Robotic Hand Orthosis Providing Grasp Assistance for Patients with Brachial Plexus Injuries The brachial plexus is a network of nerves that transfers signals originating in the cervical spinal cord to the shoulder, arm, hand, and fingers. These nerves provide motor function and sensation to those structures. Traumatic injury to the brachial plexus in adults can result in paralysis of the upper limb in varying degrees of severity. Surgical intervention can restore motion and control to the shoulder, upper arm, and lower arm through muscle and nerve grafts. However, hand mobility and control is difficult to restore, resulting in severe disability and decrease in quality of life for patients with impaired functionality following such an injury. Robotic exoskeleton technology can be utilized to provide an assistive device that provides significant improvement in the mobility and dexterity of a paralyzed hand. The overall objective of this research is to design, fabricate, integrate, and test a lightweight and portable robotic hand orthosis intended to restore hand functionality through fully controllable individual finger actuation. This objective is based on the hypothesis that use of such a robotic hand orthosis will result in significant improvement of hand ability for adults with brachial plexus injury, as evaluated through the Southampton Hand Assessment Procedure (SHAP). To achieve this, several novel design aspects are incorporated. The use of miniature linear actuators and lightweight materials allows for the motors and sensors to all mount atop the dorsum of the hand, and eliminate the need for bulky external actuation units. In addition, the actuators have inbuilt force sensing capabilities to provide feedback on the force being applied to each individual finger, even before contact is made with a grasped object. Furthermore, wrist flexion/extension is powered, resulting in a more realistic grasping paradigm than is commonly found in robotic orthoses. Moreover, an intuitive control system will be designed in order to fully capitalize on the controllability of each finger, allowing for varied grasp geometries and motions. A summary of the specific aims of this study are: 1. Design and prototype the robotic hand orthosis with the goal of creating a uniquely dexterous, lightweight and portable device. In addition, the control methodologies required to exploit the full capabilities of the orthosis will be designed. This will result in the development of an experimental research platform to determine the viability of the design and hypothesis. 2. Perform a feasibility trial of the robotic orthosis device by providing it to a small cohort of adult patients suffering from paralysis due to a brachial plexus injury. The patients will be assessed via the SHAP, and their respective scores both with and without the orthosis will be evaluated to determine their level of improvement in dexterity and function.
The proposed research, the development of an innovative robotic hand orthosis with intelligent grasping control, is relevant to public health as it will restore a large measure of functionality to the paralyzed hand of a person who has suffered a brachial plexus injury. The proposed orthosis will utilize novel technology that will result in a device that is compact, portable, dexterous, and intuitively controllable while overcoming the disadvantages of previously developed orthoses that rendered them difficult to use. The restoration of functionality to ones hands will significantly improve their quality of life as well as their ability to again participate in the workforce and complete dexterous activities in their daily lives.
