Vascular cognitive impairment in dementia

Vascular risk factors and cerebrovascular disease are common causes of dementia. Shared risk factors for vascular dementia and Alzheimer's disease, as well as frequent coexistence of these pathologies in cognitively impaired older people, suggests convergence of the aetiology, prevention and management of the commonest dementias affecting older people. In light of this understanding, the cognitive impairment associated with cerebrovascular disease is an increasingly important and recognised area of the medicine of older people. Although the incidence of cerebrovascular events is declining in many populations, the overall burden associated with brain vascular disease will continue to increase associated with population ageing. A spectrum of cognitive disorders related to cerebrovascular disease is now recognised. Cerebrovascular disease in older people is associated with specific clinical and imaging findings. Although prevention remains the cornerstone of management, the diagnosis of brain vascular disease is important because of the potential to improve clinical outcomes through clear diagnosis, enhanced control of risk factors, lifestyle interventions and secondary prevention. Specific pharmacological intervention may also be indicated for some patients with cognitive impairment and cerebrovascular disease. However the evidence base to guide intervention remains relatively sparse.     

A comparison of methods for measuring cognitive change in older adults.

Well-researched statistical methods are required to guide clinicians in determining the significance of test score changes in serial neuropsychological assessment of older adults. The following six change score methods were examined using five-year test-retest data from the Canadian Study of Health and Aging: the standard deviation method, three reliable change indices (RCIs), and two standardized regression-based methods. Changes in scores on four memory measures were examined in cognitively healthy older adults, and the RCI with a correction for practice/aging effects most accurately classified this normal variability. Diagnostic change (i.e., developing dementia versus remaining cognitive healthy) was also examined in relation to memory test score changes. All change score methods were significantly associated with diagnostic change, though the strength of association varied by measure and method. In contrast to some previous research, RCIs were found to be useful when making diagnostic discriminations in older adults.     

Comparison between two finite-element modelling methods for measuring change in craniofacial form

Finite-element modelling of form change is a useful morphometric technique for measuring differences between anatomical patterns. Two different finite-element algorithms currently are used. One method requires normalized coordinates as input data, while the second method uses globalized coordinates as input data. This study determines whether the two finite-element methods provide equivalent measures of three-dimensional form change when applied to the nasal septa of embryonic mice. Computer models of the nasal septa from mice of 15 and 17 days gestation were generated. Homologous landmarks were identified so that each nasal septum was represented by a tetrahedral finite-element. These elements were subjected to both finite-element modelling methods. Results show that the two algorithms use different interpolation functions and yield dissimilar intermediate results, but generate identical strain matrices as well as equivalent principal extensions, directions of form change, variables of form change, and graphical displays. Therefore, results are directly comparable from studies using either finite-element modelling method.     

Comparison between two finlte-element modelling methods for measuring change in craniofacial form

Finite-element modelling of form change is a useful morphometric technique for measuring differences between anatomical patterns. Two different finite-element algorithms currently are used. One method requires normalized coordinates as input data, while the second method uses globalized coordinates as input data. This study determines whether the two finite-element methods provide equivalent measures of three-dimensional form change when applied to the nasal septa of embryonic mice. Computer models of the nasal septa from mice of 15 and 17 days gestation were generated. Homologous landmarks were identified so that each nasal septum was represented by a tetrahedral finite-element. These elements were subjected to both finite-element modelling methods. Results show that the two algorithms use different interpolation functions and yield dissimilar intermediate results, but generate identical strain matrices as well as equivalent principal extensions, directions of form change, variables of form change, and graphical displays. Therefore, results are directly comparable from studies using either finite-element modelling method.     

Risk factors for cerebral hypoperfusion, mild cognitive impairment, and dementia

Putative risk factors accelerating mild cognitive decline and dementia were correlated with repeated measures of cerebral atrophy, CT, densitometry, perfusions, and cognitive testing among neurologically and cognitively normative aging volunteers. A total of 224 normative subjects at increased risk for cognitive decline were admitted to the study. Mean entry age was 59.5 +/- 15.8 years. Mean follow-up is 5.8 +/- 3.3 years. At follow-up, 22 developed mild cognitive impairment (41 CCSE >/= -3), 19 became demented-8 with Vascular type (VAD), 11 with Alzheimer's type (DAT)-and 183 remain cognitively unchanged. Cerebral atrophy, tissue densities, and perfusions were measured by Xe-CT. After age 60, cerebral atrophy, ventricular enlargement, and polio- and leuko-araiosis geometrically increased as perfusions declined. Risk factors accelerating perfusional decline, cerebral atrophy, polio-araiosis, and leuko-araiosis were: transient ischemic attacks (TIAs), hypertension, smoking, hyperlipidemia, and male gender. At age 71.5 +/- 11.9, mild cognitive impairment began accelerated by TIAs, hypertension and heart disease. Leuko-araiosis began before cognitive decline. TIAs, hypertension, and hyperlipidemia correlated with VAD. Excessive cortical perfusional decrease, gray and white matter hypodensities, and cerebral atrophy correlate with cognitive decline.     

