Bias towards lower frequencies with Force Trainer II
I am currently working on a scientific experiment that involves the Star Wars Force Trainer II. It has three dry metal electrodes; one active electrode on the forehead, and two reference electrodes that go behind the ears (feel like I remember reading this somewhere but not sure if it's true).
The experiment involves 4 actions: resting (eyes open), eyes closed, reading, and rhythmic tapping. Interestingly, there was significant change from rest (t test) in alpha and theta (for alpha, only eyes closed and tapping), but not for beta or gamma.
This is kind of counter intuitive since:
- From my research on the anterior-posterior gradient, it seems like higher frequency waves should be more towards the forehead, which is where the primary electrode is Reading from print (according to previous studies) is associated with increases in beta and gamma waves; so why wasn’t there a measured increase?
- A previous study also found cross scalp changes in delta, theta, alpha, and beta in eyes closed, but I only found changes in theta and alpha.
Is there any reason for this? Perhaps a principle that I'm missing?