Retest reliability of repetitive transcranial magnetic stimulation over the healthy human motor cortex: a systematic review and meta-analysis

Introduction Repetitive transcranial magnetic stimulation (rTMS) is used to induce long-lasting changes (aftereffects) in cortical excitability, which are often measured via single-pulse TMS (spTMS) over the motor cortex eliciting motor-evoked potentials (MEPs). rTMS includes various protocols, such as theta-burst (TBS), paired associative (PAS), and continuous with a fixed frequency. Nevertheless, subsequent aftereffects of variable seem fail repeatability. We aimed summarize standard procedures regarding their test–retest reliability. Hereby, we considered influencing factors methodological quality experiments publication bias. Methods conducted literature search PubMed March 2023. The inclusion criteria were application rTMS, TBS, or PAS at least twice healthy subjects measurements MEPs spTMS dependent variable. exclusion derived from non-stimulated hemisphere, non-hand muscles, by electroencephalography only. extracted reliability measures eligible studies. With Rosenthal fail-safe N, funnel plot, asymmetry test, examined bias accounted for influential standardized checklist. Results A total 15 studies that investigated protocols 291 identified. Reliability measures, i.e., Pearson's r intraclass correlation coefficient (ICC) applicable nine studies, mainly small moderate range two indicating good 20 Hz ( = 0.543) iTBS 0.55). follow heuristics respective inhibition facilitation, depending on protocols' frequency, pattern. There was no indication influence other rTMS. Conclusion appears be overall. Due limited number reporting values heterogeneity could not provide generalizable results. identify any protocol superior others.