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Luna PS y cols. Mimetic orthosis for lower limbs to be applied on rehabilitation for hemiplegic persons

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REVISTA MEXICANA DE INGENIERÍA BIOMÉDICA

ARTÍCULO DE INVESTIGACIÓN ORIGINAL
SOMIB

Vol. XXlX, Núm. 1 Junio 2008 pp 15 - 20

Mimetic orthosis for lower limbs to be applied on rehabilitation for hemiplegic persons
P.S. Luna,* E. Cardiel, R. Muñoz,R. Urrutia,** D. Villanueva,*** P.R. Hernández
* Universidad Politécnica de Cataluña, Barcelona, España. * * Fisiología del Esfuerzo y Desempeño Humano, FES Iztacala, UNAM. * * * Centro de Diagnóstico Biomecánico. Correspondencia: P.S. Luna CINVESTAV, Departamento de Ingeniería Eléctrica, Av. IPN Núm. 2508 Col. San Pedro Zacatenco, Del. Gustavo A. Madero 07360 México, D.F. México, E-mail:pablo.rogeli@cinvestav.mx. Artículo recibido: 16/octubre/2007 Artículo aceptado: 12/junio/2008

ABSTRACT A rehabilitation tool based on an innovative mimetic active orthosis for hemiplegics is presented. It follows concepts of neuronal learning from afferent information from movements, similar to those lost after brain damage. An artificial gait pattern is applied on knee and hip articulations of afunctional modified limb by using an exoskeleton powered by pneumatic muscles. Key Words: Active orthosis, mimetic orthosis, gait rehabilitation. RESUMEN Se presenta una herramienta para rehabilitación de personas con hemiplejía, basada en una ortesis mimética activa. La herramienta sigue los conceptos de entrenamiento neuronal por medio de la información aferente de los movimientos, similar a losque se perdieron después del daño cerebral. Se aplica un patrón artificial de marcha a las articulaciones de rodilla y cadera de un miembro modificado funcionalmente utilizando un exoesqueleto activado con músculos neumáticos. Palabras clave: Ortesis activa, ortesis mimética, rehabilitación de la marcha.

INTRODUCTION Hemiplegia is a condition that has affected the life style of many people,often over many years, or permanently in some cases. Commonly, hemiplegia is the result of a vascular brain accident that may alter posture and movement, may produce paralysis and insensitivity in the face, in an arm or a leg, or in both upper and lower limb to a greater or lesser extent1. Usually, the recovery time and movement recuperation depends on the extent of neuronal damage. Practicaltherapies are planned to induce pharmacological reduction of spasticity at first, allowing the generation of specific movements to avoid muscle atrophy. Additionally, some rehabilitation programs include movements similar to those

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performed during normal gait. These actions are mainly directed to reduce spasticity and in many cases a significant recuperation has been obtained bya combination of different features like force exercising, emphasis of gait symmetry, utilization of equilibrium reflexes, stepping automation, endurance training, and cyclic movements2,3. Literature 3,4, has reported studies about functional recover y of the brain due to neuronal plasticity. This theory maintains that the cortical motor maps are not considered immutable and can change accordingto stimuli experiences. It has been demonstrated 5, that an ischemic lesion over a specific zone in the brain cortex has evoked the utilization of a nearby zone that may adopt the lost functions when movements are induced by

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Revista Mexicana de Ingeniería Biomédica • volumen XXIX • número 1 • Junio 2008

artificial gait patterns and then afferently transmitted to the brain cortex fortraining and re-learning purposes. Information to be stored in the re-assigned zone will be provided by conditions and movements of the structures that have been functionally modified. This is the starting point of our proposal supported by a mimetic active orthosis developed in the present work. Therefore, the mimetic active orthosis has been developed to be used as a rehabilitation tool to...