Humans Can Use Multimodal Osseoperceptive Sensory Feedback to Enhance Their Sensorimotor Control of a Robotic Hand

The somatosensory function is essential for hand motor control, but it is lost following hand amputation. This study explores the potential of osseoperception — auditory and vibrotactile sensations evoked through bone stimulation — to be used as a multimodal supplementary sensory feedback modality for myoelectric robotic prostheses during object manipulation. By stimulating the wrist at the pisiform bone, the feedback system developed in this study conveyed to the user the two types of information from the digits of a robotic hand prosthesis: discrete contact events and continuous but transitory force feedback, evoking either auditory or vibrotactile sensations by varying the stimulation frequency. Able-bodied participants used the prosthetic hand to perform pick-and-lift tasks of a virtually fragile instrumented object with a predefined breaking threshold. The results demonstrated that when osseoperceptive feedback was provided, participants completed significantly more successful trials with improved motor coordination, enhanced task intuitiveness, and reduced cognitive workload. These findings suggest that osseoperceptive feedback, achieved by stimulating distal bones, is a reliable method to improve force control and overall subjective experience when using upper-limb prostheses, showcasing the potential of osseoperception in assistive robotic technologies.