We used a randomized double-blind active-controlled crossover study of 19 unmedicated children (aged 7–12 years old) with ADHD, who received either transcranial direct current stimulation (tDCS) or random noise stimulation (tRNS) while completing executive functions training. tDCS was examined in multiple ADHD studies and has been highlighted as a promising method for treating neuropsychological deficits. 

For our primary outcome, tRNS yielded a clinical improvement as indicated by the reduced ADHD rating-scale score from baseline, and in comparison to the changes observed in tDCS [β=-.42, 95% CI (-.77, -.07)]. The effect of brain stimulation one week after completion of treatment yielded further improvement [β=-.19, 95% CI (-.37, -.01)], suggesting a neuroplasticity-related effect. Finally, tRNS improved working memory compared to tDCS [β=.33, 95% CI (.02, .64)], and a larger tRNS effect on ADHD rating-scale was predicted for those who showed the greatest improvement in working memory. 

Our results provide a promising direction toward a novel intervention in ADHD, which is shown to have a lasting effect via the modulating of neuroplasticity, rather than a merely immediate effect as was shown for in previous medical interventions.