Recent years have brought huge advances in prosthetics, but there is still much work to be done in replicating the intricacy of the human hand. Scientists have developed ways to let patients control prosthetic limbs with their existing nerves, but that communication is only one way — the prosthetic hasn’t been able to send anything back. That might be about to change as researchers are seeing success with a new system that can convey a sense of touch from a prosthetic limb.
By sending touch sensations from a prosthetic hand, researchers hope to give patients the ability to accomplish complex tasks currently impossible or impractical with an artificial limb. While control of grasping is much better than it used to be, it’s too easy for the patient to crush objects or lose their grip. The new system under development can send pressure data from 20 points on the hand to the peripheral nerves in the remaining limb, giving a sensation of touch.
The work done by researchers at Cleveland Veterans Affairs Medical Center and Case Western Reserve University relies on a device called a cuff electrode. The electrodes are small — just 7mm long and are implanted in the arm to stimulate three nerve bundles. A cuff electrode is seen as more viable in the long term because it only compresses the nerves to deliver signals through the myelin sheath. Other technologies put electrodes in direct contact with the nerve cells for more sensitivity, but cannot be used for long periods.