Upper limb amputees can be induced to experience a rubber hand as their own

TLDR

The study demonstrates that upper limb amputees can be induced to perceive a rubber hand as part of their own body. This was achieved by synchronously stimulating the stump and the visible index finger of a rubber hand placed 26 cm from the stump. The synchronous stimulation produced a convincing illusion of touch and ownership of the rubber hand, confirmed by subjective questionnaires, misreaching in a pointing task, and skin‑conductance responses, illustrating a simple method to transfer tactile sensations to prosthetic limbs.

Abstract

We describe how upper limb amputees can be made to experience a rubber hand as part of their own body. This was accomplished by applying synchronous touches to the stump, which was out of view, and to the index finger of a rubber hand, placed in full view (26 cm medial to the stump). This elicited an illusion of sensing touch on the artificial hand, rather than on the stump and a feeling of ownership of the rubber hand developed. This effect was supported by quantitative subjective reports in the form of questionnaires, behavioural data in the form of misreaching in a pointing task when asked to localize the position of the touch, and physiological evidence obtained by skin conductance responses when threatening the hand prosthesis. Our findings outline a simple method for transferring tactile sensations from the stump to a prosthetic limb by tricking the brain, thereby making an important contribution to the field of neuroprosthetics where a major goal is to develop artificial limbs that feel like a real parts of the body.