Influence of mental fatigue on cognitive function in pilots and its related cognitive indexes

Objective To screen the objective indicators of evaluating mental fatigue in pilots and provide basis for aeromedical support. Methods Totally 20 male pilots were chosen to participate in cognitive evaluation including attention, executive function and control of movement before and after continuous flight mission. Attention evaluation consisted of alerting and sustained attention measured by psychomotor vigilance task (PVT), response selection measured by choice reaction time (CRT) and shift of attention measured by shifting attention test (SAT). Executive function was assessed by digit symbol substitution test (DSST), and control of movement was measured by finger tapping test (FTT). Results Significant differences were found in mean reaction time (mean RTs)pre-flight:(307.00±6.15) ms vs post-flight:(349.63±6.65) ms, mean 1/RTspre-flight:(0.003 8±0.000 11) ms vs postflight:(0.002 9±0.000 12) ms and slowest 10%RTspre-flight:(0.002 2±0.000 01) ms vs (0.001 9±0.000 01) ms (all P < 0.05). But there was no significant difference in fastest 10%RT, false starts and lapses (P> 0.05). In addition, the mean RTs of CRTpre-flight:(382.93±12.09) ms vs post-flight:(430.42±12.20) ms and SATpre-flight:(538.66±12.01) ms vs post-flight:(598.58±13.13) ms also showed significant differences in our study (P< 0.05, respectively). Conclusion Pilots show longer mean reaction time and decreased function in sustained, selective and shift of attention after flight mission, which suggests that attention is a sensitive component in assessing mental fatigue among pilots.