A Virtual Rehabilitation Suite for the Upper Limb Using a “Soft Exoskeleton”
Sophia Kousidou, N.Tsagarakis and D G Caldwell School of Computing, Science and Engineering, University of Salford, Manchester, M5 4WT, UK.
Phone: +44 (0) 161 2954010, Fax: +44 (0) 161 2955145, E-mail: S.Kousidou@pgr.salford.ac.uk
IMAACA’2004
Abstract - Strokes form the leading cause of disability in most industrialised countries. Although many mechanical devices exist for the rehabilitation of the upper arm, there is a need for a device that can be used as a multifunctional facility for treatment and analysis providing physiotherapy exercises. In this paper we present RehabLab, a virtual environment aimed for the training of stroke patients to daily activities. RehabLab uses the University of Salford Arm Exoskeleton as the actual medium for performing the physiotherapy treatment regimes.
I. INTRODUCTION
Strokes form the leading cause of disability in most industrialised countries. Fortunately over 65% of patients survive the incident, but the majority does have residual disabilities with up to 1/3 having severe disabilities particularly in the upper limb. It has been shown that early and intensive physiotherapy can improve outcomes for many of these conditions. The treatment of full or partial loss of upper limb function based on conventional physiotherapy regimes is generally labour intensive and as far as rehabilitation and physiotherapy is concerned, several mechanical systems exist or are being developed to assist in the treatment ranging from plain robotic systems to exercise machines with several of the most important, recent or novel included below.
MULOS (Motorized Upper Limb Orthotic System) [G. R. Johson and M. A. Buckley, 1997] is a 5dof system designed to provide single joint exercise. The orthosis allows the movement of the shoulder, the elbow and the forearm. The system has sufficient compliance to allow a full range of motion at the shoulder. The available modes of operation are assistive, continuous passive motion and exercise and the modes of control are point-to-point, joint-by-joint and walk-through programming. Although reports on the device were excellent and there appeared to be good potential, its development stopped in 1997. Another system used for single-joint exercise is the one designed by Cozens. The particular robotic assistant was aimed for upper limb exercise [M. E. Austin et al., 1998] using torque applied to an individual joint (single dof system). In this work the forearm is attached to a lever that, rotates in the horizontal plane and it is immobilized so that the lever can only be moved by elbow flexion/extension. A semi-circular array of light emitting diodes (LEDs) around the lever provides target lights to dictate the exercise task.
The Hybrid Arm Orthosis [N. Benjuya and S. B. Kenney, 1990] (HAO) was designed to restore hand/arm functions. It achieved upper arm major functions by using two different power sources. The shoulder and elbow joints are interconnected and simultaneously abduct and flex, respectively, by contra lateral shoulder elevation (body powered). The wrist supination and three-point jaw chuck pinch is generated by two separate switchable DC motors in sequence. In order to activate the motors, the patient slightly presses air-switches that are located on the headrest of the wheelchair. MIT researchers on the other hand, have developed a robot (SCARA) for the physical therapy of stroke victims [N. Hogan et al., 1992]. A person sitting at a table places the lower arm and wrist into a brace attached to the arm of the robot. A video screen prompts the person to perform an arm exercise, such as connecting the dots. If movement does not occur, MIT/Manus moves the person' s arm. If the person starts to move on her/his own, the robot provides adjustable levels of guidance and assistance to facilitate the person' s movements.
Researchers at the Department of Veteran Affairs in association with Stanford University have developed and clinically tested three mechatronic systems (using PUMA robots) for post-stroke therapy [C. G. Burgar et al., 2000]. The third generation was able to handle multiple functional movement patterns, to fully support the limb during 3D movements and to provide passive, active-assisted, resistive, and self-guided modes of therapy. The GENTLE/S project [P. Mark et al., 2002], is a three-year project in the European Community Framework 5 (starting in February 2000). Its objectives are to explore and identify "best therapies" for machine mediated stroke rehabilitation. The prototype is based upon a haptic master with 6 degrees of freedom (dof) although only the three translational dof are active. The system operates under
.....