Biofeedback and RPG research

If participants in the game were attached to biofeedback and/or neuro-feedback equipment while playing the game, when they reached their states of "flow" and/or other desired states (focus for those with ADD/ADHD, relaxation for those with high anxiety, etc.), it would be interesting to see exactly when they had the matching body and brainwave patterns to account for the flow state, and what events were happening in the adventure at that time.

This information could then make it easier to target the design of future modules for specific brainwave patterns desired. The equipment is not too expensive (hundreds of dollars to a few thousand), but could potentially shorten the research time by years with such immediate feedback rather than relying only on the currently planned observation-questionnaire-testing tools.

Those tools would still be important, but using biofeedback could much more quickly isolate the cause and effect process.

I wonder, has anyone ever done biofeedback or neuro-feedback research with RPGers?

How about fMRI (functional Magnetic Resonance Imaging), or PET (Positron Emission Tomography) real-time brain imaging during the activities as has been done with music therapy experiments? A lot more expensive, but could be very insightful.