Author(s): Derek Bankhead
Mentor(s): Milan Pantovic
Institution UTech
Background: Transcranial Direct Current Stimulation (tDCS) is a non-invasive neuromodulation technique that modulates cortical excitability and has shown potential in improving motor performance in simple tasks. However, its efficacy in enhancing complex, multi-joint motor skills, which are important for real-world activities of daily living, remains unclear. Objective: To investigate the influence of tDCS applied over the Supplementary Motor Area (SMA) on motor skill acquisition and retention in a complex golf putting task in healthy individuals. Methods: Twelve right-handed young adults with minimal golf experience participated in a randomized, sham-controlled, double-blinded crossover study. Participants underwent two conditions (active tDCS and sham) across consecutive days, with the order counterbalanced. During practice sessions, active tDCS was applied at 2 mA for 20 minutes using 5×5 cm² electrodes, with the anode placed over the SMA and the cathode over the right supraorbital area (SO). Performance was assessed at pre-test, during four practice blocks, immediate post-test, and at a 24-hour retention test. The primary outcome measure was the standard error (distance from the center of the target). Results: Repeated measures ANOVA revealed a significant main effect of Time, F(4.51, 49.63) = 5.82, p < 0.001, η² = 0.35, indicating performance improvements across sessions. No significant main effect of Condition, F(1, 11) = 0.15, p = 0.71, η² = 0.01, or Condition × Time interaction, F(5.35, 58.85) = 0.94, p = 0.47, η² = 0.08, was found. Both conditions showed significant improvements from pre-test to post-test (p < 0.05), with retention of skills at 24 hours. Conclusion: tDCS applied over the SMA at 2 mA did not significantly enhance motor skill acquisition or retention in a complex golf putting task compared to sham stimulation. The lack of effect may be attributed to the complexity of the task, individual variability, or suboptimal stimulation parameters. Additionally, the small sample size might have limited the ability to detect subtle differences. These findings suggest that tDCS over SMA may not provide additional benefits for complex motor skill learning in healthy individuals. Future research should explore different stimulation intensities, durations, and target areas, as well as include larger sample sizes to fully assess the potential of tDCS in complex motor learning.