In 1963, a decade before fictional TV astronaut and test pilot Steve Austin—aka "The Six Million Dollar Man"—was fitted with a bionic right arm and legs, researchers at Princess Margaret Rose Hospital in Edinburgh, Scotland, began developing electronic prosthetics to replace missing shoulders, wrists and hands. That technology is finally getting its due: Time magazine yesterday named i-LIMB Hand made by Touch Bionics one of the top 50 inventions of 2008.

Touch Bionics introduced the i-LIMB to the market last year. The prosthetic has five individually powered digits and is used by more than 400 patients worldwide, including at least five in the U.S. The i-LIMB Hand has myoelectric (muscle signal) controls that use electrical signals generated by the muscles in the remaining portion of a patient's limb to open and close its fingers. These signals are picked up by electrodes placed on the surface of the skin.

The i-LIMB is built to be modular—if one of its digits is damaged, it can be swapped for another. The robotic hand, powered by a lithium-ion battery, is capable of a number of different types of grips: "key grip,"  in which the thumb bends to the side of the index finger, allowing the user to hold onto thin items such as papers and business cards; the "power grip," in which all fingers and the thumb come together to create a full-wrap to grasp glasses, briefcases or other objects; the "precision grip," in which the index finger and thumb meet to pick up small objects and hold them when performing finer control tasks; and the "index point," in which the thumb and fingers close but the index finger remains extended (useful when dialing a phone or getting cash from an ATM).

Patients worldwide are already benefiting from Touch Bionics's technology. Among them: Kasey Edwards, an 18-year-old Floridian who lost most of his left arm to an alligator in June, is learning to use a $100,000 prosthetic arm that includes an i-LIMB connected to a carbon-fiber titanium limb extension from Orlando's Hanger Orthopedic Group. Semray Tas Ozer, a 25- year-old Turkish woman whose right hand was badly burned during childhood, earlier this year received an i-LIMB, which she hopes to use for archery (until now, she's used her teeth to draw back the bowstring). And 20 years after Mike Thompson of Jerome, Idaho, lost his hand in a truck accident, he's using a $75,000 i-LIMB to perform day-to-day tasks such as eating, drinking, slicing veggies and typing on his computer.

For a look at other advances in prosthetic limbs, check out Sam Boykin's September, 2008, Scientific American article "Open-Source Thinking Revolutionizes Prosthetic Limbs."


(Images courtesy of Touch Bionics)