1,720,969 research outputs found
Long-term beneficial impact of the randomised trial 'Train the Brain', a motor/cognitive intervention in mild cognitive impairment people: effects at the 14-month follow-up
Full text link: No treatment options are currently available to counteract cognitive deficits and/or delay progression towards dementia in older people with mild cognitive impairment (MCI). The 'Train the Brain' programme is a combined motor and cognitive intervention previously shown to markedly improve cognitive functions in MCI individuals compared to non-trained MCI controls, as assessed at the end of the 7-month intervention. Here, we extended the previous analyses to include the long-term effects of the intervention and performed a data disaggregation by gender, education and age of the enrolled participants. We report that the beneficial impact on cognitive functions was preserved at the 14-month follow-up, with greater effects in low-educated compared to high-educated individuals, and in women than in men
Verbal fluency patterns associated with the amnestic conversion from mild cognitive impairment to dementia
No full textAbstract Patients with amnestic mild cognitive impairment (aMCI) are at a higher risk of converting to Alzheimer's disease. The aim of this study was to examine the potential use of Verbal Fluency (VF) measures as markers for predicting the conversion to dementia. At baseline, 61 aMCI, aged 65 to 80 years, underwent a comprehensive neuropsychological assessment, including phonemic (PVF) and semantic verbal fluency (SVF) tasks. After 18 months, 14 individuals with aMCI had progressed to a diagnosis of dementia. The findings revealed that aMCI-converter group had lower Mini Mental State Examination and Rey Auditory Verbal Learning Task scores than aMCI-no converter and produced fewer clusters in both VF tasks and a lower number of switches in PVF at baseline (p < 0.05). According to receiver operating characteristic curve analysis, the number of clusters in PVF had the highest predictive value (AUC = 0.80) with a threshold of 5.510 for identifying aMCI-converter at baseline. Additionally, participants with higher levels of education exhibited more clusters and switches in VF tasks (p < 0.05). These results suggest that qualitative measures of VF could serve as neuropsychological markers for predicting cognitive decline in individuals with aMCI. Furthermore, the study highlights the potential influence of the education level on cognitive performance in neuropsychological tasks
Detecting cognitive impairment at the early stages: The challenge of first line assessment
No full textEnriched Environment (EE) effects on cognitive aging: system memory consolidation in aged EE mice and effects of physical and cognitive training in human subject with Mild Cognitive Impairment (MCI)
No full textBrain aging is a complex physiological process which includes an age related cognitive decline, particularly evident for long term declarative memory, working memory, attention and processing speed. There is a large literature of epidemiological studies in humans which suggests that lifestyle factors, such as physical activity, cognitive activity and social interactions, factors which are the main components of an “enriched environment”, can be protective against the development of pathological cognitive decline in elders and reduce the incidence of dementia. In parallel, studies in animals have shown that exposure to an Enriched Environment markedly improves memory performance in aged animals. This would suggest that interventions based on the “enriched environment” paradigm might benefit the cognitive status of elders. However, the literature reports no study investigating the effects of an intervention based on the combination of cognitive and physical training in aged humans already showing signs of cognitive impairment. In Pisa such a study is currently active and is the project “Train the Brain”, employing a combination of physical exercise, cognitive training and stimulation in a social setting to test whether such a non-pharmacological treatment is effective in decreasing the rate of cognitive impairment or even in obtaining a cognitive enhancement in subject with Mild Cognitive Impairment (MCI), considered subjects at risk for developing dementia.
During my PhD, within the project “Train the Brain”, I have analysed the effects of 7 months of a physical and cognitive training program in a social setting in subject with MCI using a neuropsychological battery to assess the effects of the intervention at the end of the 7 months and in subsequent follow-up tests.
In parallel I have addressed the possible mechanisms of action of an Enriched Environment on cognitive aging exploiting animal models.
The formation of long term declarative memories is a process mediated by the hippocampus and other medial temporal lobe structures and relies upon plasticity mechanisms in these structures, which allows a first, local, consolidation of the memory trace; however, it has been recently shown that for context-rich declarative memories, such as episodic memory, the successful recall of memory traces at some temporal
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distance from their formation requires the additional contribution of neocortical structures, which are progressively recruited for memory storage and recall in a process called memory system consolidation. A crucial mechanism underlying memory system consolidation consists in the functional and structural reorganisation of the pattern of cortical region activation prompted by the reactivation of hippocampal-cortical pathways and the strengthening of cortico-cortical connections, and with the fundamental involvement of cortical plasticity processes. While age related changes in hippocampal plasticity which might underlie age related changes in long-term declarative memory formation have been deeply investigated, no attempt has yet been done to investigate whether system consolidation is impaired by brain aging. Surprisingly, system consolidation has not even been considered as a possible target of the action of enriched environmental conditions in enhancing brain plasticity and improving memory performance in adult or aged animals.
I have first tested whether Enriched Environment (EE) could affect the system consolidation process in adult mice: in particular, I investigated whether EE could accelerate the time course of the activation of neocortical areas, possibly through a strengthening of the hippocampal-cortical and the cortico-cortical connections. To do so, I characterized the time course of hippocampal and cortical activation following spatial learning in a brain-wide manner following recalls delayed up to 50 days, using the expression of c-Fos protein as an indicator of neuronal activity in the different brain regions examined.
In a second experiment I studied whether EE could affect memory system consolidation in aged mice. To pinpoint the post-learning mechanisms underlying the hippocampal-cortical dialogue during the course of system-level memory consolidation, I trained aged mice, either left in standard cages or put for 40 days in EE, in the social transmission of food preference test (STFP), which involves an ethologically based form of associative olfactory memory. Mice have been tested for memory retrieval either 1 day (recent memory) or 30 days (remote memory) later and system consolidation investigated assessing the pattern of brain area activation and the state of histone acetylation in prefrontal cortical areas
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
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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