A convincing twin of Darth Vader stalks the beige cubicles of a Silicon Valley office, complete with ominous black mask, cape and light saber. But this is no chintzy Halloween costume. It's a prototype, years in the making, of a toy that incorporates brain wave-reading technology.

Behind the mask is a sensor that touches the user's forehead and reads the brain's electrical signals, then sends them to a wireless receiver inside the saber, which lights up when the user is concentrating. The player maintains focus by channeling thoughts on any fixed mental image, or thinking specifically about keeping the light-sword on. When the mind wanders, the wand goes dark.

NeuroSky worker Cynthia Lee wears a headset the company says can read brain waves and send signals wirelessly to control games.
(Paul Sakuma/Associated Press)

Engineers at NeuroSky Inc. have big plans for brain wave-reading toys and video games. They say the simple Darth Vader game — a relatively crude biofeedback device cloaked in gimmicky garb — portends the coming of more sophisticated devices that could revolutionize the way people play.

Technology from NeuroSky and other startups could make video games more mentally stimulating and realistic. It could even enable players to control video game characters or avatars in virtual worlds with nothing but their thoughts.

Adding biofeedback to Tiger Woods PGA Tour, for instance, could mean that only those players who muster Zen-like concentration could nail a putt. In the popular action game Grand Theft Auto, players who become nervous or frightened would have worse aim than those who remain relaxed and focused.

How it works

NeuroSky's prototype measures a person's baseline brain-wave activity, including signals that relate to concentration, relaxation and anxiety. The technology ranks performance in each category on a scale of one to 100, and the numbers change as a person thinks about relaxing images, focuses intently, or gets kicked, interrupted or otherwise distracted.

Boosters say toys with even the most basic brain wave-reading technology — scheduled to debut later this year — could boost mental focus and help kids with attention deficit hyperactivity disorder, autism and mood disorders. But even if the devices work as promised, some question whether people who use biofeedback devices will be able to replicate their relaxed or focused states in real life, when they're not attached to equipment in front of their television or computer.

"These techniques are used usually in clinical contexts. The gaming companies are trying to push the envelope," said Elkhonon Goldberg, clinical professor of neurology at New York University . "You can use computers to improve the cognitive abilities, but it's an art."

'These techniques are used usually in clinical contexts. The gaming companies are trying to push the envelope.'—Elkhonon Goldberg, New York University

It's also unclear whether consumers want mentally taxing games.

"It's hard to tell whether playing games with biofeedback is more fun — the company executives say that, but I don't know if I believe them," said Ben Sawyer, director of the Games for Health Project, a division of the Serious Games Initiative. The think tank focuses in part on how to make computer games more educational.

EEG technology used for  fun

The basis of many brain wave-reading games is electroencephalography, or EEG, the measurement of the brain's electrical activity through electrodes placed on the scalp. EEG has been a mainstay of psychiatry for decades.

An EEG headset in a research hospital may have 100 or more electrodes that attach to the scalp with a conductive gel and could cost tens of thousands of dollars. NeuroSky's "dry-active" sensors don't require gel, are the size of a thumbnail, and could be put into a headset that retails for as little as $20 US, said NeuroSky CEO Stanley Yang.

Yang is secretive about his company's product lineup because of a nondisclosure agreement with the manufacturer. But he said an international toy manufacturer plans to unveil an inexpensive gizmo with an embedded NeuroSky biosensor at the Japan Toy Association's trade show in late June.

Researchers at NeuroSky and other startups are also building prototypes of toys that use electromyography (EMG), which records twitches and other muscular movements, and electro-oculography (EOG), which measures changes in the retina.

Emotiv Systems Inc. has developed a gel-free headset with 18 sensors. Besides monitoring basic changes in mood and focus, Emotiv's bulkier headset detects brain waves indicating smiles, blinks, laughter, even conscious thoughts and unconscious emotions. Players could kick or punch their video game opponent — without a joystick or mouse.

"It fulfills the fantasy of telekinesis," said Tan Le, co-founder and president of San Francisco-based Emotiv.

The 30-person company hopes to begin selling a consumer headset next year, but executives would not speculate on price. A prototype hooks up to gaming consoles such as the Nintendo Wii, Sony PlayStation 3 and Microsoft Xbox 360.

Le, a 29-year-old Australian woman, said the company decided in 2004 to target gamers because they would generate the most revenue — but eventually Emotive will build equipment for clinical use. The technology could enable paralyzed people to "move" in virtual realty; people with obsessive-compulsive disorders could measure their anxiety levels, then adjust medication accordingly.

The husband-and-wife team behind CyberLearning Technology LLC took the opposite approach. The San Marcos-based startup targets doctors, therapists and parents of adolescents with autism, impulse control problems and other pervasive developmental disorders.

CyberLearning is already selling the SmartBrain Technologies system for the original PlayStation, PS2 and original Xbox, and it will soon work with the PlayStation 3 and Xbox 360.

The EEG- and EMG-based biofeedback system costs about $600, not including the game console or video games. Kids who play the race car video game Gran Turismo with the SmartBrain system can only reach maximum speed when they're focused. If attention wanes or players become impulsive or anxious, cars slow to a chug.