Longitudinal change in cognitive performance among individuals with mild cognitive impairment

The authors used mixed-effects growth models to examine longitudinal change in neuropsychological performance over a 4-year period among 197 individuals who were either normal or had mild cognitive impairment (MCI) at baseline. At follow-up, the participants were divided into 4 groups: (a) controls: participants who were normal at both baseline and follow-up (n = 33), (b) stables: participants with MCI whose Clinical Dementia Rating-Sum of Boxes (CDR-SB) score did not differ between the first and last evaluations (n = 22), (c) decliners: participants with MCI whose CDR-SB score declined between the first and last evaluations (n = 95), and (d) converters: participants who received a clinical diagnosis of Alzheimer's disease during the follow-up period (n = 47). Only the Episodic Memory factor showed a significantly greater rate of decline over the follow-up period among the converters. Two other factors were significantly lower in converters at baseline in comparison with other groups (the executive function factor and the general knowledge factor), but the rate of decline over time did not differ. Individuals with an APOE epsilon4 allele scored lower on the episodic memory and executive function factors at baseline.     

Acupuncture improved cognitive impairment caused by multi-infarct dementia in rats

Recent studies have demonstrated that acupuncture is feasible to treat vascular dementia (VD). The aim of this study was to present behavioral evidence that acupuncture could improve the learning and memory of multi-infarct dementia rats. The pattern of multi-infarct dementia in rats was made by injecting homogeneous emboli into the internal carotid artery. Of them the rats which showed damage in learning and memory (n = 43) were randomly allocated to 3 groups: impaired group (n = 14), acupuncture group (n = 15) and placebo-acupuncture group (n = 14). Moreover, normal group (n = 15) and sham-operated group (n = 15) were set as control groups. The acupuncture group was given acupuncture, which consisted of Tanzhong (CV17), Zhongwan (CV12), Qihai (CV6), Zusanli (ST36) and Xuehai (SP10). Morris water maze test was employed to assess spatial discriminational ability per group respectively and to analyze the curative effects of acupuncture. Compared to the impaired and placebo-acupuncture groups, no cognition impairment was found in the normal and sham-operated groups, and the statistic analysis showed that there were significant differences between normal and impaired groups in ANOVA. Shortened mean escape latency was detected in the acupuncture group compared with the impaired group during the same trial days. Search strategy changed from random pattern adopted by impaired and placebo-acupuncture rats to tendency or linear pattern popular in normal group. The present results suggested that the acupuncture exerted a protective effect on cognitive impairment caused by cerebral multi-infarction in rats, and acupuncture has a specificity of cure. Acupuncture as a potential clinic method in treating VD should be developed and investigated in the future.     

Sortilin receptor 1 predicts longitudinal cognitive change

The gene encoding sortilin receptor 1 (SORL1) has been associated with Alzheimer's disease risk. We examined 15 SORL1 variants and single nucleotide polymorphism (SNP) set risk scores in relation to longitudinal verbal, spatial, memory, and perceptual speed performance, testing for age trends and sex-specific effects. Altogether, 1609 individuals from 3 population-based Swedish twin studies were assessed up to 5 times across 16 years. Controlling for apolipoprotein E genotype (APOE), multiple simple and sex-moderated associations were observed for spatial, episodic memory, and verbal trajectories (p = 1.25E-03 to p = 4.83E-02). Five variants (rs11600875, rs753780, rs7105365, rs11820794, rs2070045) were associated across domains. Notably, in those homozygous for the rs2070045 risk allele, men demonstrated initially favorable performance but accelerating declines, and women showed overall lower performance. SNP set risk scores predicted spatial (Card Rotations, p = 5.92E-03) and episodic memory trajectories (Thurstone Picture Memory, p = 3.34E-02), where higher risk scores benefited men's versus women's performance up to age 75 but with accelerating declines. SORL1 is associated with cognitive aging, and might contribute differentially to change in men and women.     

