Imagine a person who is confined to a wheelchair but can still get around through nothing less than the power of thought.
They outfitted volunteers with caps with EEG sensors, and asked them to steer a helicopter on a computer screen through a series of randomly generated rings that appeared on the screen ahead of it. There were no hand controls, no joysticks. They could only try to will the helicopter forward with their minds.
It worked surprisingly well, Dr. He and his colleagues reported in the current issue of the online journal PLoS One. Eighty-five percent of the time, the volunteers could steer the virtual helicopter accurately.
"People have never done anything like this using noninvasive techniques," said He in a telephone interview. There have been other experiments before, but the most successful required that electrodes be surgically implanted in the brain. In one famous but sad case, Massachusetts researchers were able to get a young quadriplegic man to steer his own wheelchair -- but he ended the experiment, partly because he hated having wires inside his skull.
"Our technique was noninvasive," said He. The BCI -- short for brain-computer interface -- "is approaching the reliability that used to be done only by invasive procedures, though I will not say that it is better yet."
The challenge in using EEG signals is that they are, in the jargon of scientists, "noisy." The brain generates minute amounts of electricity as one thinks, and sensors can detect it, but readouts can look like random vibrations, and it is hard to tease out, say, a signal that means you want to turn left or right.
Earlier this year a team at the Berlin Institute of Technology in Germany reported they could detect drivers' intent to hit the brakes when they were at the control of a car simulator. But that was a relatively simple signal -- to brake or not -- and it came all of 130 milliseconds before the drivers actually tried to stop the car.
"While this may not seem [like] much, it may be enough to prevent accidents," said Stefan Haufe, the lead researcher, in an email to ABC News.
The Minnesota experiment was small -- three young female volunteers -- but the task was more ambitious. They set the EEG sensors to detect a particular brain wave called the sensorimotor rhythm.
"This was three-dimensional," he said . "The helicopter had to approach the ring, move forward, and go through without hitting it."
So it's one step at a time. But could it someday help a disabled person, without surgery, to use a robotic arm, or maneuver in the real world?
"We are always thinking of practical uses," said He. "That's the purpose of doing science."