. 27.5%) (P<0.001).

Conclusions

BIS-guided anesthesia was associated with reduced anesthetic exposure, early postoperative recovery of alerting and orienting functions, and reduced postoperative delirium.

Whole brain vascular imaging in a mouse model of Alzheimer's disease with two-photon microscopy

Given known correlations between vascular health and cognitive impairment, the development of tools to image microvasculature in the whole brain could help investigate these correlations. We explore the feasibility of using an automated serial two-photon microscope to image fluorescent gelatin-filled whole rodent brains in three-dimensions (3-D) with the goal of carrying group studies. Vascular density (VD) was computed using automatic segmentation combined with coregistration techniques to build a group-level vascular metric in the whole brain. Focusing on the medial prefrontal cortex, cerebral cortex, the olfactory bulb, and the hippocampal formation, we compared the VD of three age groups (2-, 4.5-, and 8-months-old), for both wild type mice and a transgenic model (APP/PS1) with pathology resembling Alzheimer's disease (AD). We report a general loss of VD caused by the aging process with a small VD increase in the diseased animals in the somatomotor and somatosensory cortical regions and the olfactory bulb, partly supported by MRI perfusion data. This study supports previous observations that AD transgenic mice show a higher VD in specific regions compared with WT mice during the early and late stages of the disease (4.5 to 8 months), extending results to whole brain mapping.

Cognitive strategies application of multiple sclerosis patients

When performing a novel task, people need to generate and apply a working strategy. The applicatio n of an appro priate working strategy enables patients with cognitive impairment (C I) to perform tasks efficiently, which in turn makes it easier to meet the challenges of daily life tasks. We investigated the strategy application abilities (SAA) of multiple sclerosis (MS) patients and compared these results with data based on healthy subjects’ performance. Seventy-six patients performed a Strategy A pplication Test (SAT) along with other cognitive tests, and completed depression, fatigue, and activity of daily living (A DL) questionnaires. O ur results indicated that 76% of the MS patients included had impaired SAA, and that this impairment was not correlated with their depression, fatigue, Expanded Disability Severity Scale (EDSS), or A DL. These findings may have important implications for the understanding of the capability of MS patients to cope with nonroutine tasks, as well as for the potential of future implementation of cognitive rehabilitation in improving the SAA of patients with MS or other cognitive disorders.

Regional white matter hyperintensities: aging, Alzheimer's disease risk, and cognitive function

White matter hyperintensities (WMH) of presumed vascular origin, as seen on T2-weighted fluid attenuated inversion recovery magnetic resonance imaging, are known to increase with age and are elevated in Alzheimer's disease (AD). The cognitive implications of these common markers are not well understood. Previous research has primarily focused on global measures of WMH burden and broad localizations that contain multiple white matter tracts. The aims of this study were to determine the pattern of WMH accumulation with age, risk for AD, and the relationship with cognitive function utilizing a voxel-wise analysis capable of identifying specific white matter regions. A total of 349 participants underwent T1-weighted and high-resolution T2-weighted fluid attenuated inversion recovery magnetic resonance imaging and neuropsychological testing. Increasing age and lower cognitive speed and flexibility (a component of executive function), were both significantly associated with regional WMH throughout the brain. When age was controlled, lower cognitive speed and flexibility was independently associated with WMH in the superior corona radiata. Apolipoprotein E ε4 and parental family history of AD were not associated with higher burden of WMH. The results contribute to a larger body of literature suggesting that white matter measures are linked with processing speed, and illustrate the utility of voxel-wise analysis in understanding the effect of lesion location on cognitive function.

A longitudinal study of differences in late- and early-onset geriatric depression: depressive symptoms and psychosocial, cognitive, and neurological functioning

OBJECTIVES

Studies suggest early-onset depression (EOD) is associated with a more severe course of the depressive disorder, while late-onset depression (LOD) is associated with more cognitive and neuroimaging changes. This study examined if older adults with EOD, compared with those with LOD, would exhibit more severe symptoms of depression and, consistent with the glucocorticoid cascade hypothesis, have more hippocampal volume loss. A second goal was to determine if LOD, compared with EOD, would demonstrate more cognitive and neuroimaging changes.

METHOD

At regular intervals over a four-year period non-demented, older, depressed adults were assessed on the Mini-Mental Status Examination and the Montgomery-Asberg Depression Rating Scale. They were also assessed on magnetic resonance imaging.

