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Sauret C.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Vaslin P.,CNRS Laboratory of Informatics, Modeling and Optimization of Systems | Lavaste F.,Arts et Metiers ParisTech | Lavaste F.,Institution nationale des invalides | And 3 more authors.
Medical Engineering and Physics | Year: 2013

Currently, rolling resistance and wheelchair stability during manual wheelchair propulsion can be assessed from the loads applied on the front and rear wheels, which are determined in a static condition. However, a user's actions on the wheelchair would change these loads during locomotion, which should affect both the rolling resistance and wheelchair stability. The goal of this study was to verify these assumptions and assess how much the rolling resistance and wheelchair stability are affected by the user's actions during propulsion. For that purpose, a mechanical model was developed using measurements of an instrumented wheelchair equipped with several six-component dynamometers. Experiments were performed by three subjects propelling the instrumented wheelchair over flat ground. The results showed variations over wide ranges of the fore-aft distribution of the total load, rolling resistance, wheelchair stability, wheelchair velocity and mechanical power dissipated by the rolling resistance during the propulsion cycle. In addition, the time courses of all these variables differed with the subject. Finally, this study demonstrated the possibility of assessing intra-cycle values of both rolling resistance and wheelchair stability during manual wheelchair displacements in the field, which provides a technical step towards evaluating a wheelchair user in his daily environment. © 2012 IPEM.

Benisty S.,Institution nationale des invalides
Geriatrie et Psychologie Neuropsychiatrie du Vieillissement | Year: 2013

Vascular dementias, VD, are dementias due to cerebrovascular lesions. Subgroups of VD include multi-infarct dementia, single infarct (or strategic infarct) dementia, subcortical ischemic vascular dementia, hemorrhagic dementia, hypoperfusion dementia. VD are also related to post-stroke dementia, mixed Alzheimer's disease and vascular dementia and vascular cognitive impairment. These various entities allow to characterize more homogenous subgroups within the heterogeneous group of vascular dementias. However, ambiguities in their definitions, associated with frequent overlaps as well as lack of consensual definition for mixed dementia limit both their theoretical value and use in clinical practice. The diagnosis of cerebrovascular diseases should be dissociated from that of dementia, which could be associated with other pathologies.

Thomas-Pohl M.,Service de Medecine Physique et de Readaptation | Rogez D.,Service de Medecine Physique et de Readaptation | Thefenne L.,Service de Medecine Physique et de Readaptation | Azoulay D.,Institution nationale des invalides | Lapeyre E.,Service de Medecine Physique et de Readaptation
Lettre de Medecine Physique et de Readaptation | Year: 2013

Prosthesis of amputees is a medicotechnical and economic challenge. Technological advances are opening up a new market, the bionic knees, in which artificial intelligence would allow the prediction of the patient's movements. Three soldiers, polytraumatised in 2010 with transfemoral amputation at different levels, primary or secondary, caused by traffic accident or improvised explosion device, were fitted this year with the bionic knee Genium® after a specific rehabilitation at theMilitary Hospital of Percy. The main purpose of this study, with an open survey after six months of experiment with the Genium®, is to know whether the promised features of the Genium® knee are acquired and used in everyday practice. These new bionic knees are living up to the expectations of the patients froma mechanical (more physiological gait, trampling and walking backwards possible, overcoming obstacles and steep downhill slope facilities, etc.) and psychological perspective. The ownership of a prosthesis and a fortiori of an advanced technology knee requires specific rehabilitation. However, the integrated automatic movements should remain manageable and controllable by the patient, with the challenge of bringing new fluid, natural and unconscious movements. The association of human body with the prosthetic foot still needs to be studied to improve movements on slopes and stairs. Not listed as refundable products by French health insurance, there is currently no standardized validation and evaluation criteria for bionic knees and the economic aspect remains a major obstacle to their prescription (associative funding for our patients). © 2013 Springer-Verlag France.

Villa C.,Institution nationale des invalides | Villa C.,Arts et Metiers ParisTech | Drevelle X.,Institution nationale des invalides | Bonnet X.,La Redoute | And 4 more authors.
Clinical Biomechanics | Year: 2015

Background Vaulting is a walking strategy qualitatively characterized in clinics by the sound ankle plantiflexion in midstance to assist prosthetic foot clearance. Even though potentially harmful, this strategy is often observed among people with transfemoral amputation to secure clearance of the prosthetic limb during swing phase. The aim of the study is to provide a quantitative analysis of the evolution of the vaulting strategy in challenging situations of daily living. Methods 17 persons with transfemoral amputation and 17 able-bodied people participated in the study. Kinematic and kinetic gait analyses were performed for level walking, 10% inclined cross-slope walking, 5% and 12% inclined slope ascending. To study vaulting strategy, peak of generated power at the sound ankle at midstance was identified and quantified in the different walking situations. In particular, values were compared to a vaulting threshold corresponding to a peak of generated power superior to 0.15 W/kg. Findings The vaulting threshold was exceeded for a larger proportion of people with amputation during cross-slope locomotion and slope ascent than during level walking. In addition, magnitude of the peak of generated power increased significantly compared to level walking in these situations. Interpretation Vaulting seems to be widely used by patients with transfemoral amputation in daily living situations. The number of patients using vaulting increased with the difficulty of the walking situation. Results also suggested that patients could dose the amount of vaulting according to gait environment to secure prosthetic toe clearance. During rehabilitation, vaulting should also be corrected or prevented in daily living tasks. © 2015 Elsevier Ltd.

Drevelle X.,Institution nationale des invalides | Villa C.,Arts et Metiers ParisTech | Bonnet X.,La Redoute | Fode P.,Institution nationale des invalides | Pillet H.,Arts et Metiers ParisTech
Clinical Biomechanics | Year: 2014

Background Vaulting is a gait compensatory mechanism used by transfemoral amputees to assist toe clearance during the prosthetic swing phase. It is defined by a plantar flexion of the contralateral ankle during the single-limb support phase. The aim of the study is to propose a method to quantify vaulting of transfemoral amputees. Methods 17 transfemoral amputees and 28 asymptomatic subjects participated in the data collection. Kinematics and kinetics of the whole body were recorded while subjects were walking on a level surface. Biomechanical gait analysis was focused on a reduced set of parameters linked to the contralateral ankle, the contralateral knee and the trajectory of the center of pressure. The patients were classified in two groups: with or without vaulting using video recordings. Differences between both groups and the control group were analyzed. Findings A higher generated ankle power was found during the single support phase of the contralateral limb of transfemoral amputees presenting vaulting. These subjects presented also a higher dissipated knee flexion power before the peak in ankle flexion power. The trajectory of the center of pressure was also modified by the vaulting. Interpretation Vaulting for transfemoral amputees is characterized by a propulsive plantar flexion at the contralateral ankle. Quantifying the ankle flexion power during the contralateral single support phase will help in understanding vaulting. © 2014 Elsevier Ltd.

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