Intraneural sensory feedback restores grip force control and motor coordination while using a prosthetic hand

Abstract

Objective. Tactile afferents in the human hand provide fundamental information about handenvironment interactions, which is used by the brain to adapt the motor output to the physical properties of the object being manipulated. A hand amputation disrupts both afferent and efferent pathways from/to the hand, completely invalidating the individual's motor repertoire. Although motor functions may be partially recovered by using a myoelectric prosthesis, providing functionally effective sensory feedback to users of prosthetics is a largely unsolved challenge. While past studies using invasive stimulation suggested that sensory feedback may help in handling fragile objects, none explored the underpinning, relearned, motor coordination during grasping. In this study, we aimed at showing for the first time that intraneural sensory feedback of the grip force improves the sensorimotor control of a transradial amputee controlling a myoelectric prosthesis. Approach. We performed a longitudinal study testing a single subject (clinical trial registration number NCT02848846). A stacking cups test (CUP) performed over two weeks aimed at measuring the subject's ability to finely regulate the grip force applied with the prosthesis. A pick and lift test (PLT), performed at the end of the study, measured the level of motor coordination, and whether the subject transferred the motor skills learned in the CUP to an alien task. Main results. The results show that intraneural sensory feedback increases the subject's ability in regulating the grip force and allows for improved performance over time. Additionally, the PLT Page 2 of 14 demonstrated that the subject was able to generalize and transfer her manipulation skills to an unknown task and to improve her motor coordination. Significance. Our findings suggest that intraneural sensory feedback holds the potential of restoring functionally effective tactile feedback. This opens up new possibilities to improve the quality of life of amputees using a neural prosthesis.

Transferrable Expertise From Bionic Arms to Robotic Exoskeletons: Perspectives for Stroke and Duchenne Muscular Dystrophy

“…This is important for the upper limb, as the sense of touch and proprioception is central for object manipulation [120]. Additionally, the restoration of sensory feedback enables natural closedloop control (Section III) and improves fine motor control in terms of coordination and dexterity [121]- [123]. However, it is important to consider that while amputees might have the level of commitment to consider invasive surgery, paretic patients or muscular dystrophy patients may not have it.…”

Biomimetic Approaches for Separated Regeneration of Sensory and Motor Fibers in Amputee People: Necessary Conditions for Functional Integration of Sensory–Motor Prostheses With the Peripheral Nerves

“…(D) Once the reconnection of the two ends of the injured nerve is achieved, these neurons will be able to reinnervate the former target tissue, divided into sensors and muscles; or in the case that the target tissue has been lost, the reconnection with bionic interfaces. (Micera et al, 2011;Zecca et al, 2017;Clemente et al, 2019;D'Anna et al, 2019;Sensinger and Dosen, 2020).…”

Psychometric characterization of incidental feedback sources during grasping with a hand prosthesis

“…In addition, the feedback can be provided using direct mechanical stimulation through skin stretch [22], movement on the skin [23], pressure cuffs/braces [24], or linear pushers [25][26][27]. More recently, several invasive solutions that directly stimulate the peripheral nerves [28][29][30][31][32][33] or somatosensory areas of the brain [34] have been presented.…”

“…However, these studies were conducted while controlling a virtual setup [35][36][37] and/or while blocking the incidental (visual and auditory) feedback sources [18,31,36,38]. Some recent studies showed benefits of feedback in realistic, clinical settings [32,[39][40][41][42][43]. However, other experiments in realistic settings failed to show functional improvements in performance [13,19,20,44,45] or demonstrated some benefits of feedback only in specific conditions [13,14,40].…”