RESULTS

Compared with LOD, EOD had more depressive symptoms, more suicidal thoughts, and less social support. Growth curve analyses indicated that EOD demonstrated higher levels of residual depressive symptoms over time. The LOD group exhibited a greater decrement in cognitive scores. Contrary to the glucocorticoid cascade hypothesis, participants with EOD lost right hippocampal volume at a slower rate than did participants with LOD. Right cerebrum gray matter was initially smaller among participants with LOD.

CONCLUSIONS

EOD is associated with greater severity of depressive illness. LOD is associated with more severe cognitive and neurological changes. These differences are relevant to understanding cognitive impairment in geriatric depression.

Neurochemical correlates of cognitive dysfunction in patients with leukoaraiosis: a proton magnetic resonance spectroscopy study

OBJECTIVES

Leukoaraiosis (LA) is a common radiological finding in the elderly and may reflect cerebral small vessel disease (SVD). Although SVD has been identified as a major cause of vascular cognitive impairment or vascular dementia, the mechanisms for this association remain unclear. We therefore aimed to measure brain metabolites in LA using proton magnetic resonance spectroscopy ((1)H-MRS) as to determine the relationship between cognitive function and neurochemical white matter profile.

METHODS

We recruited 23 patients with LA and 23 age- and sex-matched healthy controls consecutively. Multi-voxel (1)H-MRS was performed with a volume of interest located in centrum semiovale that contained mainly white matter voxels. Three main ratios of N-acetyl aspartate (NAA)/Cr, choline (Cho)/Cr and NAA/Cho were obtained. Spearman rank correlation coefficients were calculated between the cognitive function and the measured metabolite ratios.

RESULTS

We found significantly lower levels of NAA/Cho and NAA/Cr ratios in lesioned white matter in patients with LA than healthy controls (P<0.05). The ratios of NAA/Cho and NAA/Cr in normal appearing white matter (NAWM) were higher than lesioned white matter and lower than controls, but this difference was not significant (P>0.05). There was a positive relationship between Mini-Mental State Examination (MMSE) and NAA/Cho in NAWM (r = 0.417, P = 0.048), and also a positive relationship between MMSE and NAA/Cr in lesioned white matter (r = 0.551, P = 0.006) in patients with LA. A positive relationship between the Z scores of the executive function and NAA/Cho in lesioned white matter (r = 0.557, P = 0.006) was also found.

CONCLUSION

The main finding of this study was a significant reduction in the ratios of NAA/Cr and NAA/Cho in lesioned white matter, which indicates a marker of neuronal loss or dysfunction in patients with LA, which was correlated with cognitive function. This relationship between cognitive function and metabolic changes suggests that (1)H-MRS can be explored as a marker for cognitive dysfunction in patients with LA.

Neuroanatomical substrates of age-related cognitive decline

There are many reports of relations between age and cognitive variables and of relations between age and variables representing different aspects of brain structure and a few reports of relations between brain structure variables and cognitive variables. These findings have sometimes led to inferences that the age-related brain changes cause the age-related cognitive changes. Although this conclusion may well be true, it is widely recognized that simple correlations are not sufficient to warrant causal conclusions, and other types of correlational information, such as mediation and correlations between longitudinal brain changes and longitudinal cognitive changes, also have limitations with respect to causal inferences. These issues are discussed, and the existing results on relations of regional volume, white matter hyperintensities, and diffusion tensor imaging measures of white matter integrity to age and to measures of cognitive functioning are reviewed. It is concluded that at the current time the evidence that these aspects of brain structure are neuroanatomical substrates of age-related cognitive decline is weak. The final section contains several suggestions concerning measurement and methodology that may lead to stronger conclusions in the future.

Apathy is a prominent neuropsychiatric feature of radiological white-matter changes in patients with dementia

OBJECTIVE

Cerebral white-matter changes (WMCs) are frequently found in dementia and have been proposed to be related to vascular factors and a certain symptomatological profile. However, few studies have included both vascular factors and a broad spectrum of cognitive, neurological and psychiatric symptoms, easily detectable by the physician in the everyday clinical work. The objective was to study the relationships between WMCs on MRI/CT and neuropsychiatric symptoms and vascular factors in patients with cognitive impairment.

