J Adam G:
This is not an altered-state-generating test, it's an attentive vigilance test. It's a measurement of "concentration" in its purest sense of "the mind staying with something rather than wandering from it", with the tactile stimulus response serving to quantify concentration.
Exactly.
As for the electrodes... I'm not sure whether or not that would be easier than small vibration-generating motors.
I've experimented with vibration motors. They are much harder to securely attach to the body and the vibration qualities vary a bit much from motor to motor.
aac