A meta-analysis on the therapeutic efficacy of repetitive transcranial magnetic stimulation for cognitive functions in attention-deficit/hyperactivity disorders

Background Therapeutic efficacies of repetitive transcranial magnetic stimulation (rTMS) for improving cognitive functions in patients with deficit/hyperactivity disorder (ADHD) remained unclear. The aim of this meta-analysis was to investigate the therapeutic efficacy of rTMS focusing on different cognitive performances.Methods Major databases were searched electronically from inception to February 2023 by using keywords mainly "rTMS" and "ADHD" to identify randomized controlled trials (RCTs) that investigated the therapeutic efficacy of rTMS for improving cognitive functions assessed by standardized tasks in patients with ADHD. The overall effect size (ES) was calculated as standardized mean difference (SMD) based on a random effects model.Results Meta-analysis of five RCTs with 189 participants (mean age of 32.78 and 8.53 years in adult and child/adolescent populations, respectively) demonstrated that rTMS was more effective for improving sustained attention in patients with ADHD compared with the control groups (SMD = 0.54, p = 0.001).Our secondary analysis also showed that rTMS was more effective for improving processing speed than the control groups (SMD = 0.59, p = 0.002) but not for enhancing memory or executive function.Conclusions Our results supported the therapeutic efficacy of rTMS for improving sustained attention and processing speed. However, the limitation of available data warrants further studies to verify these findings.