Researcher Trips Amputees to Improve Prosthetic Design

He Huang, PhD
He Huang

He (Helen) Huang, PhD, assistant professor at the University of Rhode Island (URI), has spent the last year tripping amputees. She is interested in the events leading up to the tripping, and how those motions can be prevented.

“When we become unbalanced, our neural system reacts quickly and sends a signal to help us recover,” Huang said in a press release. “Our challenge is to see if we can detect these neural reactions fast enough to activate a mechanism in a patient’s prosthetic leg to stabilize them before they fall.”

Huang, who came to URI in 2008, received funding from the Rhode Island Science and Technology Advisory Council. She began collaborating with Susan D’Andrea, PhD, director of the Gait and Motion Analysis Laboratory at the Center for Restorative and Regenerative Medicine at Brown University in Providence, R.I., as well as with Nunnery Orthotics and Prosthetic Technologies in North Kingstown.

The research team recognized that there is room for significant improvement in balance for lower extremity amputees. New technology would decrease amputee falls and subsequent injuries.

Huang explains the study process to a participant
Huang explains the study process to a participant.
Image: URI/ Michael Salerno.

“Not enough research has been done on this part,” Huang said. “I think if this is successful, it’s going to be huge for the users of prostheses.”

According to a press release, researchers outfitted study participants with dozens of electrodes, shoes containing 99 pressure sensors and 40 light-reflective body markers, which were tracked by eight cameras positioned around the gait lab at the Providence VA Medical Center. The research team closely monitored each amputee’s muscle activity, and the ground reaction force on the prosthesis. Then, the team tripped the person.

To ensure the safety of the amputees while on the treadmill, Huang and her team hooked up the participants to a harness system that would catch them before falling when they tripped or stumbled.

The team finished collecting data and moved on to the processing stage, but preliminary results led to the development of a detector for slips and trips. Huang said she wants to determine how quickly and accurately these movements can be detected.

“As long as the person has muscle reaction, the detector will consistently recognize that event,” she said. “I would say the result is very promising.”

The grand challenge, Huang told O&P Business News, is integrating a sensor into both the socket and the prosthesis. Then, developing a control for the prosthesis.

She said she is confident in this research as a first step, but expects future collaboration from engineers, manufacturers, prosthetists and physicians before reaching the ultimate goal — a prosthesis that actively recovers from stumbles. —Stephanie Z. Pavlou, ELS


The fact that research is being done to examine “what happens” during a slip and trip is welcome news.

The advent of a prosthesis that has active stumble recovery would certainly allow many higher level (short transfemoral, hip disarticulations and hemipelvectomy) amputees to use a prosthesis or even increase their functional capabilities.

I also believe that the information gained may be beneficial in other respects. Once we understand the “muscle reaction” during a slip and fall, we may be able to use this information to help an amputee have a greater kinesthetic awareness of their prosthesis, resulting in the amputee being able to “feel” when they may be in danger of a fall.

In short, this study is the beginning between the mind-body (prosthesis) link that the amputee is missing.

— Shandon Hime, CP, FAAOP
founder, owner and head of clinical operations, Anatomical Designs

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