Houston, Texas, USA : Devices that eavesdrop on neural activity can help paralyzed people command computer tablets to stream music, text friends, check the weather or surf the internet.
Three people with paralysis below the neck were able to navigate off-the-shelf computer tablets using an electrode array system called BrainGate2. The results, published in PLOS One, are the latest to show that neural signals can be harnessed to directly allow movement.
The two men and one woman had electrode grids implanted over part of the motor cortex, an area of the brain that helps control movement. The brain implants picked up neural activity indicating that the participants were thinking about moving a cursor. Those patterns were then sent to a virtual mouse that was wirelessly paired to the tablet.
Using nothing more than their intentions to move a cursor, the three participants performed seven common digital tasks, including web browsing and sending e-mail. One participant looked up orchid care, ordered groceries online and played a digital piano. “The tablet became second nature to me, very intuitive,” she told the researchers when asked about her experience, according to the study.
Another participant enjoyed texting friends, “especially because I could interject some humor,” he told the scientists. The system even allowed two of the participants to chat with each other in real time.
For the study, the researchers used tablets with standard settings, without installing any shortcuts or features to make typing or navigation easier.
Citation : P. Nuyujukian et al. Cortical control of a tablet computer by people with paralysis. PLOS One. doi:10.1371/journal. pone.0204566.
Image : CHECKING IN A system that translates brain activity into cursor movements allowed two paralyzed people to chat with each other using off-the-shelf computer tablets
Brain implant allows paralysed woman to control a robot with her thoughts
The BrainGate implant can decode a patient’s brain signals and instruct a robotic arm to reach and grasp objects.
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 paralysed and left 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 or amputees to move prosthetics.
“At the very 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 only 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 the patient’s neural activity.
In a series of sessions, the patients learned to control the robot arm and pick up foam balls by imagining moving their own arm and hand. Neither patient could control the robotic arm as well as natural arm movements, but doctors were still delighted with their progress.
“These 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 in 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 whole research team will never forget,” he added.
The man who took part in the trial had a brain stem stroke in 2006. Describing the experience afterwards – by spelling out letters with his gaze – he said: “I just imagined moving my own 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. More advanced devices are planned that can operate wirelessly and be implanted out of sight, beneath the skin.
One concern with brain implants is that they steadily lose their ability to sense neural signals as scar tissue forms around the ultrafine electrodes. An encouraging sign from the latest trial is that doctors could still record useful signals from the woman’s brain five years after her implant was fitted.
John Donoghue, a co-author on the paper, and director of the Brain Institute at Brown University, said there was still much work to do. “We’ll have truly met our goal when someone who lost mobility to neurological injury or disease can truly interact with their environment without anyone knowing that they are employing a brain-computer interface,” he said.
In an accompanying article, Andrew Jackson at the Institute of Neuroscience at Newcastle University, said the study underlined how basic research was a crucial driver for such technological advances. In previous years, patients have used BrainGate to control a cursor on a computer screen and clench the outstretched fingers of a prosthetic hand into a fist.
“At a time when experimentation using nonhuman primates is increasingly controversial, it is worth noting that the results reported … draw directly on previous neural interface demonstrations in monkeys and on decades of basic research into the control of arm movements,” Jackson writes.
“Although robotic arms may be of practical assistance, restoring movements of the patients’ own limbs should remain the ultimate goal,” he adds.