Non-invasive somatotopic proprioceptive feedback for closed-loop robotic hand aperture control

Clinical Snapshot

Key Findings

• P Value: p<0.001 (alternating visual conditions), p=0.017 (prolonged visual deprivation)

• Effect Size: Not reported - only statistical significance provided

• Primary Outcome: Aperture control error under visual deprivation conditions

• Nnt Or Sensitivity: TENS feedback achieved control accuracy comparable to visual input from first trial

• Confidence Interval: Not reported

Clinical Application

TENS is non-invasive, widely available, and relatively inexpensive technology suitable for prosthetic integration TENS devices are TGA-approved and PBS-subsidised for pain management; potential future application for prosthetic control pending further validation in amputee populations Individuals with transradial amputation requiring prosthetic hand control, though study conducted in healthy participants

Abstract

Objective.Current robotic prostheses developed for individuals with transradial amputation often lack physiological feedback, particularly proprioceptive information, which limits control precision and increases reliance on vision.Approach.This study investigates the effect of introducing non-invasive somatotopic feedback using transcutaneous electrical nerve stimulation (TENS) to convey hand aperture information, as an artificial form of proprioceptive feedback. Twenty healthy participants with intact limbs were divided into two groups: one receiving TENS-based feedback and one without feedback. Participants performed an aperture control task under visual and non-visual conditions, with some trials including a concurrent Stroop task to assess cognitive load. We hypothesized that providing non-invasive somatotopic proprioceptive feedback via TENS mitigates key control and integration challenges, leading to improved accuracy, faster learning, and reduced reliance on vision, without increasing cognitive demands.Main results.Under visual deprivation, participants receiving TENS feedback achieved significantly smaller aperture control errors than those without feedback, both under alternating visual conditions (p<0.001) and under prolonged visual deprivation conditions (p=0.017). From the very first trial, TENS-based feedback enabled control accuracy comparable to that with visual input. Although perceptual shifts affected control accuracy under dual-task conditions, the +TENS group maintained high cognitive performance and effective control toward perceived functional targets, suggesting that the artificial feedback nonetheless supported hand control in the presence of a secondary task.Significance.These findings highlight the potential of non-invasive somatotopic proprioceptive feedback delivered through TENS to provide physiologically meaningful information and support future strategies for restoring proprioceptive function in prosthetic hand users.

References

1. 1.Lecompte, O., Achiche, S., Haddad, M., Gesta, A., & Mohebbi, A. (2026). Non-invasive somatotopic proprioceptive feedback for closed-loop robotic hand aperture control. Journal of Neural Engineering. https://doi.org/10.1088/1741-2552/ae6d76