METHODS

One hundred and seventy-six patients with Alzheimer's disease, vascular dementia, mixed dementia, and mild cognitive impairment were included. All patients underwent a standardized examination including medical history, clinical examinations, laboratory tests and brain imaging (CT or MRI). The identification and severity degree of WMCs was assessed blindly to clinical findings, using a semi-quantitative scale. For statistical analyses, patients were grouped based on absence or presence of WMCs. Significant variables in bivariate analyses were included as predictors in stepwise multiple logistic regression analyses.

RESULTS

Bivariate analyses showed significant associations between WMCs and age, gender, blood pressure, hypertension, ischaemic heart disease and TIA/RIND. Furthermore, there were significant associations between WMCs and apathy, mental slowness, disinhibition, gait disturbance and focal neurologic symptoms. The multivariate logistic model revealed apathy, mental slowness and age as the most consistent predicting factors for WMCs, together with MRI as a radiological method for the detection of WMCs.

CONCLUSIONS

The findings indicate that WMCs in patients with dementia are associated with a dysexecutive-related behavioural symptom profile, vascular factors related to small and large vessel diseases and age.

Brain flexibility and balance and gait performances mark morphological and metabolic abnormalities in the elderly

Although previous studies have found that cerebral white matter hyperintensities are associated with balance-gait disorders, no proton magnetic resonance spectroscopy data at the plane of the basal ganglia have been published. We investigated a possible relationship between balance performance and brain metabolite ratios or structural MRI measurements. We also included neuropsychological tests to determine whether such tests are related to structural or metabolic findings. All 80 participants were taken from the cohort of the Three-City study (Dijon-Bordeaux-Montpellier, France). The ratios of N-acetyl-aspartate to creatine (NAA/Cr) and choline to creatine (Cho/Cr) were calculated in the basal ganglia, thalami and insular cortex. We used univariate regression to identify which variables predicted changes in NAA/Cr and Cho/Cr, and completed the analysis with a multiple linear or logistic regression. After the multivariate analysis including hypertension, age, balance-gait, sex, white matter lesions, brain atrophy and body mass index, only balance-gait performance remained statistically significant for NAA/Cr (p=0.01) and for deep white-matter lesions (p=0.02). The Trail-Making Test is independently associated with brain atrophy and periventricular white-matter hyperintensities. Neuronal and axonal integrity at the plane of the basal ganglia is associated with balance and gait in the elderly, whereas brain flexibility is associated with structural MRI brain abnormalities.

Biomarkers of cerebrovascular disease in dementia

There is increasing recognition that cerebrovascular disease contributes significantly to the development and progression of patients with dementia. The concepts of pure vascular and pure degenerative dementia have been replaced with a recognition that, in many patients, there is a spectrum of neurodegenerative and vascular processes. This is supported by preliminary studies showing response to vascular therapeutics and ventriculo-peritoneal shunting in patients with Alzheimer's disease. This article examines the imaging biomarkers that are available for the characterization of microvascular abnormality in the ageing brain, with particular reference to microvascular angiopathy, cerebral embolic disease, orthostatic hypotension and abnormalities of Monro-Kellie homeostasis.

Subcortical ischemic vascular disease and cognition: A systematic review

Subcortical Ischemic Vascular Disease (SIVD) is underdiagnosed. This review investigates the relationship among SIVD severity, cognitive status and neuroimaging markers.

METHODS

Cohort, cross-sectional and case control studies were searched on ISI, Medline, Scielo, PsychoInfo and LILACS databases published between 1995 and 2006.

RESULTS

The most impaired cognitive domains were executive, attentional and memory retrieval mechanisms. These cognitive features were frequently associated to White Matter Lesions (WML).

CONCLUSIONS

WML is an independent factor in cognitive decline. However, the threshold for this impact is not yet clearly established.

The relation between white-matter lesions and cognition

PURPOSE OF REVIEW

To summarize recent findings and developments in the field of the relation between white-matter lesions and cognition.

RECENT FINDINGS

Recent studies have provided further evidence that white-matter lesions exert a detrimental effect on cognitive profile. New magnetic-resonance techniques may help in clarifying the meaning and extent of this effect. Evidence is also increasing about lesion progression occurring over time, at least in patients with severe white-matter lesions, and this progression is one of the factors related to cognitive decline in the elderly. The need to delay or halt the progression of white-matter lesions has led to clarification of the role of some risk factors and to performance of therapeutic trials where white-matter lesions are used as a surrogate marker for the end point of small-vessel disease. In addition to cognitive effects, white-matter lesions have a role in the decline of other functional performances, and this places individuals with higher-grade lesions at increased risk of developing disability.

