1,721,059 research outputs found
Can we share data? - Kinematic consistency during walking in three different treadmill-based laboratories
No full textBACKGROUND: Three-dimensional gait analysis is crucial for diagnosis and treatment planning. Treadmill-based laboratories efficiently collect 3D gait data over many consecutive steps. Pooling/sharing data across treadmill-based laboratories could enhance clinical utility. However, the inter-laboratory consistency of gait kinematics from treadmill-based systems is unknown. RESEARCH QUESTION: How consistent are lower-limb kinematics of healthy subjects measured in three different treadmill-based gait laboratories? METHODS: Eighteen volunteers (14 women; 27 ± 9 years; BMI 24 ± 3 kg/m ) walked in three treadmill-based laboratories (Motek Medical, The Netherlands) within one week. Per laboratory, participants completed 3-minute walking trials (0.9, 1.1, 1.3 m/s) wearing a non-weight-bearing harness and identical clothes and shoes. The same marker-set (Human-Body Model 2) and virtual reality configurations were used. Statistical Parametric Mapping was used to compare time-normalized kinematic curves of the lower-limb, averaged over 40 steps, between laboratories. Root mean square differences (RMSD) calculated over periods of the gait cycle with statistically significant differences were considered clinically meaningful when > 5°. RESULTS AND SIGNIFICANCE: Kinematics curves from all laboratories followed similar patterns. Only 17 % of all curves displayed clinically relevant differences. These differences included more knee flexion in laboratory 2 compared to the others (RMSD 6.0-8.6°) and less hip flexion in laboratory 3 compared to laboratory 2 (all speeds) and to laboratory 1 (1.3 m/s; RMSD 5.4-6.4°). Reported differences are likely due to varying operator protocols rather than to the measurement system. The findings indicate that inter-laboratory data sharing using such infrastructure is possible but training to align protocols is essential
Checks and balances : a meta-analysis on the known-groups validity of functional postural control tests in children
No full textINTRODUCTION: Pediatric physical therapists commonly treat children with postural control deficits. Ideally, pediatric functional postural control tests should therefore be able to identify postural control deficits in children with various disorders. Despite a plethora of available tests, evidence for their validity - especially known-groups - remains scarce. This review aims to determine the known-group validity of available functional postural control tests to differentiate various pediatric pathological groups of different ages from their typically developing (TD) peers.
EVIDENCE ACQUISITION: PubMed, Web of Science and Scopus were systematically searched (last update: February 2023; PROSPERO: CRD42023408982). Forty case-control studies with a pathological pediatric sample (N.=1331) and TD peers (N.=1889) were included and selected for data-extraction and -analysis. Risk of bias was assessed using the SIGN checklist and level of evidence was scored using GRADE. Random-effect meta-analyses were performed to estimate pooled standardized mean differences (SMD) for the various test types and subclassified based on pathology and/or age.
EVIDENCE SYNTHESIS: When compared with TD peers, children with underlying pathologies performed significantly worse on pediatric functional postural control test batteries (SMD=-2.21), the Timed Up and Go Test and variants (SMD=2.30), the One Leg Stance test and variants (SMD=-2.14), while the Reach tests showed a smaller difference (SMD=-1.19). Subclassification within the meta-analyses showed that pathology was an influencing factor for the test batteries and the one leg stance test and variants. Age was an influencing factor for the reach tests. None of the included functional postural control tests exceeded a low level of evidence.
