Effets de l'application de charges aux membres inférieurs sur le patron de marche des personnes hémiparétiques chroniques

Placer une charge au niveau du membre inférieur est une approche sans fondement scientifique, utilisée par les cliniciens, pour renforcer certains muscles clés de la marche. Cette étude a déterminé les modifications du patron de marche lors de l’ajout d’une charge à la cheville parétique ou non parétique chez des personnes ayant une hémiparésie suite à un accident vasculaire cérébral et a comparé les résultats à ceux d’un groupe témoin. Il est supposé qu’une charge placée à la jambe parétique/non dominante (charge ipsilatérale) augmenterait les efforts (moments et puissance) à la hanche parétique/non dominante lors de l’oscillation et qu’une charge placée controlatéralement augmenterait les efforts lors de la phase d’appui principalement pour les abducteurs de hanche stabilisant le bassin dans le plan frontal. La marche avec et sans charge de cinq individus hémiparétiques chroniques et 5 personnes en santé a été analysée en laboratoire par l’enregistrement des forces de réaction du sol et des mouvements des membres inférieurs. Ces informations ont permis de calculer les paramètres temps-distance, les angles à la hanche parétique/non dominante et au tronc, les moments nets, les puissances et le travail mécanique à la hanche parétique/non dominante. Des tests statistiques non-paramétriques ont servi à déterminer l’effet de la condition, avec charge (ipsi- et controlatérale) ou sans charge et à comparer les résultats entre les deux groupes. L’ajout d’une charge n’a pas modifié la vitesse de marche des sujets. Les phases d’appui et d’oscillation étaient rendus plus symétriques par la charge, même si peu de différences apparaissaient dans le plan sagittal avec ou sans la charge. Dans le plan frontal, le moment abducteur de hanche des sujets hémiparétiques a diminué avec la charge controlatérale, tandis qu'il a augmenté chez les sujets en santé. L’utilisation d’une stratégie posturale ou dynamique au tronc pourrait expliquer la différence de l’effet de la charge sur le moment abducteur à la hanche. Au vu de ces résultats, il est nécessaire de poursuivre l’évaluation de cette approche de renforcement musculaire spécifique à la tâche avant d’en recommander son utilisation.

Rôle des informations proprioceptives dans l’équilibre à la marche chez les personnes en santé et hémiparétiques

L'utilisation des informations proprioceptives pour le contrôle de l’équilibre à la marche est encore mal comprise chez les sujets en santé ou hémiparétiques suite à un accident vasculaire cérébral. Le but de cette étude était d’évaluer le rôle des informations proprioceptives dans le maintien de l'équilibre à la marche chez les patients en santé et hémiparétiques. Une analyse de mouvement en trois dimensions a été faite chez treize participants en santé et six hémiparétiques qui marchaient sur un tapis roulant instrumenté pour déterminer leur difficulté à maintenir l’équilibre postural et dynamique, évaluée respectivement par les forces stabilisante et déstabilisante. Des vibrations étaient appliquées en continu ou pendant la phase d’appui sur les muscles postérieurs du cou et sur le triceps sural du côté non-dominant/parétique. La vibration continue ou à l’appui du triceps sural a diminué, chez les sujets en santé, la difficulté à maintenir l’équilibre dynamique et postural (p< 0,01), avec une position du corps plus en arrière, sans changement des paramètres temporels de marche. L'équilibre et les paramètres temporels de la marche n'étaient pas modifiés significativement par la vibration à la nuque (p>.17). Aucun effet des vibrations n'a été mesuré chez les patients hémiparétiques (p> 0,45). Les informations proprioceptives sont donc bien utilisées lors de la marche, mais leur rôle dépendrait des conditions de marche et des afférences visuelles disponibles. Un changement dans les capacités d’intégration expliquerait l'absence d'effet des vibrations chez les patients hémiparétiques. D’autres études sont nécessaires pour comprendre l’intégration des informations proprioceptives et visuelles dans le contrôle de l’équilibre à la marche.

L’effet de la prothèse totale du genou sur la cinématique 3D : vers le développement de biomarqueurs mécaniques de la douleur

