The brain wave change they are describing has not been seen before, as i read it. Good or bad, it shows that doing a physical AND mental components together has produced something new and unstudied. there are some studies done on meditation, visualizations, and breath control too, and i must assume they haven't plotted the same feature there. I know there are also some papers coming out now showing some faults in MRI software and analysis that may undermine some of the results from those studies , but these are EEGs, so prob not as much an issue.
The tCDS paper seems to say you can choose either memory optimization , or flexibility and focus in thinking, but you won't get both....
"The evidence of harm would be the evidence that you can hurt some cognitive functions with the same stimulation protocols that help another cognitive function. But they're completely correct that we don't have any evidence saying you're definitely hurting yourself. We do have evidence that you're definitely changing your brain."
interview:
http://www.wbur.org/commonhealth/2016/07/11/caution-brain-hacking
Paper:
http://onlinelibrary.wiley.com/doi/10.1002/ana.24689/references
I was aware of the variability of responses to stim, but not the paper that leveraging one brain function could impair another. This was also written to give the docs some info to help inform their patients.
edit
I'll also tuck this in here, as i posted it to open thread.
Texting changes brain waves to new, previously unknown, pattern.
http://sciencebulletin.org/archives/2623.html
Makes me wonder if they were using spell check, or the new, shortend speak. By using constructed kernels, or images of words and concepts, it looks like machine learning retrieval or construction is already being practiced here ?