BBC News has a fascinating short video report of a robotic hand that is connected to the nerve fibres of an amputated arm and which allows the patient to actually feel touches with the robot fingers.
Although it doesn’t mention it in the report, the technology is from the SmartHand research group who are attempting to use knowledge about the cognitive neuroscience of action and body sensation to make fully integrated naturally controlled prosthetics.
There’s an interesting part of the video where the patient says “When I grab something tightly I can feel it in the finger tips, which is strange because I don’t have them anymore”.
In other words, despite the fact that the robot hand feeds touch information into the nerve fibres into the arm stump, the patient feels the sensations ‘in’ the robot fingers.
This is essentially the ‘rubber hand illusion‘ and the same research group demonstrated exactly this in a recent experiment where they induced touch sensations in a robot hand by stroking it and the stump simultaneously.
This is interesting because a recent study found that sensations in people with intact arms only transferred to a realistic looking rubber hand and not a wooden one, whereas this research team uses a obviously false robot limb.
The fact that touches transfer to an obviously false hand for someone with an amputation but not for people with intact limbs is interesting, because it suggests that brain’s remaining body-image ‘maps’ for the amputated hand may be being recruited to enhance the illusion.