Robot-Assisted Rehabilitation of Forearm and Hand Function After Stroke

Abstract

Stroke is the leading cause of adult disability in industrialized countries, affecting more than 10,000 people every year in Singapore. Brain damage most often results in strong impairment of the arm and hand motor functions in stroke survivors, which critically affects their activities of daily living (ADL) such as eating, manipulating objects, or writing. Therefore, physical rehabilitation is performed in hospital centers using intense arm and hand training, electrostimulation, or drug treatment. The results obtained with these therapies suggest that it is possible to partially restore hand function in stroke subjects and thus improve their quality of life. In particular, studies have shown that intense practice of repetitive movements can help improving the strength and functional use of the affected arm or hand. Robot-assisted rehabilitation is a recent approach to stroke therapy which promises to redefine current clinical strategies. Indeed, robotic devices can increase the intensity of therapy, objectively measure subjects' performance, progressively adapt assistance/resistance to the users' abilities, and propose motivating virtual reality exercises to perform therapy. This thesis investigates robot-assisted rehabilitation after stroke, and presents the development of a new robotic device, the Haptic Knob, to train hand, wrist and forearm function. This robot is developed to exercise grasping and forearm pronation/supination, two fundamental tasks required in activities of daily living, and among those stroke survivors desire to recover most. The Haptic Knob considers the biomechanical constraints of the human hand, is adaptable to various levels of impairments, and can provide comfortable interaction. Further, the device is compact, safe and easy to use. Motivating game-like exercises are implemented, where subjects have to interact with the robot, actively perform movements or generate grasping force while receiving interactive visual, sensorimotor or psychological feedback. This approach facilitates concentration, motivates training and stimulates motor learning.To validate the design and evaluate the feasibility of a therapy with the developed robot, a pilot study is conducted with chronic stroke subjects using the Haptic Knob, in combination with two other robotic devices specially developed for arm and finger rehabilitation. This study is one of the first to propose stroke survivors a personalized robot-assisted therapy at all levels of the arm, i.e. arm, hand and fingers. In a second step, a larger clinical study using the Haptic Knob only is conducted to evaluate the potential of this device as a rehabilitation tool. Results demonstrate the positive effects of robot-assisted therapy with the Haptic Knob, as participants to the studies show significant improvements in arm, wrist and hand motor function. Further the proposed therapy helps in decreasing impairments such as weakness and abnormal muscle tone observed in stroke subjects, leading to noticeable improvements in hand and wrist function that were maintained after the completion of the therapy. The results of this thesis provide new arguments in favor of robot-assisted stroke rehabilitation and contribute to improve our knowledge on motor recovery after stroke.