Patients Put on Thinking Caps

SAN FRANCISCO -- Any geek worthy of the moniker has dreamed of connecting his or her brain directly to a computer for blissful freedom from keyboard and mouse. For quadriplegics, that ability would give life a whole new dimension.

If people with physical handicaps could control a computer by just thinking, they could also operate light switches, television, even a robotic arm -- something the 160,000 people in the United States who can't move their arms and legs would surely welcome.

Work in that brain-computer interface, or BCI, technology has ramped up considerably in the past five years. More than half of the scientific papers on the topic were published in just the past two years. Also, by connecting their patients' brains directly to a computer, researchers have seen improvement in patients' ability to control a cursor.

Cyberkinetics is leading research on BCIs in the private sector. Last year the company enrolled its first patient, Matthew Nagle, in a clinical trial to test its BrainGate system. From his wheelchair, Nagle can now open e-mail, change TV channels, turn on lights, play video games like Tetris and even move a robotic hand, just by thinking.

"Not bad, man, not bad at all," Nagle says in a video as he uses BrainGate to control a hand for the first time since he was stabbed in the neck during a fight at Wessagussett Beach in Weymouth, Massachusetts. The stab wound severed his spine and left him paralyzed and on a respirator.

The device, which is implanted underneath the skull in the motor cortex, consists of a computer chip that is essentially a 2-mm-by-2-mm array that consists of 100 electrodes. Surgeons attached the electrode array like Velcro to neurons in Nagle's motor cortex, which is located in the brain just above the right ear. The array is attached by a wire to a plug that protrudes from the top of Nagle's head.

The electrodes transmit information from 50 to 150 neurons through a fiber-optic cable to a device about the size of a VHS tape that digitizes the signals. Another cable runs from the digitizer to a computer that translates the signal.

Video

Watch Cyberkinetics' BrainGate in action. (23 MB, requires Windows Media Player)

But other researchers are working on simpler, noninvasive BCIs. Jonathan Wolpaw, a professor at the Wadsworth Center in New York, published a paper in December 2004 in the Proceedings of the National Academy of Sciences showing that his noninvasive electroencephalogram, or EEG, cap could pick up brain signals at least as well as Cyberkinetics' invasive technology.

Both patients and their doctors would prefer not to open the skull to implant a BCI, but it's not yet clear whether a BCI sitting outside the head will be as good at picking up brain waves as an implanted device. Experts generally thought the answer was no until Wolpaw published his results.

"It's clear that noninvasive methods can be a lot better than most people gave them credit for," he said. "How much better they can get and how much better invasive methods can get is all up in the air."