Interesting item from my colleagues at the IDG News service today on a system being shown at the CeBIT show in Germany that literally uses brain waves to input commands on a computer screen. The system consists of a cap that fits over the user’s head, with a few dozen holes through which electrodes are attached so they rest on the scalp. The electrodes are connected via thin cables to a “biosignal amplifier,” which transmits the signals from the brain to a computer. Different parts of the brain are used to process different types of thoughts. Vertical and horizontal hand movements are handled in an area called the sensory motor cortex, for example, said Christoph Guger, CEO of g.tec, which built the BCI system.
According to g.tec’s Web site, a Brain-Computer Interface (BCI) provides a communication channel between the human brain and the computer. Mental activity leads to changes of electrophysiological signals like the Electroencephalogram (EEG) or Electrocorticogram (ECoG). The BCI system detects such changes and transforms it into a control signal which can, for example, be used as spelling device or to control a cursor on the computer monitor. One of the main goals is to enable completely paralyzed patients (locked-in syndrome) to communicate with their environment. The IDG News story says to use a BCI to move a computer cursor, the electrodes are placed over the corresponding part of the brain, where they read tiny fluctuations in voltage and feed them into a software program that analyzes them to figure out what the person is thinking. The software needs to be trained to read the signals, which takes several hours to do properly. The subject responds to commands on a computer screen, thinking “left” and “right” when they are instructed to do so, for example. Another test involves looking at a series of blinking letters, and thinking of a letter when it appears. The software “learns” what the brain’s voltage fluctuations look like when those directions or letters are thought of, Guger said. The system today is also quite slow – even a trained system can “read” only 18 characters per minute, or three or four words. Still, that may be helpful for a disabled person who cannot communicate through speech or movement. About 200 disabled people worldwide are using the software at home to communicate, according to Guger, although they need professional help to set it up. Another issue is accuracy. In a test at a conference in Austria about two years ago, 300 attendees were trained on the system for 30 minutes. After that time the system could figure out simple binary responses from most of the people 60 percent of the time – or “better than random,” Guger said. At Cebit, a colleague of Guber’s donned the BCI system and played the game “Pong” against a reporter. It has also been used to write letters, operate artificial limbs and steer a wheelchair. “It’s not safe enough for wheelchairs today though; if it reads a command wrongly you could veer off into the road,” Guger said. He sells his BCI systems mainly to scientists for research work. They are priced from $26,000 depending on their sophistication.
