Transcutaneous Electrical Nerve Stimulation at Proximal Brachial Plexus to Evoke Tactile Sensation in the Hand

Abstract Tactile feedback is critical for human interaction with external information. Similarly, tactile feedback can enrich the user’s sensations when using prosthesis. To explore a potential scheme for tactile feedback, this study applied a non-invasive Transcutaneous Electrical Nerve Stimulation (TENS) to elicit tactile sensations in the hand, which involved median nerve, ulnar nerve, and radial nerve. Ten able-bodied subjects (8 males, 2 females) were recruited to participate in the study. An array of 4 $$\times $$ 2 electrodes was positioned on the medial aspect of the brachii muscle’s short head in the upper arm, which is in proximity to the median nerve, ulnar nerve, and radial nerve. Different electrode pairs were randomly selected to elicit distinct sensations at various positions on the hand, and the subjects reported the sensory areas. Then, the sensory areas and sensory thresholds were confirmed through psychophysical methods. According to the experimental results, tactile sensations were elicited at different locations on the subjects’ hand through TENS of different electrode pairs. All subjects reported extensive and detailed sensory areas in the fingers, palm, and dorsum, corresponding to the sensory innervation areas of different nerves. The study effectively demonstrated the ability of TENS in evoking tactile feedback in the hand, paving the way for future optimization and development of prosthetic hands.