A paralyzed woman in the Netherlands has become the first person to use a brain–computer interface to communicate by thought alone. It is the first time a brain–computer interface has been used at home in a person’s day-to-day life, without medical experts on hand to help.
The work was presented at the annual Society for Neuroscience meeting by Nick Ramsey, a specialist in brain-computer interfaces (BCI) at the Brain Center Rudolf Magnus at UMC Utrecht in the Netherlands. The research paper is published this month in the New England Journal of Medicine.
The patient, who is 58 years old and wishes to remain anonymous, was diagnosed with amyotrophic lateral sclerosis (ALS) in 2008. ALS, also known as Lou Gehrig’s disease or motor neuron disease, destroys the neurons that are required for voluntary muscle control. There’s no known cure. Within a couple of years, ALS usually causes complete paralysis. In this case, the patient still has control of her eyes, but that’s about it.
“It’s special to be the first,” says HB, who is 58 years old and wishes to remain anonymous. She was diagnosed with amyotrophic lateral sclerosis (ALS) in 2008. The disease ravages nerve cells, leaving people unable to control their bodies. Within a couple of years of diagnosis, HB had lost the ability to breathe and required a ventilator. “She is almost completely locked in,” says Nick Ramsey at the Brain Center of University Medical Center Utrecht in the Netherlands.
The device is surgically implanted into the brain, with two electrodes placed over the motor cortex region of the brain, which controls movement.
The exact placement of these electrodes is crucial – one has to be positioned over the part of the brain responsible for moving the right hand, and the other is placed over the part of the brain that kicks into gear when you want to count backward.
These electrodes are connected to a pacemaker-sized transmitter implanted into de Bruijne’s chest, and this transmitter is able to wirelessly communicate with a computer program displayed on a screen in front of her.
When de Bruijne watches the screen, she’ll see a square moving over letters. Once the square has landed on a letter she wants to use, she must imagine moving her right hand to click on the letter.
Of course, she can’t move her right hand, but her brain still produces the same signal that it would if she could, and the electrodes pass this signal on to the transmitter, to be passed on to the computer program.
After just six months of training, de Bruijne can use the system with 95 percent accuracy.
The device has pros and cons.
Placing electrodes on the surface of the brain is a good compromise between using sensitive but invasive deep electrodes and superficial EEG, which sits on a person’s skull, says Nicholas Hatsopoulosat the University of Chicago in Illinois. And because the system is powered wirelessly, it is invisible to others – something that many candidates for brain implants say is important to them.
The uncomplicated nature of the system is what makes it so suitable for home use. “It’s an extremely simple system, and doesn’t require any fancy computers,” says Ramsey. The downside of this is that the device is unlikely to be able to be used for more complex tasks, such as controlling robotic limbs, for instance, says Andrew Jackson at Newcastle University in the UK. “There’s a limit to the amount of information you can get,” he says.
Having said that, it is a useful approach for those who are paralyzed, whether from motor neuron diseases such as ALS or as the result of a severe stroke, for example. “For these patients, it could be a really important thing,” says Hatsopoulos.
Ramsey and his colleagues hope to trial the system in other individuals. Now that his team has improved the tablet’s software, Ramsey expects the next volunteer to be able to learn to use the device more quickly. More sophisticated software that is better able to predict and complete words based on the first couple of letters could also speed things up.
Source – newscientist.com