A man paralysed from the shoulders down has regained the ability to move his fingers thanks to a computer chip that sends signals from his brain to his muscles.
Ian Burkhart, 24, can now move his right hand in six different ways – including grasping and picking up small items – following the implant of the flexible chip two years ago. The procedure, published in the Nature journal, is thought to be the first of its kind.
Burkhart broke his neck six years ago after diving into waves during a beach holiday and has been unable to move ever since. After Ohio University scientists studied images of his brain they asked him to copy hand movements in videos and were able to implant the chip into his motor cortex – the area of the brain that controls movement.
The chip works by detecting the electrical activity that arises when Buckhart thinks about moving his hand and sends a message through a cable to a connected computer. Machine learning algorithms then determine which motion is being imagined and send it to an electrode sleeve wrapped around his arm.
The custom made sleeve has 130 electrodes embedded and delivers electric stimulation to the paralysed right forearm muscles.
"For the first time, a human with quadriplegia regained volitional, functional movement through the use of intracortically recorded signals linked to neuromuscular stimulation in real-time," the researchers wrote in their paper. The researchers added that their work offered new hope to people living with paralysis.
The system allows Burkhart to move his hand and wrist in half a dozen different ways: wrist flexion, wrist extension, middle flexion, thumb flexion, and hand opening. He has been able to grasp and move large objects, pour water from a glass, move his fingers to play Guitar Hero, and swipe a credit card.
"The first day that we hooked it up I was able to get movement. It was something really small — being able to open and close my hand — but it was something that I hadn’t been able to do for about three years," Burckhart said. The system, which initially gave him headaches, isn't perfect though.
At present it can only be used in a laboratory – where Burkhart has been training using it three times a week – and doesn't provide him with any sense of feeling.
The study recognised that other methods of 'reanimation' were possible but said the method presented "provides an advantage" over electrical stimulation methods such as EEG or EMG.
"These devices typically allow control over fewer movements than those demonstrated in this study, because of the relatively low information content of their control signal sources compared with intracortically recorded signals," the researchers explained.
Research around human-brain interfaces continues to develop at pace. In one case a 28-year-old using a prosthetic developed by Darpa was able to "feel" physical sensations for the first time in ten years. The prosthetic allowed the individual to be able to identify which mechanical finger was being touched by another person.
Scientists at École polytechnique fédérale de Lausanne, Switzerland, along with those from Italy have also developed an artificial fingertip that allowed an amputee to tell the difference between rough and smooth textures in real-time.
BrainGate, a company creating brain-machine interfaces, has developed a chip that can be inserted into the brain to control a robotic arm. The work from BrainGate has allowed its users to move the arm, for example, to raise a glass to their mouth. Braingate has been conducing a trial where it has tested paralysed people's ability to manipulate computer cursors, prosthetic arms and even wheelchairs using their brains.