Case Western Reserve University researchers have secured a $9.9 million grant from the U.S. Department of Defense Congressionally Directed Medical Research Program to launch a groundbreaking clinical trial testing sensory-enabled neural prostheses for upper limb amputees. The four-year study will recruit 12 participants to compare standard prosthetic devices with the university's innovative iSens neuroprosthesis system.
The iSens (implanted Somatosensory Electrical Neurostimulation and Sensing system) represents a paradigm shift in prosthetic technology by providing bi-directional communication between the user and device. The system uses electrodes implanted in the arm that detect muscle movements to control the prosthetic hand while simultaneously stimulating peripheral nerves to send tactile feedback from the prosthetic fingertips directly to the brain.
"People with upper-limb-loss deserve to have better technologies that can improve their lives," said Emily Graczyk, assistant professor of biomedical engineering at Case Western Reserve University and lead researcher on the project. Graczyk, who is also an investigator at the Louis Stokes Cleveland Department of Veterans Affairs Medical Center, emphasized that restoring touch sensation can profoundly impact multiple aspects of quality of life.
Revolutionary Technology Development
The neuroprosthesis technology has been in development at Case Western Reserve University since 2015, initially supported by an eight-year, $14 million grant from the Defense Advanced Research Projects Agency (DARPA). The research was featured in a 2023 segment on 60 Minutes, highlighting its potential to transform prosthetic experiences for amputees.
Dustin Tyler, the Arthur S. Holden Professor of biomedical engineering and study co-investigator, noted that the significant funding removes a major barrier to translation. "This grant will allow us to complete this clinical trial that wouldn't necessarily get venture capital investment at this stage," Tyler explained. Tyler also serves as director of Case Western Reserve's Human Fusions Institute, which focuses on expanding human capabilities through advanced, human-connected technology.
The researchers were surprised in early studies by how dramatically the sense of touch transformed the prosthesis from a sporadically used tool to something that genuinely felt like having one's own hand. An implanted neural control device communicates between the electrodes and prosthesis through Bluetooth technology.
Comprehensive Three-Phase Trial Design
The clinical trial features a meticulously designed three-phase structure, with each participant completing approximately 18 months of study involvement:
Phase One begins with a three-month initial testing period documenting how participants use their current prostheses. Following this baseline assessment, each participant undergoes outpatient surgery to implant electrodes and electronic modules in their arm. The research team then spends three to six months in laboratory visits setting up each participant's neuroprosthetic system, building personalized controllers for intuitive muscle signal control and calibrating nerve stimulation for optimal touch sensation relay.
Phase Two employs a crossover design where participants are randomly assigned to use either their existing prosthesis or the touch-enabled iSens research prosthesis. Participants complete regular surveys about usage patterns, task performance, and user experience while returning monthly for laboratory testing demonstrations. After this period, participants switch to the alternate device, providing direct comparative data.
Phase Three further randomizes participants into groups using the iSens prosthesis with either only touch sensation enabled or only advanced motor control enabled, followed by another switch period.
"We expect our neuroprosthesis to make life better for people with amputation," Graczyk said, "but we don't know if the biggest factor will be improved sensation or improved control, or both."
Multidisciplinary Collaboration
The research involves extensive collaboration across multiple institutions and specialties. Case Western Reserve University collaborators include Hamid Charkhkar, assistant professor of biomedical engineering and Cleveland VA investigator; Ronald Triolo, professor of biomedical engineering and executive director of the Advanced Platform Technology Center at Cleveland VA; and Ming Wang, professor of population and quantitative health sciences.
Clinical collaborators from Cleveland medical centers include Kevin Malone, chief of hand and upper extremity surgery at University Hospitals Cleveland Medical Center; J. Robert Anderson, orthopedic hand surgeon at University Hospitals and Director of Orthopedic Hand Surgery at Cleveland VA; Kyle Chepla, plastic surgeon at MetroHealth Medical Center; and Gilles Pinault, chief of vascular surgery at Cleveland VA. Linda Resnik, professor of health services, policy and practice at Brown University, also contributes to the research effort.
Broader Implications for Prosthetic Technology
The research addresses not only anatomical functionality but also the emotional and psychological needs associated with limb loss. According to Graczyk, having a sense of touch improves multiple aspects of quality of life, "including the sense of connectedness to loved ones, self-sufficiency, self-image and social interaction."
The technology's development represents a significant advancement over traditional prosthetics, which often lack feedback mechanisms and can feel disconnected from the user's lived experience. The iSens system's ability to make prosthetic limbs feel like extensions of the body rather than artificial devices could revolutionize how amputation is perceived and managed.
Researchers plan to begin enrolling participants early next year, with anticipation building in both the research community and among potential participants. If successful, the trial could pave the way for widespread adoption of sensory-enabled prosthetics and potentially open pathways for applications in other areas, such as rehabilitation for stroke patients or neurological disorders affecting motor function.
