After I gulp down the last of my vodka, I head back to the testing room at SAM Technology. Earlier that morning, I was fitted with a specially designed black cap dotted with pockets for sensors that detect electrical activity at different spots on the head. The headset is plugged into a small amplifier, which sends its signals wirelessly via Bluetooth to a computer in the testing room. The device captures and processes my brain waves as I play a series of computer games both sober and somewhat drunk. The games are designed to assess working memory--my ability to hold information in my mind for a short time--and my ability to multitask.

An hour later, Gevins and Ilan show me the results of my testing. Their software analyzes a combination of rhythmic brain activity--different frequency rhythms are linked to different cognitive states, such as relaxation or attention--and evoked potentials, electrical signals linked to specific events in the world, like the appearance of a target in a video game. "You were tense; the alcohol relaxed you a lot," says Gevins, perusing plots of my brain activity on the computer screen.

After drinking, my performance on the games actually improved, probably because I had more practice playing the game. But the EEG data revealed the true impact on my brain function: my brain had to work harder on the more complicated tasks after drinking. And it was slower to react to the targets on the computer screen. (My reaction time was actually faster, probably because my motor system had more practice hitting the mouse. So without the EEG, it would have been impossible to see the effect on the brain.)

Gevins says that one of the most promising venues for the technology will be in guiding prescribing decisions. For example, children with attention deficit hyperactivity disorder (ADHD) are often given stimulant drugs to boost attention, but doctors typically rely on reports from parents and teachers to determine the effectiveness of the medication. "They rarely undergo testing to determine how well the medication is working," says Gevins. A pilot study from Gevins's group on children with ADHD suggests that EEG can quickly reveal which children will benefit from Ritalin, a commonly prescribed drug, and when they have reached the optimal dose. He now hopes to partner with a larger company to run clinical trials of the device to determine if it can truly help children with ADHD.