Towards Magnetically Induced Skin Stretch for Hand Proprioceptive Feedback

Skin stretch feedback is increasingly recognized in rehabilitation and prosthetics for its ability to convey proprioceptive cues. Magnetically-induced skin stretch can offer interesting perspectives, not only for non-invasive stimulation but also for integration within the body. This study presents the first step towards the development of the MISS (Magnetically Induced Skin Stretch) device, a wearable system that uses magnetic interactions to provide proprioceptive feedback through skin stretch. By manipulating two magnets attached to the skin, the device aims to convey stretch sensations for hand proprioception. After preliminary Finite Element Method Magnetics simulations (FEMM), we came to the MISS design, which consists of a C-shaped ferromagnetic core with two solenoids at its ends. When the solenoids are powered, they generate a magnetic field that interacts with the magnets, causing controlled skin displacements to produce both stretch and pinch sensations. Psychophysical tests with the device positioned on the hand dorsum were performed to evaluate the skin deformations, whose outcomes support the device's potential application in proprioceptive feedback for prosthetics and hand rehabilitation.