Efficacy of Non-Invasive Brain Stimulation in Improving Working Memory in Children and Adolescents with...

Background/Objectives: Attention-Deficit/Hyperactivity Disorder (ADHD) is associated with working memory deficits linked to frontoparietal alterations. Non-invasive brain stimulation (NIBS) is a potential intervention to modulate neuroplasticity and improve this executive function. In this study, we aimed to evaluate the clinical efficacy of non-invasive brain stimulation techniques (tDCS/rTMS) for strengthening working memory in children and adolescents with ADHD. Methods: This systematic review adhered to the PRISMA 2020 guidelines, with a search of Scopus and Web of Science conducted to identify relevant studies published between 2011 and 2026. Eligibility criteria, defined a priori, included original empirical studies (RCTs and quasi-experimental designs) focusing on pediatric populations (≤18 years) diagnosed with ADHD. Eligible interventions involved tDCS or rTMS with explicit working memory outcomes. Only peer-reviewed articles published in English or Spanish were included. Reviews, case reports, and studies exclusive to adults were excluded. Data on application parameters, durability, and safety were extracted for narrative synthesis. Results: Six studies met the criteria. Both tDCS and rTMS targeting the left dorsolateral prefrontal cortex showed improvements in working memory, particularly in executive components measured using digit span backward and N-back tasks. High-frequency rTMS (10 Hz) with repeated sessions showed more consistent effects, while tDCS showed modest and variable improvements. Evidence regarding long-term effects was limited. Both techniques were well-tolerated, with mild and transient adverse events. Conclusions: NIBS shows promise as a complementary intervention to improve working memory in pediatric ADHD; however, current evidence is limited. Larger, standardized, longitudinal trials are required to confirm its efficacy and clinical utility.