Bionic Fingers Offer a Solution for Partial Hand Loss

A new prosthesis system provides electronically powered artificial fingers that can type on a keyboard as well as grasp and manipulate objects.

ProDigits, a customizable platform adapted to the needs of individual patients, is composed of modular prosthetic fingers, with each one powered by a motor operating under myoelectric control. Building a prosthesis that closely resembles the patients missing anatomy is achieved by matching the sound hand, or any remaining fingers, to the prosthesis. Thumb solutions can be built using either powered or nonpowered options. Candidates for ProDigits must have amputation at transmetacarpal level or higher of one or more fingers; it is possible to support candidates with a portion of the finger remaining, however, this affects the aesthetics of the overall prosthesis.


There are two control strategies that can be employed to control the ProDigits: either myoelectric sensors that register muscle signals from the residual finger or palm, or a pressure sensitive switch input in the form of a force sensitive resistor (FSR) touch pad, which relies on the remnant digit or tissue surrounding the metacarpal bone to provide the necessary pressure to activate the finger. The appropriate input option is chosen based on the signal site, the available space, or patient preference. Bluetooth enabled solutions assist the clinician in adjusting the finer motor functions to the specific patient or user. A unique stall feature allows patients or users to point single digits for typing, hand gestures, or the use of a telephone. When grasping, a built-in detection feature tells each individual finger when it has sufficient grip on an object and, therefore, when to stop powering. The individual fingers then lock into position until the patient triggers an "open” signal, through a simple muscle flex. ProDigits are a product of Touch Bionics (Livingston, United Kingdom).

"Vocational and social reengagement is very important to a patient's rehabilitation after a traumatic event. Partial-hand injuries are, by their nature, challenging aesthetically and functionally,” said Stuart Mead, CEO of Touch Bionics. "With ProDigits, our goal is to provide all that we can to reinstate a patient's function and interaction with other people in their chosen lifestyle and career.”

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Touch Bionics