Science & Research

Prof develops prosthetic assessment tool

By
Contributing Writer
Wednesday, November 14, 2012

For upper limb amputees, adjusting to a new prosthetic arm can be difficult. While getting physically comfortable with new prosthetics is its own challenge, another difficulty is being able to objectively measure improvement over time.

In a study published last month in the journal Archives of Physical Medicine and Rehabilitation, Associate Research Professor in Public Health Linda Resnik and her colleagues describe a new metric to measure functional activities for adults with upper limb amputations. 

Resnik’s group makes up one of the core initiatives at the Veteran Affairs Center of Excellence for Neurorestoration and Neurotechnology, which opened last month and is a collaboration between the University and several medical centers.

The assessment tool allows clinicians to grade a patient’s performance on everyday tasks, such as zipping a zipper or using silverware to cut food – “things that you need to do to take care of yourself and perform basic household functions,” Resnik said.

“There aren’t any measurement tools like this,” Resnik said. Previously, generic self-report measures for persons with upper limb involvement problems such as stroke or arthritis were available, but there were no performance-based measures developed particularly for prosthetic users. 

The numerous catastrophic injuries from the Afghanistan and Iraq Wars developed the need to optimize the prosthetic upper limb devices, Resnik and her team wrote in the study. 

“In the field of amputation care and research, there hasn’t been a lot of work with upper limb amputees,” Resnik said. Only 3 percent of amputees suffer from upper-limb amputations, according to the study. But in the case of soldier amputees, 22 percent suffer from upper-limb amputations, Resnik said. “This was really calling the need to improve care for this group of people. There was a need recognized to serve the service members by advancing prosthetic technology,” she said, adding that current prosthetic devices are not as well developed. 

After the metric was developed, patients were tested with it during VA studies of the DEKA Arm, a state-of-the-art prosthetic device. 

The arm uses a “strap-and-go” method that allows the amputee to use the device without undergoing invasive medical procedures. The DEKA Arm allows for 10 powered degrees of freedom, compared to current commercial devices that only offer four. One distinctive facet of the DEKA Arm is its integration of foot control by the user that dictates the mechanistic movement of the prosthetic.

With such new technology comes the need to teach rehabilitators how the DEKA Arm functions and how to apply this knowledge to treating patients.

“What we’re doing now is writing up the results for the optimization technology,” Resnik said. She and her associates are now working on a home study in which users take the DEKA Arm home for three months after they have been trained with operating the device for one to two months. “This study will really tell us a lot on the effectiveness of the device,” Resnik said.

Because of the niche demand for such advanced technology, costs for these prosthetics are often prohibitive for amputees, according to the study. An above-the-elbow prosthetic can range anywhere from $7,000 to $100,000, depending on the sophistication of the device. A lifetime of prosthetic care for a bilateral upper limb amputee is estimated to cost a total of $1,992,782. 

Resnik said she hopes prosthetics will become more affordable for amputees generally. Though the VA and Department of Defense cover all the costs for veteran amputees, costs can be a prohibitive factor for non-veterans, Resnik said.

  • Anonymous

    Great job covering this! I think it’s important to spread awareness regarding the need to progress amputee prosthetic technology. It’s a small group, yes, but a group in much greater need than non-amputees can ever relate to.