78 research outputs found
Conception d'une interface cerveau-ordinateur pour une meilleure surveillance des réveils peropératoires au cours d'une anesthésie générale
International audienceEach year, several million of general anesthesia are realized in France. A recent study shows that, between 0.1-0.2 % of patients are victims of intraoperative awareness. This kind of awakening could cause post-traumatic syndromes for the patient. Unfortunately, today, no monitoring system is able to avoid the intraoperative awareness phenomenon. Interestingly, if there are no subject's movement due to curare, an electroencephalographical study of the motor cortex can help to detect an intention of movement. The dynamic study of motor cerebral activity during general anesthesia is essential if we want to create a brain-computer interface adapted to the detection of intraoperative awareness. The goal of this thesis is first, to realize a feasibility study. To this end, a clinical protocol is built to allow EEG data recording during general anesthesia with propofol. Then, the development of temporal analysis specific methods allows to quantify patterns of desynchronization and synchronization phases observed in delta, alpha and beta frequency bands. This will result in the creation of this interface.Chaque annĂ©e en France, plusieurs millions dâanesthĂ©sies gĂ©nĂ©rales sont rĂ©alisĂ©es. Parmi celles-ci, on estime quâentre 0.1 et 0.2% des patients subissent un rĂ©veil peropĂ©ratoire. Actuellement, aucun dispositif de surveillance ne permet dâempĂȘcher ce type de rĂ©veil alors mĂȘme quâil peut entraĂźner de graves sĂ©quelles psychologiques chez les patients(en anglais, Post-Traumatic Stress Disorder, PTSD). Or, lâĂ©tude par Ă©lectroencĂ©phalographie (EEG) de l'activitĂ© cĂ©rĂ©brale au niveau des aires motrices peut rĂ©vĂ©ler une intention de mouvement du patient reflĂ©tant une reprise de conscience, et ce mĂȘme si aucun mouvement n'est perceptible visuellement par le personnel mĂ©dical. Une BCI exploitant ces intentions de mouvements fournirait un outil innovant aux personnels mĂ©dicaux et permettrait de limiter le nombre de PTSDs. Cependant, l'Ă©tude de la dynamique de l'activitĂ© cĂ©rĂ©brale motrice au cours de l'anesthĂ©sie gĂ©nĂ©rale reste nĂ©cessaire pour concevoir une interface cerveau-ordinateur adaptĂ©e Ă la dĂ©tection des rĂ©veils peropĂ©ratoires. Lâobjectif de cette thĂšse est donc de rĂ©aliser une Ă©tude de faisabilitĂ© visant la crĂ©ation dâune interface permettant de dĂ©tecter ce type de rĂ©veil. Pour cela, un protocole expĂ©rimental clinique est mis en place pour permettre l'acquisition de donnĂ©es EEG du cortex moteur pendant l'anesthĂ©sie gĂ©nĂ©rale sous propofol. Par la suite, le dĂ©veloppement de mĂ©thodes d'analyse temporelle spĂ©cifiques permettra de quantifier les caractĂ©ristiques des phases de dĂ©synchronisation et de synchronisation observĂ©es dans les bandes de frĂ©quences delta, alpha et bĂȘta et conduira Ă la crĂ©ation de lâinterface elle-mĂȘme
Etude de la dynamique des composantes cérébrales motrices au cours de l'anesthésie générale
National audienceCe rapport vise aÌ exposer le travail que jâai reÌaliseÌ de FeÌvrier aÌ AouÌt 2015 lors dâun stage sâinscrivant dans le cadre du parcours « Recherche » de la speÌcialiteÌ Â« Analyse Comportementale et IngeÌnierie de lâInteraction » du Master Science Cognitive et MeÌdias NumeÌriques de lâUniversiteÌ de Lorraine.Jâai inteÌgreÌ lâeÌquipe Neurosys dont les travaux portent sur lâexploration de la relation fonctionnelle entre les eÌleÌments du cerveau par des approches matheÌmatiques, biologiques et informatiques. LâeÌquipe posseÌde plusieurs axes de recherches. Elle eÌtudie aÌ la fois les eÌveÌnements se deÌroulant entre le niveau des neurones individuels et le niveau des populations de neurones, mais aussi le rapport de causaliteÌ entre le niveau des populations de neurones et le comportement humain. LâeÌquipe Neurosys sâinteÌresse de preÌs aux meÌcanismes neurophysiologiques sous-jacents aux actes moteurs, aÌ lâeÌtat de conscience et aÌ la meÌmoire. Depuis quelques anneÌes, lâeÌquipe souhaitait rassembler ses diffeÌrentes theÌmatiques au coeur dâun sujet dâeÌtude visant aÌ mieux comprendre de quelle manieÌre les substances chimiques utiliseÌes pendant lâanestheÌsie geÌneÌrale peuvent alteÌrer la conscience, le controÌle