D. Guiraud - Academia.edu (original) (raw)

Papers by D. Guiraud

2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

Pathological gait assessment and assistive control based on functional electrical stimulation (FE... more Pathological gait assessment and assistive control based on functional electrical stimulation (FES) in post-stroke individuals, brings out a common need to robustly quantify kinematics facing multiple constraints. This study proposes a novel approach using inertial sensors to compute dorsiflexion angles and spatio-temporal parameters, in order to be later used as inputs for online close-loop control of FES. 26 post-stroke subjects were asked to walk on a pressure mat equipped with inertial measurement units (IMU) and passive reflective markers. A total of 930 strides were individually analyzed and results between IMU-based algorithms and reference systems compared. Mean absolute (MA) errors of dorsiflexion angles were found to be less than 4°, while stride lengths were robustly segmented and estimated with a MA error less than 10 cm. These results open new doors to rehabilitation using adaptive FES closed-loop control strategies in "foot drop" syndrome correction.

Direct stimulation of peripheral nerves can successfully provide sensory feedback to amputees whi... more Direct stimulation of peripheral nerves can successfully provide sensory feedback to amputees while using hand prostheses. Recent clinical studies have addressed this important limitation of current prostheses solutions using different implantable electrode concepts. Longevity of the electrodes is key to success. We have improved the long-term stability of the polyimide-based transverse intrafascicular multichannel electrode (TIME) that showed promising performance in clinical trials by integration of silicon carbide adhesion layers. The TIMEs were implanted in the median and ulnar nerves of three trans-radial amputees for up to six months. Here, we present the characterization of the electrical properties of the thin-film metallization as well as material status post explantationem for the first time. The TIMEs showed reliable performance in terms of eliciting sensation and stayed within the electrochemical safe limits maintaining a good working range with respect to amplitude modu...

Journal of Neurosurgery: Spine, 2019

OBJECTIVESpinal cord injuries (SCIs) result in loss of movement and sensory feedback, but also or... more OBJECTIVESpinal cord injuries (SCIs) result in loss of movement and sensory feedback, but also organ dysfunction. Nearly all patients with complete SCI lose bladder control and are prone to kidney failure if intermittent catheterization is not performed. Electrical stimulation of sacral spinal roots was initially considered to be a promising approach for restoring continence and micturition control, but many patients are discouraged by the need for surgical deafferentation as it could lead to a loss of sensory functions and reflexes. Nevertheless, recent research findings highlight the renewed interest in spinal cord stimulation (SCS). It is thought that synergic recruitment of spinal fibers could be achieved by stimulating the spinal neural networks involved in regulating physiological processes. Paradoxically, most of these recent studies focused on locomotor issues, while few addressed visceral dysfunction. This could at least partially be attributed to the lack of methodological...

Sensors, 2019

Individuals who sustained a spinal cord injury often lose important motor skills, and cannot perf... more Individuals who sustained a spinal cord injury often lose important motor skills, and cannot perform basic daily living activities. Several assistive technologies, including robotic assistance and functional electrical stimulation, have been developed to restore lost functions. However, designing reliable interfaces to control assistive devices for individuals with C4–C8 complete tetraplegia remains challenging. Although with limited grasping ability, they can often control upper arm movements via residual muscle contraction. In this article, we explore the feasibility of drawing upon these residual functions to pilot two devices, a robotic hand and an electrical stimulator. We studied two modalities, supra-lesional electromyography (EMG), and upper arm inertial sensors (IMU). We interpreted the muscle activity or arm movements of subjects with tetraplegia attempting to control the opening/closing of a robotic hand, and the extension/flexion of their own contralateral hand muscles a...

IEEE transactions on neural systems and rehabilitation engineering : a publication of the IEEE Engineering in Medicine and Biology Society, Jan 14, 2016

This article introduces a new human-machine interface for individuals with tetraplegia. We invest... more This article introduces a new human-machine interface for individuals with tetraplegia. We investigated the feasibility of piloting an assistive device by processing supra-lesional muscle responses online. The ability to voluntarily contract a set of selected muscles was assessed in five spinal cord-injured subjects through electromyographic (EMG) analysis. Two subjects were also asked to use the EMG interface to control palmar and lateral grasping of a robot hand. The use of different muscles and control modalities was also assessed. These preliminary results open the way to new interface solutions for high-level spinal cord-injured patients.

