Up to now, despite the vast leaps made in the field of prosthetics over the last few years, amputees have been unable to feel fine textures. This could be about to change after the research done by Silvestro Micera and his team at the École Polytechnique Fédérale de Lausanne in Switzerland in the development of a bionic fingertip.
The device was pioneered with amputee Dennis Sørensen who lost his lower arm in a fireworks accident in 2003. The bionic fingertip, which has electromechanical sensors which deform on passing over a surface, was connected to electrodes in Sørensen’s upper arm. As the fingertip was passed over plastic surfaces manufactured to have different textures he recalls “I could tell the difference between smooth and rough – it was amazing”. Sørensen was able to differentiate between rough and smooth surfaces 96% of the time.
The scientists wanted to know if this sensation was analogous to the sense of touch from a real finger. To do this the device was tested on non-amputees by inserting an electrode into their upper arms rather like an acupuncture needle would be. The participants then wore a EEG cap to record their brain signals. The volunteers were able to distinguish between smooth and rough surfaces 77% of the time and their brainwaves were similar to those of Sørensen’s, suggesting that this device really does give an experience like touch in real fingertips.
With the findings of this experiment it is hoped that the electromechanical sensors can be integrated into prosthetics to allow amputees to manipulate objects with more ease. Calagaro Oddo of the Biorobitics institute in Italy claims the device could also be used in robotics in fields as diverse as “surgery, rescue and manufacturing”.
Image credit: Hillary Sanctuary EPFL
Video credit: New Scientist (https://www.youtube.com/watch?feature=player_embedded&v=zsuhazxu-HQ)