Two groups have developed technologies for artificial arms that give people finer control over the limb than over conventional prostheses.

Credit: M. Ortiz Catalan et al., Sci. Transl Med. 6, 257re6 (2014)

Daniel Tan at the Louis Stokes Veterans Affairs Medical Center in Cleveland, Ohio, and his colleagues implanted electrodes in the arm muscles of two people, who each had a prosthetic arm and hand. Pressure sensors in the bionic fingers together with the embedded electrodes, which sent complex electrical patterns to residual nerves in the arm, enabled the subjects to sense different types of touch — such as tapping and constant pressure — without feeling the tingling caused by previous devices. This allowed them to handle delicate objects such as cherries.

In a separate study, Max Ortiz-Catalan at Chalmers University of Technology in Gothenburg, Sweden, and his co-workers attached an artificial arm (pictured) to a man's humerus bone, using the implant to direct electrodes to specific arm muscles. The electrodes detected the man's intended movements better than conventional skin sensors, allowing for more-precise control of the prosthesis.

Sci. Transl. Med. 6, 257ra138; 257re6 (2014)