For patients who are paralyzed, even small daily tasks can be impossible. But an ongoing trial on prosthetics might be moving closer and closer to providing patients with motion using nothing but their brains.
The program is called BrainGate, and it attempts to put robotic parts - like prosthetic arms or legs - under the control of the patient's brain. By thinking about moving the arm, the patient could, in theory, actually move that arm. And recent work has shown that it could move beyond theory and actually work. In a paper released today in Nature, doctors describe a woman who was able to, using only the power of her brain, reach out for a drink and take a sip of water.
"The smile on her face was a remarkable thing to see. For all of us involved, we were encouraged that the research is making the kind of progress that we had all hoped," the trial's lead investigator, Leigh Hochberg, said in the press release.
The two patients in the study, a 58-year-old woman and a 66-year-old man were both unable to speak or move due to strokes several years ago. But with the BrainGate system they could move again - using their brains to control robotic arms.
Here's how it works:
There are sensors monitoring brain signals that go into a computer software. The software then turns these brain signals into digital commands that tell the robot what to do. The sensor on the brain is about the size of a small Asprin, and contains 100 electrodes recording the activity of brain cells. The little bundle is implanted into the patients motor cortex, the part of the brain that controls movement.
This is especially promising considering that the woman controlling the robotic arm had her stroke fifteen years ago. Some wondered if, after so long, the neurons in the motor area of the brain might simply shut down or not work anymore. But here they are, controlling a robot's arm to take a drink of water.
The Atlantic interviewed the woman - who's real name is Cathy Hutchinson - about her time with BrainGate. The first time she was able to do anything with her implanted electrodes she was shocked.
Cathy's device was implanted in 2005, and the researchers first target was for her to control a computer cursor. As Cathy concentrated on moving her hand, her efforts unspooled on screens in front of the researchers, who tried to use the information from her brain as a sort of virtual mind-controlled mouse. When the researchers turned control of the cursor over to Cathy's neurons, the cursor immediately began to move haltingly across the screen. Cathy couldn't believe her eyes. "I was numb with shock and disbelief," she wrote to me, "so I moved the cursor all over the screen."
Now, she's not just moving a mouse, she's moving a whole arm. Take that paralysis!
Obviously there's still a long way to go before the BrainGate system can be used clinically. Right now, there are only two individuals in their study (although they are recruiting more) and there are still lots of concerns. What if the device stops working after a while? What if some people can never learn to control the hand?
Despite these questions though, this is a promising first step, Roderic Pettigrew, director of the NIH's National Institute of Biomedical Imaging and Bioengineering, said in the press release. "The researchers have begun the long, difficult process of testing and refining the system with feedback from patients, and they've found that it is possible for a person to mentally control a robotic limb in three-dimensional space. This represents a remarkable advance," he said.
Image: The BrainGate Collaboration