SUMMARY

White-matter lesions cannot be considered as mere incidental findings, at least in patients who show severe lesions. The pathogenesis of white-matter lesions must be clarified further and strategies found to delay their progression.

Vascular risk factors and white matter hyperintensities in patients with amnestic mild cognitive impairment

BACKGROUND

Subjects affected by aMCI are considered at high risk for AD. Nevertheless, the role of both vascular risk factors and WMH is matter of debate.

PATIENTS AND METHODS

We enrolled consecutively 21 aMCI subjects according to Petersen Criteria; the study included routine screening for dementia, neuropsychological evaluation and brain MRI. Six vascular risk factors were assessed and WMH was quantified by means of a semiautomatic lesion-detection program.

RESULTS

Conversion to AD, according to NINCDS-ADRDA criteria, was 47.6%. Converters tended to be more affected by the most of vascular risk factors while no difference was noted in WMH. The best predictors of conversion to AD were scores obtained at several neuropsychological examination.

CONCLUSION

Our results show that criteria for aMCI identify subjects with a high risk to develop AD. WMH doesn't seem to have a role in progression from aMCI to AD, while some vascular risk factors seem to promote it.

Semantic clustering indexes for the Hopkins Verbal Learning Test-Revised: initial exploration in elder control and dementia groups

This study examined the validity of semantic clustering indexes developed for the Hopkins Verbal Learning Test-Revised (HVLT-R). Participants were healthy adults and patients diagnosed with probable dementia of the Alzheimer's type (DAT) or vascular dementia (VaD). Neuropsychological test records, which included the HVLT-R, were collected from an archival database. Ratio semantic clustering (RSC) scores were calculated for each HVLT-R recall trial. Factor analysis including RSC and other HVLT-R scores yielded high loadings of RSC scores on a distinct clustering factor. Group comparisons showed that normal controls had higher HVLT-R recall and RSC scores than DAT and VaD patients. Only the DAT group showed significant decline in RSC from the final learning trial to delayed recall, and only the DAT group performed more poorly than controls on other semantic processing measures (e.g., HVLT-R semantically-related false positives, Boston Naming Test). Results suggest that these newly developed semantic clustering indexes are easily calculated and potentially useful for discriminating between elder controls and dementia patients.

Aging and brain activation with working memory tasks: an fMRI study of connectivity

BACKGROUND

White matter changes in aging and neuropsychiatric disorders may produce disconnection of neural circuits. Temporal correlations in regional blood oxygen level dependent (BOLD) signals may be used to assess effective functional connectivity in specific circuits, such as prefrontal cortex (PFC) circuits supporting working memory (WM) tasks. We hypothesized healthy older subjects would show lower connectivity than younger subjects.

METHODS

Healthy younger (n = 9, 25.9 (SD 6.0) years) and older adults (n = 11, 68.3 (4.9) years) performed WM tasks during functional MRI. Subjects viewed images and were instructed to label them, either simultaneously or after a delay; BOLD responses with and without delay were contrasted to assess differential WM activation and connectivity. Two tasks were used: a semantic task, with line drawings categorized as 'alive' or 'not living', and an emotional task, with emotive faces as stimuli and subjects selecting the better emotional description.

RESULTS

In both tasks, older subjects activated larger regions and had greater inter-individual variability in extent of activation. In the semantic task, connectivity was lower in the older subjects for the amygdala/orbital PFC circuit (p = 0.04). Contrary to our predictions, older subjects exhibited higher connectivity than younger subjects in the circuit linking orbital and dorsolateral PFC in both semantic (p = 0.04) and emotional (p = 0.02) tasks.

CONCLUSIONS

Healthy subjects exhibited age-dependent differences in connectivity in working memory circuits, but this may reflect effects of aging on white matter, compensatory mechanisms, and other factors. Volumetric determination of white matter hyperintensities in future studies may clarify the functional importance of structural damage.