The impact of cerebrovascular aging on vascular cognitive impairment and dementia

As human life expectancy rises, the aged population will increase. Aging is accompanied by changes in tissue structure, often resulting in functional decline. For example, aging within blood vessels contributes to a decrease in blood flow to important organs, potentially leading to organ atrophy and loss of function. In the central nervous system, cerebral vascular aging can lead to loss of the integrity of the blood-brain barrier, eventually resulting in cognitive and sensorimotor decline. One of the major of types of cognitive dysfunction due to chronic cerebral hypoperfusion is vascular cognitive impairment and dementia (VCID). In spite of recent progress in clinical and experimental VCID research, our understanding of vascular contributions to the pathogenesis of VCID is still very limited. In this review, we summarize recent findings on VCID, with a focus on vascular age-related pathologies and their contribution to the development of this condition.     

Comparison of cognitive impairment associated with major depression following stroke versus traumatic brain injury

Several studies have reported an association between cognitive impairment and major depression following stroke but failed to find a similar association among patients with traumatic brain injury (TBI). This study examined the hypothesis that age differences between stroke and TBI patients would account for the differences in the effect of major depression on cognitive function. We examined subjects' cognitive function using the Mini-Mental State Examination and compared findings among patients with stroke or TBI. Results indicated that stroke patients with major depression (N = 73) were significantly older and more cognitively impaired than similar TBI patients (N = 35), even after matching patients for lesion volume and years of education. After matching for age, however, there was no association of major depression with cognitive impairment in this relatively young stroke population. These findings support the hypothesis that age, presumably related to physiological response to brain injury, accounts for differences in the effect of major depression on cognitive function between stroke and TBI patients.     

Time-restricted feeding (TRF) for prevention of age-related vascular cognitive impairment and dementia

Aging is the most significant risk factor for vascular cognitive impairment (VCI), and the number of individuals affected by VCI is expected to exponentially increase in the upcoming decades. Yet, there are no current preventative or therapeutic treatments available against the development and progression of VCI. Therefore, there is a pressing need to better understand the pathophysiology underlying these conditions, for the development of novel tools and interventions to improve cerebrovascular health and delay the onset of VCI. There is strong epidemiological and experimental evidence that lifestyle factors, including nutrition and dietary habits, significantly affect cerebrovascular health and thereby influence the pathogenesis of VCI. Here, recent evidence is presented discussing the effects of lifestyle interventions against age-related diseases which in turn, inspired novel research aimed at investigating the possible beneficial effects of dietary interventions for the prevention of cognitive decline in older adults.     

Comparison of four methods for measuring femoral anteversion

This study evaluates the most valid and reproducible method for directly measuring anteversion (torsion) in dried femora using a commercially available measuring machine. Each femur was placed horizontally on the surface of the machine and readings were obtained from the head, the shaft distal to the lesser trochanter, and the distal end. Using computer software, four different anteversion angles were calculated: the center head-neck line to the retrocondylar line (Method 1); the center head-neck line to the transcondylar line (Method 2); the anterior head-trochanter line to the retrocondylar line (Method 3); and the anterior head-trochanter line to the transcondylar line (Method 4). The methods were applied to 20 femora, which were measured twice by one observer. The most reproducible method of measuring femoral anteversion uses the bone surfaces on the anterior aspect of the head and greater trochanter and on the posterior aspect of the condyles (Method 3.95% confidence limits of ± 0.4°). The other methods are shown to be reproducible to ±2.4°, ±3.3° and ±1.7° (Methods 1, 2, and 4, respectively, 95% confidence limits). Conversion factors between the different methods are: 12.5° + 0.8 x (anteversion angle) to change each of Method 2 to Method 1 and Method 4 to Method 3; and 8° + 0.7 x (anteversion angle) to change each of Method 1 to Method 3 and Method 2 to Method 4 (correct to within ±3°). © 1993 Wiley-Liss, Inc.     

多发梗塞性痴呆和阿尔采默氏痴呆的脑 CT 改变及认知障碍对比研究

本文对28例多发梗塞性痴呆(MID)患者和25例阿尔采默氏痴呆(DAT)患者的脑CT 改变及认知障碍特点进行了对比研究。结果发现,MID 患者脑室周围低密度改变的比率(82%)显著高于 DAT 组患者(36%)。而 DAT 组患者的脑沟较 MID 组的显著增宽。MID 组患者第三脑室扩大与智能损害严重程度呈显著正相关。MID 患者的智能损害不完全,可保留某方面的能力致疾病严重阶段。