Amputees weigh risk against opportunity in considering new prosthetic technology

SAN ANTONIO — Patients with limb loss may have different priorities for prostheses than the researchers who develop new devices, said a speaker at the American Orthotic and Prosthetic Association National Assembly, here.

Susannah Engdahl, MS, and colleagues at the University of Michigan conducted a survey of adults with major upper limb amputation to ascertain whether patients are willing to accept a level of risk in order to try new technological advancements in prosthetics. Engdahl is a doctoral candidate in the Department of Biomedical Engineering at University of Michigan.

Susannah Engdahl

Susannah Engdahl


The anonymous survey of 104 participants included questions about four types of prosthetic technology: myoelectric prostheses; targeted muscle reinnervation (TMR); peripheral nerve interfaces (PNI); and cortical interfaces (CI). The researchers hypothesized amputees would be more willing to try noninvasive devices but would be more willing to try invasive techniques that promised higher levels of functionality.

Survey participants were recruited from the University of Michigan Orthotics and Prosthetics Center and from online forums and support groups.

Among all participants, 92% had unilateral limb loss and 84% underwent amputation due to trauma or congenital deficiencies.

The researchers found participants were more willing to try noninvasive devices overall.

“The myoelectric device was the most popular and the cortical interfaces were the least popular. This fit with our hypothesis,” Engdahl said.

Many survey respondents said they would not be open to undergoing brain surgery no matter the benefits of CI, she said. However, Engdahl said overall respondents were more open to invasive devices than expected, with 25% to 40% of patients expressing willingness to try a CI depending on the performance capabilities it offered.
The survey included six performance levels which survey respondents weighed against the perceived risks of the devices. Performance levels from lowest to highest included ability to open and close the hand; the ability to open and close the hand and rotate the wrist; ability to perform a simple grasp; ability to perform several types of grasps while controlling force; ability to perform fine tasks such as writing with a pen; and ability to perform fine tasks and experience touch sensation.
“Our two most advanced performance levels, which were fine motor control and sensation, were actually the two least popular of the six performance levels,” Engdahl said.
Engdahl said the results show the need for patients to be included in prosthetic research so new devices reflect their needs and values.
“Close communication between patients, clinicians and researchers is important as we continue to develop these devices,” Engdahl said. “We can do all the research we want, but if patients are not interested in using the devices that we come up with, there is a problem.”

Engdahl and colleagues hope to expand the study and are still recruiting participants. For more information, visit – by Amanda Alexander

Reference: Engdahl S. Surveying the interest of individuals with upper limb loss in novel prosthetic control technologies. Presented at: American Orthotic and Prosthetic Association National Assembly; Oct. 7-10, 2015; San Antonio.

Disclosure: Engdahl reports the study received funding from the University of Michigan Office of Research, the NIH and the National Science Foundation.

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