Exploring transcutaneous electrostimulation for proprioceptive feedback in upper limb prostheses: a pilot study

Myoelectric upper-limb prosthetic users frequently encounter challenges related to proprioceptive deficits, which can impair their ability to perceive limb position and movement. As a result, there has been growing interest in developing strategies to enhance sensory feedback in these users. One promising approach is the use of transcutaneous electrostimulation (TES) to modulate kinesthetic perception and improve proprioception.

This study consists of two experiments. In the first experiment, TES was applied to the finger flexor muscles of ten able-bodied participants and one prosthetic user to explore its effects on kinesthetic perception. In the second experiment, TES was combined with a myoelectric prosthesis in an object discrimination task. Three able-bodied participants and one prosthetic user were asked to distinguish between two cylinders of different sizes using their prosthetic limb, with the goal of assessing the potential of TES to enhance feedback during functional tasks.

In the first experiment, TES evoked the illusion of finger extension, exceeding 1 cm in able-bodied participants and reaching up to 4 mm in the prosthetic user. In the second experiment, TES facilitated object discrimination, with able-bodied participants achieving over 80% accuracy and the prosthetic user exceeding 85% under different conditions.

TES holds promise as a non-invasive approach for enhancing proprioceptive feedback in prosthetic users, with initial results indicating its potential to improve kinesthetic perception. However, challenges such as the occurrence of unintended tactile sensations highlight the need for further refinement of the technique. Future studies will be needed to refine TES parameters and to investigate its integration within more structured experimental settings, in order to better evaluate its potential in real-world prosthetic applications.