O&P Technology:
Soaring into the New Millennium...
Part 2
| an excerpt from the
article:
O&P Technology: |
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| The Myoelectric PCU Link: The Next-Best Thing to Being There |
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Michael Tompkins, Animated Prosthetics, Inc.,
Greensboro, North Carolina, realized that in order to improve the
performance of myoelectric arms, "We must always know what's going on
inside that arm, and we must be able to readily adjust it." This
objective prompted research that led him to develop a system he started
patient testing about three years ago. Tompkins didn't want to announce the success of his ACS (Animation Control System) prosthetic arm until new longer lived batteries were available- and in 1996, he adapted the new lithium ion/lithium polymer batteries for prosthetic use, working in cooperation with three different battery manufacturers. Yet word spread so rapidly that currently more than 50 systems have been fitted and are in use. What is it that makes this largely unheralded new system so unique and popular? Just six letters: ACS and PCU. While the ACS mounted inside the prosthetic arm monitors and controls all functions related to the operation of the hand and wrist, the PCU (Prosthesis Configuration Unit) uses its freestanding, compact five-inch video screen to display readings from the ACS. Prosthetists can view real-time readings while the patient is wearing the prosthesis and can make appropriate adjustments and view immediate feedback to check the success of those adjustments. Since information is transferred between ACS and PCU by radio waves, the patient can move freely and naturally for more accurate readings. The prosthetist can monitor movements even from a different room, so children can play unselfconsciously. Since changes in the patient's capability, muscle tone, and electrical signal control occur continuously, the ACS/PCU allows the prosthesis to be adjusted and customized to the patient's status today, Tompkins emphasizes. The latest development in the system, introduced in December 1999, allows interaction via the Internet or modem/phone line. Practitioners can arrange an Internet consultation with Tompkins or another animation specialist regarding an unusual or problematic case. On his remote PCU, Tompkins will be able to view the same readings the patient's ACS is simultaneously sending to the prosthetist's PCU screen, thus Tompkins can point our meaningful indicators, suggest adjustments, or make them himself; and observe the immediate results of those adjustments. The Internet conference capabilities of his system are still evolving, Tompkins observes. "It's still so new, and the possibilities are so extensive, it's going to take time to develop them all properly." What's Next? What does Tompkins foresee in the future, both for his system and electronic prostheses overall? "We're working toward a virtual office," Tompkins points out. "Within the next couple of years, we should be able to send the prosthetist all he needs to fit a patient along with a camera or video device so we can watch as he fits the patient, effectively teaching and advising as he gets his initial 'hands-on' training with a new system." This method could be used for cases beyond the initial training stage, as well, Tompkins acknowledges, if prosthetists just want backup or a second opinion on a difficult case. "Through the camera, we'd be right with him, to advise and assist." Tompkins views this as an integrated part of the product, and one that's "not too far out, even today. All the parts and pieces exist now. The limiting factors are today's bulky hardware and bandwidth limitations on the Internet. It will be a lot easier very soon; we should be there within the next two years," he confirms. The same principle can be used to serve patients in remote areas. The product would include a video device to allow remote adjustment by patients in their own homes, says Tompkins, as the process is monitored via the PCU. "Although we can build artificial hands to perform an incredible range of precision functions," he notes, "we won't be able to achieve better performance until we're able to extract more specific information from the patient, using new techniques to track and identify how the brain sends specialized commands through the nerves. "Someday- maybe ten or 15 years in the future- we'll be surgically connecting prostheses directly to nerve endings. But until then, we'll need better patient sensing devices, and battery technology must keep up, too," he adds. "Patients claim that prosthetic arms are still too heavy now." He points out that the six-inch circuit board they used in their prostheses five years ago is now ice-cube sized. "I think within the next year and a half or two, we'll see a whole new family of batteries that will outperform the lithium ion; and all prosthetic control functions will also be integrated into a single chip." Tompkins is also working to establish the first foundation for research and development for upper arm prosthetics, especially for children. "It takes time and funding to progress in all the directions we need to explore and improve," he points out, "and other foundations don't fund medical research and development." |
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Reprinted with permission |