2010 3rd IEEE RAS & EMBS International Conference on Biomedical Robotics and Biomechatronics, 2010

A model-based Functional Electrical Stimulation (FES) would be very helpful for the adaptive move... more A model-based Functional Electrical Stimulation (FES) would be very helpful for the adaptive movement synthesis of spinal-cord-injured patients. The nonlinearity of the neuromuscular system can be captured through modeling and identification process. However, there are still critical limitations in FES: rapid muscle fatigue and time-varying property. In actual FES, in order to minimize the fatigue, the intermittent stimulation is adopted. In this case, fatigue and recovery occur in sequence. Thus, the time-varying muscle response is really difficult to be predicted for FES force control. In this paper, we propose an identification method to identify unknown internal states and the maximal force parameter which are inside the nonlinear differential equation. Among the internal parameters of muscle model, maximal force Fm should be mainly changed corresponding to the current muscle condition. Muscle fatigue or recovery itself is difficult to be modeled and predicted, however observing the input-output information from the muscle, the adaptive estimation will be achieved to correspond to the varying muscle response effected by a fatigue or unknown metabolic factor of human system. This identification method itself can be expected to be applied for general use in rehabilitation robotics.

Medical & biological engineering & computing, 2015

We investigated the synthesis of electrical stimulation patterns for functional movement restorat... more We investigated the synthesis of electrical stimulation patterns for functional movement restoration in human paralyzed limbs. We considered the knee joint system, co-activated by the stimulated quadriceps and hamstring muscles. This synthesis is based on optimized functional electrical stimulation (FES) patterns to minimize muscular energy consumption and movement efficiency criteria. This two-part work includes a multi-scale physiological muscle model, based on Huxley's formulation. In the simulation, three synthesis strategies were investigated and compared in terms of muscular energy consumption and co-contraction levels. In the experimental validation, the synthesized FES patterns were carried out on the quadriceps-knee joint system of four complete spinal cord injured subjects. Surface stimulation was applied to all subjects, except for one FES-implanted subject who received neural stimulation. In each experimental validation, the model was adapted to the subject through a...

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2009

The knowledge and prediction of the behavior of electrically activated muscles are important requ... more The knowledge and prediction of the behavior of electrically activated muscles are important requisites for the movement restoration by FES in spinal cord injured subjects. The whole parameter's identification of a physiological musculoskeletal model for FES is investigated in this work. The model represents the knee and its associated quadriceps muscle. The identification protocol is noninvasive and based on the in-vivo experiments on paraplegic subjects. The isometric and nonisometric data was obtained by stimulating the quadriceps muscles of 3 paraplegic subjects through surface electrodes. A cross validation has been carried out using nonisometric data set. The normalized RMS errors between the identified model and the measured knee response are presented for each subject.

lirmm.fr

... However, this method is intended for persons having functional ability but activity difficult... more ... However, this method is intended for persons having functional ability but activity difficulties, and are not suitable for paraplegic persons. ... posture is given by the q vector, which can be obtained by solving (6). If the measured quantities y and anthropometric parameters Lj were ...

Rehabilitation Robotics, 2007

Le monde professionnel des malvoyants et nonvoyants est tres longtemps reste limite a cause du ma... more Le monde professionnel des malvoyants et nonvoyants est tres longtemps reste limite a cause du manque d'outils approprie, mais aussi a cause du manque de formation technique accessible a cette categorie de personnes. Les developpements rapides des reseaux informatiques, et les progres importants du materiel rendent possible et profitable pour les personnes handicapees visuelles, l'ouverture de notre section. Cet article tente de montrer quel travail necessite cette adaptation dans les matieres les plus sensibles.

