An interdisciplinary team of researchers from the University of Massachusetts Amherst has created a low-cost shoe insole containing force-sensitive resistors (FSR) that intends to enhance the treatment of mobility-impairing health problems such as stroke, Parkinson’s disease and osteoarthritis.
UMass Amherst assistant professor Sunghoon Ivan Lee. Image Credit: University of Massachusetts Amherst.
The insole measures two important kinetic parameters that are relevant to how people walk; that is, the ground reaction force (GRF) and center of pressure (CoP). Those parameters contain very important information, especially for people who have gait problems.
Sunghoon Ivan Lee, Study Lead Investigator and Assistant Professor, Manning College of Information and Computer Sciences, University of Massachusetts Amherst
The research was funded in part by Lee’s 2018 National Institutes of Health Trailblazer Award for Young Investigators, which was just published in IEEE Transactions on Biomedical Engineering and chosen as a featured article. Lee worked with kinesiologist Katherine Boyer, a gait specialist, and Ph.D. candidate Skylar Holmes, both in the School of Public Health and Health Sciences, in addition to senior author Brandon Oubre, an information and computer sciences Ph.D. candidate.
For people with neurological, musculoskeletal and other diseases that limit movement, data from the insole sensors might make it easier for physicians to track disease development over time and intervene early.
Currently, only expensive scales and special cameras that track reflective “dots” mounted to the body can be used to quantify these gait metrics in a lab.
It’s not easily accessible for people, especially those living in rural or underserved areas, so it’s difficult to monitor how these parameters evolve throughout the course of their therapy or rehabilitation. And the lab environment does not really represent how they walk naturally outside of the laboratory.
Sunghoon Ivan Lee, Study Lead Investigator and Assistant Professor, Manning College of Information and Computer Sciences, University of Massachusetts Amherst
The researchers’ goal was to develop a low-cost, wearable system that could correctly assess where a person’s pressure is placed on the sole while they walk.
For healthy individuals, there’s a normal way to put the pressure on the ground when you walk: You hit with the heel and then you will roll around the outer edge of your sole, then your toes will be in contact with the ground and then finally you take off. But these inexpensive sensors are not very accurate, that’s the caveat.
Sunghoon Ivan Lee, Study Lead Investigator and Assistant Professor, Manning College of Information and Computer Sciences, University of Massachusetts Amherst
As a result, the study team created an artificial intelligence system to analyze the data from the sensors, yielding precise information on the kinetic parameters. “That’s the key contribution of our paper,” Lee adds.
Despite the lack of force-sensitive resistor data, the insole devices were found to properly predict GRF and CoP based on models.
In the future, the researchers want to utilize insoles with sensors in clinics and patients’ homes to offer real-time data on their stride that can be wirelessly transmitted to health care specialists.
“There will be many hurdles to enable this vision, but that’s the ultimate thing that we’re aiming for,” Lee concluded.
Journal Reference:
Oubre, B., et al. Estimating Ground Reaction Force and Center of Pressure Using Low-Cost Wearable Devices. IEEE Transactions on Biomedical Engineering. doi.org/10.1109/TBME.2021.3120346.