Grants We Funded

Abstract

Impact Statement: Extremity amputation affects over 185,000 individuals in the United States annually and has debilitating functional consequences. Modern prosthetic devices offer advanced movement and sensory capabilities but are often abandoned due to significant cognitive burden. This is partially due to lack of a user-prosthetic interface that can convey stable, high-fidelity neural signaling needed for natural motor control and sensory feedback. The Composite Regenerative Peripheral Nerve Interface (C-RPNI) is an impactful development because it has the potential to facilitate bi-directional concurrent multimodal sensory and motor signaling, allowing for real-time intuitive closed-loop sensorimotor neuroprosthetic control.

Project Summary: While recent innovations have led to the development of advanced prostheses with multiple degrees of freedom and sensors for sensory stimuli detection, an ideal user-prosthetic interface that can tap into the prosthetic's full potential has yet to be realized. Lack of natural sensory feedback other than visual feedback and non-intuitive device control leads to significant cognitive burden and prosthetic abandonment in up to 75% of cases. To prevent prosthetic rejection, development of an interface that facilitates the neural signaling required for high-fidelity intuitive motor control and concurrent natural multimodal sensory feedback is critical. Current interfaces are hampered by inability to extract meaningful signals chronically, need for complex decoding algorithms, low spatial resolution, and therefore less recording and stimulation specificity. Our lab has developed the composite regenerative peripheral nerve interface (C-RPNI), which is a construct created by implanting transected peripheral nerves into a segment of muscle graft sutured to dermal graft. We have previously shown that the dermal component is innervated by sensory afferents while the muscle component is innervated by motor fibers. Following electrical stimulation, the C-RPNI can elicit separate sensory and motor signals without histological damage to the nerve. The long-term goal of this research is to develop a neuroprosthetic interface that restores natural limb motion and provides sensory feedback. The overall objective of the current study is to utilize C-RPNI for the facilitation of simultaneous yet independent multimodal sensory and motor signaling necessary for ideal prosthetic function. The central hypothesis is that the C-RPNI is a neural interface that can facilitate physiologically relevant bi-directional concurrent multimodal sensory and motor signaling, thereby allowing for a real-time sensorimotor control system. This central hypothesis will be tested through the pursuit of two aims: (1) identify the mechanosensory and proprioceptive sensory modalities that can be elicited with stimulation of C-RPNI; (2) determine feasibility of concurrent sensory and motor signaling by C-RPNI and whether sensory input via the C-RPNI will alter motor output during volitional ambulation. The results of these studies will vertically advance the C-RPNI closer to clinical fruition and provide a suitable neural interface for intuitive closed-loop sensorimotor neuroprosthetic control.

Biography
Widya Adidharma, MD completed her Bachelors of Science in Neuroscience and Human Biology from Michigan State University College of Natural Science on a full-ride merit scholarship and graduated with high honors. She obtained her Medical Degree from the University of Washington School of Medicine and was inducted into the Alpha Omega Alpha honor medical society. Throughout her undergraduate and medical school years, she won a number of research scholarships, published several peer-reviewed manuscripts and presented at multiple national conferences. She returned to Michigan for her residency in Plastic and Reconstructive Surgery at the University of Michigan. She has since joined the Neuromuscular Laboratory, where she will complete her research academic development time. She recently won a PSF Pilot Grant for her work in the Dermal Sensory Regenerative Peripheral Nerve Interface (DS-RPNI) and is co-editor of the upcoming 3rd edition of the textbook, Michigan Manual of Plastic Surgery. Dr. Adidharma combines her background in neuroscience and clinical training in plastic surgery to develop and lead translational projects in peripheral nerve injury.