A woman paralyzed from the neck down has been able to feed herself chocolate and move everyday items using a brain-controlled robotic arm. Aided by tiny electronic implants in her brain she could move the robotic limb almost as freely and naturally as people move a human limb. In a study published in the online version of The Lancet medical journal, the DARPA-backed scientists announced the robot hand that offers far more accurate and natural movements than any previous prosthetic limbs.
Jan Scheuermann, a 53-year-old patient, was diagnosed with spinocerebellar degeneration 13 years ago, a rare degenerative disease that wears away brain and spinal structures. She cannot voluntarily move her arms or legs.
Less than a year after she told the research team, “I’m going to feed myself chocolate before this is over,” Ms. Scheuermann savored its taste and announced as they applauded her feat, “One small nibble for a woman, one giant bite for BCI.”
Scheuermann was surgically implanted with microlectrodes that recorded brainwaves in the motor cortex. The electrodes pick up signals from individual neurons and computer algorithms are used to identify the firing patterns associated with particular observed or imagined movements, such as raising or lowering the arm, or turning the wrist, explained lead investigator Jennifer Collinger, Ph.D. That intent to move is then translated into actual movement of the robot arm, which was developed by Johns Hopkins University’s Applied Physics Lab.
Two days after the operation, the team hooked up the two terminals that protrude from Ms. Scheuermann’s skull to the computer. “We could actually see the neurons fire on the computer screen when she thought about closing her hand,” Dr. Collinger said. “When she stopped, they stopped firing. So we thought, ‘This is really going to work.’”
Within a week, Ms. Scheuermann could reach in and out, left and right, and up and down with the arm, which she named Hector, giving her 3-dimensional control that had her high-fiving with the researchers. “What we did in the first week they thought we’d be stuck on for a month,” she noted.
Before three months had passed, she also could flex the wrist back and forth, move it from side to side and rotate it clockwise and counter-clockwise, as well as grip objects, adding up to what scientists call 7D control. In a study task called the Action Research Arm Test, Ms. Scheuermann guided the arm from a position four inches above a table to pick up blocks and tubes of different sizes, a ball and a stone and put them down on a nearby tray. She also picked up cones from one base to restack them on another a foot away, another task requiring grasping, transporting and positioning of objects with precision.
At the end, the volunteer completed the tasks with a success rate of up to 91.6%, and more than 30 seconds faster than at the start of the trial. The researchers said they were sure this is a success as they used an exhaustive benchmark test designed to identify genuine changes and root out flukes or anecdotal evidence.
“The participant did the manoeuvres with co-ordination, skill and speed almost similar to that of an able-bodied person,” the study’s lead author, Prof. Andrew B. Schwartz of the University of Pittsburgh and his co-authors said in Sunday’s online issue of the medical journal the Lancet.
Next step: texture, temperature and wireless
The next step for BCI technology will likely use a two-way electrode system that can not only capture the intention to move, but in addition, will stimulate the brain to generate sensation, potentially allowing a user to adjust grip strength to firmly grasp a doorknob or gently cradle an egg.
After that, “we’re hoping this can become a fully implanted, wireless system that people can actually use in their homes without our supervision,” Dr. Collinger said. “It might even be possible to combine brain control with a device that directly stimulates muscles to restore movement of the individual’s own limb.”
For now, Ms. Scheuermann is expected to continue to put the BCI technology through its paces for two more months, and then the implants will be removed in another operation.
“This is the ride of my life,” she said. “This is the rollercoaster. This is skydiving. It’s just fabulous, and I’m enjoying every second of it.”