Single-site non-invasive peripheral nerve stimulation with multidimensional encoding enables object differentiation...

Objective.The goal of this study was to evaluate the efficacy of a multidimensional encoding approach, delivered through a single site of noninvasive peripheral nerve stimulation (PNS), in facilitating object discrimination with a sensorized myoelectric prosthetic hand.Approach.Ten participants without amputation received transcutaneous electrical neural stimulation (TENS) coupled with a channel-hopping interleaved pulse scheduling (CHIPS) strategy of the median nerve at the wrist, whereas four participants with transradial amputation received TENS with CHIPS of the ulnar nerve on the residual limb near the elbow. Participants used a multiple-degree-of-freedom dexterous myoelectric prosthetic hand with force and aperture sensors, which provided signals that were mapped to stimulation values using the multidimensional encoding approach. This approach provided percepts of flutter frequency and intensity within a single sensory percept region. All participants were blindfolded and wore noise-canceling headphones during a task that required discrimination between six objects differing in size (two levels) and compliance (three levels).Main Results.All participants demonstrated performance significantly above chance level for object identification. Notably, all four participants with amputation effectively employed multidimensional percepts in their phantom limbs to differentiate between objects. Their performance was comparable to, and in some instances surpassed, that of participants without amputation.Signifcance.The findings indicate that the multidimensional encoding approach using TENS with CHIPS-based PNS reliably transmits meaningful sensory information, such as object size and compliance, to users of sensorized myoelectric prostheses. This approach enables the perception of complex sensations in the phantom limb, potentially reducing the number of required stimulation sites, and represents a promising advancement in haptic feedback systems aimed at mitigating prosthesis abandonment.