La prothèse totale du genou (PTG) est une chirurgie couramment pratiquée pour traiter les patients souffrant d’arthrose sévère du genou. Bien que cette technique chirurgicale soit efficace pour diminuer la douleur, améliorer la fonction du genou et rentable d’un point de vue socio-économique, un pourcentage non négligeable de patients n’est pas satisfait suite à la chirurgie, principalement due à une douleur persistante ou due à une perception d’avoir une mauvaise fonction articulaire, sans cause identifiée. Cependant, l’impact de cette chirurgie sur la cinématique tridimensionnelle (3D) du genou demeure mal compris. Dans le but de mieux comprendre pourquoi certains patients ressentent toujours de la douleur suite à cette chirurgie, cette étude analysera, dans un premier temps, l’effet prospectif de la chirurgie sur la cinématique 3D du genou. Puis dans un second temps, comparera la cinématique 3D de sujet souffrant de douleur à celle de sujets asymptomatiques suite à la prothèse. Pour parvenir à ces deux objectifs, deux études distinctes ont été entreprises. Une première étude prospective a porté sur l’évolution de la cinématique 3D du genou d’un groupe de 19 sujets, recrutés sur la liste d’attente pour prothèse totale du genou de deux chirurgiens du CHUM, hôpital Notre-Dame, puis la cinématique a été comparée avec un groupe contrôle de 17 sujets avec des genoux sains. Une seconde étude a comparé la cinématique 3D de 20 sujets souffrant de douleur post-PTG avec 20 sujets avec des genoux asymptomatiques suite à leur chirurgie. La première étude a permis de montrer que la cinématique dans le plan frontal suite à la prothèse totale du genou était corrigée vers celle des sujets sains. Contrairement à celle mesurée dans les autres plans (sagittal et axial) qui, malgré de petites corrections, demeure différente de la cinématique des sujets sains. La seconde étude a permis d’identifier un marqueur biomécanique de la douleur chez les sujets souffrant de douleur post-PTG. Effectivement, contrairement aux sujets asymptomatiques, suite à leur chirurgie, les patients souffrants de douleur marchent avec une contracture en flexion plus importante tout au long de la phase d’appui. Les résultats de ces deux études tendent à montrer que la prothèse totale du genou modifie la cinématique 3D du genou, sans toutefois redevenir semblable à celle d’un genou normal. De plus, certains marqueurs biomécaniques peuvent être associés à de la douleur suite à la chirurgie. Une meilleure compréhension de l’impact de la PTG sur la cinématique 3D du genou permettra d’offrir de meilleurs traitements en préparation et après la chirurgie et pourrait mener à de nouveaux designs de prothèses.

Estudo comparativo da marcha de indivíduos hemiparéticos no solo e na esteira

The purpose of the study was to compare hemiparetic gait overground and on the treadmill. Seventeen chronic stroke patients were included in the study. They walked overground and on a treadmill level at the same speed. The Qualisys Medical AB motion analysis system was used to quantify the joint kinematic of the paretic lower limb and the spatio-temporal parameters on the two conditions: overground walking and treadmill walking on three samples of 5-minutes. During the first sample, the subjects walked on the treadmill with greater cadence, shorter stride length, shorter step time on the lower paretic limb, greater range of motion in the hip and knee, greater knee flexion at the initial contact, more extension of the knee and lower dorsiflexion of the ankle at the stance phase. It is important to emphasize that the maximal knee flexion and ankle dorsiflexion just occurred later on the treadmill. Comparisons between each walking sample on the treadmill hadn t revealed any changes on the gait parameters over time. Nonetheless, when analyzing the third walking sample on the treadmill and overground, some variables showed equivalence as such as the total range of motion of the hip, the knee angle at the initial contact and its maximal extension at the stance phase. In summary, walking on a treadmill, even thought having some influence on the familiarization process, haven t demonstrated a complete change in its characteristics of hemiparetic chronic patients

Effects of obstacle height on obstacle crossing in mild Parkinson's disease

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Velocidade ideal da esteira para estimular passadas do andar em bebês

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Parâmetros da marcha em portadores de diabetes mellitus

O Diabetes mellitus é uma enfermidade crônica que leva a alterações sensitivas e motoras. Tais alterações comprometem o equilíbrio e a deambulação, predispondo seus portadores à ocorrência de quedas. Esta revisão teve por objetivo levantar, na literatura recente, estudos que visassem avaliar parâmetros da marcha e aspectos envolvidos com a deambulação. Para isso, foi realizada uma busca nas bases de dados MEDLINE, SciELO, LILACS e PEDro, cruzando as palavras-chave: Neuropatias Diabéticas x Marcha; Diabetes Mellitus x Marcha e Pé Diabético x Marcha. Após passarem pelos critérios de seleção, foram obtidos 15 artigos, os quais foram sintetizados e discutidos, sendo, portanto, incluídos nesta revisão. Ficou claro que a neuropatia diabética leva a déficits na amplitude do passo, velocidade e cadência da marcha em superfícies planas, sem mudanças bruscas de direção ou paradas, e déficits de equilíbrio e coordenação em aclives, declives e terrenos irregulares. Acarreta, também, aumento dos índices de pressão plantar e, devido à alteração de ativação do tríceps sural, dificuldade na fase de apoio terminal e pré-balanço. Assim, o próximo contato inicial ocorrerá de maneira inadequada, com o antepé e sem absorção de choques.

