Assessment of the static upright balance index and brain blood oxygen levels as parameters to evaluate pilot workload

OBJECTIVE: To investigate the potential for static upright balance function and brain-blood oxygen parameters to evaluate pilot workload. METHODS: Phase 1: The NASA Task Load Index (NASA-TLX) was used to compare the workloads of real flights with flight simulator simulated flight tasks in 15 pilots (Cohort 1). Phase 2: To determine the effects of workload, 50 cadets were divided equally into simulated flight task load (experimental) and control groups (Cohort 2). The experimental group underwent 2 h of simulated flight tasks, while the control group rested for 2 h. Their static upright balance function was evaluated using balance index-1 (BI-1), before and after the tasks, with balance system posturography equipment and cerebral blood oxygen parameters monitored with near infrared spectroscopy (NIRS) in real time. Sternberg dual-task and reaction time tests were performed in the experimental and control groups before and after the simulated flight tasks. RESULTS: (Phase1) There was a significant correlation between the workload caused by real flight and simulated flight tasks (P<0.01), indicating that NASA-TLX scales were also a tool for measuring workloads of the stimulated flight tasks. (Phase 2) For the simulated flight task experiments, the NASA-TLX total scores were significantly different between the two groups (P<0.001) and (pre-to-post) changes of the BI-1 index were greater in the experimental group than in controls (P<0.001). The cerebral blood oxygen saturation levels (rsO(2)) (P<0.01) and ΔHb reductions (P<0.05) were significantly higher in the experimental, compared to the control group, during the simulated flight task. In contrast to the control group the error rates (P = 0.002) and accuracy (P<0.001) changed significantly in the experimental group after the simulated flight tasks. CONCLUSIONS: The simulated flight task model could simulate the real flight task load and static balance and NIRS were useful for evaluating pilots’ workload/fatigue.