An investigation into the perceptual embodiment of an artificial hand using transcutaneous electrical nerve stimulation (TENS) in intact-limbed individuals

Abstract

Background:

Perceptual embodiment of an artificial limb aids manual control of prostheses and can be facilitated by somatosensory feedback. We hypothesised that transcutaneous electrical nerve stimulation (TENS) may facilitate perceptual embodiment of artificial limbs.

Objective:

To determine the effect of TENS on perceptual embodiment of an artificial hand in 32 intact-limbed participants.

Methods:

Participants were exposed to four experimental conditions in four counterbalanced blocks: (i) Vision (V) watching an artificial hand positioned congruently to the real hand (out of view); (ii) Vision and strong non-painful TENS in the real hand (V+T); Vision and Stroking (V+S) of the artificial and real hand with a brush; Vision, Stroking and TENS (V+S+T) watching artificial hand being stroked whilst real hand was stroked and receiving TENS.

Results:

Repeated measure ANOVA detected effects for Condition (P < 0.001), Block (P < 0.001) and Condition x Block interaction (P < 0.001). Pairwise comparisons detected more intense perceptual embodiment for V+S+T compared with V (P < 0.001) and V+T (P < 0.001), and for V+S compared with V (P < 0.001) and V+T (P < 0.001).The intensity of perceptual embodiment increased for later blocks (P < 0.001).

Conclusions:

A sensation of TENS was generated within the artificial hand in individuals with intact limbs and this facilitated perceptual embodiment. The magnitude of effect was modest.