1,720,973 research outputs found

    Breakdown of Specific Functional Brain Networks in Clinical Variants of Alzheimer's Disease

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    Alzheimer's disease (AD) is characterized by different clinical entities. Although AD phenotypes share a common molecular substrate (i.e., amyloid beta and tau accumulation), several clinicopathological differences exist. Brain functional networks might provide a macro-scale scaffolding to explain this heterogeneity. In this review, we summarize the evidence linking different large-scale functional network abnormalities to distinct AD phenotypes. Specifically, executive deficits in early-onset AD link with the dysfunction of networks that support sustained attention and executive functions. Posterior cortical atrophy relates to the breakdown of visual and dorsal attentional circuits, while the primary progressive aphasia variant of AD may be associated with the dysfunction of the left-lateralized language network. Additionally, network abnormalities might provide in vivo signatures for distinguishing proteinopathies that mimic AD, such as TAR DNA binding protein 43 related pathologies. These network differences vis-a-vis clinical syndromes are more evident in the earliest stage of AD. Finally, we discuss how these findings might pave the way for new tailored interventions targeting the most vulnerable brain circuit at the optimal time window to maximize clinical benefits

    Obstructive Sleep Apnea in Acromegaly and the Effect of Treatment: A Systematic Review and Meta-Analysis

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    Obstructive Sleep Apnea (OSA) is a common disorder characterized by upper airway collapse requiring nocturnal ventilatory assistance. Multiple studies have investigated the relationship between acromegaly and OSA reporting discordant results

    Cognitive profiles and clinical factors in type III spinal muscular atrophy: a preliminary study

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    Cognitive abilities are often affected in progressive neurodegenerative disorders, but there is a lack of understanding about whether spinal muscular atrophy (SMA) patients experience cognitive deficits and, if so, whether they are associated with clinical factors. A sample of 22 type III SMA patients and 22 healthy controls completed a comprehensive neuropsychological battery, including tests in memory, executive function, language, visuospatial, and global cognitive functioning. Clinical severity was assessed using the Hammersmith Functional Motor Scale, the Revised Upper Limb Module and the Six Minute Walk Test. SMA patients showed poorer performance in visuospatial abilities, executive functions and language as compared to healthy controls. In the SMA sample, patients with greater motor difficulties had lower performance in attention, but higher performance in measures of language, verbal fluency, and memory. In men, but not women, cognitive test performance was associated with motor functioning. Our findings showing cognitive changes in SMA type III may reflect the presence of intrinsic brain pathology and cognitive adaptation mechanisms following physical dysfunction, which may be mediated by other factors, such as sex

    Positive Aspects of Caregiving Are Associated With Lower Risk of Frailty and Sleep Disruption in the National Study of Caregiving

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    BACKGROUND AND OBJECTIVES: Older adult caregivers have compounded risk for adverse health outcomes; however, evidence investigating the association between caregiving and frailty has been limited. In the National Study of Caregiving (NSOC), we examined the cross-sectional association between caregiving experiences and frailty and sleep disruption. RESEARCH DESIGN AND METHODS: We included 621 caregivers aged 65 and older from the 2011 NSOC round. They completed a phone interview, including 36 items about caregiving. Using principal component analysis, we identified 3 caregiving components: general burden, positive emotions, and financial-led burden. Frailty was assessed via low energy, shrinking, weakness, reduced activity, and poor self-rated health. Sleep disruption was assessed with 2 questions regarding sleep interruption and trouble falling back asleep. RESULTS: In models adjusted for age, sex, education, depression and anxiety symptoms, and medical conditions, positive emotions were associated with a reduced relative risk of frailty (relative risk [RR] = 0.94, 95% confidence interval [CI] 0.90, 0.99) while general burden (proportional odds ratio [POR] = 1.96, 95% CI 1.30, 2.93) and financial-led burden (POR = 1.94, 95% CI 1.22, 3.06) were associated with sleep interruption. DISCUSSION AND IMPLICATIONS: Caregiver burden was associated with increased frailty and sleep interruption. Positive emotions were associated with decreased frailty risk. Interventions aimed at reducing the burden and increasing positive emotions in caregivers may improve frailty outcomes

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    Variations on the Author

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    “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

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    We 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
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