2 research outputs found
Une approche logicielle du traitement de la dyslexie : Ă©tude de modĂšles et applications
Neuropsychological disorders are widespread and generate real public health problems. In particular in our modern society, where written communication is ubiquitous, dyslexia can be extremely disabling. Nevertheless we can note that the diagnosis and remediation of this pathology are fastidious and lack of standardization. Unfortunately it seems inherent to the clinical characterization of dyslexia by exclusion, to the multitude of different practitioners involved in such treatment and to the lack of objectivity of some existing methods. In this respect, we decided to investigate the possibilities offered by modern computing to overcome these barriers. Indeed we have assumed that the democratization of computer systems and their computing power could make of them a perfect tool to alleviate the difficulties encountered in the treatment of dyslexia. This research has led us to study the techniques software as well as hardware, which can conduct to the development of an inexpensive and scalable system able to attend a beneficial and progressive changing of practices in this pathology field. With this project we put ourselves definitely in an innovative stream serving quality of care and aid provided to people with disabilities. Our work has been identifying different improvement areas that the use of computers enables. Then each of these areas could then be the subject of extensive research, modeling and prototype developments. We also considered the methodology for designing this kind of system as a whole. In particular our thoughts and these accomplishments have allowed us to define a software framework suitable for implementing a software platform that we called the PAMMA. This platform should theoretically have access to all the tools required for the flexible and efficient development of medical applications integrating business processes. In this way it is expected that this system allows the development of applications for caring dyslexic patients thus leading to a faster and more accurate diagnosis and a more appropriate and effective remediation. Of our innovation efforts emerge encouraging perspectives. However such initiatives can only be achieved within multidisciplinary collaborations with many functional, technical and financial means. Creating such a consortium seems to be the next required step to get a funding necessary for realizing a first functional prototype of the PAMMA, as well as its first applications. Some clinical studies may be conducted to prove undoubtedly the effectiveness of such an approach for treating dyslexia and eventually other neuropsychological disorders.Les troubles neuropsychologiques sont trĂšs rĂ©pandus et posent de rĂ©els problĂšmes de santĂ© publique. En particulier, dans notre sociĂ©tĂ© moderne oĂč la communication Ă©crite est omniprĂ©sente, la dyslexie peut sâavĂ©rer excessivement handicapante. On remarque nĂ©anmoins que le diagnostic et la remĂ©diation de cette pathologie restent dĂ©licats et manquent dâuniformisation. Ceci semble malheureusement inhĂ©rent Ă la caractĂ©risation clinique par exclusion de la dyslexie, Ă la multitude de praticiens diffĂ©rents impliquĂ©s dans une telle prise en charge ainsi quâau manque dâobjectivitĂ© de certaines mĂ©thodes existantes. A ce titre, nous avons dĂ©cidĂ© dâinvestiguer les possibilitĂ©s offertes par lâinformatique actuelle pour surmonter ces barriĂšres. Effectivement, nous avons supposĂ© que la dĂ©mocratisation des systĂšmes informatiques et leur puissance de calcul pourraient en faire un outil de choix pour pallier les difficultĂ©s rencontrĂ©es lors de la prise en charge de la dyslexie. Cette recherche nous a ainsi menĂ© Ă Ă©tudier les techniques, aussi bien logicielles que matĂ©rielles, pouvant conduire au dĂ©veloppement dâun systĂšme bon marchĂ© et Ă©volutif qui serait capable dâassister un changement bĂ©nĂ©fique et progressif des pratiques qui entourent cette pathologie. Avec ce projet, nous nous plaçons dĂ©finitivement dans un courant innovant au service de la qualitĂ© des soins et des aides apportĂ©es aux personnes souffrant dâun handicap. Notre travail a ainsi consistĂ© Ă identifier diffĂ©rents axes dâamĂ©lioration que lâutilisation de lâoutil informatique rend possible. Chacun de ces axes a alors pu faire lâobjet de recherches exhaustives, de modĂ©lisations et de dĂ©veloppements de prototypes. Nous avons Ă©galement rĂ©flĂ©chi Ă la mĂ©thodologie Ă mettre en Ćuvre pour concevoir un tel systĂšme dans sa globalitĂ©. En particulier, nos rĂ©flexions et ces diffĂ©rents accomplissements nous ont permis de dĂ©finir un framework logiciel propice Ă lâimplĂ©mentation dâune plate-forme logicielle que nous avons appelĂ©e la PAMMA. Cette plate-forme devrait thĂ©oriquement pouvoir disposer de tous les outils permettant le dĂ©veloppement souple et efficace dâapplications mĂ©dicales intĂ©grant des processus mĂ©tiers. Il est ainsi attendu de ce systĂšme quâil permette le dĂ©veloppement dâapplications, pour la prise en charges des patients dyslexiques, conduisant