White matter plasticity and enhanced remyelination in the maternal CNS

Myelination, the process in which oligodendrocytes coat CNS axons with a myelin sheath, represents an important but poorly understood form of neural plasticity that may be sexually dimorphic in the adult CNS. Remission of multiple sclerosis during pregnancy led us to hypothesize that remyelination is enhanced in the maternal brain. Here we report an increase in the generation of myelin-forming oligodendrocytes and in the number of myelinated axons in the maternal murine CNS. Remarkably, pregnant mice have an enhanced ability to remyelinate white matter lesions. The hormone prolactin regulates oligodendrocyte precursor proliferation and mimics the regenerative effects of pregnancy. This suggests that maternal white matter plasticity imparts a striking ability to repair demyelination and identifies prolactin as a potential therapeutic agent.

Executive Function Deficits in Acute Stroke

OBJECTIVES

To establish the frequency of executive dysfunction during acute hospitalization for stroke and to examine the relationship of that dysfunction to stroke severity and premorbid characteristics.

DESIGN

Inception cohort study.

SETTING

Inpatient wards at a Veterans Affairs hospital.

PARTICIPANTS

Consecutive sample of inpatients with radiologically or neurologically confirmed stroke. Final sample included 47 patients screened for aphasia and capable of neuropsychologic testing. Two nonstroke inpatient control samples (n=10 each) with either transient ischemic attack (TIA) or multiple stroke risk factors were administered the same research procedure and tests.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Composite cognitive impairment ratio (CIR), calculated from 8 scores indicative of executive function on 6 neuropsychologic tests by dividing number of tests completed into the number of scores falling below cutoff point, defined as 1.5 standard deviations below normative population mean.

RESULTS

Stroke patients had a mean CIR of .61, compared with .48 for TIAs and .44 for stroke-risk-only. Analysis of variance revealed that CIRs of stroke-risk-only patients but not TIAs were lower than those of the stroke patients (P=.02). Impairment frequencies were at least 50% for stroke patients on most test scores. The Symbol Digit Modalities Test (75% impairment) and a design fluency measure distinguished stroke from nonstroke patients. CIR was not related to stroke severity in the stroke patient sample, but was related to estimated premorbid intelligence.

CONCLUSIONS

Executive function deficits are common in stroke patients. The data suggest that limitations in information processing due to these deficits may require environmental and procedural accommodations to increase rehabilitation benefit.

Predictors of Outcome in Patients With Cerebral Venous Thrombosis and Intracerebral Hemorrhage

BACKGROUND AND PURPOSE

Although intracerebral hemorrhages are frequent in patients with cerebral venous thrombosis, and lead to worse outcome, predictors of outcome in cerebral venous thrombosis patients with intracerebral hemorrhages have never been evaluated in adequately powered studies.

METHODS

This study was conducted as a part of the International Study on Cerebral Vein and Dural Sinus Thrombosis. We evaluated predictors of outcome in cerebral venous thrombosis patients who had an "early intracerebral hemorrhage," ie, intracerebral hemorrhages already present at time of diagnosis of cerebral venous thrombosis by a logistic regression analysis, with a modified Rankin scale 3 to 6 at month 6 as dependent variable. The same analysis was performed with "delayed intracerebral hemorrhages," ie, intracerebral hemorrhages that occurred after the diagnosis of cerebral venous thrombosis, as dependent variable.

RESULTS

Of 624 patients recruited in International Study on Cerebral Vein and Dural Sinus Thrombosis, 245 (39%) had an early intracerebral hemorrhage: at month 6, 51 (21%) of them had a modified Rankin Scale 3 to 6. Independent predictors of having modified Rankin scale 3 to 6 at month 6 were older age (adjusted odds ratio for 1-year increase in age, 1.05; 95% CI, 1.02 to 1.08); male gender (adjusted odds ratio, 3.25; 95% CI, 1.29 to 8.16); having a deep cerebral venous system thrombosis (adjusted odds ratio, 5.43; 95% CI, 1.67 to 17.61) or a right lateral sinus thrombosis (adjusted odds ratio, 2.56; 95% CI, 1.03 to 6.40); and having a motor deficit (adjusted odds ratio, 2.94; 95% CI, 1.21 to 7.10). Of the 36 patients who had a delayed intracerebral hemorrhage, those who had a modified Rankin scale 3 to 6 at month 6 were less likely to have received heparin at the acute stage, and more likely to have had early intracerebral hemorrhage.

CONCLUSIONS

Among patients with early intracerebral hemorrhage, those who were older, men, had a thrombosis of the deep cerebral venous system or of the right lateral sinus, and a motor deficit were at higher risk for death or dependency at month 6. This subgroup of patients with predictors of poor outcome can be the target for new therapeutic strategies.

