Transcranial Direct Current Stimulation (tDCS) influences brain activity in children with ADHD: Findings from a Randomized, Sham-Controlled Pilot Study.

Background: Transcranial Direct Current Stimulation (TDCS) has been reported as a clinical intervention for children with neurodevelopmental disorders. However recent studies have failed to demonstrate clinical effects with tDCS in children with ADHD suggesting unreliability in outcomes. Identification of biomarkers of response using EEG may enhance intervention rigor. The objective of this study was to examine the effects of 12 sessions of tDCS using an anodal F3 (directed to left dorsolateral prefrontal cortex) and cathodal vertex montage combined with cognitive training on brain function as measured by EEG spectral power in children with ADHD

Materials & Methods: Nine children with ADHD (age-years) (11.68±2.23; 5 boys) had EEG performed and represent a subset of the 25 children reported in a clinical study (Schertz et al, 2022). In addition to computerized cognitive training, three of these children received active tDCS and 6 children received sham tDCS. A standard 10-20 EEG was collected using a 16-lead headcap within 1 week of Pre- and Post- intervention. We examined resting state changes in spectral power in the delta, theta, alpha, beta, low and high gamma frequency bands at F3 and corresponding contralateral F4. Group (Active vs. Sham) and Channel (F3 vs. F4) two-way ANOVA comparisons were performed to determine if brain function was modified at the stimulation site despite lack of clinical effect.

Results: The Active and Sham tDCS Groups did not differ prior to the intervention. However, we identified robust within-subject post-pre-intervention differences in increased power in favor of the Active group at each frequency band (p’s<0.005). The effect was bilateral at all frequency bands except alpha, in which the Post-Pre-change at F3 was lower than at F4 (p<0.04).

Conclusion: Findings confirm that a standard tDCS stimulation protocol can change individual brain function, despite a lack measurable group-level clinical effect in children with ADHD.