Introduction
sleep disturbances, hyperactivity, Attention-deficit/hyperactivity disorder, impulsivity, ADHD, neurodevelopmental disorder
Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by inattention, hyperactivity, and impulsivity [Current gold-standard treatments for ADHD symptoms include pharmacological treatments, psychosocial interventions, or their combination [Transcranial electrical stimulation (tES) has been suggested as a possible intervention avenue for children and adults with ADHD [Transcranial Random Noise Stimulation (tRNS) is a more novel form of tES, in which stimulation is delivered via both electrodes, and which presumably amplifies neural responses via the mechanism of stochastic resonance [The effect of CT alone on clinical symptoms in ADHD is still inconclusive. While one meta-analysis concluded that CT alone has a limited efficacy and transfer effects in ADHD [Here, we conducted the first sham-controlled RCT to examine the potential effects of tRNS combined with CT on symptoms, EFs, processing speed (PS), and sleep metrics in unmedicated children with ADHD. Specifically, ADHD has been associated with sleep disturbances [More recently, studies suggested that electrophysiological signals should be analyzed for both their periodic and aperiodic (1/f-like) properties of the neural power spectra [We hypothesized that tRNS combined with CT will lead to improvements in ADHD symptoms (reduction in ADHD-RS scores) and in behavioral and parent-reported EFs (improvement in parent-reported EF scores and in WM and PS behavioral metrics), compared with sham stimulation + CT; and that these effects would endure at follow-up. Finally, based on studies showing modulations in RS-EEG activity following tRNS, we hypothesized that the intervention would lead to modulation in both the periodic and aperiodic neural activity, showing lower aperiodic exponent.