Replacement Fingers Offer a Touch of Hope
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13 April 2010
By Anne Eisenberg
Eric Jones sat in a middle seat on a recent flight from the New York area to Florida, but he wasn’t complaining. Instead, he was quietly enjoying actions that many other people might take for granted, like taking a cup of coffee from the flight attendant or changing the channel on his video monitor.
These simple movements were lost to Jones when the fingers and thumb on his right hand were amputated three years ago. But now he has a prosthetic replacement: a set of motorized digits that can clasp cans, flimsy plastic water bottles or even thin slips of paper.
Jones’s prosthesis, called ProDigits, is made by Touch Bionics in Livingston, Scotland. The device can replace any or all fingers on a hand; each replacement digit has a tiny motor and gear box mounted at the base. Movement is controlled by a computer chip in the prosthesis.
ProDigits was released commercially last December, said Stuart Mead, the chief executive of Touch Bionics. About 60 patients have been fitted worldwide, he said, and some have been wearing it for four years. The cost is $60,000 to $75,000, including fitting and occupational therapy.
Prodigits may be opened and closed not only by sensors that pick up muscle contractions, but also by dime-size pads put at the base of the fingers to detect pressure exerted by remnant bone. Jones starts the action by flexing or relaxing a muscle in the palm. Sensors in the prosthesis pick up the signals sent by the muscles and send the message to the computer chip that controls the motor.