Mind Reading Typing tool : For Paralysed People Is Fastest Yet

Mind Reading Typing Tool : For Paralysed People Is Fastest Yet

                              Three people with paralysis have learned to type by thought alone using a brain implant – at the fastest speeds recorded using such a system.

Two have motor neurone disease, also known as ALS – a degenerative disorder that destroys neurons associated with movement – while the other has a spinal cord injury. All three have weakness or paralysis in all of their limbs. There is a chance that those with ALS will eventually lose the ability to speak, too, says Jaimie Henderson, a neurosurgeon at Stanford University Medical Center in California.

People who have lost the ability to talk may be offered devices that allow them to select letters on a screen using head, cheek or eye movements. This is how Stephen Hawking communicates, for example. But brain-machine interfaces are also being developed in the hope that they may one day be a more intuitive way of communicating. These involve reading brain activity, either externally or via an implant embedded in the brain, and turning it into a signal that can be used to direct something in the environment.

At the moment, these devices are a little slow. Henderson and his colleagues wanted to make a device that was quicker and easier to use than those currently in trials.

Picking up speed

First the team placed a silicone patch, covered in a hundred tiny probes, onto a region of their volunteers’ brains called the primary motor cortex. This area is responsible for movement. The implant was then connected to a computer, via a wire.

As a participant thought about moving different body parts, the team’s computer translated the associated brain activity into movements of a cursor on a screen. By improving the speed at which the computer could decode the brain activity, the team was able to minimise the time between thought and cursor movement. “As we learn more about how the motor cortex works, we can create decoders that are better at approximating a person’s intent,” says Henderson.

Within a day, the participants learned to control the cursor well enough to select letters and type words on a screen. On average, the volunteers were able to type between six and eight words a minute. “It’s two to four times faster than what was previously achieved [using a brain-machine interface],” says Henderson. He says they are approaching half the speed at which a person with no motor disability would physically text.

The three volunteers were pleased with the device (see box, below): “This is like one of the coolest video games I’ve ever gotten to play with,” says Dennis DeGray. “And I don’t even have to put a quarter in it.” Another said it was “quite intuitive”.

“This device is great,” says Nicho Hatsopoulos at the University of Chicago in Illinois. “The most impressive thing is the number of characters they could type per minute.” But he says the device will have to be more durable and portable before it can be made commercially available. “Personally, I’d want something wireless, and proven to last for a long time,” he says.

For now, the brain-machine interface is only an experimental device. Henderson and his team will continue to test and develop it in other people with paralysis.

What’s on your Mind right now? Comment Below...