1,720,959 research outputs found
Outcome measures and prognostic indicators in patients with amyotrophic lateral sclerosis
No full textLong-term survival in amyotrophic lateral sclerosis: a population-based study
No full textOBJECTIVE:
To determine the long-term survival in amyotrophic lateral sclerosis (ALS) and identify predictors of prolonged survival in a population-based cohort of newly diagnosed patients.
METHODS:
An incident cohort from a population-based registry during the years 1998 through 2002 in Lombardy, Italy was followed until death or to February 28, 2013. Age, sex, date of onset of symptoms, site of onset, date of diagnosis, and El Escorial diagnostic category were collected. Survival was assessed using Kaplan-Meier curves. Cox proportional hazards function was used to identify independent prognostic predictors. Standardized mortality ratios (SMRs) were used to assess the 5-year and 10-year excess mortality of ALS patients.
RESULTS:
Included were 280 men and 203 women aged 18 to 93 years. Spinal onset ALS was present in 312 cases (64.6%). Definite ALS was diagnosed in 213 cases (44.1%), probable ALS in 130 (26.9%), possible ALS in 93 (19.3%), and suspected ALS in 47 (9.7%). The cumulative time-dependent survival at 1, 5, and 10 years from diagnosis was 76.2%, 23.4%, and 11.8%, respectively. Independent predictors included younger age, the diagnosis of possible/suspected ALS, spinal onset, and symptoms having started >12 months previously at diagnosis. SMR was 9.4 at 5 years and 5.4 at 10 years. SMR at 10 years was higher until age 75 year, predominating in women, and became nonsignificant for males thereafter.
INTERPRETATION:
The outcome in ALS varies with phenotype. Longer survival is predicted by younger age, spinal onset, male gender, and suspected ALS. After age 75 years, 10-year survival in men with ALS is similar to the general population
Outcome measures and prognostic indicators in patients with amyotrophic lateral sclerosis
No full textThe purpose of the study was to assess frequency and predictors of disability measures in ALS. One hundred and fourteen newly diagnosed patients resident in eight administrative districts of Lombardy, Italy (population 4,947,554), included in a population-based registry, were followed for 2570 person-months (mean 22.5 months). The cumulative time-dependent risk of wheelchair, percutaneous endoscopic gastrostomy, and assisted ventilation was estimated according to the Kaplan-Meier method. Predictors of disability (age, sex, disease duration at diagnosis, type of onset, El-Escorial diagnosis) were assessed with the Cox proportional hazard function. During follow-up, 29 patients (25.4%) became wheelchair bound, 51 (44.7%) received gastrostomy, and 47 (41.2%) received assisted ventilation. The median time to loss of ambulation was 46.7 months (95% CI 36.5-56.8). The median time to gastrostomy and assisted ventilation was 31.1 months (95% CI 26.8-35.4) and 34.6 months (95% CI 29.6-39.6), respectively. Spinal onset ALS was the only predictor of loss of ambulation. Predictors of gastrostomy were older age, definite ALS, and shorter disease duration. Shorter disease duration was the only predictor of assisted ventilation. In conclusion, patients with ALS differ in terms of measures and predictors of disability. These factors are sources of bias and confounding in randomized clinical trials
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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