Implantable Intelligent Engineered System to Enable Virtual Bidirectional Muscle-Prosthesis Mechanical Interaction for Amputees

Approximately 15,000 people in the United States suffer amputation of the forearm and loss of the hand each year, causing severe physical disability. Although externally worn robotic prosthetic hands are available, as many as 45 percent of users eventually abandon them because the devices lack natural movement control and sensory feedback. This project will develop and test the Myo-Bridge, a novel implantable robotic device that creates a virtual mechanical link between an amputee's residual muscles and an external robotic prosthetic hand. By restoring a more direct, mechanical connection between muscles and prosthesis, the Myo-Bridge is expected to dramatically improve the naturalness and intuitiveness of prosthesis control, enhancing the function, independence, and quality of life of people with upper limb amputation. These benefits will enable greater workforce participation and reduce burden on the healthcare system, advancing national health and prosperity. The project will support training of two graduate students, engage rising twelfth-grade students in hands-on research activities, and involve outreach to amputees and clinicians to guide the technology development process. The Myo-Bridge addresses three longstanding challenges in prosthesis technology: (1) replicating the smooth, fluid movement of a biological limb, (2) accurately estimating and executing the user's movement intent, and (3) restoring natural proprioceptive sensation of prosthesis motion and force. These challenges persist because modern prostheses rely on electromyogram signals and electrical stimulation for control and sensory feedback, which are inherently noisy and imprecise. The Myo-Bridge overcomes these limitations by leveraging the concept of extended physiologic perception and integrating advances in robotic teleoperation and haptic force feedback. Mechanical signals derived from residual muscle contraction will be sensed and transmitted wirelessly to drive a motorized prosthetic hand, while a dedicated feedback mechanism will convey information about prosthesis loading and constraint back to the user's muscles. The first research aim will design, fabricate, and test a physical prototype through an iterative engineering design process, culminating in an anatomically scaled prototype evaluated in a human cadaver model. The second will test a wearable version of the Myo-Bridge on able-bodied subjects and compare control performance against pattern recognition-based myoelectric control and the intact biological hand, using standardized clinical tests of hand dexterity, motion capture analysis, and a grip force control task. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.