Many of the articles I read on transcranial direct current stimulation follow a similar pattern. The intrepid reporter is strapped with electrodes to the skull and, after reporting a tingling feeling, describes some cognitive benefit from the procedure.
A good piece by Kira Peikoff in The New York Times breaks that pattern and acknowledges the limits of our knowledge about tDCS:
“In January, the journal Brain Stimulation published the largest meta-analysis of tDCS to date. After examining every finding replicated by at least two research groups, leading to 59 analyses, the authors reported that one session of tDCS failed to show any significant benefit for users.”