1,720,997 research outputs found
White matter hyperintensities and amyloid are independently associated with entorhinal cortex volume among individuals with mild cognitive impairment
No full textLarger entorhinal cortex volume was associated with better memory but not with performance on a task of executive functioning. Lower levels of Ab1-42 and higher temporal WMH volumes were associated with smaller entorhinal cortex volume. When entered simultaneously, temporal lobe WMH volume was more reliably associated with entorhinal cortex volume than was Ab1-42. The findings were similar for hippocampus volume and when the sample was restricted to MCI patients who subsequently transitioned to AD
White matter hyperintensities and cerebral amyloidosis: necessary and sufficient for clinical expression of Alzheimer disease?
No full textWhite matter hyperintensities contribute to the presentation of AD and, in the context of significant amyloid deposition, may provide a second hit necessary for the clinical manifestation of the disease. As risk factors for the development of WMHs are modifiable, these findings suggest intervention and prevention strategies for the clinical syndrome of AD
Neuropsychological predictors of rapidly progressive Alzheimer's disease
No full textAbstract
OBJECTIVE:
Alzheimer's disease (AD), the most common cause of dementia, typically shows a slow clinical progression over time. 'Rapidly progressive' AD, a variant of the disease characterized by an aggressive course, exhibits distinct clinical, biological, and neuropathological features. Here, we investigate neuropsychological predictors of rapid decline in a group of mild patients with AD.
METHODS:
One hundred fifty-three mild patients with AD admitted to a memory disorder clinic and followed for up to 3 years were included in this study. A comprehensive neuropsychological (NP) battery was performed at the time of enrollment. Patients were defined as 'rapidly progressive' if they exhibited a drop of 6 or more points on the Mini Mental State Examination (MMSE) between two consecutive annual visits. This event defined the main outcome in multiple analyses of variance and Cox proportional hazards models that investigated the impact of NP predictors. Categorical principal component analysis (CATPCA) was also employed in order to delineate clusters of NP tests and to test their effect on the outcome.
RESULTS:
Of 153 subjects, thirty-seven (24%) were classified as 'rapidly progressive'; those subjects showed younger age of symptoms onset compared to slow decliners (68 vs 71.5 years old). Baseline lower performance on a neuropsychological test of naming predicted a rapid decline over the follow-up (P = 0.001). Three clusters of NP were defined by CATPCA: (i) executive/language, (ii) visuospatial memory, and (iii) verbal memory. The executive/language component predicted a rapid decline over the follow-up (P = 0.016).
CONCLUSION:
Early executive/language impairment is highly predictive of a rapid progression of AD
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Correction: APOE4-mediated Alzheimer disease and “Vascular”—“Meningeal Lymphatic” components: towards a novel therapeutic era? (Molecular Psychiatry, (2021), 26, 10, (5472-5474), 10.1038/s41380-021-01242-7)
No full textIn this article ref. 12 was incorrect and should have been “Nasrabady SE, Rizvi B, Goldman JE, Brickman AM. White matter changes in Alzheimer’s disease: a focus on myelin and oligodendrocytes. Acta Neuropathol Commun. 2018;6:22. https://doi.org/10.1186/s40478-018-0515-3.” The original article has been corrected. © The Author(s), under exclusive licence to Springer Nature Limited 2021
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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