Mental typewriter

A computer controlled by the power of thought alone has been demonstrated at a major trade fair in Germany.

The device could provide a way for paralysed patients to operate computers, or for amputees to operate electronically controlled artificial limbs. But it also has non-medical applications, such as in the computer games and entertainment industries.

The Berlin Brain-Computer Interface (BBCI) ? dubbed the "mental typewriter" ? was created by researchers from the Fraunhofer Institute in Berlin and Charité, the medical school of Berlin Humboldt University in Germany. It was shown off at the CeBit electronics fair in Hanover, Germany.

The machine makes it possible to type messages onto a computer screen by mentally controlling the movement of a cursor. A user must wear a cap containing electrodes that measure electrical activity inside the brain, known as an electroencephalogram (EEG) signal, and imagine moving their left or right arm in order to manoeuvre the cursor around.

"It's a very strange sensation," says Gabriel Curio at Charité. "And you can understand from the crowds watching that the potential is huge."
Learning algorithms

Curio says users can operate the device just 20 minutes after going through 150 cursor moves in their minds. This is because the device rapidly learns to recognise activity in the area of a person's motor cortex, the area of the brain associated with movement. "The trick is the machine-learning algorithms developed at the Fraunhofer Institute," Curio says.

John Chapin, an expert in using implanted electrodes to control computers, agrees EEG sensing technology is advancing rapidly. "There's been a lot of progress on the non-invasive side in recent years," he told New Scientist.

The German researchers hope to develop a commercial version of the device as an aid for paralysed patients and amputees.

Chapin adds that brain-computer interfaces could have a range of uses beyond the medical. "Signals from the brain give you a fraction of a second advantage," he says. The device could make a novel game controller and be used in other ways. The researchers have even begun testing the machine as a driving aid, as it can sense a sudden reaction and control a vehicle's brakes before even the driver can.

The next stage is to develop a cap that does not have to be attached directly to the scalp. This should make the device easier to use and cause less skin irritation for the wearer.