Archive for February, 2009
Patients Test an Advanced Prosthetic Arm
by andreas on Feb.25, 2009, under medical devices
By surgically rearranging the nerves that normally connect to the lost limb, physicians have developed an intuitive way for amputee patients to control a robotic arm.
Todd Kuiken and colleagues at the Rehabilitation Institute of Chicago first reported the technique in a single patient in 2007, and now they have tested it in several other patients. The patients could all successfully control the advanced prosthetic, which features motorized shoulders, elbows, wrists and hands. They could move the arm in space, mimic hand motions, and pick up a varietyt of objects, including a water glass, a delicate cracker, and a checker rolling across a table.
The motorized arm prostheses most commonly used today co-opt existing shoulder movements to control the hand, elbow or wrist on the limb. These devices can be frustrating and slow: the user must consciously contract those muscles to trigger a movement, and only one movement can be performed at a time.
Kuiken has developed an entirely new kind of interface. Using a surgical procedure called targeted muscle reinnervation, surgeons transfer nerves that previously carried signals to the amputated limb to muscles in the chest and upper arm. The rerouted nerves then grow into the muscles, which contract when the patient thinks about moving the lost limb. Those signals are read by sensors on the prosthetic limb and translated into movement.
More information is available from Technology Review.
