On Oct. 29, MIT researchers said a magnetic sensing system tested in three people with below-knee amputations could provide more precise muscle signals for controlling prosthetic limbs than conventional methods that use electrodes.
The system uses tiny magnetic beads implanted in remaining muscles and a sensor array worn on the skin to track the beads as they move through body tissue. It measures changes in the beads’ positions to estimate muscle mechanics, including muscle length and movement. This means it does not rely only on electrical activity linked to muscle contraction.
In the study, researchers tested the approach with three participants and compared its signals with electromyography (EMG), which is commonly used to measure muscle activity. The team reported that the magnetic measurements supported more accurate and responsive signals for prosthetic control. They also reported that, on the measures they evaluated, the system could match or outperform standard surface and implanted EMG.
The results suggest the system may help prostheses respond more naturally to a user’s movements. However, the small study does not show how well it will work in everyday use. The researchers say further testing is needed before the technology can be considered a practical option for routine prosthetic control.