Researchers in California have created a way to place a call on a cell phone using just your thoughts. Their new brain-computer interface is almost 100 percent accurate for most people after only a brief training period.

The system was developed by Tzyy-Ping Jung, a researcher at the Swartz Center for Computational Neuroscience at the University of California, San Diego, and colleagues. Besides acting as an ultraportable aid for severely disabled people, the system might one day have broader uses, he says. For example, it could create the ultimate hands-free experience for cell-phone users, or be used to detect when drivers or air-traffic controllers are getting drowsy by sensing lapses in concentration.

Like many other such interfaces, Jung's system relies on electroencephalogram (EEG) electrodes on the scalp to analyze electrical activity in the brain. An EEG headband is hooked up to a Bluetooth module that wirelessly sends the signals to a Nokia N73 cell phone, which uses algorithms to process the signals.