1,721,015 research outputs found
The influence of head growth in fetal life, infancy, and childhood on intelligence at the ages of 4 and 8 years
No full textOBJECTIVE: We investigated the effects of head growth prenatally, during infancy, and during later periods of development on cognitive function at the ages of 4 and 8 years. METHODS: We studied 633 term-born children from the Avon Longitudinal Study of Parents and Children cohort whose head circumference was measured at birth and at regular intervals thereafter. Their cognitive function was assessed with the Wechsler Preschool and Primary Scale of Intelligence at the age of 4 years and with the Wechsler Intelligence Scale for Children at the age of 8 years. Linear regression analysis was used to calculate postnatal head growth between successive time points, conditional on previous size, and to examine the relationship between head growth during different periods of development and later IQ. RESULTS: When the influence of head growth was distinguished for different periods, only prenatal growth and growth during infancy were associated with subsequent IQ. At 4 years, after adjustment for parental characteristics, full-scale IQ increased an average of 2.41 points for each 1-SD increase in head circumference at birth and 1.97 points for each 1-SD increase in head growth during infancy, conditional on head size at birth. At 8 years, head circumference at birth was no longer associated with IQ, but head growth during infancy remained a significant predictor, with full-scale IQ increasing an average of 1.56 points for each 1-SD increase in growth. CONCLUSION: The brain volume a child achieves by the age of 1 year helps determine later intelligence. Growth in brain volume after infancy may not compensate for poorer earlier growth
Critical periods of brain growth and cognitive function in children
No full textThere is evidence that IQ tends to be higher in those who were heavier at birth or who grew taller in childhood and adolescence. Although these findings imply that growth in both foetal and postnatal life influences cognitive performance, little is known about the relative importance of brain growth during different periods of development. We investigated the relationship between brain growth in different periods of pre- and postnatal life and cognitive function in 221 9-year-old children whose mothers had taken part in a study of nutrition in pregnancy and whose head circumference had been measured at 18 weeks gestation, birth and 9 months of age. Cognitive function of the children and their mothers was assessed with the Wechsler Abbreviated Scale of Intelligence. Full-scale IQ at age 9 years rose by 1.98 points [95% confidence interval (CI) 0.34 to 3.62] for each SD increase in head circumference at 9 months and by 2.87 points (95% CI 1.05 to 4.69) for each SD increase in head circumference at 9 years of age, after adjustment for sex, number of older siblings, maternal IQ, age, education, social class, duration of breastfeeding and history of low mood in the post-partum period. Postnatal head growth was significantly greater in children whose mothers were educated to degree level or of higher socio-economic status. There was no relation between IQ and measurements of head size at 18 weeks gestation or at birth. These results suggest that brain growth during infancy and early childhood is more important than growth during foetal life in determining cognitive function
Precision therapies for rare childhood neurogenetic movement disorders
No full textGenetic childhood movement disorders are a heterogeneous group of individually rare conditions that cause abnormal movements such as dystonia, chorea, myoclonus, tremor, and parkinsonism. Many also cause delayed development, epilepsy, and significant disability. Genetic aetiologies are broad, with most delineated conditions caused by variants in single genes with dominant or recessive inheritance. Commonly these may cause neurotransmitter defects or impact on neuronal development and excitability. Despite understanding the genetic, and often the biochemical, basis underlying these conditions, there are very few precision therapies or disease-modifying treatments available. Three such disorders considered in detail in this thesis are the neuronal ceroid lipofuscinosis CLN2-Batten disease, the neurotransmitter disorder aromatic L-amino acid decarboxylase deficiency (AADC deficiency), and pantothenate kinase-associated neurodegeneration (PKAN) which causes neurodegeneration with brain iron accumulation.
I describe work to understand several aspects of precision therapies in these rare disorders. First, I delineate the progression of movement disorders in a cohort of children with CLN2-Batten disease receiving enzyme replacement therapy, describing a stereotypic phenotypic progression despite targeted therapy. Next, I describe the adverse events, biomarker changes and neurodevelopmental outcomes in the UK cohort of children with AADC deficiency who have received brain-targeted gene therapy. Several chapters describe work to develop and implement a clinical trial for PKAN focussing on understanding and tracking disease progression in our cohort, assessing and validating clinical outcome measures, developing novel ophthalmological outcome measures, and finally statistical work underpinning the UK clinical trial.
This thesis describes clinical research at different stages to advance precision therapies of different modalities for three childhood neurogenetic movement disorders. It emphasises the importance of selecting and validating outcome measures, how to design clinical trials for a rare disorder, and that ongoing assessment following implementation is essential in these conditions
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
Planning interventional trials in childhood arterial ischaemic stroke using a Delphi consensus process
Get PDFAIM: There is a paucity of data from randomized controlled treatment trials in childhood arterial ischaemic stroke. Our objectives were to identify and plan a trial through use of a Delphi consensus process. METHOD: The Delphi panel consisted of Australian, New Zealand, and European paediatric neurologists with interests in childhood stroke. Four rounds were conducted using a REDCap (Research Electronic Data Capture) Web-based application: the first consisted of open-ended questions; the second evaluated agreement for the most important trial; the third and fourth reached consensus on design. RESULTS: Forty-seven out of 66 neurologists answered the first round. Eight areas of research for important and feasible trials were identified. In the second round, 43 paediatric neurologists ranked the three highest rated trials: (1) aspirin versus aspirin plus steroids in focal arteriopathy (n=31); (2) heparin versus aspirin (n=6); and (3) heparin versus aspirin versus modern anticoagulation (n=6). The third and fourth surveys reached consensus among 43 out of 44 respondents on design of the highest ranked trial, and allowed agreement on inclusion/exclusion criteria, clinical/neuroimaging data, and treatment protocols. CONCLUSION: The Delphi consensus process is an efficient method of identifying and planning paediatric stroke trials. An international, multicentre trial is now in preparation
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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