The epidemiology of mild cognitive impairment (MCI) and Alzheimer’s disease (AD) in community-living seniors: protocol of the MemoVie cohort study, Luxembourg

BACKGROUND: Cognitive impairment and Alzheimer’s disease (AD) are increasingly considered a major public health problem. The MemoVie cohort study aims to investigate the living conditions or risk factors under which the normal cognitive capacities of the senior population in Luxembourg (≥ 65 year-old) evolve (1) to mild cognitive impairment (MCI) – transitory non-clinical stage – and (2) to AD. Identifying MCI and AD predictors undeniably constitutes a challenge in public health in that it would allow interventions which could protect or delay the occurrence of cognitive disorders in elderly people. In addition, the MemoVie study sets out to generate hitherto unavailable data, and a comprehensive view of the elderly population in the country. METHODS/DESIGN: The study has been designed with a view to highlighting the prevalence in Luxembourg of MCI and AD in the first step of the survey, conducted among participants selected from a random sample of the general population. A prospective cohort is consequently set up in the second step, and appropriate follow-up of the non-demented participants allows improving the knowledge of the preclinical stage of MCI. Case-control designs are used for cross-sectional or retrospective comparisons between outcomes and biological or clinical factors. To ensure maximal reliability of the information collected, we decided to opt for structured face to face interviews. Besides health status, medical and family history, demographic and socio-cultural information are explored, as well as education, habitat network, social behavior, leisure and physical activities. As multilingualism is expected to challenge the cognitive alterations associated with pathological ageing, it is additionally investigated. Data relative to motor function, including balance, walk, limits of stability, history of falls and accidents are further detailed. Finally, biological examinations, including ApoE genetic polymorphism are carried out. In addition to standard blood parameters, the lipid status of the participants is subsequently determined from the fatty acid profiles in their red blood cells. The study obtained the legal and ethical authorizations. DISCUSSION: By means of the multidisciplinary MemoVie study, new insights into the onset of cognitive impairment during aging should be put forward, much to the benefit of intervention strategies as a whole

Prevalence of mild cognitive impairment and its subtypes in the Heinz Nixdorf Recall study cohort.

We investigated the prevalence of mild cognitive impairment (MCI) and its subtypes according to the original (MCI-original) and modified (MCI-modified; neglecting cognitive complaints) Petersen criteria.4,145 subjects (aged 50-80 years) from a German population-based study completed a cognitive screening test and were poststratified into 2 groups with sample sizes of 1,125 for impaired and 3,020 for age-appropriate performance. Random samples of 445 impaired participants and 211 age-appropriate participants received a detailed neuropsychological evaluation. The prevalence of MCI was estimated by a bias correction estimator based on stratum weights. The association between MCI and age, gender and education was analyzed in a logistic regression model.The estimated MCI prevalence was 7.8% (95% CI: 5.7-9.9%) for the original, and 12.1% (95% CI: 9.8-14.4%) for the modified criteria. In the MCI-original group, amnestic MCI subtypes were slightly less common than non-amnestic MCI subtypes (3.5 vs. 4.3%). MCI-original was associated with lower education and older age. In the MCI-modified group, the amnestic subtypes were more common than the non-amnestic MCI subtypes (7.8 vs. 4.3%), and MCI was associated with age, gender and education.Prevalence rates of MCI are high in the general population and vary considerably according to the criteria applied

Dual-Curable Epoxy-Amine Thermosets: Influence of Stoichiometry and Ratio between Hardeners on Thermal and Thermomechanical Properties

Sequential dual-curable thermosets based on off-stoichiometric and stoichiometric amine–epoxy formulations have been developed, employing different reactivities of two curing agents in terms of temperature. The first curing step is triggered by a self-limiting polycondensation between epoxy and amine groups of a reactive hardener m-xylylenediamine (MXDA) at lower temperatures, and the second one by a reaction of remaining unreacted epoxy groups with amine groups of a latent curing agent dicyanodiamine (DICY) at higher temperatures, respectively. Differential scanning calorimetry (DSC) of reactive dual-curing systems reveals two distinct curing peaks. A reduction of their maxima was achieved by adding AJICURE MY-24 as an accelerator to lower the curing temperature. DSC, rheology, and dynamic mechanical analysis (DMA) demonstrated that a wide range of properties, such as gel time of reactive samples, glass transition, and network density of intermediate and final materials, can be tuned by the proper choice of the ratio between both hardeners. The gel time increases, up to 9 h at room temperature, with increasing DICY fraction. The intermediate materials vary from highly viscous through flexible to rigid with increasing MXDA fraction. However, it was also observed that the stoichiometry of the whole formulations does not influence the shape and glass transition of partially cured samples. Furthermore, the glass transitions of final stoichiometric systems are much higher than those of off-stoichiometric ones. The glass transition temperature of stoichiometric systems, determined by DMA, varied from 91.3 to 100.2 °C. All in all, this study presents a strategy to create stoichiometric dual-curing epoxy resin systems, which opens further possibilities to combine other reactive and latent curing agents in order to obtain the desired properties of partially and fully cured materials

Automatic segmentation of cerebral white matter hyperintensities using only 3D FLAIR images.

