After hooking up a computer to human brains, scientists were able to program the computer to "read" the thoughts of disabled patients, thereby enabling them to control the cursor on the screen.
The researchers are hoping the breakthrough will one day lead to ways to help disabled patients connect better with the world around them.
"We have been fundamentally interested in creating a brain-computer interface that could help people with severe disabilities interact with the world," said Dr. Eric C. Leuthardt, lead author of a paper describing the findings in the April 7 issue of the Journal of Neural Engineering.
People with spinal cord injury, paralysis, who have had a stroke in the part of the brain that controls speech, and even amputees who are unable to operate a keyboard or mouse may benefit from this, said Justin C. Sanchez, director of the Neuroprosthetics Research Group at the University of Miami Miller School of Medicine.
Engineered connection between brain and body
"Right now, people who have paralysis will use 'intermediate steps' to control things, like a puffer tube [that you breathe into] or a joystick," Sanchez said. "Interfacing directly with the brain opens up the possibilities. They'd be able to do more things and do things more naturally. They could think about doing something and express it immediately in a seamless way," he explained.
"People have a disconnect between the brain and the body," he added. "What we're trying to deliver back to them is an engineered connection between the brain and the body."
This is, in a sense, a "neural" or "speech prosthetic", in much the same way people have artificial arms or legs.
These researchers looked at four patients, aged 36 to 48, all with intractable epilepsy who were already undergoing placement of an electrode in their brain to determine where the seizures were originating.
The electrodes were then used to connect the brain to the computer.
How the study was done
Then, with the electrodes still in the brain, the researchers did very simple speech tests; for example, four simple-sounding words. They looked at the electrical "signatures" of each word or sound when it was being spoken or merely thought about to see if they could be distinguished from each other.
They could, and so Leuthardt and his team then programmed the signatures into the computer to correspond with certain instructions, such as moving the cursor left or right.
When the person said or thought the word or sound, they were basically able to manipulate the computer with their mind or speech with 68 to 91% accuracy within 15 minutes.
"We're starting to parse apart the different components of human speech and we're excited because speech is very rich. There's a lot of information we can convey with that," said Leuthardt, who is assistant professor of neurosurgery and of biomedical engineering at Washington University in St. Louis.
Similar brain-computer interfaces have been used to restore the sight of one patient and stimulate limb movement in others.
The scientists envision one day having tiny, permanent implants in people's brains. And not just the brains of disabled people.
"It would be a way to interface with your computer in a much more rich relationship than just a keyboard and a mouse," Sanchez said.
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