Effect of transcranial direct current stimulation on psychomotor skill acquisition during laparoscopic training: a randomized controlled trial

BACKGROUND: Acquisition of laparoscopic psychomotor skills is essential for safe minimally invasive surgery but is associated with a steep learning curve. Simulation-based training improves proficiency; however, additional strategies to accelerate skill acquisition are sought. Transcranial direct current stimulation (tDCS) has been shown to facilitate motor learning, but its effect on laparoscopic training remains uncertain. METHODS: In this prospective, sham-controlled trial, 33 medical students without prior laparoscopic experience were allocated to active tDCS (n = 16) or sham stimulation (n = 17) during laparoscopic simulation training. Stimulation was delivered using the Halo Sport system (1.4 mA, 20 min) over bilateral primary motor cortices. Baseline psychomotor abilities were assessed using the Vienna Test System (Motor Performance Series, 2HAND, and 3D spatial ability tests). Laparoscopic skills were evaluated using the Laparoscopic Skills Testing and Training (LASTT) model, including camera navigation (CN), hand-eye coordination (HE), and bimanual coordination (Bi), on days 1, 3, 5, and 7. Group differences in final performance (day 7) were analyzed using linear models and ANCOVA, adjusting for baseline performance and prespecified covariates. RESULTS: Both groups demonstrated significant improvement across all laparoscopic tasks over time (all p < 0.001). Active tDCS was independently associated with higher final bimanual coordination performance compared with sham stimulation (adjusted ANCOVA: F (1,13) = 14.92, p = 0.002). No independent effect of tDCS was observed for camera navigation (p = 0.581) or hand-eye coordination (p = 0.439). Baseline visuospatial ability (3D test) was an independent predictor of final performance in camera navigation and hand-eye coordination (both p < 0.01). Positive correlations were found between 3D scores and CN (r = 0.397) and HE (r = 0.390), as well as between 2HAND and HE (r = 0.341). CONCLUSIONS: Bihemispheric tDCS applied during laparoscopic simulation selectively enhanced acquisition of bimanual coordination, while performance in camera navigation and hand-eye coordination was primarily determined by baseline visuospatial ability. These findings support a task-specific role for neuromodulation as an adjunct to simulation-based laparoscopic training and highlight the importance of visuospatial profiling for personalized training strategies.