Wireless Non-Invasive Advanced Control of Microprocessor Prostheses and Orthoses II

Multiple orthotics and prosthetics users would benefit from sensors that can collect physiological information from the user and transmit it wirelessly to the prosthesis. For example, prosthetic sockets have long been one of the primary sources of complaints for both upper- and lower-limb amputees. However, if a user decides to utilize osseointegration in place of wearing a socket, there would no longer be a convenient place to house the electrodes within the socket. These electrodes could be hard-wired back to the prosthesis, but the cables would likely be snagged and require frequent repairs. In addition, these tethered sensors will make donning the prosthesis more difficult. Wireless transmission of physiological data would not only be advantageous for osseointegrated patients, but also to clinicians that fit patients with conventional sockets. For example, there are often times when physiological information from locations proximal to/outside the socket could potentially be used as additional control inputs with conventional socket fittings. Additionally, upper limb prosthesis users generally don’t have the option to improve their comfort and suspension with a prosthetic liner since EMG electrodes must touch the skin to transduce the myoelectric signal. This also means that they cannot use prosthetic socks for volume measurement, as is often seen with lower limb prosthesis users. Seeing the value of liners and socks in those with lower limb absence along with the discomfort reported from those who wear upper limb sockets, it would be reasonable to assume that upper limb prosthesis users would also benefit from the ability to improve their socket comfort and volume management with prosthetic liners and socks. To address these issues, Liberating Technologies, Inc., along with our colleagues from Worcester Polytechnic Institute (WPI), propose to continue development of the ASTERISK wireless sensor toolkit to make these sensors suitable for a larger scale take-home clinical trial. These improvements include miniaturizing the form factor, upgrading to the latest communication protocol, performing power optimization, implementing battery charging, and other ruggedization activities. System capability expansion is also planned through increasing the number of nodes supported and interfacing with existing prosthetic technologies. Mobile application developments will implement sensor calibration and control sensor mapping along with status reporting and diagnostics. Our overall clinical hypothesis is that, after implementing the described technical enhancements, allowing users to wear a liner with their myoelectrically controlled prosthesis will allow them to realize the benefits of liners and therefore increase their overall satisfaction with the prosthetic device while not sacrificing functional performance.