In 1999, Nicolelis and some colleagues successfully constructed a working bionic arm for rats. Rats controlled the arm using implanted electrodes in the area of their brain responsible for voluntary muscle movements.
Since then, bionic limbs have come a long way. Implants are more invasive than EEG, but they can target specific neural regions (rather than scanning the whole brain). In research trials, bionic arms have allowed paraplegics to grasp and carry objects like chocolate or a cup of coffee. These arms are large, cumbersome, and primarily aimed at those with a high degree of paralysis.
For amputees, myoelectric prosthetics can translate neural signals from muscles in the remaining part of the limb into movement in the arm. Electromyogram sensors pick up on muscle movement in the upper limb and tell the prosthetic how to move. The FDA approved its first such mind-controlled prosthetic limb, the DEKA arm, earlier this year and similar devices are in clinical testing.
Other mind-controlled prosthetics use special electrodes inserted into two arm nerves (the ulnar and median) to give the wearer a basic sense of touch. Targeted muscle re-innervation, a surgical procedure that rewires some of the neural circuitry at the amputation site, can also improve an individual’s control and manipulation of a bionic prosthetic.