moteur et la meÌmoire.Mon travail a alors consisteÌ aÌ initialiser, mettre en place et reÌdiger un protocole clinique permettant dâeÌtudier lâactiviteÌ ceÌreÌbrale motrice au cours de lâanestheÌsie geÌneÌrale. Pour cela, jâai duÌ eÌtablir une collaboration avec le service dâAnestheÌsie-ReÌanimation du Centre Hospitalier Universitaire de Nancy-Brabois. De cet objectif principal deÌcoulait plusieurs objectifs secondaires dont jâai eÌgalement eu la charge : la veÌrification et la gestion adeÌquate du mateÌriel (eÌlectroenceÌphalographie, stimulateur du nerf meÌdian, logiciel dâacquisition OpenVibe) qui sera utiliseÌ lors de lâacquisition des donneÌes aÌ lâhoÌpital, la recherche dâun protocole clinique optimiseÌ et le reÌglage des deÌtails administratifs permettant lâacceptation du protocole par la direction de la recherche du CHRU. En reÌaliteÌ, ce stage est la continuiteÌ directe des diffeÌrents stages que jâai pu reÌaliser au cours des anneÌes preÌceÌdentes. En effet, jâai deÌjaÌ eu lâoccasion de travailler sur le theÌme du mouvement volontaire et des Interfaces Hommes Machines et lâeÌteÌ dernier, jâai reÌaliseÌ une eÌtude bibliographique visant aÌ comprendre les effets de lâanestheÌsie geÌneÌrale sur le cortex moteur.ApreÌs avoir expliqueÌ la probleÌmatique en lien avec mon sujet de stage, je preÌsenterai dans la partie Introduction les diffeÌrents eÌleÌments utiliseÌs pour reÌpondre aÌ cette probleÌmatique ; apreÌs quoi je deÌtaillerai le mateÌriel et les meÌthodes lieÌes aÌ lâenregistrement des donneÌes ceÌreÌbrales ainsi quâaÌ leur bonne analyse. Puis, je preÌsenterai des reÌsultats sur des sujets sains et volontaires exeÌcutant diffeÌrents types dâimaginations motrices, et ayant donneÌ lieu aÌ la soumission dâun article pour la confeÌrence System Man and Cybernetics. Par la suite, je preÌsenterai eÌgalement des reÌsultats plus intermeÌdiaires concernant la poursuite de ce travail. Enfin, dans la partie Discussion, nous verrons que les futures perspectives sur ce sujet sont nombreuses et novatrices
HUBUNGAN TINGKAT PENDIDIKAN KEPALA KELUARGA DENGAN TINGKAT KESIAPSIAGAAN BENCANA TSUNAMI DI DESA ALUE NAGA KECAMATAN SYIAH KUALA KOTA BANDA ACEH
ABSTRAKTsunami pada Desember 2004, yang dipicu oleh gempa berkekuatan 9.0 SR di sebelah utara pulau Sumatra mengakibatkan kerugian yang sangat besar. Aceh merupakan daerah paling parah dengan korban tewas sebanyak 123.000 jiwa, 113.000 orang hilang, 406.000 orang kehilangan tempat tinggal. Faktor utama timbulnya banyak korban akibat bencana gempa bumi adalah kurangnya pengetahuan masyarakat tentang bencana dan kesiapan mereka dalam mengantisipasi bencana. Sekolah merupakan salah satu media transformasi ilmu pengetahuan yang paling efektif dalam menyerap dan mengaplikasikan pengetahuan kesiapan menghadapi bencana dengan menggunakan metode yang tepat dan benar. Tujuan penelitian ini adalah untuk mengetahui apakah ada hubungan tingkat pendidikan formal dengan tingkat kesiapsiagaan dalam menghadapi bencana tsunami. Populasi penelitian ini 494 orang kepala keluarga dan terdapat jumlah sampel sebanyak 84 responden. Pengambilan sampel yang digunakan adalah non-probability sampling. Pengumpulan data menggunakan angket dengan wawancara terarah dan diolah dengan menggunakan statistik uji Kolmogorov Smirnov dengan hasil 55 responden (66%) memiliki kesiapsiagaaan rendah dan tingkat pendidikan yang paling banyak adalah pendidikan dasar berjumlah 67 responden (80%). Kesimpulan dalam penelitian ini adalah terdapat pengaruh tingkat pendidikan dengan tingkat kesiapsiagaan kepala keluaga di Desa Alue Naga kecamatan Syiah Kuala Kota Banda Aceh dengan nilai p=0,000 (pBanda Ace
Comparison Between Discrete and Continuous Motor Imageries: toward a Faster Detection
