Predicting individual differences in response to sleep loss: application of current techniques.

BACKGROUND: Fatigue's negative impact on safety represents one of the top threats to military transportation. Biomathematical models have been developed to predict the response to fatigue; however, current models do not take into account stable individual differences in fatigue susceptibility. Readiness Screening Tools (RSTs) can capture individual differences in fatigue response, but cannot predict performance long-term. The objective of this study was to combine an existing biomathematical model of fatigue with existing RST-derived measures to determine current ability to predict individual differences in fatigue response. We hypothesized that the predictive ability of the biomathematical model could be significantly improved by incorporating cognitive and oculometric measures shown to be sensitive to individual differences in fatigue response. METHODS: Data on multiple cognitive and oculometric measures were collected at rested baseline and then every 3 h across 25 h of continual wakefulness. Results characterized actual fatigued performance at the group and individual levels. Actual performance was compared to predicted performance decrements over the same time period. The unique variance explained by each approach was then combined to determine if RST-derived individual difference measures added significant predictive power to the model. RESULTS: Addition of individual-difference sensitive RST measures to an existing fatigue model significantly increased the amount of variance in performance explained by the model from 13.8 to 35.7%. DISCUSSION: Simply leveraging RSTs' ability to capture individual differences in fatigue susceptibility can substantially improve biomathematical prediction of fatigued performance.

A single dose of armodafinil significantly promotes vigilance 11 hours post-dose.

OBJECTIVE: This study was conducted to test the ability of armodafinil to promote vigilance among air traffic control operators 8 to 11 hours post-dose. METHODS: Forty-eight U.S. Naval air traffic control students were assigned to one of two groups, 150 mg dose of armodafinil or placebo. At 8:00 a.m., participants were administered armodafinil or a placebo, after which they completed a standard work day. Participants returned at 3:45 p.m. to complete the 4-hour performance portion of the study, where they performed the psychomotor vigilance task. RESULTS: The analysis showed a significant difference in vigilance between the armodafinil group and placebo (p < 0.05). Psychomotor vigilance task data revealed that participants receiving a 150 mg dose of armodafinil experienced significantly fewer lapses of attention compared to the control group. CONCLUSIONS: These results justify additional investigation into the efficacy of armodafinil to promote sustained vigilance in military operational settings where fatigue-related performance decrements are especially problematic.