A brain-computer interface allows a person to transfer thoughts and commands to a computer directly. Instead of using a keyboard, mouse, light pen or other input device, a user of such an interface simply thinks his or her commands and the computer responds to them.

Some of the latest work involves hooking a user up to electroencephalography sensors (better known as EEG sensors) that are connected to a computer on one end and the user's head on the other. The user wears a kind of cap with sensors on it designed to capture brain activity, and the interface measures the subject's brain responses and sends the information to a computer running a particular application such as a text input program.

Not surprisingly, private industry has gotten into the brain-computer interface development business alongside academia. It makes sense for them to do so, as the market for a reliable brain-computer interface could be quite lucrative, depending on the application for which it's used. Guger Technologies is one such company. At the CeBIT 2010 exhibition, the company unveiled the Intendix, which purports to let people type just by thinking of the letters that make the words -- in effect, typing in their head. The user wears an EEG-sensor cap and stares at a grid of letters that flash. When the letter flashes that the user wants to type, the Intendix registers the jump in brain activity and types the corresponding letter. The device is still pretty pricey, but it's easy to imagine how much it could help certain disabled people communicate more easily [source: Singularity Hub].

Emotiv is another company working in the brain-computer interface space. It markets EPOC, a "neuroheadset" that, like the Intendix, translates brain signals into computer commands, communicating wirelessly with the destination device [source: Emotiv].

It may yet be awhile before brain-computer interface devices and the programs that use them become commonplace, but their promise in the medical, military and entertainment arenas is undeniable. Perhaps they will one day replace touch-screens as the most "gee whiz" step away from mice and keyboards.