Un travail de recherche, en particulier pluri-disciplinaire, est par essence un travail d'équipe,... more Un travail de recherche, en particulier pluri-disciplinaire, est par essence un travail d'équipe, équipe sans laquelle bien peu de résultats que je présente auraient vu le jour. J'ajoute qu'au delà d'une vraie collaboration professionnelle, une véritable amitié et confiance réciproque se manifestent entre nous. Un sincère merci donc à mes compagnons de route du moment et présents dès le début de DEMAR, Bernard, Christine, David, Guy, Jean-Louis, Jérôme, Philippe et Philippe, Serge, puis Martine et Nacim, sans oublier l'aide précieuse de Catherine puis Annie en tant qu'assistantes. La recherche ne serait pas non plus possible sans tous nos étudiants en thèse et bien sûr ceux que j'ai eu le plaisir d'encadrer, Hassan et ses gâteaux libanais, Jean Denis et son humour déconcertant, Samer et sa gentillesse extrême, Gaël et son dévouement, Quant à Guillaume, Jérémy, Mourad et Mitsuhiro, ils ont déjà proposé un travail rigoureux préfigurant de bons travaux à venir, et le tout dans une ambiance vraiment très conviviale. Enfin, Maria et Amine sont les deux derniers étudiants que je vais co-encadrer, et je souhaite que notre travail en commun soit aussi riche qu'avec leurs prédécesseurs. Il y a enfin des personnes qui se trouvent au bon moment au bon endroit, et lorsque je regarde l'itinéraire qui est le mien, rien n'était vraiment prévisible et quelques personnes ont largement infléchi un parcours professionnel pas vraiment standard. Pierre Rabischong a eu l'audace d'un pari scientifique fou en proposant en trois ans de développer une neuroprothèse unique au monde, et j'ai saisi la chance de pouvoir y participer alors que je n'étais plus chercheur mais enseignant. Bernard Espiau a su me proposer, au moment où ces recherches allaient disparaître, un cadre scientifique qui a été le point de départ d'une toute nouvelle aventure. Guy Charvin, fidèle ami, a toujours répondu présent aussi bien sur des aspects professionnels que lors de questionnements plus humains. Michel Bénichou, Charles Fattal et Marc Possover, tous trois médecins dans des spécialités complémentaires, répondent toujours à mes sollicitations, et sans leur confiance, leur expertise et leur soutien, je ne pourrai tout simplement pas mener mes recherches. Tout s'est joué parfois à quelques jours près, mais finalement c'est un peu comme ça que je conçois ma carrière : se rendre utile à l'autre, ne pas s'ennuyer, et saisir quelques opportunités au vol ! Enfin, à l'IUT de Béziers 1 , au LIRMM 2 et à l'INRIA Sophia Antipolis-Méditerranée, leurs directeurs et chefs de départements successifs ont été des soutiens sans faille non seulement à mes projets personnels, mais aussi à l'équipe, son ambition scientifique et les membres 1 Département GTR 2 Départements Microélectronique et Robotique J'espère ne pas avoir trop déçu, ni décevoir dans le futur, ceux qui m'ont fait confiance. Mais la perfection n'étant pas de ce monde, cela se produira probablement un jour, restons indulgents. "Je n'assure rien, mon Dieu et mon père, ce ne sont que des doutes que je propose. Assistez moi s'il vous plaît et soyez mon guide dans cette recherche." Augustin (354-430), Confessions, livre XI, chapitre XVII

IEEE/ASME Transactions on Mechatronics, 2011

This study investigates a torque estimation method for muscle fatigue tracking, using stimulus ev... more This study investigates a torque estimation method for muscle fatigue tracking, using stimulus evoked electromyography (eEMG) in the context of a functional electrical stimulation (FES) rehabilitation system. Although FES is able to effectively restore motor function in spinal cord injured (SCI) individuals, its application is inevitably restricted by muscle fatigue. In addition, the sensory feedback indicating fatigue is missing in such patients. Therefore, torque estimation is essential to provide feedback or feedforward signal for adaptive FES control. In this work, a fatigue-inducing protocol is conducted on five SCI subjects via transcutaneous electrodes under isometric condition, and eEMG signals are collected by surface electrodes. A myoelectrical mechanical muscle model based on the Hammerstein structure with eEMG as model input is employed to capture muscle contraction dynamics. It is demonstrated that the correlation between eEMG and torque is time-varying during muscle fatigue. Compared to conventional fixed-parameter models, the adaptedparameter model shows better torque prediction performance in fatiguing muscles. It motivates us to use a Kalman filter with forgetting factor for estimating the time-varying parameters and for tracking muscle fatigue. The assessment with experimental data reveals that the identified eEMG-to-torque model properly predicts fatiguing muscle behavior. Furthermore, the performance of the time-varying parameter estimation is efficient, suggesting that real-time tracking is feasible with a Kalman filter and driven by eEMG sensing in the application of FES.