Item does not contain fulltextMagnetic Resonance (MR) white matter hyperintensities have been shown to predict an increased risk of developing cognitive decline. However, their actual role in the conversion to dementia is still not fully understood. Automatic segmentation methods can help in the screening and monitoring of Mild Cognitive Impairment patients who take part in large population-based studies. Most existing segmentation approaches use multimodal MR images. However, multiple acquisitions represent a limitation in terms of both patient comfort and computational complexity of the algorithms. In this work, we propose an automatic lesion segmentation method that uses only three-dimensional fluid-attenuation inversion recovery (FLAIR) images. We use a modified context-sensitive Gaussian mixture model to determine voxel class probabilities, followed by correction of FLAIR artifacts. We evaluate the method against the manual segmentation performed by an experienced neuroradiologist and compare the results with other unimodal segmentation approaches. Finally, we apply our method to the segmentation of multiple sclerosis lesions by using a publicly available benchmark dataset. Results show a similar performance to other state-of-the-art multimodal methods, as well as to the human rater.1 september 201

Long-term air pollution and traffic noise exposures and cognitive function:A cross-sectional analysis of the Heinz Nixdorf Recall study

Investigations of adverse effects of air pollution (AP) and ambient noise on cognitive functions are apparently scarce, and findings seem to be inconsistent. The aim of this study was to examine the associations of long-term exposure to AP and traffic noise with cognitive performance. At the second examination of the population-based Heinz Nixdorf Recall study (2006-2008), cognitive performance was evaluated in 4086 participants. Long-term residential exposure to size-specific particulate matter (PM) and nitrogen oxides (NOx) with land use regression, to and traffic noise (weighted 24-h (L-DEN) and nighttime (L-NIGHT) means), was assessed according to the European Union (EU) Directive 2002/49/EC. Multiple regression models were calculated for the relationship of environmental exposures with a global cognitive score (GCS) and in five cognitive subtests, using single- and two-exposure models. In fully adjusted models, several AP metrics were negatively associated with four of five subtests and with GCS. For example, an interquartile range increase in PM2.5 was correlated with verbal fluency, labyrinth test, and immediate and delayed verbal recall. A 10 dB(A) elevation in L-DEN and L-NIGHT was associated with GCS. Similar but not significant associations were found for the cognitive subtests. In two-exposure models including noise and air pollution simultaneously, the associations did not change markedly for air pollution, but attenuated numerically for noise. Long-term exposures to AP and traffic noise are negatively correlated with subtests related to memory and executive functions. There appears to be little evidence for mutual confounding

Supplementary Material for: Population-Based Distribution and Psychometric Properties of a Short Cognitive Performance Measure in the Population-Based Heinz Nixdorf Recall Study

Background: Providing a valid and sensitive measure of different domains of cognitive performance in epidemiologic studies of early old-age populations presents a methodological challenge, given the broad range of variability in cognitive functioning in this age group. Objectives: (1) To provide data on the distribution of cognitive performance scores in a representative sample of an early old-age population, and (2) to assess psychometric properties of a short cognitive performance measure developed within the framework of a cohort study. Design: Population-based cohort study. Setting and Participants: As part of the second examination of the Heinz Nixdorf Recall Study, 4,145 participants aged 50–80 years underwent a short cognitive performance assessment composed of 5 subtests with a mean duration of 7.31 min. Additionally, a subsample of 656 participants had a detailed neuropsychological and neurological examination. Methods: Age- and education-specific cognitive performance scores in the total sample were calculated. Based on data from the subsample, concurrent validity was examined by comparing findings with a clinically validated neuropsychological assessment. Results: In the total sample, younger and more highly educated participants had higher scores of cognitive performance. In the subsample, a good accuracy [area under the curve (AUC) = 0.81 (0.74–0.87)] of the short cognitive performance assessment compared with results from a clinically established Alzheimer disease assessment scale and diagnosis of mild cognitive impairment [AUC = 0.82 (0.78–0.82)] was observed. Conclusion: This brief, cognitive performance measure, documenting good psychometric properties, can be useful in future epidemiological investigations exploring different domains and overall cognitive functioning in early old-age populations

Prevalence of mild cognitive impairment and its subtypes in the Heinz Nixdorf Recall study cohort.

AIMS: We investigated the prevalence of mild cognitive impairment (MCI) and its subtypes according to the original (MCI-original) and modified (MCI-modified; neglecting cognitive complaints) Petersen criteria. METHODS: 4,145 subjects (aged 50-80 years) from a German population-based study completed a cognitive screening test and were poststratified into 2 groups with sample sizes of 1,125 for impaired and 3,020 for age-appropriate performance. Random samples of 445 impaired participants and 211 age-appropriate participants received a detailed neuropsychological evaluation. The prevalence of MCI was estimated by a bias correction estimator based on stratum weights. The association between MCI and age, gender and education was analyzed in a logistic regression model. RESULTS: The estimated MCI prevalence was 7.8% (95% CI: 5.7-9.9%) for the original, and 12.1% (95% CI: 9.8-14.4%) for the modified criteria. In the MCI-original group, amnestic MCI subtypes were slightly less common than non-amnestic MCI subtypes (3.5 vs. 4.3%). MCI-original was associated with lower education and older age. In the MCI-modified group, the amnestic subtypes were more common than the non-amnestic MCI subtypes (7.8 vs. 4.3%), and MCI was associated with age, gender and education. CONCLUSIONS: Prevalence rates of MCI are high in the general population and vary considerably according to the criteria applied