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Two paralyzed people successfully use robot arm

May 16, 2012|By Thomas H. Maugh II
  • A 58-year-old woman uses a robotic arm controlled by her own brain waves to grasp a cup and bring it to her mouth.
A 58-year-old woman uses a robotic arm controlled by her own brain waves… (The BrainGate Collaboration )

After years of work with primates and able-bodied humans, researchers have successfully demonstrated in paralyzed humans that an implanted electrode in the brain can successfully control the movement of a robot arm, allowing the patients to drink and perform other functions for the first time since they were disabled.

One female patient who had been a quadriplegic for 15 years was able to bring a cup of coffee to her mouth and sip it through a straw for the first time since she was disabled by a stroke.

"She had a smile on her face that I and the research team will never forget," Dr. Leigh R. Hochberg of the Department of Veterans Affairs said at a news conference announcing the results of the project. Their report was published in the journal Nature.

The achievement was the result of a collaboration, called BrainGate, between the VA, the National Institutes of Health, Brown University, Massachusetts General Hospital, Harvard Medical School and the German Aerospace Center's Institute of Robotics and Mechatronics in Oberpfaffenhofen. The German company devised the five-fingered robot arm, called Justin, and the other participants developed the implantable electrode and the computer programming necessary to use it.

The two patients involved in the study had suffered strokes that limited their movements to facial muscles and talking. The 58-year-old woman had her stroke 15 years ago, while a 66-year-old man had his only three years ago.

The electrode sensor, about the size of a baby aspirin, contains an array of 96 hair-thin electrodes and is implanted in the brain near the motor cortex, the part of the brain that directs movement.

Once patients had recovered from the surgery, they watched while researchers manipulated the robot arm, imagining that they were doing it themselves. Computers detected and recorded the resulting brain waves.

After several repetitions, the computer developed an algorithm that translated the brain waves into movements by the arm. The arm itself has sensors and protective software that stops motion gently if the arm encounters any object, such as the patient's face.

"I think about moving my hand and wrist," one of the two unidentified patients said. It "feels natural to imagine my right hand moving in the direction I want the robotic arm to move."

The arm itself is bulky and expensive, as are the computer equipment and programming required to run it. The arm is thus still very much a laboratory tool used to further development of the technology. Researchers hope eventually to use the sensor in the brain to control movements of the patient's own limbs, which would provide unprecedented mobility.

A video of a patient using the robotic arm is available here.

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