/ 7 March 2006

Brain-controlled device could help the disabled

Researchers in Berlin have come a step closer to developing a device that will enable people to write and manipulate objects by reading their mind.

The so-called mental typewriter that translates thoughts into cursor movements on a computer screen will be on display at the computer technology fair CeBIT, which opens in the German city of Hanover on March 9.

”It’ll be our first public presentation,” says Mirjam Kaplow, spokesperson for the Fraunhofer Institute for Computer Architecture and Software Technology, which is developing the project along with the Department of Neurology at the Charite hospital.

The teams led by professors Klaus-Robert Mueller and Gabriel Curio have spent several years working on the Brain Computer Interface — a system which allows for a direct dialogue between man and machine.

The long-term objective of the research is to create a brain-controlled device that could allow people with severe disabilities to communicate with the outside world.

Even if a person who is completely paralysed cannot move his eyes left or right he can still think with the left and right parts of his brain. These thoughts or signals would be enough to activate the device.

Signals from the brain are measured by 128 electrodes affixed to the subject’s scalp, similar to an electroencephalogram (EEG). With the help of a software programme, specific signals are picked out among the nebulous mass of information.

The computer’s self-learning capacity allows it to identify individual brain patters and constantly improve its performance, says Mueller.

”It’s like being at a cocktail party when you have to absorb what the person opposite you is saying above the din of music, the clinking of glasses and the sound of other voices,” Mueller told Deutsche Presse-Agentur.

By analysing neural signals it is possible to determine before the actual movement takes place whether a person intends to move his or her right or left hand, for example.

”In one session the subject has different groups of letters to his left and right, which he picks out in his mind. After several more steps, he can choose a single letter,” says Kaplow.

Another variation allows the thought process on the right side to move an arrow in a circle and that on the left side to click on individual letters.

”This way it takes five to 10 minutes to write a sentence,” according to Kaplow.

A lot of time is taken up affixing the electrodes to the volunteer’s scalp, a procedure which usually last for about one hour.

”The breakthrough will come when we develop a contact-free EEG, something that looks like a cap, says Kaplow, who expects progress on this front during the current year.

Such a mobile electroencephalogram could be used by the emergency services to examine injured patients at the scene of an accident, she says.

Other research groups in Germany and the United States are working on similar interface systems.

At one project in the southern German city of Tuebingen, volunteers have to learn how to control their thought processes. That is not the case in Berlin, where the computer does that for them.

Brain-computer interfaces could also spread to the entertainment industry, creating a whole new class of video games. The could also be integrated into car safety systems by braking the vehicle in response to a driver’s thoughts. – Sapa-DPA