CONCLUSIONS: Pediatric functional postural control tests that assess multiple aspects of postural control (such as test batteries) seem to offer higher known-groups validity than single-task tests (e.g. reach tests). The underlying pathology has a larger impact on the validity of these tests than age. There remains an overall low level of evidence for the known-groups validity of pediatric functional postural control tests indicating the need for research with more homogenous groups and norm reference data
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
Onderzoek naar de aard van spasticiteit bij kinderen met cerebrale parese gebaseerd op biomechanische en electrofysiologische metingen
No full textSpasticity occurs in 85% of children diagnosed with cerebral palsy (CP). It is defined as a motor disorder that is characterized by velocity-dependent hyper-sensitivity of stretch reflexes. When a muscle with spasticity is stretched, this hypersensitivity causes a pathological increase in muscle activity and a subsequent disruption of fluent motion. Spasticity can cause pain, lead to secondary muscle and bone deformities and limits normal mobility and everyday functionality. To effectively treat spasticity, it is of utmost importance that its assessment is carried out accurately and provides quantitative data.In standard clinical practice, the severity of the patients spasticity is assessed by grading thelevel of resistance felt when stretching a passive muscle. An alternative approach involves the measurement of the joint angle at which the movement is disrupted during a quick passive stretch. Both assessments relyon the subjective interpretation of the clinician who performs the tests. Furthermore, the reliability of these methods is compromised, since the velocity at which the muscle is being stretched is uncontrolled. Also, it is always possible that an increase in resistance during a passive stretch is not caused by spasticity, but by non-neural mechanical muscle properties, such as stiffness. As such, these clinical scales and approaches have been deemed invalid and unreliable for the assessment of spasticity.Many attempts have been made to find an alternative, more objective form of spasticity assessment. However, due to its complex pathophysiology, spasticity has proved to be difficult to isolate. Thus far, its assessment is only feasible in research settings with methods that are difficult to apply in clinical environments, and this difficultyespecially applies to pediatric populations. Consequently, the scope ofthis PhD was to create a reliable, valid and clinically applicable method for spasticity assessment in children with CP, which could also be used to explore the nature of spasticity in these children.The first part of the PhD project reviewed the existing literature on spasticity assessment (Chapter 1). The results of this review showed that, despite the abundance of research carried out on the topic, not one method was proven to be sufficiently sound for the assessment of multiple muscles in children with CP. Additionally, there is no consensus regarding theassessment protocol or the types of parameters that can quantify spasticity. Nevertheless, the identified literature created a framework upon which to construct a new method.The second part of the PhD project focused on the development of the instrumented spasticity assessment(ISA) (Chapter 2, 3). ISA simultaneously collects electrophysiological and biomechanical signals during passive muscle stretches at different velocities. It has been designed to assess spasticity in four lower limb muscles, but the method can easily be extended to other muscles. The parameters obtained from integrated signal processing provide an objective,quantitative measure of spasticity. The studies outlined in Chapters 2 and 3 of this PhD set out to test the applicability of these parameters for spasticity assessment in children with CP. The study results showed that the developed parameters were: (A) reliable; (B) able to distinguish between non-involved muscles and muscles with spasticity; (C) sensitive to treatment with Botulinum Toxin A (BTX); (D) usable to predict the effect of treatment with BTX; and (E) sensitive enough to differentiate between different BTX injection techniques.These findings went far beyond the initial expectations of the research. They not only confirmed ISAs suitability for the assessment of spasticity in clinical environments, but also established ISA as a method to fine-tune existing forms of treatment and to improve management protocols. The findings from this part of the research are far-reaching, since they create a firm platform from which to explore many other possible avenues that can benefit clinical practice.In the third part of the PhD project, we used ISA to unveil the heterogeneity of spasticity in children with CP (Chapter 4). In order to do so, the results we obtained by testing ISA on a large number of children were used to classify muscles into sub-groups according to their activation pattern and stretch-reflex thresholds. Preliminary results show that different muscles tend to cluster into one or the othersub-group. Nevertheless, the actual etiology that underlies this classification remains unexplored. In a next step, the research focused on analyzing the influence of spasticity versus the influence of non-neural mechanical muscle properties on the resistance that occurs during passive muscle stretch. In a final part, the relation between ISA parameters andmarkers of spasticity during gait was explored. Even though this research uncovered several interesting moderate to good relations between ISA and gait, the results confirmed that other influences besides spasticitymight also be important in defining how children with CP walk.Inconclusion, this doctoral thesis has made a fundamental contribution tothe everyday clinical management of spasticity by providing a means to quantitatively describe this complex phenomenon. This step is central tofurther improving the way spasticity is treated and lays the groundworkfor many future investigations that will undoubtedly contribute to the better care of children with CP.status: Publishe
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
Developmental coordination disorder in infancy and early childhood : an uncharted phase of life
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