(26) Development of a Take-Home Neurostimulation System to Provide Sensation to Upper-Limb Prosthesis Users

Introduction: Existing upper-limb myoelectric prostheses restore partial functionality but lack direct sensory feedback, placing higher demands on visual and cognitive attention, which, in many cases, leads to reduced use or abandonment of the prosthesis. However, advancements in neural interfaces have shown that electrical stimulation of residual nerves can provide intuitive sensory feedback. The goal of this work is to develop a prosthetic system for daily use that provides intuitive and useful haptic feedback.

Methods: The neural-enabled prosthetic hand (NEPH) system is among the first sensory neuroprostheses designed for long-term, real-world use, with careful consideration to usability, durability, and safety. Developed in collaboration with industrial and clinical partners, the NEPH system, features a fully implantable, wirelessly controlled intrafascicular neural interface designed to selectively activate small groups of sensory fibers within nerve fascicles in the user’s residual limb. It delivers precisely controlled electrical stimuli to residual nerves, evoking localized sensations in distinct regions of the phantom hand. When integrated with an instrumented prosthetic hand, the system provides graded, functionally relevant sensory feedback synchronized with prosthetic activity, including real-time information on grip force and hand aperture. The system was designed with priorities of ease of use, minimal wiring, and robust construction to support long-term, daily use in various settings. The NEPH system is being evaluated in a first-in-human, multi-site clinical trial under an Investigational Device Exemption from the FDA and IRB approval. In this study, participants are implanted with the system, which they first use in a controlled laboratory environment, followed by daily use at home to assess real-world performance.

Results: Preliminary findings suggest the system is safe for extended use and easily incorporated into daily routines; its fully implantable neurostimulator design reduces infection risk as it requires no percutaneous wiring. Minimal external components simplify donning, doffing, and charging, while participants report high satisfaction and confidence linked to intuitive feedback. The system’s robust construction also supports at-home usage on par with conventional myoelectric prostheses.

Conclusion: The NEPH system effectively integrates task-relevant sensory feedback into a prosthesis that remains practical for daily use. These findings demonstrate the feasibility of long-term, at-home neurostimulation systems and provide valuable insights for future improvements in device hardware, software, and clinical protocols. Additionally, data from ongoing long-term use studies will offer further understanding of the impact of sensory feedback on prosthesis use, functional performance, and quality of life.