Informing Ankle-Foot Prosthesis Prescription through Haptic Emulation of Candidate Devices

<p>Robotic prostheses can improve walking performance for amputees, but prescription of these devices has been hindered by their high cost and uncertainty about the degree to which individuals will benefit. The typical prescription process cannot well predict how an individual will respond to a device they have never used because it bases decisions on subjective assessment of an individual's current activity level. We propose a new approach in which individuals `test drive' candidate devices using a prosthesis emulator while their walking performance is quantitatively assessed and results are distilled to inform prescription. In this system, prosthesis behavior is controlled by software rather than mechanical implementation, so users can quickly experience a broad range of devices. To test the viability of the approach, we developed a prototype emulator and assessment protocol, leveraging hardware and methods we previously developed for basic science experiments. We demonstrated emulations across the spectrum of commercially available prostheses, including traditional (e.g. SACH), dynamic-elastic (e.g. FlexFoot), and powered robotic (e.g. BiOM® T2) prostheses. Emulations exhibited low error with respect to reference data and provided subjectively convincing representations of each device. We demonstrated an assessment protocol that differentiated device classes for each individual based on quantitative performance metrics, providing feedback that could be used to make objective, personalized device prescriptions.</p

Emulating prosthetic feet during the prescription process to improve outcomes and justifications

<p>The current process of prescribing prosthetic feet is hampered by imprecise classifications based on self-assessment, recommendations based on subjective prediction, burdensome justification requirements, and slow, costly testing of devices. These problems have been exacerbated by the introduction of robotic prostheses, which can improve gait performance for some individuals, but are very expensive. We propose an alternative process, in which a versatile robotic emulator is used to preview patient interactions with a range of prostheses, while objective data related to effort, stability, speed and preference are collected, all prior to prescription. Results from pilot testing with a prototype emulator system demonstrate accurate haptic rendering of a wide range of prosthesis classes and differentiation of user performance across these classes. Eventually, emulation-based prescription could reduce bias, cost and waste in the prescription process, while simultaneously improving patient outcomes.</p