The myokinetic stimulation interface: development of a system for the generation of selective 90 Hz vibrations using remotely controlled magnets

Active hand-prostheses can significantly improve the quality of life of amputees. These multi-articulate, technologically-complex devices can perform different grasping tasks that allow amputees to recover some of the functionality lost due to the missing limb. Bidirectional prostheses can also provide sensory feedback to the patient. This information, if properly conveyed, can be incorporated into the patient's cognitive framework, thus improving the dexterity in the control of the device. This furthermore reduces the cognitive burden typically associated with unidirectional prostheses, whose control largely relies on visual feedback. The lack of additional feedback can potentially make the prosthesis feel unnatural, and might even lead to its abandonment by the patient. This thesis proposes a novel human-machine interface (HMI), coined myokinetic stimulation interface, potentially able to provide sensory feedback through high-frequency vibrations, directly applied to specific muscles of the amputee's forearm. These vibrations are generated using implantable permanent magnets, actuated by external coils that could be placed inside the prosthesis' sleeve. An overview of the state of the art techniques for the generation of sensory feedback, and for the untethered control of the motion of permanent magnests, as well as the results of in-vivo experiments regarding proprioception that have been carried out in the past are presented first. Details about the theory and the implementation of the device are presented next. The results obtained using a physical prototype of the device are presented and discussed, followed by the results obtained from in-vivo experiments using Sprague-Dawley rats. These experiments were performed to study the capability of the proposed stimulation technique to generate activation signals in peripheral nerves of the rats' forelimbs. The most relevant, concluding notions of this work are presented at the end.