Effect of a Dual Task on Postural Control in Dyslexic Children

Several studies have examined postural control in dyslexic children; however, their results were inconclusive. This study investigated the effect of a dual task on postural stability in dyslexic children. Eighteen dyslexic children (mean age 10.3±1.2 years) were compared with eighteen non-dyslexic children of similar age. Postural stability was recorded with a platform (TechnoConcept®) while the child, in separate sessions, made reflex horizontal and vertical saccades of 10° of amplitude, and read a text silently. We measured the surface and the mean speed of the center of pressure (CoP). Reading performance was assessed by counting the number of words read during postural measures. Both groups of children were more stable while performing saccades than while reading a text. Furthermore, dyslexic children were significantly more unstable than non-dyslexic children, especially during the reading task. Finally, the number of words read by dyslexic children was significantly lower than that of non-dyslexic children and, in contrast to the non-dyslexic children. In line with the U-shaped non-linear interaction model, we suggest that the attention consumed by the reading task could be responsible for the loss of postural control in both groups of children. The postural instability observed in dyslexic children supports the hypothesis that such children have a lack of integration of multiple sensorimotor inputs

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Saccadic eye movements in young children : developmental approach to oculomotor control and saccadic adaptation

Pour percevoir le monde qui nous entoure, nous effectuons des mouvements rapides des yeux afin de placer les objets d'intérêt en fovéa, région de l'oeil où l'acuité visuelle est maximale. Ces mouvements oculaires, appelés saccades, sont précis malgré leur rapidité d'exécution. Le mécanisme assurant leur précision tout au long de la vie est l'adaptation saccadique. L'adaptation saccadique peut être facilement induite en laboratoire grâce au paradigme non invasif de double saut de la cible (McLaughlin, 1967) qui simule une « imprécision » de la visée d'une cible en déplaçant celle-ci pendant la saccade de manière répétée. Le système saccadique corrige progressivement l'erreur de visée induite artificiellement, la saccade amenant directement l'oeil vers la nouvelle position de la cible après seulement une cinquantaine d'essais. A ce jour, si les paramètres saccadiques (latence, amplitude, durée, vitesse moyenne et pic de vitesse) sont très bien documentés chez l'adulte, ils restent peu décrits chez le très jeune enfant. De plus, aucune étude n'a examiné la plasticité du système saccadique chez les enfants de moins de huit ans. Le but de ce travail de thèse est double. Il vise d'une part à caractériser les paramètres saccadiques chez le très jeune enfant. Pour ce faire, les mouvements oculaires d'un groupe de 115 bébés âgés de 7 à 42 mois ont été enregistrés pendant 140 essais (Etude 2). Nous avons mis au point un protocole expérimental original adapté à l'âge de ces jeunes participants que nous avons préalablement validé chez des adultes (Etude 1). D'autre part, nous avons étudié si la plasticité du système oculomoteur des bébés de cet âge possède les mêmes caractéristiques que celle des adultes en induisant, grâce au paradigme de double saut de la cible, une adaptation en diminution d'amplitude (Etude 3) et une adaptation en augmentation d'amplitude de la saccade (Etude 4). Les résultats reposant sur plus d'une centaine de saccades consécutives par participant montrent que les bébés sont capables de sélectionner un stimulus visuel comme cible et d'effectuer une saccade oculaire vers celle-ci. Le système oculomoteur est cependant immature à cet âge puisque les saccades des bébés ont des latences plus longues et sont plus hypométriques, i.e. moins précises que celles des adultes. Cependant, les performances saccadique des bébés s'améliorent avec l'âge pour la latence et, contre toute attente, au fur et à mesure des essais pour la précision de leur visée. Par ailleurs, les modifications adaptatives en réponse au saut intra-saccadique de la cible sont présentes chez un plus grand nombre d'adultes que d'enfants en diminution d'amplitude et inversement en augmentation d'amplitude. Cependant, l'efficacité de l'adaptation saccadique est similaire chez les deux groupes de participants. Nos études contribuent à la compréhension du développement du contrôle oculomoteur : le déclenchement de la saccade devient plus rapide (latence) avec l'âge mais la forte hypométrie de la saccade reste la même entre 7 et 42 mois. De façon inattendue, la précision saccadique s'améliore au cours de la session expérimentale suggérant une capacité d'apprentissage à court terme (Etude 2). Dans les Etudes 3 et 4, la plasticité du système oculomoteur est révélée pour la première fois chez des enfants d'âge préscolaire, signant des mécanismes adaptatifs fonctionnels chez le jeune enfant qui ne leur permettent cependant pas d'obtenir la précision saccadique des adultes.To perceive the world around us, we perform rapid eye movements to bring objects of interest into the fovea, the eye region where visual acuity is optimal. These eye movements, called saccades, are accurate despite their high velocity. The mechanism that ensures accuracy throughout life is called saccadic adaptation. Saccadic adaptation can be easily induced in the laboratory by using the noninvasive double-step target paradigm (McLaughlin, 1967) that simulates targeting errors of the saccade by displacing repeatedly the target during the saccade. The saccadic system progressively reduces the error induced artificially so that after only fifty trials, the eyes rech the new position of the target. Today, if saccadic parameters (latency, amplitude, duration, average velocity and peak velocity) are well documented in adults, they remain poorly described in the very young children. Moreover, no study has examined the plasticity of the saccadic system in children aged under eight years-old. The goal of this thesis is twofold. On the one hand, it aims at characterizing saccadic parameters in very young children. To do this, the eye movements of a group of 115 babies aged 7-42 months-old were recorded during 140 trials (Study 2). We developed an original experimental protocol adapted to the age of these young participants, which first validated in adults (Study 1). One the other hand, we investigated whether the plasticity of the babies' oculomotor system has the same characteristics as adults' by inducing an adaptive shortening of saccade amplitude (backward adaptation; Study 3) and an adaptive lengthening of saccade amplitude (forward adaptation; Study 4). The results based on more than a hundred consecutive saccades per participant show that babies are able to select a stimulus as a visual target and generate a saccade toward it. However, the oculomotor system is immature at this age because babies' saccades have longer latencies and are more hypometric, i.e. less accurate than saccades in adults. Nevertheless, saccade latency improves with age in the child group. Unexpectedly, saccade accuracy improves over trials. Furthermore, adaptive changes in response to the intra-saccadic target step are present in a larger number of adults than children for backward adaptation and conversely for forward adaptation. However, the efficiency of saccadic adaptation is similar in the two groups of participants. Our studies allow to better understanding the development of oculomotor control: saccades are initiated faster with age but the high saccade hypometria remains the same between the age of 7 and 42 months. Unexpectedly, saccade accuracy improves over the course of the experimental session suggesting a short-term learning ability (Study 2). In Studies 3 and 4, the plasticity of the oculomotor system is revealed for the first time in preschool children. These results suggest that adaptive mechanisms are functional in young children. This ability however does not allow them to be as accurate as adults

