Neural Correlates of Transcranial Direct-Current Stimulation Enhanced Surgical Skill Acquisition
Supervisor / Principle Investigator:
MD Class of 2021
Background: Recent changes in surgical training environments have impacted the ability of trainees to learn complex surgical skills. To provide the 300 million surgical procedures required to address the global burden of disease, there is vital need to define methods of enhancing surgical training. Transcranial direct-current stimulation (tDCS) alters cortical excitability and can augment motor skill learning. Recently, we demonstrated that tDCS may enhance surgical skill learning, however the mechanisms of this are not entirely defined. Here, we examined how tDCS changes electrical activity in the brain during surgical skill learning.
Methods: Double-blind, sham-controlled trial. Medical trainees (n=22) were randomized to 20 minutes of sham or anodal tDCS (1mA; anode, dominant primary motor cortex; cathode, contralateral supraorbital area) concurrent to Fundamentals of Laparoscopic Surgery pattern cutting and peg transfer training. Continuous EEG was recorded. Outcomes of pattern cutting and peg transfer were scored at baseline, during one hour of training, directly after training, and six weeks later. 32-lead EEG was examined across high-beta (20-30Hz), alpha (8-13Hz), and delta (0.5-3.5Hz) frequency-bands during baseline and post-training task performance.
Results: Participants receiving anodal tDCS had greater improvements in pattern cutting scores than participants receiving sham (p=0.011). There was no intervention effect on peg transfer. High-beta and alpha power at electrode Fp1 was correlated with baseline pattern cutting skill (both r>0.524, p<0.009), with weaker correlations at C3 and P3 (r>0.396, p<0.056). Training and tDCS both altered frequency-band power. Notably, change in pattern cutting score was correlated with change in high-beta power at electrode F4 (r=0.664, p<0.001), and change in delta power at Fp1 (r=-0.513, p=0.018). All procedures were well-tolerated and no adverse events reported.
Conclusion: Supplementing surgical training with tDCS holds the potential to revolutionize medical training. Identifying changes in neural activity may identify targets for neuromodulation to more effectively enhance complex motor learning.