Identifying potentially flawed items in the context of small sample IRT analysis

Although Classical Test Theory has been used by the measurement community for almost a century, Item Response Theory has become commonplace for educational assessment development, evaluation and refinement in recent decades. Its potential for improving test items as well as eliminating the ambiguous or misleading ones is substantial. However, in order to estimate its parameters and produce reliable results, IRT requires a large sample size of examinees, thus limiting its use to large-scale testing programs. Nevertheless, the accuracy of parameter estimates becomes of lesser importance when trying to detect items whose parameters exceed a threshold value. Under this consideration, the present study investigates the application of IRT-based assessment evaluation to small sample sizes through a series of simulations. Additionally, it introduces a set of quality indices, which exhibit the success rate of identifying potentially flawed items in a way that test developers without a significant statistical background can easily comprehend and utilize

Τραυματισμός νωτιαίου μυελού και νευρογένεση - Συστηματική ανασκόπηση

Εισαγωγή: Ο τραυματισμός του Νωτιαίου Μυελού είναι μία από τις πιο συχνές παθήσεις του ανεπτυγμένου κόσμου με καταστροφικές συνέπειες και πολύ συχνά κακή πρόγνωση. Μέχρι σήμερα οι θεραπευτικές παρεμβάσεις έχουν καταφέρει να μειώσουν αισθητά το ποσοστό θνητότητας μετά από τραυματισμό του νωτιαίου μυελού χωρίς όμως αντίστοιχη αύξηση της κλινικής βελτίωσης και συνεπώς ποιότητας ζωής. Η βασική έρευνα στρέφεται ολοένα και περισσότερο σε θεραπευτικές παρεμβάσεις με πρωταρχικό στόχο την νευρογένεση. Σκοπός: Ο σκοπός της παρούσης μελέτης είναι η δημιουργία μίας συστηματικής ανασκόπησης της υπάρχουσας βιβλιογραφίας που μελετάει την ύπαρξη και το βαθμό νευρογένεσης στο επίπεδο νωτιαίου μυελού που προκαλούν οι διάφορες πειραματικές θεραπευτικές παρεμβάσεις μετά από τραυματισμό. Υλικά και Μέθοδοι: Πραγματοποιήθηκε συστηματικπή ανασκόπηση της ηλεκτρονικής βάσης δεδομένων της US National Library of Medicine - National Institutes of Health, PubMed/MEDLINE και έγινε αναζήτηση με τις εξής λέξεις κλειδιά: “spinal cord injury AND neurogenesis” στις 01 Σεπτεμβρίου 2019. Δεν εφαρμόστηκαν περιορισμοί στο έτος δημοσίευσης, το είδος ή φύλο πειραματοζώου. Συγκεκριμένα κριτήρια επιλογής και αποκλεισμού κατά PRISMA, εφαρμόστηκαν από δύο ανεξάρτητους ερευνητές για την επιλογή των τελικών άρθρων. Στα τελικά άρθρα πραγματοποιήθηκε περιγραφική στατιστική ανάλυση. Αποτελέσματα: Από την ανάλυση των 73 μελετών, προκύπτει ότι το πιο χρησιμοποιούμενο πειραματόζωο είναι ο επίμυς (61,64%). Προτίμηση υπάρχει και στο φύλο του πειραματοζώου με ξεκάθαρη υπεροχή των θηλυκών πειραματοζώων έναντι των αρσενικών (64,38% vs 23,28% αντίστοιχα). Από την στατιστική ανάλυση των νευρικών δεικτών ανοσοϊστοχημείας προκύπτει ότι ο πιο συχνά χρησιμοποιούμενος δείκτης για την μέτρηση της νευρογένεσης είναι οι Τuj-1 (beta III tubulin) και NeuN και ακολουθούνται από τους Neurofilament-H και Nestin. Το μεγαλύτερο ποσοστό εμφάνισης παρουσιάζουν δείκτες ειδικοί για ώριμους νευρώνες και άωρους νευρώνες (38,66% και 20,88% αντίστοιχα). Παρόμοια ανάλυση έγινε και για τους δείκτες κυτταρικού πολλαπλασιασμού με το μεγαλύτερο ποσοστό με διαφορά να κατέχει το BrdU (66,66%). Τέλος, ως πιο συχνή συνέκφραση επιλέγεται αυτή με BrdU και NeuN (19,64%), ενώ ακολουθείται από την BrdU+Nestin και BrdU+Tuj-1 με ποσοστό 10,71% αμφότερες. Συμπέρασμα: Στην παρούσα συστηματική ανασκόπηση πεδίου (scoping systematic review) παρατηρείται μία σαφής επιλογή είδος πειραματοζώου (επίμυς) και φύλου (θήλυ) που διακιολογείται λόγω κόστους και μεγέθους καθώς και της πιθανής αντοχής των θυληκών πειραματοζώων στην ανάπτυξη ουρολοίμωξης. Οι επιλογής νευρικών δεικτών της σειράς του ώριμου νευρώνα και η συνέκφραση αυτών με δείκτες κυτταρικού πολλαπλασιασμού επιλέγεται για την αύξηση της ειδικότητας του αποτελέσματος. Το επόμενο βήμα είναι η δημιουργία ερωτήματος PICO για την σύγκριση του νευρογενετικού αποτελέσματος αναλόγως των θεραπειών μέσω συστηματικής ανασκόπησης και ποσοτικής ανάλυσης του μεγέθους μέσω μετα-ανάλυσης, που θα δηλωθεί επισήμως σε παγκόσμιο φορέα (PROSPERO).Introduction: Spinal cord injury is one of the most common diseases in the developed world with catastrophic consequences and bad prognosis. To date, therapeutic interventions have been able to significantly reduce mortality rates after spinal cord injury, whereas there is a lack of increase in clinical improvement and therefore quality of life. In basic research there is an ever-increasing focus on therapeutic interventions aimed primarily at neurogenesis. Aim: The aim of the present study is to establish a systematic review of the existing literature to investigate the presence and degree of neurogenesis at the level of the spinal cord, caused by various experimental therapeutic interventions after injury. Materials and Methods: A systematic review of the US National Library of Medicine - National Institutes of Health, PubMed / MEDLINE database was conducted with the following keywords: “spinal cord injury AND neurogenesis” on September 1, 2019. No limits were applied to publication year, the type or sex of laboratory animals. Specific PRISMA selection and exclusion criteria were applied by two independent researchers to select the final articles. Descriptive statistical analysis was performed in the final articles. Results: The analysis of 73 studies showed that the most used experimental animal is the rat (61.64%). There is also preference in the sex with a clear predominance of female animals over male (64.38% vs 23.28% respectively). Statistical analysis of the neuroimmunohistochemistry markers shows that the most commonly used for measuring neurogenesis are Tuj-1 (beta III tubulin) and NeuN, followed by Neurofilament-H and Nestin. The neuronal markers with the highest incidence are those expressed in mature and immature neurons (38.66% and 20.88% respectively). A similar analysis was performed for cell proliferation markers, with the predominance of BrdU (66.66%). Finally, the most common co-expression is BrdU and NeuN (19.64%), followed by BrdU + Nestin and BrdU + Tuj-1 with 10.71% both. Conclusion: In the present scoping systematic review there is a clear preference in the type of animal (rat) and sex (female) selected for spinal cord injury, most likely due to cost and size as well as the possible resistance of female animals to the development of urinary tract infections. The selection of neural markers of the mature neuron series and their co-expression with cell proliferation markers is chosen to increase the specificity of the neurogenetic outcome. Further studies comparing the neurogenetic effect with each treatment, via systematic review and meta-analysis, are needed