Advances in white matter imaging: a review of in vivo magnetic resonance methodologies and their applicability to the study of development and aging

Several newer magnetic resonance imaging (MRI) techniques are increasingly being applied to the study of white matter development and pathology across the lifespan. These techniques go beyond traditional macrostructural volumetric methods and provide valuable information about underlying tissue integrity and organization at the microstructural and biochemical levels. We first provide an overview of white matter development and discuss the role of white matter and myelin in cognitive function. We also review available studies of development that have employed traditional volumetric measures. Then, we discuss the contributions of four newer imaging paradigms to our understanding of brain development and aging. These paradigms are Diffusion Tensor Imaging (DTI), Magnetization Transfer Imaging (MTI), T2-Relaxography, and Magnetic Resonance Spectroscopy (MRS). Studies examining brain development during childhood and adulthood as well as studies of the effects of aging are discussed.

Is there a difference in risk factors for single and multiple symptomatic lesions in small vessel disease?

OBJECTIVES/PURPOSES

Small vessel disease (SVD) is associated with traditional vascular risk factors (RF). The aim of our study was to determine whether different SVD types, single lacunar infarction (LI) and multiple LI (MLI) with or without white matter lesions (WML), have different RF profiles.

PATIENTS AND METHODS

Forty RF parameters were analysed in 201 consecutive patients with magnetic resonance imaging finding of SVD.

RESULTS

History of arterial hypertension, higher systolic and mean blood pressure (BP) but also hypotension, and higher plasma homocysteine levels were more frequent in MLI compared to single LI patients (p<0.05). Patients with one LI were younger, more frequently had clinically evident stroke and family history of cardiovascular disease (CVD) (p<0.05). Significant difference between groups was found only in these RF, indicating that similar pathological processes led to both types of SVD.

CONCLUSION

Positive correlation with age and family history of CVD necessitates further analyses of other factors, predominantly genetic, as the key to the answer why patients develop different lesions in SVD.

Frequency and clinical determinants of poststroke cognitive impairment in nondemented stroke patients

The objective of this study was to examine the prevalence and clinical correlates of poststroke cognitive impairment in Chinese stroke patients in Hong Kong. One hundred seventy-nine stroke patients were interviewed by a psychiatrist 3 months after their stroke. Cognitive impairment was determined according to the Mini-Mental State Examination score. Thirty-nine participants (21.8%) had cognitive impairment. Univariate analysis found that cognitive impairment was associated with age, female sex, level of education, previous stroke, prestroke Rankin score, National Institutes of Health Stroke Scale dysarthria and total scores, urinary incontinence, and cerebral atrophy index. Multivariate logistic regression suggested that female sex, education, National Institutes of Health Stroke Scale dysarthria score, urinary incontinence, and atrial fibrillation were independent risk factors of poststroke cognitive impairment. After removal of 54 patients with previous stroke from the sample, the frequency of cognitive impairment decreased to 18.4%. It was concluded that cognitive impairment is common among nondemented Chinese stroke patients in Hong Kong.

The role of quantitative structural imaging in the early diagnosis of Alzheimer's disease

The goal of this article is to review the role of structural neuroimaging in the diagnosis of Alzheimer's disease (AD). We present relevant neuroanatomy, highlight progress in the domain of AD imaging, and review the clinical characteristics of the prodromal phase of AD. We describe the history of the diagnostic issue by examining at cross-section and longitudinally the differences between patients who have AD and normal controls. We also present how subsequent works applied these characteristic traits to the early detection of the prodromal disease and to prediction of future decline. The article delineates the differences between subjects who have mild cognitive impairment and AD, which illustrate the spreading of the pathology with disease progression. The last section describes problems encountered in the differential diagnosis.

Age-related microvascular degeneration in the human cerebral periventricular white matter

Clinical studies have identified white matter (WM) lesions as hyperintensive regions in the MRI images of elderly patients. Since a cerebrovascular origin was attributed to such lesions, the present analysis set out to define the microvascular histopathologic changes in the periventricular WM in the aged. Post-mortem samples of the frontal, parietal, and occipital periventricular WM of 40-90-year-old subjects were prepared for quantitative light and electron microscopy. Light microscopic examination revealed microvascular fibrohyalinosis as the most common type of microvascular damage in the elderly. Ultrastructural analysis identified the microvascular thickening as collagen deposits affecting the basement membrane. The vascular density did not correlate with the age. The basement membrane pathology significantly increased, while the number of intact microvessels gradually decreased, with advancing age in the frontal and occipital WM. Finally, peripheral atherosclerosis coincided with massive microvascular fibrosis, particularly in the frontal WM. Our results demonstrate an age-related microvascular degeneration in the periventricular WM, which may contribute to the development of WM lesions by hindering a sufficient supply of nutrients to the affected WM sites. Furthermore, the data accord with previous observations identifying the frontal lobe as the site at which WM vulnerability is most pronounced. Finally, atherosclerosis in large, peripheral vessels is considered to be a predictive marker of microvascular pathology in the WM.

