On a positive side, this could lend some good statistics on the possible dangers of having a wifi device attached to your skull all day.

Instead of using this in a already developed product, it would make more sense in giving it to testers. Hey Frank, put on this headband before sliding into the testcube. Using camcorders and taking notes is already a part of usability testing, and this gear might be an added gadget in the arsenal.

However, having more socially intelligent people running usability tests might prove a better solution in the long run. But then again we can't play around with gadgets and get printouts of nice charts of the stress levels of my shiny new UI.