Análise do equilíbrio postural de indivíduos diabéticos por meio de baropodometria

Objective of this study was to analyze the postural balance of neuropathic diabetic individuals through baropodometry, related to losses in the sensorimotor system. Twenty-eight healthy and 25 diagnosed with diabetic neuropathy were subjected to static evaluation (measurement of displacement of body center of pressure) and dynamic (temporal analysis of the stance phase of gait cycle). The tactile sensitivity of the feet was assessed by Semmes Weinstein monofilaments and isometric muscle strength of ankle dynamometry. Analyses of multivariânvia (MANOVAs) and variance (ANOVAs) indicated lower performance in tactile sensitivity, muscle strength and dynamic balance, but showed no difference for static equilibrium of diabetic neuropathy. With this study by regression analysis, one can infer that the equilibrium differences in gait of neuropathic insensitivity may result from tactile and muscle strength. © FTCD/FIP-MOC.

Coordination of spinal motion in the transverse and frontal planes during walking in people with and without recurrent low back pain

STUDY DESIGN. Observational cohort study. OBJECTIVE. To investigate spinal coordination during preferred and fast speed walking in pain-free subjects with and without a history of recurrent low back pain (LBP). SUMMARY OF BACKGROUND DATA. Dynamic motion of the spine during walking is compromised in the presence of back pain (LBP), but its analysis often presents some challenges. The coexistence of significant symptoms may change gait because of pain or adaptation of the musculoskeletal structures or both. A history of LBP without the overlay of a current symptomatic episode allows a better model in which to explore the impact on spinal coordination during walking. METHODS. Spinal and lower limb segmental motions were tracked using electromagnetic sensors. Analyses were conducted to explore the synchrony and spatial coordination of the segments and to compare the control and subjects with LBP. RESULTS. We found no apparent differences between the groups for either overall amplitude of motion or most indicators of coordination in the lumbar region; however, there were significant postural differences in the mid-stance phase and other indicators of less phase locking in controls compared with subjects with LBP. The lower thoracic spinal segment was more affected by the history of back pain than the lumbar segment. CONCLUSION. Although small, there were indicators that alterations in spinal movement and coordination in subjects with recurrent LBP were due to adaptive changes rather than the presence of pain. © 2013, Lippincott Williams & Wilkins.

Avaliação da distribuição da pressão plantar e equilíbrio de diabéticos neuropatas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise cinematográfica tridimensional da articulação metacarpofalangiana de equinos submetidos à elevação da pinça ou talões

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Joint loading decreased by inexpensive and minimalist footwear in elderly women with knee osteoarthritis during stair descent

Objective Previous studies indicate that flexible footwear, which mimics the biomechanics of walking barefoot, results in decreased knee loads in patients with knee osteoarthritis (OA) during walking. However, the effect of flexible footwear on other activities of daily living, such as descending stairs, remains unclear. Our objective was to evaluate the influence of inexpensive and minimalist footwear (Moleca) on knee adduction moment (KAM) during stair descent of elderly women with and without knee OA. Methods. Thirty-four elderly women were equally divided into an OA group and a control group (CG). Stair descent was evaluated in barefoot condition, while wearing the Moleca, and while wearing heeled shoes. Kinematics and ground reaction forces were measured to calculate KAM by using inverse dynamics. Results. The OA group experienced a higher KAM during midstance under the barefoot condition (233.3%; P = 0.028), the Moleca (379.2%; P = 0.004), and heeled shoes (217.6%; P = 0.007). The OA group had a similar knee load during early, mid, and late stance with the Moleca compared with the barefoot condition. Heeled shoes increased the knee loads during the early-stance (versus barefoot [16.7%; P < 0.001] and versus the Moleca [15.5%; P < 0.001]), midstance (versus barefoot [8.6%; P = 0.014] and versus the Moleca [9.5%; P = 0.010]), and late-stance phase (versus barefoot [10.6%; P = 0.003] and versus the Moleca [9.2%; P < 0.001]). In the CG, the Moleca produced a knee load similar to the barefoot condition only during the early-stance phase. Conclusion. Besides the general foot protection, the inexpensive and minimalist footwear contributes to decreasing knee loads in elderly women with OA during stair descent. The loads are similar to the barefoot condition and effectively decreased when compared with heeled shoes.

