1,720,973 research outputs found
Endoscopic Third Ventriculostomy in Patients with Secondary Triventricular Hydrocephalus from a Haemorrhage or Ischaemia in the Posterior Cranial Fossa
No full textBackground: The aim of this project was to evaluate the efficacy of endoscopic third ventriculostomy (ETV) in the treatment of acute hydrocephalus caused by a haemorrhage or ischaemia in the posterior cranial fossa. Methods: 21 patients who had acute triventricular hydrocephalus resulting from ischaemia in 8 cases, and from cerebellar haemorrhage in 13 cases were treated with endoscopic third ventriculostomy. This series was compared with a control group of 30 patients, with clinical neuroradiological characteristics comparable to the preceding group (18 acute post-haemorrhage hydrocephalus and 12 post-ischaemia in the posterior cranial fossa), treated by external ventricular drainage (EVD). All patients were monitored clinically and by brain computed axial tomography (CT) to measure the dimensions of the lateral and third ventricles. The criteria used to define efficacy were based on the image of the postoperative cerebral CT scan. Results: No patient suffered haemorrhagic complications from surgical procedures or additional neurological deficits. There was no postoperative mortality or added morbidity. In all cases there was an improvement of intracranial hypertension. Clinical improvement was associated with a reduction of the ventricular dimensions documented by serial CT scans. Conclusions: We consider that, in selected cases, ETV can be suggested as the first choice treatment instead of the classic EVD. In the overall management of such patients, ETV has no or a very low rate of complications and allows shorter hospitalisation and earlier transfer to rehabilitative structures
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
Cognitive improvement after endoscopic third ventriculostomy surgery in long-standing overt ventriculomegaly in adults
No full textOBJECTIVE Long-standing overt ventriculomegaly in adults (LOVA) is a chronic form of hydrocephalus that can lead to cognitive deficits. Data on the cognitive profile of patients with LOVA and cognitive outcomes of endoscopic third ventriculostomy (ETV) are, however, scarce and mostly qualitative. METHODS Twenty-three consecutive patients with LOVA hydrocephalus underwent ETV surgery, and their cognitive status was assessed before surgery, immediately after surgery, and at the 5-month follow-up. Cognitive function was assessed using a neuropsychological battery measuring 6 cognitive domains: general cognitive status, attention/executive function, language, visuospatial skills, short-term memory, and long-term memory. Cognitive reserve was also estimated through a measure of premorbid IQ to assess its potential influence together with other clinical and demographic variables. RESULTS Patients with LOVA did not experience general cognitive decline but rather selective long-term memory (p 0.532). CONCLUSIONS These findings confirm the effectiveness of ETV surgery and highlight the role of cognitive reserve in promoting plasticity of brain and cognitive functions thus fostering and predicting cognitive recovery
Cubik system: maximizing possibilities of in-house computer-guided surgery for complex craniofacial reconstruction
No full textCraniofacial reconstruction represents a major challenge due to the complex anatomical morphology. Although implant production has often been outsourced to external companies, in-house planning and manufacturing has developed in many centres. This note introduces a conceptualized modular mould system to perform any desired craniofacial reconstruction, named ‘Cubik’, inspired by the famous Rubik's cube. A sophisticated virtual process is described that simulates realistic cranio-orbital resections, and the workflow to create multi-component moulds in order to achieve intraoperatively moulded implants is presented. The description focuses on the appropriate definition of interfaces between the subdivision surfaces of the planned implant, which is the key element to successful design and function of the moulds during surgery and is the peculiarity of the Cubik system. The use of Cubik does not prolong the overall duration of surgery, and it appears to be a very versatile tool, allowing personalized implants with different morphology to be created, which are suitable to cover every potential defect of the skull and the orbital region. This study extends the potential of in-house production, allowing highly accurate implantable craniofacial implants to be fabricated, and in the future this might represent a solution to achieve in-house replacement of other segments of the facial skeleton
Prospective analysis on possible changes of cognitive functions in children on follow-up for brain tumor
No full textPurpose: This study was aimed at evaluating cognitive functioning in children with brain tumors before and after surgery and at the end of all adjunctive treatments. Methods: All newly diagnosed children with primary brain tumor were prospectively assessed. Neurocognitive evaluations were performed before surgery (T0), within 7–10 days from surgery (T1) and 18–24 months after the end of all treatments (T2). Language, memory, attention, executive functions, visual-constructional, and sensorimotor skills were evaluated at T0, T1, and T2, whereas intelligent quotient (IQ) was explored at T0 and T2. Results: Twenty-five patients (M:F = 15:10, mean age 10.9 ± 3.4 years) were enrolled between January 2019 and December 2022. At baseline, patients showed major deficits in narrative memory (6.6 ± 3.7, p < 0.001) and visuo-spatial memory (copy design tasks: general 6.8 ± 3.9, p < 0.001; specific 6.2 ± 3.3, p < 0.001; and motor 5.2 ± 3.2, p < 0.001). In the post-surgery phase (T1), significant deficits remained in narrative memory (6.2 ± 3.3, p < 0.001) and visual-motor coordination (copy design tasks: specific 5.9 ± 3.0, p < 0.001; motor 4.8 ± 4.3 p < 0.001), while attention and visual-constructional abilities significantly improved (p = 0.04 and p = 0.001 respectively). Nine out of 25 patients (36%) reached the T2 evaluation: persistency of deficits in the area of visuo-spatial processing and a possible decline in median IQ values in comparison to T0 evaluation (93 vs 100, p = 0.05) were shown. Conclusions: Children with brain tumors may present several neuropsychological impairments since diagnosis. Surgery may have a positive impact in relation to the recovery of some cognitive functions. However, cognitive decline may worsen over time. Baseline and periodic neurocognitive evaluations should be encouraged to indicate targets for cognitive monitoring, to early detect functional difficulties
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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