| An important caveat from the inclusion criteria (touched on in the body of the IEEE piece, to their credit): > We chose to exclude measures that have only been replicated by a single research group to ensure all data included in and conclusions generated by this review accurately reflect the effects of tDCS itself, rather than any unique device, protocol, or condition utilized in a single lab. If you looked at the (paywalled) appendix Table S3, you will see that (by eye) 100-something measures have been excluded. The researchers had justifiable reasons for doing so and it is a decision I (as a non-expert, granted) agree with, but it means the headline is incorrect; the analysis found no effect for a certain set of measures (albeit quite a few -- more than I want to type or count) in four domains. Also, like all good articles it includes a few paragraphs on limitations; I found the following one particularly interesting (and probably relevant to "brain hackers", of which I am not one): > This paper only explores cognitive measures undertaken during or following one session of tDCS. As noted in the results section, there are many studies which have utilized a multiple-day stimulation paradigm. It is wholly possible that several sessions of tDCS are required in order for a reliable effect to be seen. In this instance, it has been argued tDCS impacts cognition via repeated exposure and, possibly, overnight consolidation. |
Therefore, on the balance, no measures have been shown to be effective (either because they're not effective, or because they haven't been replicated).