Analysis of human body kinematics using a hybrid markerless video acquisition and processing

A main objective of the human movement analysis is the quantitative description of joint kinematics and kinetics. This information may have great possibility to address clinical problems both in orthopaedics and motor rehabilitation. Previous studies have shown that the assessment of kinematics and kinetics from stereophotogrammetric data necessitates a setup phase, special equipment and expertise to operate. Besides, this procedure may cause feeling of uneasiness on the subjects and may hinder with their walking. The general aim of this thesis is the implementation and evaluation of new 2D markerless techniques, in order to contribute to the development of an alternative technique to the traditional stereophotogrammetric techniques. At first, the focus of the study has been the estimation of the ankle-foot complex kinematics during stance phase of the gait. Two particular cases were considered: subjects barefoot and subjects wearing ankle socks. The use of socks was investigated in view of the development of the hybrid method proposed in this work. Different algorithms were analyzed, evaluated and implemented in order to have a 2D markerless solution to estimate the kinematics for both cases. The validation of the proposed technique was done with a traditional stereophotogrammetric system. The implementation of the technique leads towards an easy to configure (and more comfortable for the subject) alternative to the traditional stereophotogrammetric system. Then, the abovementioned technique has been improved so that the measurement of knee flexion/extension could be done with a 2D markerless technique. The main changes on the implementation were on occlusion handling and background segmentation. With the additional constraints, the proposed technique was applied to the estimation of knee flexion/extension and compared with a traditional stereophotogrammetric system. Results showed that the knee flexion/extension estimation from traditional stereophotogrammetric system and the proposed markerless system were highly comparable, making the latter a potential alternative for clinical use. A contribution has also been given in the estimation of lower limb kinematics of the children with cerebral palsy (CP). For this purpose, a hybrid technique, which uses high-cut underwear and ankle socks as “segmental markers” in combination with a markerless methodology, was proposed. The proposed hybrid technique is different than the abovementioned markerless technique in terms of the algorithm chosen. Results showed that the proposed hybrid technique can become a simple and low-cost alternative to the traditional stereophotogrammetric systems.

Riabilitazione e valutazione di pazienti con deficit neurologici mediante l'utilizzo di realtà virtuale, feedback aumentati, sensori inerziali e tecnologie video a basso costo.

La neuroriabilitazione è un processo attraverso cui individui affetti da patologie neurologiche mirano al conseguimento di un recupero completo o alla realizzazione del loro potenziale ottimale benessere fisico, mentale e sociale. Elementi essenziali per una riabilitazione efficace sono: una valutazione clinica da parte di un team multidisciplinare, un programma riabilitativo mirato e la valutazione dei risultati conseguiti mediante misure scientifiche e clinicamente appropriate. Obiettivo principale di questa tesi è stato sviluppare metodi e strumenti quantitativi per il trattamento e la valutazione motoria di pazienti neurologici. I trattamenti riabilitativi convenzionali richiedono a pazienti neurologici l’esecuzione di esercizi ripetitivi, diminuendo la loro motivazione. La realtà virtuale e i feedback sono in grado di coinvolgerli nel trattamento, permettendo ripetibilità e standardizzazione dei protocolli. È stato sviluppato e valutato uno strumento basato su feedback aumentati per il controllo del tronco. Inoltre, la realtà virtuale permette l’individualizzare il trattamento in base alle esigenze del paziente. Un’applicazione virtuale per la riabilitazione del cammino è stata sviluppata e testata durante un training su pazienti di sclerosi multipla, valutandone fattibilità e accettazione e dimostrando l'efficacia del trattamento. La valutazione quantitativa delle capacità motorie dei pazienti viene effettuata utilizzando sistemi di motion capture. Essendo il loro uso nella pratica clinica limitato, una metodologia per valutare l’oscillazione delle braccia in soggetti parkinsoniani basata su sensori inerziali è stata proposta. Questi sono piccoli, accurati e flessibili ma accumulano errori durante lunghe misurazioni. È stato affrontato questo problema e i risultati suggeriscono che, se il sensore è sul piede e le accelerazioni sono integrate iniziando dalla fase di mid stance, l’errore e le sue conseguenze nella determinazione dei parametri spaziali sono contenuti. Infine, è stata presentata una validazione del Kinect per il tracking del cammino in ambiente virtuale. Risultati preliminari consentono di definire il campo di utilizzo del sensore in riabilitazione.

Combining series elastic actuation and magneto-rheological damping for the control of agile locomotion

All-terrain robot locomotion is an active topic of research. Search and rescue maneuvers and exploratory missions could benefit from robots with the abilities of real animals. However, technological barriers exist to ultimately achieving the actuation system, which is able to meet the exigent requirements of these robots. This paper describes the locomotioncontrol of a leg prototype, designed and developed to make a quadruped walk dynamically while exhibiting compliant interaction with the environment. The actuation system of the leg is based on the hybrid use of series elasticity and magneto-rheological dampers, which provide variable compliance for natural-looking motion and improved interaction with the ground. The locomotioncontrol architecture has been proposed to exploit natural leg dynamics in order to improve energy efficiency. Results show that the controller achieves a significant reduction in energy consumption during the leg swing phase thanks to the exploitation of inherent leg dynamics. Added to this, experiments with the real leg prototype show that the combined use of series elasticity and magneto-rheologicaldamping at the knee provide a 20 % reduction in the energy wasted in braking the knee during its extension in the leg stance phase.