Neurally Integrated Lower Limb Prosthesis for Home and Community Use
Abstract
Individuals living with lower limb loss face many functional and psychosocial challenges related to their amputations. Compared to able-bodied individuals, lower limb amputees experience increased fall rates, lower balance confidence, higher ambulatory energy expenditure, and overuse of their intact limb. These deficits are partly attributed to lack of appropriate sensory input from their missing limb, which further limits their ability to quickly adjust motor responses based on prosthetic foot-floor interactions. These issues are of higher importance for Warfighters with limb loss who intend to regain maximum function and return to active duty. Most notably, fall incidence is higher among younger amputees compared to older ones, possibly due to participation in riskier behaviors or performance of a wider range of daily activities. In addition to the obvious physical and functional effects of amputation, limb loss can also have noticeable psychological consequences. Relative to national norms, Veterans with lower limb loss have reduced levels of perceived ability, poorer satisfaction with social role participation, poor body image, and reduced balance confidence. These physical and cognitive challenges can lead to activity avoidance and reduced social participation among Warfighters with limb loss, which can have a subsequent negative effect on quality of life at personal and professional levels, including their ability to return to active duty. Therefore, development of novel prosthetic devices to enhance whole-person performance is necessary. In our prior and ongoing studies funded by the Defense Advanced Research Projects Agency, Department of Defense (DOD), and Department of Veterans Affairs, we developed and are deploying a neuroprosthesis that restores plantar sensation to individuals with lower limb loss. This is achieved by electrically activating the remaining nerves in the residual limb via an implanted neural interface. Through extensive laboratory tests, we demonstrated that our technology successfully elicits sensations perceived instantaneously as if arising from the missing limb. Furthermore, these elicited sensations have shown to significantly improve standing balance stability and ambulation. In this proposed 4-year project, we aim to take the next logical step to understand the real-world benefits of this technology by investigating its effects when used freely at home and in the community during self-selected daily activities. We will enroll a total of six participants with lower limb loss. Each will receive two multi-contact, non-penetrating nerve cuff electrodes implanted around the remaining peripheral nerves located in the back of the thigh of the residual limb. A safe range of electrical currents will be delivered to the nerve cuffs to stimulate the nerve and elicit sensations as if they were arising from the missing foot. These sensations correspond to the location that pressure is applied to an instrumented prosthetic foot, with sensation intensity varying based on the magnitude of the pressure applied. Our team has already completed the technical development of a wearable, lightweight, self-contained version of this system (i.e., neuroprosthesis) suitable for use outside the laboratory. By conducting a 15-month-long home use trial, we will establish if the neuroprosthesis can provide reliable operation at home, in the community, and in rugged outdoor environments. Furthermore, we will determine its effects on functional and subjective outcomes during mobility-related activities of daily living. Additionally, we will incorporate effective fall prevention training developed in previous DoD-funded efforts so recipients can rapidly adapt their motor responses to the neuroprosthesis, compensate for destabilizing perturbations, and regain pre-amputation balance confidence and gait mechanics. This study will generate the required scientific evidence necessary for widespread di
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 04, 2024
- Source ID
- HT94252310623
Entities
People
- Hamid Charkhkar
Organizations
- Louis Stokes Cleveland VA Medical Center
- United States Army