Man controls robotic arm with his mind
A man paralyzed by a gunshot more than a decade ago can shake hands, drink and play "rock, paper, scissors" by controlling a robotic arm with his thoughts, researchers have reported.
Two years ago, doctors in California implanted a pair of tiny chips into the brain of Erik Sorto. The chips decoded his thoughts to move the free-standing robotic arm. The 34-year-old has been working with researchers and occupational therapists to practice and fine-tune his movements.
It's the latest attempt at creating mind-controlled prosthetics. These can help disabled people gain more independence. In the last decade, several people outfitted with brain implants have used their minds to control a computer cursor or steer prosthetic limbs.
Here are some things to know about the new work, published by the journal Science:
Doctors at the University of Southern California implanted small chips into Sorto's brain during a five-hour surgery. That was in 2013. The sensors recorded the electrical activity of about 100 brain cells as Sorto imagined reaching and grasping.
Researchers asked Sorto to think about what he wanted to do instead of breaking down the steps of the movements. That was according to principal investigator Richard Andersen at the California Institute of Technology.
After weeks of imagining movements, Sorto trained with Caltech scientists and therapists at Rancho Los Amigos National Rehabilitation Center. They worked to get the robotic arm to move. The movements started with a handshake. They graduated to more complicated tasks. The sensors relayed their signals to the arm. Thus, they bypassed Sorto's damaged spinal cord.
Scientists have long strived to make robotic arms produce movements that are as natural as possible. Previous research targeted a region of the brain known as the motor cortex. It controls movement.
The latest work has zeroed in on a different area of the brain the posterior parietal cortex that's involved in the planning of movements. The hope is that this strategy will lead to smoother motions.
It's unclear whether the new approach is better. No side-by-side comparisons have been made yet. But it gives researchers a potential new target in the brain.
In 2012, a Massachusetts woman paralyzed for 15 years directed a robotic arm to pick up a bottle of coffee. Then she brought it to her lips. In another instance, a quadriplegic man in Pennsylvania used a robotic arm to give a high-five. He could also make it stroke his girlfriend's hand.
Erik Sorto has a caregiver at home, but he goes to the rehab center several times a week. He practices using the robotic arm.
Since suffering a gunshot wound 13 years ago, he longed to have a drink without help. The first time he tried with the prosthetic arm, he was so excited that he lost his concentration. That caused the arm to spill the drink. On the second try, he directed the arm to pick up the bottle and bring it to his mouth. Then he sipped through a straw.
It tasted "like a little piece of heaven," Sorto said.
Despite progress in the last decade, hurdles remain before brain-controlled prosthetics can help paralyzed people in their daily lives. Experts said computer programs must run faster to interpret brain signals. The brain implants must also be more durable.
Currently, wire connections run from a patient's brain to outside the skull. That increases the risk of infections. Future systems need to be wireless and contained within the body like pacemakers. That is according to experts J. Andrew Pruszynski of Western University in Canada and Jorn Diedrichsen of University College London. They wrote about it in an accompanying editorial in Science.
Critical thinking challenge: Why did researchers implant chips in Eriks brain instead of his arm?