Analytical Creeping Wave Model and Measurements for 60 GHz Body Area Networks

International audienceThe propagation of 60 GHz electromagnetic waves around a human body is studied analytically and experimentally. The body is treated here as a circular lossy cylinder, which is an approximation of the human torso. Analytical formulations based on creeping wave theory are given and discussed for both vertical and horizontal polarizations. An exact path gain expression is derived from analytical formulations and a simpler first order approximation is given. Path gain coefficients are shown for frequencies spanning the world available 60 GHz unlicensed band and for several sizes of the torso. Finally, the results of an experimental campaign conducted in an anechoic chamber to isolate the contribution of on-body propagation are reported. The measurement of the distance dependence of the received power on a brass cylinder and on a human body for both vertical and horizontal polarizations confirmed theoretical predictions

Extending LMS to Support IRT-Based Assessment Test Calibration

Developing unambiguous and challenging assessment material for measuring educational attainment is a time-consuming, labor-intensive process. As a result Computer Aided Assessment (CAA) tools are becoming widely adopted in academic environments in an effort to improve the assessment quality and deliver reliable results of examinee performance. This paper introduces a methodological and architectural framework which embeds a CAA tool in a Learning Management System (LMS) so as to assist test developers in refining items to constitute assessment tests. An Item Response Theory (IRT) based analysis is applied to a dynamic assessment profile provided by the LMS. Test developers define a set of validity rules for the statistical indices given by the IRT analysis. By applying those rules, the LMS can detect items with various discrepancies which are then flagged for review of their content. Repeatedly executing the aforementioned procedure can improve the overall efficiency of the testing process

