Robot-assisted rehabilitation after stroke

Our daily activities are dependent on the use of our hands and arms. People suffering from functional deficits of the upper limb following a stroke are often severely limited in the execution of simple tasks. Traditional therapy to regain sensorimotor functions has some limitations, but can be complemented with robotic devices, which allow increasing the intensity of treatment proposed to post-stroke patients and providing objective measures to assess hand function.

We are developing novel robotic devices to train and assess the hand and forearm functions. The HapticKnob is a 2-degrees of freedom (DOF) robot designed to train hand grasping and forearm pronation/supination developed at the National University of Singapore. In a previous study with chronic stroke patients, significant improvement in upper limb motor function was observed after a 6-week therapy with the HapticKnob, suggesting that robot-assisted training of distal segments of the upper limb might be beneficial for restoring arm and hand function..

We developed an improved version of the HapticKnob, called the ReHapticKnob, with the same two DOF to train and assess hand grasping and forearm rotation. This new device is able to render a wider range of impedances (Z-Width) thanks to a novel design concept and state of the art interaction control algorithms. Pilot data have been collected with 6 patients with neurological injuries, and we are currently preparing a clinical study with the ReHatpicKnob, taking advantage of the high fidelity virtual object rendering ability of the robot to propose exercises to train and assess motor and sensory function in stroke patients.

Figure 1: Two generations of hand rehabilitation robots: the HapticKnob (left) and the new ReHapticKnob (right).

References

• Metzger, J.-C., Lambercy, O., and Gassert, R. (2011). High-Fidelity Rendering of Virtual Objects with the ReHapticKnob - Novel Avenues in Robot-Assisted Rehabilitation of Hand Function, Proc. Haptics Symposium 2012.
• Lambercy, O., Dovat, L., Yun H., Wee S.K., Kuah C., Chua K.S.G., Gassert R., Milner T., Teo C.L. and Burdet E. (2011). Effects of a robot-assisted training of grasp and pronation/supination in chronic stroke: a pilot study. Journal of NeuroEngineering and Rehabilitation, 8:63.
• Metzger, J.-C., Lambercy, O., Chapuis, D. and Gassert, R. (2011). Design and characterization of the ReHapticKnob, a robot for assessment and therapy of hand function, Proc. IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pages 3074-3080
• Lambercy O., Dovat L., Gassert R., Burdet E., Teo C.L., Milner T. (2007). A haptic knob for rehabilitation of hand function. IEEE Trans Neural Syst Rehabil Eng. 2007 Sep;15(3):356-66.

Contacts

Collaborators
Dr. med. Dipl. Phys. ETHZ Fabio Conti (Clinica Hildebrand Centro di Riabilitazione Brissago)
Prof. Dr. Marco Santello (Arizona State University)

Financial Support
This work is supported by the NCCR Neural Plasticity and Repair, Swiss National Science Fundation and the ETH CHIRP1 Research Grant on Cortically-Driven Assistance Adaptation during Sensorimotor Training.