A team from the University of Lincoln in the UK are developing the first toddler-sized myoelectric prosthetic. The medical device, called SIMPA (Soft-Grasp Infant Myoelectric Prosthetic Arm), is made using 3D printing, which allows for dramatic cost reductions.
Myoelectric prostheses, which use sensors and muscle-stimulation to perform various hand functions, are commonly used by adults. However, because the devices are typically expensive to produce, they have remained less common for children, whose ongoing physical growth requires prosthetic resizing or replacement.
For this reason, low-cost 3D printed prosthetic hands have become a popular solution, as they can be customized to the child, printed locally and scaled up without a significant investment. In terms of function, however, these low-cost prosthetics have been more limited than myoelectric counterparts.
Now, thanks to work done at the University of Lincoln, 3D printing and myoelectric technologies are being combined to create highly functional but still low-cost prosthetics for children—and specifically toddlers.
The lightweight device is made up of a sensor-equipped armband which detects electrical signals conducted by the wearer’s muscles. These signals are then sent to soft grip fingers which translates them into hand motions, like gripping and holding.
“Many traditional active prosthetics are unsuitable for toddlers as they are very time consuming to construct and heavy,” explained Dr. Khaled Goher, Senior Lecturer in the School of Engineering at the University of Lincoln and the lead engineer on the SIMPA project.
“Our proposed system would utilise a seven-channel paediatric armband with motion sensors allowing infants to benefit from and become familiar with active prosthetics, with evidence showing that the earlier the exposure, the more likely for the prosthetics to be accepted and used throughout life.”
By leveraging 3D printing, it is possible to customize the SIMPA prosthetic to the child and produce components for it at a relatively low cost. This means that children can become accustomed to myoelectric prostheses at a younger age, making it easier to use them as adults—effectively reducing rejection rates for the devices.
“So far, the device has been tested for grasp force and effectiveness using a range of everyday objects including toys, bottles and building blocks but the next stage of the project is to test the prototype design on toddlers,” added Dr. Goher. “We are planning to use algorithm training which would utilise games to engage with the toddlers and attune the system to the ‘grab’ signals from the armband.”