Achieving Sense of Touch with Bionic Limbs and Prosthetics
Understanding the physical mechanisms and sense of touch in the biological world is vital to successful skin replacement and creation of bionic limbs that mirror the touch sensation.
For humans, the ability to experience a normal sense of touch is a high priority, but it is not always possible. If human skin has been damaged or a person is suffering from peripheral neuropathy (numbness or tingling) then restoring a biological sense of touch can be tricky. Likewise, it is a challenge to give prosthetic hands a basic touch-sensing ability, but a lot of progress is being made.
A new prosthetic hand recently invented in the United States has given amputees an ability to “feel” as they grasp and manipulate objects. Created by a team of biomedical engineers from Cochlear, Florida International University (FIU) and Arizona State University, the hand has demonstrated the viability of wirelessly enabled peripheral nerve stimulation to help restore critical function to people with upper limb amputations.
There are a wide variety of motorised prosthetic hands on the market, but these devices generally don’t provide wearers with skills to manage contact, force, or grasp of objects. The wearer just looks at the hand and the things they are trying to grab or manipulate and manages as best they can, as most prosthetics don’t have the sensory feedback to the limb needed to restore normal functionality.
In their creation of a prosthetic hand, Professor Jung and her colleagues from Florida International University drew on cochlear implant (bionic ear) technology to create a portable wireless system that includes a motorized prosthetic hand refitted with an electronic neuro-stimulator. Twelve fine wire longitudinal intrafascicular electrodes were placed in the nerves of the upper arm and connected to a neuro-stimulator implanted in the shoulder.
The end result is a wireless bi-directional communication of signals to and from the person’s own muscle and sensors on the artificial hand. This enables the wearer to open and close the hand and grasp objectives with force
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