RFM Revue française …, 1996

... Auteur(s) / Author(s). LEROUX JL (1) ; MICALLEF JP (1) ; GUIRAUD D. (1) ; RABISCHONG P. (1) ;... more ... Auteur(s) / Author(s). LEROUX JL (1) ; MICALLEF JP (1) ; GUIRAUD D. (1) ; RABISCHONG P. (1) ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). (1) Unité 103 INSERM, 34090 Montpellier, FRANCE Résumé / Abstract. ...

Proceedings 2007 IEEE International Conference on Robotics and Automation, 2007

The reliability, the ease of donning and doffing and the robustness of controllers constitute the... more The reliability, the ease of donning and doffing and the robustness of controllers constitute the primary criteria to evaluate any control strategy based on Functional Electrical Stimulation (FES). This technique is used to excite muscles that are under lesions and no ...

— The new generation of implanted neuroprostheses allows muscles to be controlled with fine accur... more — The new generation of implanted neuroprostheses allows muscles to be controlled with fine accuracy, high selectivity and the repeatability of the muscle’s response can be achieved. Thus, the closed loop control of such systems becomes possible. The SUAW project succeeded in the implantation of an advanced neuroprosthetic device on two patients, but the movement generation remains open loop and is tuned empirically. Nevertheless, the good results obtained give us the opportunity to envisage the system evolves towards closed loop control and automatic synthesis of the stimulation patterns generating the desired movement. To achieve this goal, some preliminary researches have to be carried out, beginning with a specific modelling that can be used in the context of Functional Electrical Stimulation (FES). The main issues concern muscle modelling including the interaction with the skeleton, fatigue, FES parameters as inputs, and the identification of dynamic parameters, and afterwards,...

Abstract—To investigate interhemispheric imbalance following “awake surgeries ” of slow-growing t... more Abstract—To investigate interhemispheric imbalance following “awake surgeries ” of slow-growing tumors we recorded EEG in a visuo-manual RT paradigm. Increase of cortical excitability within the ipsilesional hemisphere was signed by increased ERPs amplitude for two patients. The cortical excitability in the lesioned hemisphere may be increased to maintain performances and cerebral plasticity. U I.

Annals of Neurology

Objective: Hand amputation is a highly disabling event, which significantly affects quality of li... more Objective: Hand amputation is a highly disabling event, which significantly affects quality of life. An effective hand replacement can be achieved if the user, in addition to motor functions, is provided with the sensations that are naturally perceived while grasping and moving. Intraneural peripheral electrodes have shown promising results toward the restoration of the sense of touch. However, the long-term usability and clinical relevance of intraneural sensory feedback have not yet been clearly demonstrated. Methods: To this aim, we performed a six months clinical study with three trans-radial amputees who received implants of transverse intrafascicular multichannel electrodes (TIMEs) in their median and ulnar nerves. After calibration, electrical stimulation was delivered through the TIMEs connected to artificial sensors in the digits of a prosthesis to generate sensory feedback, which was then used by the subjects while performing different grasping tasks. Results: All the subjects, notwithstanding their important clinical differences, reported stimulationinduced sensations from the phantom hand for the whole duration of the trial. They also successfully integrated the sensory feedback into their motor control strategies while performing experimental tests simulating tasks of real life (with and without the support of vision). Finally, they reported a decrement of their phantom limb pain and a general improvement in mood state. Interpretation: The promising results achieved with all subjects show the feasibility of the use of intraneural stimulation in clinical settings.

2003 IEEE International Conference on Robotics and Automation (Cat. No.03CH37422), 2003