Forget speech-recognition software: How about typing a letter just by thinking it? In a quiet corner of the Cebit trade show a small Austrian company is showing a "brain-computer interface," a technology that could one day transform how we use computers, play video games and even talk to each other. It sounds like science fiction but is a clever application of science and technology. The system does not really read thoughts; rather, it measures fluctuations in electrical voltage in the brain and translates them into 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 shown at Cebit. 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.