The Effects of Repetitive Transcranial Magnetic Stimulation on Gait, Motor Function, and Balance in Parkinson’s Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

<b>Objective</b>: This study aimed to systematically evaluate the therapeutic effects of repetitive transcranial magnetic stimulation (rTMS) on gait, motor function, and balance in patients with Parkinson's disease (PD) and identify optimal stimulation parameters for clinical application. <b>Methods</b>: This systematic review and meta-analysis of randomized controlled trials (CTs) was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, EMBASE, Cochrane Central, Scopus, and Ovid-LWW were searched until December 2024 for RCTs evaluating the effects of rTMS on PD-related gait, balance, or motor outcomes. Nineteen studies (<i>n</i> = 547) met the inclusion criteria. Data on study characteristics, rTMS protocols (frequency, target area, pulses, session duration, number of sessions, and treatment duration), and outcome measures (freezing of gait questionnaire [FOG-Q], gait speed, Unified Parkinson's Disease Rating Scale Part III [UPDRS-III], UPDRS total, and timed up and go [TUG] test) were extracted. Effect sizes (Hedges' g) were pooled using inverse variance meta-analysis, heterogeneity was assessed using I², and publication bias was assessed using funnel plots and Egger's regression. <b>Results</b>: rTMS produced significant improvements in gait freezing (FOG-Q: g = -0.74; 95% confidence interval [CI] [-1.05, -0.43]; <i>p</i> < 0.001), gait speed (g = 0.62; 95% CI [0.29, 0.95]; <i>p</i> < 0.001), and motor symptoms (UPDRS-III: g = -0.42; 95% CI [-0.70, -0.15]; <i>p</i> = 0.003). No significant effects were observed for UPDRS total (g = 0.18; <i>p</i> = 0.58) or balance (TUG, g = -0.29; <i>p</i> = 0.06). Egger's test indicated publication bias for gait speed (<i>p</i> = 0.016); however, trim-and-fill imputed zero studies. Subgroup analyses indicated that high-frequency stimulation of the supplementary motor area (SMA) for ≥20 min over 10 sessions (total duration <2 weeks or ≥2 weeks) optimally improved gait speed, whereas low-frequency stimulation targeting M1 and SMA with >1000 pulses per session for 20 min over 10 sessions within <2 weeks most effectively improved the UPDRS-III scores. <b>Conclusions</b>: rTMS exerts moderate and significant benefits on gait and motor performance in PD, particularly when tailored protocols involving SMA or M1 stimulation are employed. High-frequency SMA protocols improve gait speed, whereas low-frequency M1/SMA protocols optimize motor symptom relief. These findings provide evidence-based guidance for rTMS implementation in PD rehabilitation.