Ă un diagnostic plus rapide et plus prĂ©cis ainsi quâĂ une remĂ©diation plus adaptĂ©e et plus efficace. De notre effort dâinnovation ressortent des perspectives encourageantes. Cependant, ce type dâinitiative ne peut se concrĂ©tiser quâautour de collaborations pluridisciplinaires disposant de nombreux moyens fonctionnels, techniques et financiers. La constitution dâun tel consortium semble donc ĂȘtre la prochaine Ă©tape nĂ©cessaire Ă lâobtention des financements pour rĂ©aliser un premier prototype fonctionnel de la PAMMA, ainsi que de premiĂšres applications. Des Ă©tudes cliniques pourront ĂȘtre alors menĂ©es pour prouver indubitablement lâefficacitĂ© dâune telle approche dans le cadre de la prise en charge de la dyslexie, ainsi quâĂ©ventuellement dâautres troubles neuropsychologiques
Ătude de corrĂ©lats Ă©lectrophysiologiques pour la discrimination d'Ă©tats de fatigue et de charge mentale : apports pour les interfaces cerveau-machine passives
Mental state estimation on the basis of cerebral activity and its resulting physiological activities has become a challenge for passive Brain-Computer Interfaces (BCI), in particular to address a need in neuroergonomics. This thesis work focuses on mental fatigue and workload estimation. Its purpose is to provide efficient and realistic processing chains. Thus, one issue was the modulation of workload markers as well as classification performance robustness depending on time-on-task (TOT). The impact of workload and TOT on attentional state markers was also assessed. For those purposes, an experimental protocol was implemented to collect the electroencephalographic (EEG), cardiac (ECG) and ocular (EOG) signals from healthy volunteers as they performed for a prolonged period of time a task that mixes working memory load and selective attention. Efficient signal processing chains that include spatial filtering and classification steps were designed in order to better estimate these mental states. The relevance of several electrophysiological markers was compared, among which spontaneous EEG activity and event-related potentials (ERPs), as well as various preprocessing steps such as spatial filtering methods for ERPs. Interaction effects between mental states were brought to light. In particular, TOT negatively impacted mental workload estimation when using power features. However, the chain based on ERPs was robust to this effect. A comparison of the type of stimuli that can be used to elicit the ERPs revealed that task-independent probes still allow very high performance, which shows their relevance for real-life implementation. Lastly, ongoing work that aims at assessing task-robust workload markers, as well as the usefulness of auditory ERPs in a single-stimulus paradigm will be presented as prospects.L'estimation de l'Ă©tat mental d'un individu sur la base de son activitĂ© cĂ©rĂ©brale et de ses activitĂ©s physiologiques rĂ©sultantes est devenue l'un des challenges des interfaces cerveau-machine (ICM) dites passives, dans le but notamment de rĂ©pondre Ă un besoin en neuroergonomie. Ce travail de thĂšse se focalise sur l'estimation des Ă©tats de fatigue et de charge mentale. Son objectif est de proposer des chaines de traitement efficaces et rĂ©alistes dans leur mise en Ćuvre. Ainsi, un des points Ă l'Ă©tude a Ă©tĂ© la modulation des indicateurs de charge ainsi que la robustesse des performances de classification en fonction du temps passĂ© sur une tĂąche (TPT). L'impact de la charge et du TPT sur les marqueurs d'Ă©tat attentionnel a aussi Ă©tĂ© Ă©valuĂ©. Pour ce faire, un protocole expĂ©rimental a Ă©tĂ© mis en Ćuvre afin de recueillir les signaux Ă©lectro-encĂ©phalographiques (EEG), cardiaques (ECG) et oculaires (EOG) de participants volontaires sains lors de la rĂ©alisation prolongĂ©e d'une tĂąche combinant charge en mĂ©moire de travail et attention sĂ©lective. Des chaĂźnes de traitement performantes incluant une Ă©tape de filtrage spatial et une classification supervisĂ©e ont Ă©tĂ© mises en place afin de classer au mieux ces Ă©tats. La pertinence de plusieurs marqueurs Ă©lectrophysiologiques a Ă©tĂ© comparĂ©e, notamment l'activitĂ© EEG spontanĂ©e et les potentiels Ă©voquĂ©s (PEs), ainsi que diffĂ©rentes Ă©tapes de prĂ©traitement dont les mĂ©thodes de filtrage spatial pour PEs. Des effets d'interactions ont Ă©tĂ© mis au jour entre les diffĂ©rents Ă©tats mentaux, dont un effet nĂ©gatif du TPT sur les performances en classification de la charge mentale lorsque l'on utilise des marqueurs mesurant la puissance moyenne de l'EEG dans des bandes de frĂ©quence d'intĂ©rĂȘt. La chaĂźne basĂ©e sur les PEs est en revanche robuste Ă cet effet. Une comparaison du type de stimuli utilisables pour Ă©liciter les PEs a rĂ©vĂ©lĂ© que des stimuli tĂąche-indĂ©pendants permettent tout de mĂȘme d'obtenir des performances trĂšs Ă©levĂ©es, ce qui montre leur pertinence pour une implĂ©mentation en situation rĂ©elle. En perspective seront prĂ©sentĂ©s des travaux en cours visant Ă mettre en Ă©vidence des marqueurs de charge mentale robustes Ă la tĂąche, ainsi que l'utilitĂ© des potentiels Ă©voquĂ©s auditifs en paradigme de simple stimulus