La valorisation du babeurre passe par les lipides polaires.

Les lipides laitiers présents dans le babeurre : un atout nutritionnel valorisableLe babeurre est un co-produit de l’industrie beurrière encore mal valorisé bien qu’il soit riche en certains lipides laitiers fonctionnels particuliers pouvant présenter des bénéfices nutritionnels. Le projet VALOBAB propose de développer des procédés dans une approche durable pour concentrer ces lipides à partir du babeurre et les étudier notamment concernant leurs propriétés nutritionnelles.Valorisation du babeurre au travers de ses lipidesLa nutrition joue un rôle majeur dans la prévention des maladies métaboliques et cardiovasculaires. De plus, les consommateurs ont, plus que jamais, la volonté de consommer de «bons aliments» associant plaisir et santé. Dans ce contexte, les lipides polaires sont des micro-constituants alimentaires importants largement utilisés dans l’industrie, notamment pour leur contribution à la texture plaisante des aliments. Les lécithines de soja et d’oeuf sont les principales sources commerciales de phospholipides alors que les lipides polaires du lait ne sont que rarement utilisés. Ces derniers sont présents dans le lait sous forme de membrane des globules gras et contiennent des phospholipides mais aussi d’autres lipides polaires bioactifs, les sphingolipides, qui pourraient présenter un intérêt dans le cadre de la prévention des maladies métaboliques. Le babeurre est la source majeure de lipides polaires d’origine laitière.Le projet VALOBAB a pour objectifs de mettre au point un procédé durable et éco-conçu pour concentrer les lipides polaires laitiers, d'évaluer leur fonctionnalité dans les aliments et de mettre en évidence leur intérêt nutritionnel chez l’homme dans une perspective de valorisation du babeurre pour des applications nutritionnelles.Une approche multidisciplinaire dans l’optique d’une valorisation largeLe projet repose sur les 3 piliers du développement durable (environnement, société et économie), il associe pour atteindre ses objectifs différentes disciplines scientifiques : génie des procédés appliqués à l’industrie laitière, sciences des aliments et physico-chimie, analyse sensorielle, métabolisme et nutrition, microbiologie

A Rolling-Horizon Approach for a Surgery Case Scheduling Problem with Sterilizing Constraints

International audienceIn this paper, we study a real scheduling problem which consists in scheduling a set of elective surgical cases that arrive over the time taking into account the uncertainties on their duration, and the delay to sterilize surgical instruments. The objectives are to schedule as many surgeries as possible, and to minimize the overtime of the surgical block staff and the number of instruments processed in emergency in the sterilizing unit. This research was performed in collaboration with the University Hospital of Angers in France, which has also provided historical data for the experiments. We propose a rolling horizon approach based on the iterative resolution of a robust mixed integer linear programming model, in which the objective functions are taken into account in a lexicographic order. The experiments on real data show a reduction of more than 50% of overtime, and around 87% less stress situations in the sterilizing unit

A robust LP-based approach for a dynamic surgical case scheduling problem with sterilisation constraints

International audienceThe purpose of this article is to investigate a practical scheduling problem in which a group of elective surgical cases are scheduled over time, while considering their unpredictable durations and potential delays in the sterilisation of surgical instruments. The primary objectives were to schedule the maximum number of surgeries and decrease overtime for the surgical staff, as well as limit the number of instruments requiring emergency sterilisation. The study was conducted in collaboration with the University Hospital of Angers in France, which also contributed historical data for the experiments. We propose two robust mixed integer linear programming models, which are then solved iteratively through a rolling horizon approach, in which the objective functions are taken into account in lexicographic order. Experiments on randomly generated instances indicated which of the two approaches had better performance. Comparison of the results for a real-world scenario involving actual planning at the hospital indicated a greater than 69% decrease in overtime, and a minimum of 92% fewer stressful situations in the sterilising unit

Surgical Case Scheduling with sterilizing activity constraints

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Robust Surgical Case Scheduling problem with sterilizing activities constraints: a relax and fix approach

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A MILP formulation for an operating room scheduling problem under sterilizing activities constraints

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