1,720,967 research outputs found
Monitoring cognitive changes: psychometric properties of six cognitive tests
No full textObjectives. Repeated neuropsychological assessments are often used to monitor change in cognitive functioning over time. Thus, knowledge about the reliability and stability of neuropsychological tests and the effects of age and IQ is of paramount importance. In this study we document, for six cognitive tests: test-retest reliabilities, practice effects, reliable change (RC) indices corrected for practice, and the impact of premorbid IQ and age.
Design. A sample of 188 normal adults (aged 40-70 years) were administered, on two occasions, one or more of the following tests: the Graded Naming Test (GNT), the Silhouettes Test, two tests of verbal fluency, the Modified Wisconsin Card Sorting Test, and a new test of speed and attention (the Symbol Digit Test). There was a I month interval between assessments. At first assessment, all participants were administered the revised National Adult Reading Test (NART).
Results. The test-retest reliability of the tests ranged from very good (the GNT and Silhouettes Test) to moderate (verbal fluency tests and Symbol Digit Test) and to poor (Modified Card Sorting Test). Significant, although modest, practice effects were found on all tests. RC indices were generally large except for the Graded Naming Test and the Silhouettes Test. Premorbid IQ scores significantly correlated with performance on all the tests, the exception being semantic fluency. Age only correlated with the Silhouettes Test and the new Symbol Digit Test. Neither NART IQ nor age correlated with practice effects.
Conclusion. The psychometric properties of the GNT and Silhouettes Test indicated that they are useful tools for monitoring even small cognitive changes. In contrast, the verbal fluency tests and the new Symbol Digit Test are only suitable for monitoring large changes in performance. The Modified Card Sorting Test is an unreliable tool for monitoring 'executive' functions
The impact of extensive medial frontal lobe damage on 'Theory of Mind' and cognition
No full textThe ability of humans to predict and explain other people's behaviour by attributing to them independent mental states, such as desires and beliefs, is considered to be due to our ability to construct a 'Theory of Mind'. Recently, several neuroimaging studies have implicated the medial frontal lobes as playing a critical role in a dedicated 'mentalizing' or 'Theory of Mind' network in human brains. Here, we report a patient, G.T., who suffered an exceptionally rare form of stroke-bilateral anterior cerebral artery infarction, without rupture or the complications associated with anterior communicating artery aneurysms. Detailed high-resolution neuroanatomical investigations revealed extensive damage to the medial frontal lobes bilaterally, including regions identified to be critical for 'Theory of Mind' by functional neuroimaging of healthy human subjects. For the first time in such a patient, we carried out a thorough assessment of her cognitive profile including, critically, an experimental investigation of her performance on a range of tests of 'Theory of Mind'. G.T. had a dysexecutive syndrome characterized by impairments in planning and memory, as well as a tendency to confabulate. Importantly, however, she did not have any significant impairment on tasks probing her ability to construct a 'Theory of Mind', demonstrating that the extensive medial frontal regions destroyed by her stroke are not necessary for this function. These findings have important implications for the functional anatomy of 'Theory of Mind', as well as our understanding of medial frontal function. Possible reasons for the discrepancies between our results and neuroimaging studies are discussed. We conclude that our findings urge caution against using functional imaging as the sole method of establishing cognitive neuroanatomy
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
The role of the thalamus in amnesia: a tractography, high-resolution MRI and neuropsychological study.
No full textAlthough it is well established that thalamic lesions may lead to profound amnesia, the precise contribution of thalamic sub-regions to memory remains unclear. In an influential article Aggleton and Brown proposed that recognition memory depends on two processes supported by distinct thalamic and cortical structures. Familiarity is mediated by the mediodorsal (MD) thalamic nucleus and the entorhinal/perirhinal cortex. Recollection is mediated by the anterior thalamic nucleus (AN), the mamillothalamic tract (MTT) and the hippocampus. The authors also suggested that the lateral dorsal nucleus (LD) may contribute to the thalamic/hippocampus system, thereby implying that the LD may play a role in recollection. Given the finding that material specific amnesia can occur following thalamic lesions, we tested an extension of the Aggleton and Brown model. We predicted that patients with bilateral lesions with a bias to the left or right MD or AN/MTT/LD may exhibit impaired familiarity or recollection on verbal or non-verbal memoranda. We report two patients with highly focal thalamic lesions and profound memory impairments affecting verbal and non-verbal memoranda. For the first time, diffusion-weighted imaging was employed to perform tractography of the MTT along with high-resolution anatomical MRI and detailed assessments of verbal and non-verbal memory. Our data support only some aspects of the Aggleton and Brown model. Both patients had left MD nucleus and AN/MTT lesions and performed poorly on familiarity and recall for verbal memoranda, just as predicted by the model. However, both patients' performance for non-verbal memoranda (human faces and topography) is more difficult to reconcile with the model. Patient 1 had damage to the right AN/MTT/LD with sparing of the MD: familiarity should therefore have been preserved but was not. Patient 2 had damage to the right MD with sparing of AN/MTT: recollection should have been preserved but was not. This finding raises the possibility that fractionation of familiarity and recollection to separate thalamic nuclei may not fully capture the role of thalamic sub-regions in memory function
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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