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1.
IEEE Trans Haptics ; 8(2): 140-51, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25838528

RESUMO

This paper presents a novel electromyography (EMG)-driven hand exoskeleton for bilateral rehabilitation of grasping in stroke. The developed hand exoskeleton was designed with two distinctive features: (a) kinematics with intrinsic adaptability to patient's hand size, and (b) free-palm and free-fingertip design, preserving the residual sensory perceptual capability of touch during assistance in grasping of real objects. In the envisaged bilateral training strategy, the patient's non paretic hand acted as guidance for the paretic hand in grasping tasks. Grasping force exerted by the non paretic hand was estimated in real-time from EMG signals, and then replicated as robotic assistance for the paretic hand by means of the hand-exoskeleton. Estimation of the grasping force through EMG allowed to perform rehabilitation exercises with any, non sensorized, graspable objects. This paper presents the system design, development, and experimental evaluation. Experiments were performed within a group of six healthy subjects and two chronic stroke patients, executing robotic-assisted grasping tasks. Results related to performance in estimation and modulation of the robotic assistance, and to the outcomes of the pilot rehabilitation sessions with stroke patients, positively support validity of the proposed approach for application in stroke rehabilitation.


Assuntos
Eletromiografia , Exoesqueleto Energizado , Força da Mão/fisiologia , Robótica/instrumentação , Reabilitação do Acidente Vascular Cerebral , Dedos/fisiologia , Humanos , Aparelhos Ortopédicos , Robótica/métodos , Acidente Vascular Cerebral/fisiopatologia
2.
Proc Inst Mech Eng H ; 228(9): 935-41, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25231666

RESUMO

In the medical world, the term "congruence" is used to describe by visual inspection how the articular surfaces mate each other, evaluating the joint capability to distribute an applied load from a purely geometrical perspective. Congruence is commonly employed for assessing articular physiology and for the comparison between normal and pathological states. A measure of it would thus represent a valuable clinical tool. Several approaches for the quantification of joint congruence have been proposed in the biomechanical literature, differing on how the articular contact is modeled. This makes it difficult to compare different measures. In particular, in previous articles a congruence measure has been presented which proved to be efficient and suitable for the clinical practice, but it was still empirically defined. This article aims at providing a sound theoretical support to this congruence measure by means of the Winkler elastic foundation contact model which, with respect to others, has the advantage to hold also for highly conforming surfaces as most of the human articulations are. First, the geometrical relation between the applied load and the resulting peak of pressure is analytically derived from the elastic foundation contact model, providing a theoretically sound approach to the definition of a congruence measure. Then, the capability of congruence measure to capture the same geometrical relation is shown. Finally, the reliability of congruence measure is discussed.


Assuntos
Fenômenos Biomecânicos/fisiologia , Articulações/fisiologia , Humanos , Modelos Biológicos , Estresse Mecânico , Suporte de Carga/fisiologia
3.
J Biomech ; 38(6): 1205-12, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15863104

RESUMO

The knowledge of the contact areas at the tibiotalar articulating surfaces during passive flexion is fundamental for the understanding of ankle joint mobility. Traditional contact area reports are limited by the invasive measuring techniques used and by the complicated loading conditions applied. In the present study, passive flexion tests were performed on three anatomical preparations from lower leg amputation. Roentgen Stereophotogrammetric Analysis was used to accurately reconstruct the position of the tibia and the talus at a number of unconstrained flexion positions. A large number of points was collected on the surface of the tibial mortise and on the trochlea tali by a 3-D digitiser. Articular surfaces were modelled by thin plate splines approximating these points. Relative positions of these surfaces in all the flexion positions were obtained from corresponding bone position data. A distance threshold was chosen to define contact areas. A consistent pattern of contact was found on the articulating surfaces. The area moved anteriorly on both articular surfaces with dorsiflexion. The average position of the contact area centroid along the tibial mortise at maximum plantarflexion and at maximum dorsiflexion was respectively 58% posterior and 40% anterior of the entire antero-posterior length. For increasing dorsiflexion, the contact area moved from medial to lateral in all the specimens.


Assuntos
Articulação do Tornozelo/fisiologia , Modelos Biológicos , Movimento/fisiologia , Amplitude de Movimento Articular/fisiologia , Tálus/fisiologia , Tíbia/fisiologia , Adulto , Articulação do Tornozelo/diagnóstico por imagem , Simulação por Computador , Humanos , Imageamento Tridimensional/métodos , Técnicas In Vitro , Pessoa de Meia-Idade , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Tálus/diagnóstico por imagem , Tíbia/diagnóstico por imagem
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