Effects of Cerebellar Transcranial Direct Current Stimulation on Motor Learning in Healthy Individuals: A Systematic Review and Meta-Analysis.

Cerebellar transcranial direct current stimulation (tDCS) may enhance motor learning, but findings vary across tasks and stimulation protocols. This systematic review and meta-analysis quantified its effects on motor adaptation and motor skill learning in healthy adults and examined potential moderators. PubMed, the Cochrane Library, MEDLINE, Scopus, Web of Science and Embase were searched from inception to 17 August 2026. The protocol was registered with PROSPERO (CRD42024596088). Randomized controlled and crossover studies comparing cerebellar tDCS with sham stimulation and reporting practice-dependent or time-dependent changes in motor performance were eligible. Twenty studies comprising 739 participant observations were included. The random-effects model showed that anodal cerebellar tDCS significantly improved motor learning (SMD = -0.52, 95% CI -0.90 to -0.14, p = 0.007; I2 = 83%), with negative values favouring tDCS. Although meta-regression identified no significant moderators, exploratory subgroup analyses yielded significant SMDs for online stimulation (-0.66), 2 mA (-0.44), 25 min (-0.93), a 25-cm2 electrode montage (-0.99), motor skill learning (-0.49) and outcome assessments at < 24 (-0.52) and ≥ 24 h (-1.11). Leave-one-out sensitivity analysis and trim-and-fill analysis did not materially change the pooled result, although Egger's regression test indicated small-study effects. These findings indicate that anodal cerebellar tDCS can facilitate motor learning and support further investigation of stimulation protocols, longer term retention and clinical applications. Nevertheless, the magnitude and generalisability of the effect require confirmation in larger, adequately powered trials.