Olympic volleyball player Kerri Walsh recently added a new routine to her training regimen. Three times a week, she spends about 20 minutes playing games on her iPad with a portable brain monitor strapped to her head.

This device is called Versus, and it was developed by a company called SenseLabs. It uses electroencephalography, or EEG, technology to monitor her brainwaves. When she appears calm and focused, her scores on the games go up. The idea is that the feedback will help her learn how to center her mind not just when she's playing these games, but when she's playing volleyball—and throughout the rest of her life as well.

The device uses a technique called neurofeedback. This has been around since the 1960s, but traditionally, the EEG equipment needed to practice neurofeedback was limited to research centers and specialized clinics. Now, devices like the Versus are bringing the technique into the homes of corporate executives, elite athletes like Walsh, and others.