Clinical and radiographic subtypes of vascular cognitive impairment in a clinic-based cohort study

BACKGROUND AND PURPOSE

There is a need for empirical studies to define criteria for vascular cognitive impairment (VCI) subtypes. In this paper, we report the predictive validity of a subtype classification scheme based on clinical and radiographic features.

METHODS

Nine Canadian memory clinics participated in the Consortium to Investigate Vascular Impairment of Cognition. This cohort consisted of 1347 patients, of whom 324 had VCI, and was followed for up to 30 months.

RESULTS

Clinical and neuroimaging features defined three subtypes: vascular cognitive impairment, no dementia, (n=97), vascular dementia (n=101) and mixed neurodegenerative/vascular dementia (n=126). Any ischemic lesion on neuroimaging increased the odds (odds ratio=9.31; 95% confidence interval 6.46, 13.39) of a VCI diagnosis. No VCI subtype, however, was associated with a specific neuroimaging abnormality. Compared to those with no cognitive impairment, patients with each VCI subtype had higher rates of death and institutionalization (hazard ratio for combined adverse events=6.08, p<0.001).

CONCLUSIONS

Both clinical features and radiographic features help establish a diagnosis of VCI. The outcomes of VCI subtypes, however, are more strongly associated with clinical features than with radiographic ones.

Computed tomographic changes in lacunar syndromes

BACKGROUND

Lacunes are small deep infarcts due to occlusion of long-perforating arterial branches. The clinical presentation and outcome are variable. The present study investigates the prognostic value of comparing repeated computed tomographic (CT) scans in patients with a lacunar syndrome (LACS).

PATIENTS AND METHODS

From a series of 220 patients, subsequently admitted with a first-ever stroke, 32 were diagnosed as LACS. CT scans without contrast enhancement were performed on day 3 and 10 after onset of the symptoms. A lacune was considered as responsible for the LACS when its location corresponded to the expected cerebral hemisphere and when it changed in size and/or in X-ray attenuation on the CT scans from day 3 to 10. The size of the lacune was also measured and compared on both time points. The patients were divided into two groups according to the modified Rankin (R) scale at 3 months, in those who were independent (R 0-1-2) and in those who remained handicapped (R 3-4-5).

RESULTS

The patients who remained disabled at 3 months were older and more severely impaired on admission, and had more frequent cardiac problems and cognitive decline than the independent ones. On CT scans of the brain a higher incidence of leukoaraiosis was observed in this group. Only in three patients of each group no relevant lacune could be observed both on day 3 and 10. The average size of the symptomatic lacune on day 3 and 10 was not statistically different between both groups, when comparing all patients with a LACS. When comparing only those patients with a visible symptomatic lacunar infarct on one of the CT scans, however, the average size of the symptomatic deep infarct was smaller in the independent than the handicapped patients on day 3 as well as on day 10. The lacune decreased in average size from day 3 to 10 in the former group but remained unchanged in the group of disabled patients.

CONCLUSION

The outcome of patients with a LACS depends on several factors including age, cognitive and cardiac status, the presence of leukoaraiosis and also the size of the symptomatic lacune.

Childhood-onset growth hormone deficiency, cognitive function and brain N-acetylaspartate

Cognitive deficits have been reported in adults with childhood-onset growth hormone (GH) deficiency. We evaluated cognitive deficits simultaneously with parameters for neuronal integrity using (1)H magnetic resonance spectroscopy (MRS) in a cross-sectional design. We studied 11 adults (mean age 24.5 years) with childhood-onset GH deficiency, which persisted after reaching final height. All subjects were evaluated after interruption of GH supplementation for at least 3 months. We performed neuropsychological assessment (NPA) using tests evaluating memory, mental processing speed, reading ability and executive functioning. MRS was used to assess brain N-acetylaspartate (NAA)/choline ratios. Data were compared with an age-, sex- and education-matched control group (n=9, mean age 27.3 years). NPA demonstrated attenuated performance of the patients in the delayed verbal memory recall score (P<0.05) and the trail making A test (P<0.05), a measure of planning of behavior, processing speed and attention. Other neuropsychological tests were not affected. NAA/choline ratios were significantly reduced (P<0.01) in GH deficient subjects. Specific cognitive defects indicating affected memory and attention were found in patients with childhood-onset GH deficiency. These defects occur simultaneously with reduced neuronal integrity.

