1,720,959 research outputs found
Visual neglect as a disconnection syndrome? A confirmatory case report
No full textVisual neglect has classically been associated with right hemisphere injury in parietal, frontal, or temporal cortex, in the basal ganglia or in the thalamus. More recently, visual neglect has been associated with injury extended into fronto-parietal white matter tracts. However, in most published cases white and gray matter injuries were associated. We present the anatomo-clinical study of a patient presenting with severe acute left visual neglect due to ischemic infarct limited to the right cerebral hemisphere white matter. Magnetic resonance diffusion tensor imaging tractography was instrumental to accurately localize the injury to the right arcuate fasciculus that is a component of the large-scale networks controlling visuo-spatial attention. These results add to a growing appreciation that neglect may result from disruption of a distributed attentional network. Paolo Bartolomeo and Alberto Bizzi as senior authors equally contributed to this work
Mental representation of normal subjects about sources of knowledge in different semantic categories and unique entities
No full textSFEMG: A piece in the diagnostic puzzle of myasthenia
No full textWe very much thank Haran (2014) for his comments on our paper. We completely agree that interpretation of the results coming from a diagnostic test must be done with great caution and that only a comprehensive evaluation of the clinical picture and instrumental results will lead to correct diagnosis and proper management of our patients. This is always true, especially in a treatable disease such as myasthenia.
Our view is clearly expressed in the very last sentence of the manuscript: “The results of SFEMG should not be interpreted in isolation from the clinical presentation and ancillary test results” (Padua et al., 2014); however, Haran’s reply gives us the opportunity to emphasize the concept even more, which is also the subject of a recent editorial (Caliandro et al., 2013). We know that myasthenia may be difficult to diagnose in individual cases and that we must use all available tools to reach the correct diagnosis (Caliandro et al., 2009), as Haran and coworkers did with their patient (Haran et al., 2013) who, although rare, is a paradigmatic myasthenic patient with antibodies to muscle-specific tyrosine kinase (MuSK-MG) (Evoli et al., 2003 and Evoli et al., 2012). In our work on the reliability of SFEMG in diagnosing myasthenia gravis, we concluded that patients with normal findings at SFEMG are unlikely to be affected by myasthenia gravis because the results from the sensitivity analysis underline that the positive likelihood ratio is always low in both evaluations and therefore, SFEMG has a small value as the confirmatory test for myasthenia gravis diagnosis. Meanwhile, the negative likelihood ratio, although with a wide range, has a low value in both analyses and, therefore, SFEMG has a moderate-to-large value as the test useful in identifying healthy subjects. All this means that normal findings at SFEMG are more meaningful than pathological findings, but of course, a normal SFEMG does not definitively exclude the diagnosis of myasthenia gravis
Reliability of SFEMG in diagnosing myasthenia gravis: Sensitivity and specificity calculated on 100 prospective cases.
No full textObjective
The study aimed to determine the utility of single-fibre electromyography (SFEMG) in the diagnosis of myasthenia gravis (MG) in subjects with a clinical suspicion of the disease.
Methods
We performed a prospective, single-blinded study on 100 consecutive patients. SFEMG was not considered a criterion in making the MG diagnosis. For all cases, a different physician than the one performing SFEMG made the diagnosis of MG. All subjects underwent standard SFEMG of a single muscle, the orbicularis oculi.
Results
SFEMG was abnormal in 67 of 100 patients. A final diagnosis of definite MG was made in 54 patients (30 men/24 women). SFEMG was positive in 53 of 54 patients diagnosed with MG. The sensitivity of SFEMG in diagnosing MG was 98% (95% CI: 0.94–1.02), while the specificity was 70% (95% CI: 0.54–0.86), with a positive predictive value of 79% (95% CI: 0.74–0.79) and a negative predictive value of 97% (95% CI: 0.94–0.99).
Conclusions
In this cohort of patients, normal SFEMG findings were unlikely to occur in patients with MG
Different views about the nature of gender-related asymmetries in task based on biological or artefact categories
Get PDFSex-related asymmetries in the ability to process different semantic categories have been reported both in normal subjects and in brain-damaged patients, but the nature of these asymmetries is still controversial. Some authors suggest that these differences might be due to social-role related familiarity factors, whereas others attribute them to inborn neural differences rooted in evolution. Drawing in part on this second line of thought, some authors have suggested that gender-related asymmetries might be due to differences in stimulus processing between men and women, namely, to the tendency of females to focus mainly on perceptual features and of males to focus equally on both perceptual and functional features. To test this hypothesis, we asked 53 male and 65 female undergraduate students to evaluate the relevance of a number of perceptual and functional features in the representation of various kinds of biological and artefact categories. Contrary to the hypothesis, evaluation of the weight of different sources of knowledge in representing living and artefact categories was similar in males and females
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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