Integrating the Human into the Total System: Degradation of Performance under Stress

The problem this paper will address is the identification of field-deployable methodologies that can, in the near future, enable an officer and enlistee echelon serviceperson to estimate changes in the decision-making capability of highly trained operators. One required component for realization of this goal is the ability to quantify and fuse measures that reflect decision-making capability in real time, and transmit this assessment to leadership. A program funded by the Army Research Laboratory Human Research and Engineering Directorate under the direction of the Center for Strategic and Innovative Technology at the University of Texas at Austin led to findings that total sleep deprivation of 24 to 36 hours had an adverse effect on complex decision-making and target identification in experienced soldiers and military cadets. These behavioral changes were correlated with changes in activation of the frontal and parietal regions of the brain as determined by functional Magnetic Resonance Imaging (fMRI). Diffusion tensor imaging indicated a correlation between the observed fractional anisotropy involving several major fiber pathways of the brain and sustained performance during the period of sleep deprivation. Electroencephalographic (EEG) properties of the sleep-deprived persons were also correlated with behavioral performance..