Bionic hand – i-LIMB

Remember “Star Wars” and Luke’s artificial hand? Our reality isn’t too far away because Scottish company called Touch Bionics developed a “bionic hand” for amputees, called the i-LIMB. i-LIMB is one of the most sophisticated prosthetic hand commercially available, as it lets the wearer assume different grips by sensing electrical impulses in the muscles in their upper arm. That enables delicate grip while holding small objects.

The inclusion of a thumb that can, like the human thumb, be rotated into different positions enables important grip configurations, many of which have not been available to amputees before. The grasp of the hand is much more like that of a human hand with the articulating fingers able to close tightly around objects.

Built-in detection tells each individual finger when it has sufficient grip on an object and, therefore, when to stop powering. Individual fingers lock into position until the patient triggers an open signal through a simple muscle flex.

Whereas previous myoelectric hands could only be opened and closed, the i-LIMB Hand offers numerous different grip patterns.

The i-LIMB Hand relies on some of the most advanced control software yet seen in the prosthetics industry. This software provides speed and grip-strength control to the device while patients generate signals to control the device in a way that does not differ from how traditional devices operated in the past. Two small metal electrode plates, which detect the minute electrical signals generated by the remaining muscles in the limb stump, are placed against the skin to pick up signals. Traditionally one electrode is placed on the top of the forearm and the other on the bottom.

Patients usually have a sensation that their hand still exists despite it being amputated, something often referred to as ‘phantom’ feelings. When encouraged to generate a strong signal, the patient is often asked to move and flex their missing hand to generate a strong control signal. Before too long, these reflexes become intuitive.

It’s an impressive-looking device, and it certainly seems to have made a big impression on those who have tested it. But it’s also just one of many novel prosthetic technologies out there which need to be perfected in order to make it more natural and useful.