Grasp Force Assistance via Throttle-Based Wrist Angle Control on a Robotic Hand Orthosis for C6-C7 Spinal Cord Injury

Individuals with hand paralysis resulting from a C6-C7 spinal cord injury (SCI) frequently rely on tenodesis for grasping. However, tenodesis generates limited grasping force and demands constant exertion to maintain a grasp, leading to fatigue and sometimes pain. We introduce the MyHand-SCI, a wearable robot that provides grasping assistance through motorized exotendons. Our user-driven device enables independent, ipsilateral operation via a novel control method, Throttle-based Wrist Angle (TWA), that allows users to maintain grasps without requiring continued wrist extension. A pilot case study with a person with C6 SCI shows an improvement in functional grasping and grasping force, as well as a preserved ability to modulate grasping force while using our device, thus improving their ability to manipulate everyday objects. This research is a step towards developing effective and intuitive assistive devices for individuals with hand impairments after SCI.