The Guardian (London) - Final Edition

May 17, 2012 Thursday

Brain implant lets woman's thoughts move robot arm

BYLINE: Ian Sample Science correspondent


LENGTH: 560 words


A woman who lost the use of her limbs after a devastating stroke nearly 15 years ago has taken a sip of coffee by guiding a robotic arm with her thoughts.

The 58-year-old used a brain implant to control the robot and bring a flask of the coffee to her lips, the first time she had picked up anything since she was left paralysed and unable to speak by a catastrophic brain-stem stroke.

Doctors hailed the feat as the first demonstration of an implant that directly controls a reaching and gripping robotic arm by sensing and decoding the patient's brain signals.

The work is part of a US clinical trial of an experimental implant called BrainGate that doctors see as a first step towards devices that can bypass damage to the nervous system and allow paralysed people to regain control of their limbs and amputees to move prosthetics.

"At the beginning I had to concentrate and focus on the muscles I would use to perform certain functions," the woman said. "BrainGate felt natural and comfortable, so I quickly got accustomed to the trial."

Writing in the journal Nature, researchers described trials in which the woman, known as S3, and a 66-year-old man, referred to as T2, used the implant to control two different designs of robotic arm. The pill-sized device is surgically implanted a few millimetres into the motor cortex on the surface of the brain, where its 96 hair-thin electrodes pick up neural activity.

The patients learned to control the robot arm and pick up foam balls by imagining moving their own limb. Neither patient could control the robotic arm as well as natural arm movements, but doctors were still delighted with their progress.

"The results are the first peer-reviewed demonstration of a three-dimensional reaching and grasping task using direct brain control of a robotic device," said Leigh Hochberg, a neuroengineer at Brown University, Rhode Island. "One of the participants was also able to use the investigational BrainGate system to pick up a bottle of coffee and drink from it. This was the first time in nearly 15 years that she had been able to pick up anything solely of her own volition. The smile on her face when she did this is something that I and our research team will never forget."

The man who took part in the trial had a brain-stem stroke in 2006. He said: "I just imagined moving my arm and (the robotic) arm moved where I wanted it to go."

The BrainGate device plugs directly into the brain, but protrudes through the skull where it is connected to a computer by a cable. Researchers plan more advanced devices that can operate wirelessly and be implanted out of sight beneath the skin.

One concern with brain implants is that they steadily lose ability to sense neural signals as scar tissue forms around the ultra fine electrodes. In an encouraging sign from the latest trial doctors could still record useful signals from the brain five years after implantation.

In a second Nature article, Andrew Jackson, of the Institute of Neuroscience at Newcastle University, tells how, previously, patients used BrainGate to control a computer screen cursor and clench the fingers of a prosthetic hand. But he writes: "Restoring movements of the patients' own limbs should (be) the ultimate goal."



Years since patient S3 had a paralysing stroke. Now, with the BrainGate implant, she can 'thought control' a robotic arm

LOAD-DATE: May 17, 2012




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