Clinical significance of subcortical vascular disease in patients with mild cognitive impairment

Patients with mild cognitive impairment (MCI) typically present with memory complaints. Some of these patients have subcortical vascular disease on computed tomography (CT) scan, namely white matter changes and lacunar infarcts, however it is not known whether these findings are associated with more pronounced cognitive deficits. In the present study we compare demographic, clinical and neuropsychological characteristics of MCI patients according to the presence or the absence of subcortical vascular disease. Forty consecutive patients with memory complaints, at least one neuropsychological memory test below 1 SD the normal for age and education, and maintained activities of daily living, were included. Patients with dementia, history of stroke or transient ischemic attack, or other brain disorders, were excluded. Twenty-five (62.5%) patients with MCI had no ischemic lesions on CT scan, and 15 (37.5%) were found to have subcortical vascular changes. MCI patients with subcortical vascular changes were older (77.1 +/- 6.8 vs. 70.8 +/- 7.5 years old), and more often males. The number of vascular risk factors, the frequency of neurological signs, the Hachinski score and the neuropsychological tests scores were not significantly different. The presence of subcortical vascular disease on CT scan is frequent in older patients with MCI, but does not appear to be associated with the severity of cognitive deficits.

Neuropsychology of cognitive ageing, minimal cognitive impairment, Alzheimer's disease, and vascular cognitive impairment

In this review, the neuropsychological symptoms of different diseases in the elderly are described. After a brief explanation of relevant principles in the neuropsychological assessment of older individuals, a summary of the complex relation between ageing and cognition is presented. It may be concluded that cognitive decline is not an inevitable outcome of ageing, and may well be the result of unrecognised pathology. The term mild cognitive impairment is reserved for patients whose impairment is objectively demonstrable but is not pronounced in more than one domain of cognition and does not seriously affect activities of daily living. The initial phase of Alzheimer's disease is marked by a progressive deterioration of episodic memory. When the process advances, the impairment spreads to other functions, such as semantic memory, language and visuo-spatial ability. Vascular dementia is the second most common type of dementia; however, it is increasingly being recognised that vascular dementia is actually a heterogeneous syndrome and that several vascular pathologies can lead to cognitive deterioration. In contrast to the striking deficits produced by cortical infarcts, lesions of the subcortical white matter are mainly associated with a non-specific slowing of behaviour. Cerebrovascular disease also plays an important role in forms of cognitive decline other than dementia, and as such, it appears to be no less prevalent in old age than Alzheimer's disease. Neuropsychology is an important asset to the study and treatment of cognitive decline, but must be embedded in a multi-disciplinary context.

Quercetin, a natural flavonoid, attenuates vacuolar formation in the optic tract in rat chronic cerebral hypoperfusion model

Epidemiological studies suggest that the intake of flavonoids is inversely associated with risk of cardiovascular diseases and stroke, but there is no evidence showing the effect of flavonoids on vascular dementia. Because quercetin, a natural flavonoid, is known to scavenge free radicals, we investigated whether quercetin attenuates white matter damage in rats with chronic cerebral hypoperfusion, as a model of vascular dementia. Chronic hypoperfusion was induced by ligation of the bilateral carotid arteries in male Wistar rats, which received vehicle alone, 100 mg/kg quercetin, or 200 mg/kg quercetin intraperitoneally at 4-day intervals for 8 weeks after operation. Sham-operated rats were also studied. The area of vacuoles in the optic tract observed after hematoxylin and eosin staining was significantly reduced in the 200 mg/kg quercetin-treated hypoperfusion group versus the vehicle-treated hypoperfusion group (1.7+/-0.2% versus 3.9+/-0.3%; P<0.05). The present results are consistent with the idea that chronic treatment with quercetin could be protective against at least a part of ischemic white matter damage.