International audienceA large number of Brain-Computer Interfaces (BCIs) are based on the detection of changes in sensorimotor rhythms within the electroencephalographic signal [1]. Moreover, motor imagery (MI) modifies the neural activity within the primary sensorimotor areas of the cortex in a similar way to a real movement [2]. In most MI-based BCI experimental paradigms, subjects realize a continuous MI, i.e. one that lasts for a few seconds, with the objective of facilitating the detection of event-related desynchronization (ERD) and event-related synchronization (ERS) [3]. Currently, improving efficiency such as detecting faster a MI is a major issue in BCI to avoid fatigue and boredom. In this regards, a recent article showed that a brief intention of movement corresponding to a 2s-MI, leads to more informative ERS features than continuous motor imageries [4]. Thus, in this study, we are investigating differences between continuous MIs and discrete, i.e. simple short, MIs. Material, Methods and Results: 17 healthy subjects carried out real movements, discrete and continuous MIs, in the form of an isometric flexion movement of their right hand index finger. Each subject realized first a session of real movements, and then a discrete and a continuous sessions of motor imageries in a randomized order. Each session is divided into runs for a total number of 100 trials. Beeps were used as go and stop signals. Finally we computed ERD/ERS% for 9 electroencephalographic channels (FC3, C3, CP3, FCz, Fz, CPz, FC4, C4, CP4) using the " band power method " [3] (Fig. 1), topographic and time-frequency representations. Figure 1. Grand average (n = 17) ERD/ERS% curves estimated for the real movement (blue), the discrete motor imagery (red) and the continuous motor imagery (black) within the beta band (18-25 Hz) for electrode C3
ERD modulations during motor imageries relate to usersâ traits and BCI performances
International audienceImproving user performances is one of the major issues for Motor Imagery (MI)-based BCI control. MI-BCIs exploit the modulation of sensorimotor rhythms (SMR) over the motor and sensorimotor cortices to discriminate several mental states and enable user interaction. Such modulations are known as Event-Related Desynchronization (ERD) and Synchronization (ERS), coming from the mu (7-13 Hz) and beta (15-30 Hz) frequency bands. This kind of BCI opens up promising fields, particularly to control assistive technologies, for sport training or even for post-stroke motor rehabilitation. However, MI-BCIs remain barely used outside laboratories, notably due to their lack of robustness and usability (15 to 30% of users seem unable to gain control of an MI-BCI). One way to increase user performance would be to better understand the relationships between user traits and ERD/ERS modulations underlying BCI performance. Therefore, in this article we analyzed how cerebral motor patterns underlying MI tasks (i.e., ERDs and ERSs) are modulated depending (i) on nature of the task (i.e., right-hand MI and left-hand MI), (ii) the session during which the task was performed (i.e., calibration or user training) and (iii) on the characteristics of the user (e.g., age, gender, manual activity, personality traits) on a large MI-BCI data base of N=70 participants. One of the originality of this study is to combine the investigation of human factors related to the user's traits and the neurophysiological ERD modulations during the MI task. Our study revealed for the first time, associations between ERD and both age, level of study, impression management and anxiety
Relationship between ERD modulations, MI-based BCI performance and users' traits
International audienceImproving user performances is one of the major issues for Motor Imagery (MI)-based BCI control. MI-BCIs exploit the modulation of sensorimotor rhythms (SMR) over the motor and sensorimotor cortices to discriminate several mental states and enable user interaction. Such modulations are known as Event-Related Desynchronization (ERD) and Synchronization (ERS), coming from the mu (7-13 Hz) and beta (15-30 Hz) frequency bands. This kind of BCI opens up promising fields, particularly to control assistive technologies, for sport training or even for post-stroke motor rehabilitation. However, MI-BCIs remain barely used outside laboratories, notably due to their lack of robustness and usability (15 to 30% of users seem unable to gain control of an MI-BCI). One way to increase user performance would be to better understand the relationships between user traits and ERD/ERS modulations underlying BCI performance. Therefore, in this study we analyzed how cerebral motor patterns underlying MI tasks (i.e., ERDs) are modulated depending (i) on nature of the task (i.e., right-hand MI and left-hand MI), (ii) the session during which the task was performed (i.e., calibration or user training) and (iii) on the characteristics of the user (e.g., age, gender, manual activity, personality traits) on a large MI-BCI data set (N=70 participants). Our results confirmed a stronger ERD contralateraly, while we still observed a bilateral ERD overall. We also observed stronger ERD during calibration (with sham feedback) than during online training (with real-time feedback and instructions to explore promising MI strategies). Finally, and more importantly, our study revealed for the first time, associations between ERD and both age, level of study, impression management and anxiety. This may suggest that such factors should be taken into account when designing MI-BCI based on ERD or when selecting an ERD-based BCI for a given user
Towards a new passive Brain-computer interface to detect accidental awareness during general anesthesia
International audienc
Learning How to Generate Kinesthetic Motor Imagery Using a BCI-based Learning Environment: a Comparative Study Based on Guided or Trial-and-Error Approaches
This paper received the 1st Place in the IEEE Brain BMI Workshop Best Student Paper AwardInternational audienceKinesthetic Motor Imagery (KMI) is a mental task which, if performed properly, can be very relevant in sports training or rehabilitation with a Brain-Computer Interface (BCI). Unfortunately, this mental task is generally complex to perform and can lead to a high degree of variability in its execution, reducing its potential benefits. The reason why the task of KMI is so difficult to perform is because there is no standardized way of instructing the subject in this mental task. This study presents an innovative BCI called Grasp-IT thought to support the learning of the KMI task, and the evaluation of two different learning methods: (i) a first one guided by an experimenter and based on the notion of progressiveness and (ii) a second one where the learners are alone and practice by trial and error. Our findings based on EEG analyses and subjective questionnaires validate the design of the Grasp-IT BCI and opens up perspectives on KMI learning modalities
Interfaces cerveau-ordinateur pour la reeducation post-AVC : apport d'un environnement de stimulation affordant.
Ce rapport fait Ă©tat de mon travail rĂ©alisĂ© au cours de mon projet recherche au sein de lâĂ©quipe Neurosys au Laboratoire Lorrain de Recherche en Informatique et ses Applications (LORIA), Ă Nancy. Les accidents vasculaires cĂ©rĂ©braux (AVC) constituent un problĂšme social grandissant. Dans ce contexte, aux vues des mĂ©thodes de rĂ©Ă©ducation actuelles ainsi que des avancĂ©es technologiques, de nouvelles mĂ©thodes pour aider les personnes qui ont subi un AVC sont possibles. Grasp'it est un protocole de rĂ©Ă©ducation des personnes qui ont Ă©tĂ© victimes d'AVC par EEG (Ă©lectroencĂ©phalogrammes) et se sert notamment d'une interface virtuelle 3D sous Unreal Engine pour le feedback. Dans ce document est dĂ©taillĂ©e l'Ă©volution de l'interface utilisĂ©e par Grasp'it, les fonctionnalitĂ©s rajoutĂ©es, le changement de l'indice visuel et les rĂ©flexions pour les Ă©volutions futurs avec l'aide des Serious Games, afin de concevoir le protocole le plus performant et le plus agrĂ©able possible
Discrete motor imageries can be used to allow a faster detection
International audienceMotor imagery (MI) modifies the neural activity within the primary sensorimotor areas of the cortex and can be measured through the analysis of elec-troencephalographic (EEG) recordings. It is particularly interesting for Brain-Computer Interface (BCI) applications. In most MI-based BCI experimental paradigms, subjects realize continuous motor imagery (CMI), i.e. a repetitive and prolonged intention of movement, for a few seconds. The system detects the movement based on the event-related desynchronization and the event-related synchronization features in electroencephalographic signal. Currently, improving efficiency such as detecting faster a motor imagery is an important issue in BCI to avoid fatigue and boredom. The purpose of this study is to show the difference, in term of classification, between a discrete motor imagery, i.e. a single short MI, and a CMI. The results of experiments involving 16 healthy subjects show that a BCI based on DMI is as effective as a BCI based on CMI and could be used to allow a faster detection
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