Combined Transcranial Direct Current Stimulation and Virtual Reality in Healthy Populations: A Systematic Review of Evidence, Limitations, and Methodological Challenges

Objectives: This systematic review examined studies combining transcranial direct current stimulation (tDCS) with virtual reality (VR) in healthy or non-clinical populations. The aim was to evaluate whether active tDCS provides additional benefits when delivered during VR-based tasks or interventions aimed at improving behavioral abilities. Methods: Following PRISMA guidelines, a comprehensive search of electronic databases (2000–September 2025) identified randomized and non-randomized studies employing simultaneous tDCS and VR in healthy individuals. Studies reporting psychological or cognitive quantitative outcomes were included. Risk of bias was assessed using RoB-2 and ROBINS-I tools. Results: Twelve studies met inclusion criteria. The included studies were highly heterogeneous in terms of sample size, VR systems, stimulation parameters, targeted cortical regions, outcome measures, and control conditions. Most designs compared active tDCS during VR with sham tDCS during the same VR exposure. Therefore, the available evidence mainly addresses whether tDCS adds value to VR-based procedures, rather than whether tDCS and VR exert independent or synergistic effects. Some studies reported favorable between-group effects on emotional control or skill acquisition. However, in other cognitive domains both active and sham/control VR groups improved, suggesting that VR training or exposure itself may have contributed substantially to the observed changes. Moreover, small sample sizes, multiple outcome testing, and limited correction for multiple comparisons reduce confidence in borderline findings. Conclusions: Current evidence suggests that active tDCS may incrementally enhance selected VR-based outcomes in healthy populations, particularly in emotional control and skill-learning domains. However, the literature does not yet support strong claims of synergistic interaction between tDCS and VR. Future studies should use adequately powered factorial designs including VR-only, tDCS-only, combined, and sham/no-intervention conditions to disentangle independent, additive, and interaction effects.