Therapeutic Management: When and What

Migraine is a widespread brain disease that is classified as the second most disabling condition and has the third highest prevalence of all medical conditions. Despite its non-emergent or life-threatening nature, migraine can progress to chronic type, a subform associated with significant morbidity and drug overuse. In the management of migraine, it is important therefore to introduce early prophylactic treatment in order to limit migraine chronification. In this chapter, we will go through all the treatment options, both acute and preventive, pharmaceutical and non-pharmaceutical following this flowchart: 1. Introduction; 2. General principles; 2.1 Symptomatic therapy; 2.2 Prophylactic management; 3. Pharmaceutical therapies; 3.1 Symptomatic; 3.1.1 Disease-specific; 3.1.2 No disease-specific; 3.2 Prophylactic; 3.2.1 Disease-specific; 3.2.2 No disease-specific; 3.3 Non-Pharmaceutical therapies; 3.4 Neuromodulation; 3.4.1 Invasive; 3.4.5 Non-invasive; 3.5 Nutrient (nutraceuticals); 3.6 Dietary interventions; 3.7 Acupuncture; 3.8 Physical therapy; 4. Cognitive behavioral therapies; 5. Patient centricity and patient education

Millington Effect and Propagation Enhancement in 60-GHz Body Area Networks

International audienceMillington effect for on-body propagation enhancement is presented in the 60-GHz band. Millington’s equations are developed to describe propagation above a flat inhomogeneous surface. This study focuses on mixed paths (human skin - metallic) for on-body scenarios. It is shown that adding metallic paths on the human skin can improve the power link budget between two nodes placed on the body. Two different schemes are studied experimentally to assess the analytical model using a flat phantom with electric properties of human skin and different lengths of metallic inserts. The first scheme considers a metallic plate between the transmitting and receiving antennas, while the second scheme proposes locating the metallic plates under the antennas. It is shown that the second scheme yields a better link budget than the first one for the same length of metal. Moreover, a numerical study is performed to assess the impact of the following different parameters: the location of the metal plate, size of the plate and the height of the antennas. Excellent agreement between numerical and experimental results has been shown. In the best cases, the presented techniques allow to improve the path loss of 10 to 20 dB

Post-COVID-19 Parkinsonism and Parkinson's Disease Pathogenesis: The Exosomal Cargo Hypothesis

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease after Alzheimer's disease, globally. Dopaminergic neuron degeneration in substantia nigra pars compacta and aggregation of misfolded alpha-synuclein are the PD hallmarks, accompanied by motor and non-motor symptoms. Several viruses have been linked to the appearance of a post-infection parkinsonian phenotype. Coronavirus disease 2019 (COVID-19), caused by emerging severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, has evolved from a novel pneumonia to a multifaceted syndrome with multiple clinical manifestations, among which neurological sequalae appear insidious and potentially long-lasting. Exosomes are extracellular nanovesicles bearing a complex cargo of active biomolecules and playing crucial roles in intercellular communication under pathophysiological conditions. Exosomes constitute a reliable route for misfolded protein transmission, contributing to PD pathogenesis and diagnosis. Herein, we summarize recent evidence suggesting that SARS-CoV-2 infection shares numerous clinical manifestations and inflammatory and molecular pathways with PD. We carry on hypothesizing that these similarities may be reflected in exosomal cargo modulated by the virus in correlation with disease severity. Travelling from the periphery to the brain, SARS-CoV-2-related exosomal cargo contains SARS-CoV-2 RNA, viral proteins, inflammatory mediators, and modified host proteins that could operate as promoters of neurodegenerative and neuroinflammatory cascades, potentially leading to a future parkinsonism and PD development

CGRP and migraine from a cardiovascular point of view: what do we expect from blocking CGRP?

Calcitonin gene-related peptide (CGRP) is a neuropeptide with a pivotal role in the pathophysiology of migraine. Blockade of CGRP is a new therapeutic target for patients with migraine. CGRP and its receptors are distributed not only in the central and peripheral nervous system but also in the cardiovascular system, both in blood vessels and in the heart. We reviewed the current evidence on the role of CGRP in the cardiovascular system in order to understand the possible short- and long-term effect of CGRP blockade with monoclonal antibodies in migraineurs. In physiological conditions, CGRP has important vasodilating effects and is thought to protect organs from ischemia. Despite the aforementioned cardiovascular implication, preventive treatment with CGRP antibodies has shown no relevant cardiovascular side effects. Results from long-term trials and from real life are now needed