Transcranial Direct Current Stimulation and Aviator Performance During Simulated Flight

INTRODUCTION: Transcranial direct current stimulation (tDCS) is a promising method for maintaining cognitive performance. Anticipated changes in rotary-wing aircraft are expected to alter aviator performance.METHODS: A single-blind, randomized, sham-controlled study evaluated effects of 2-mA anodal tDCS to the right posterior parietal cortex on aviator performance within a Black Hawk simulator. A mixed design with one between-subjects factor was assessed: stimulation prior to flight (20 constant min) and during flight (two timepoints for 10 min each). The within-subjects factor included active vs. sham stimulation. Randomly assigned to each stimulation group were 22 aviators. Aircraft state metrics derived from the simulator were used to evaluate performance. Subjects completed two flights (active stimulation and sham stimulation) with an in-flight emergency introduced at the end to assess whether the timing of tDCS application (prior or during flight) affected the ability to maintain attention and respond to an unexpected event.RESULTS: Results found active stimulation during flight produced statistically significant improvements in performance during the approach following the in-flight emergency. Subjects maintained a more precise approach path with glideslope values closer to zero (M = 0.05) compared to the prior-to-flight group (M = 0.15). The same was found for localizer values (during flight, M = 0.07; prior to flight, M = 0.17). There were no statistically significant differences between groups on secondary outcome measures.DISCUSSION: These findings suggest stimulation during flight may assist in maintaining cognitive resources necessary to respond to an unexpected in-flight emergency. Moreover, blinding efficacy was supported with 32% of subjects correctly guessing when active stimulation was being delivered (52% correctly guessed the sham condition).Feltman KA, Kelley AM.