A new glove with more than three dozen actuators across all five fingers and the palm, developed by Cornell researchers, aims to reduce swelling for people suffering from edema.
The glove, known as EdemaFlex, was proven safe for unsupervised home use in a seven-participant study, with hand volume decreasing by up to 25% after one 30-minute session.
It's the latest iteration of the technology from Cindy (Hsin-Liu) Kao, associate professor of human centered design in the College of Human Ecology, who previously developed KnitDema, which proved the concept of shape-memory alloy actuators delivering constant, gentle and sequential pressure to relieve swelling in a single finger. Then came MediKnit, which proposed a better way to fabricate soft medical devices - such as KnitDema.
"The lower extremities has always been part of our goal," said Kao, director of the Hybrid Body Lab. "We're also thinking about it in terms of women's health and in other body locations. We definitely see a lot of potential."
Kao is senior author of "EdemaFlex: Textile-Based Soft-Robotic Platform Toward Personalized Hand Edema Therapy," which published Feb. 24 in npj Flexible Electronics, a Nature publication. Co-authors include Dr. Joan Stilling, assistant professor of clinical rehabilitation medicine at Weill Cornell Medicine, who provided medical and design consultation.
Like KnitDema, EdemaFlex provides sequential pressure from the ends of the fingers toward the palm and wrist to push edematous fluid out of the hand. Thread-like shape memory alloy (SMA) springs woven into the knitted material are activated by a small printed circuit board, and compress sequentially to mobilize fluid out of the swollen area.
A total of 37 actuators - six in each finger and seven in the palm - combine to deliver sequential distal-to-proximal compression. The glove is fabricated from two varieties of yarn, including Sting yarn that's 17% spandex.
The duration and intensity of SMA spring compression is adjustable, depending on the needs of the individual patient.
One challenge, Kao said, was determining the patterning of the actuators so as not to interfere with the lymphatic or venous systems of the hand. That's where Stilling and her team came in.
"Clinicians help to identify specific patient needs based on their individual anatomy and reason for hand swelling, like patterning the compression location and intensity or adjusting the glove design to be more easily worn when the hand is difficult to open," Stilling said. "Dr. Kao and her team bring cutting-edge techniques and testable prototypes with visual feedback to the clinic. Our strong partnership allows for not only development of innovative and personalized devices, but also ones that are easily used, effective and address real-world problems."
For the study, seven people with clinically diagnosed hand edema participated in a three-day evaluation, including a one-day home-based trial. Clinicians conducted fittings with each patient and sent measurements back to the lab via a software design platform.
"An important part of what we did was the introduction of this software platform," Kao said. "It allowed us to take a bitmap of the hand and feed the information into the knitting machine and to produce a first prototype."
