Negative Acceleration and Adaptive Automation Approaches to Counter the Effect of Acceleration Induced Loss of Consciousness

Abstract

Gravity-induced loss of consciousness (GLOC) is a major human factors problem facing fighter pilots today. A recent study by Tripp et al. (2006) reported that the GLOC episode consists of 24 sec of unconsciousness and confusion/disorientation followed by 55 sec in which performance efficiency is compromised. Hence, fighter pilots in the throes of GLOC can travel 12 miles while not in control of their aircraft. Using a centrifuge to simulate gravitational forces together with tracking and math tasks to simulate flight control and navigation, this study attacked the GLOC problem in two ways: (1) by employing negative acceleration following GLOC onset to decrease GLOC recovery time and (2) by assessing the utility of a of cerebral tissue oxygen saturation (rSO2) measure as a possible triggering mechanism for an adaptive automation recovery system. Negative acceleration had no significant effect on the duration of the GLOC episode. Declines in rSO2 from baseline pinpointed when pilots would cease active flight control and when GLOC would set in. Thus, the rSO2 measure may be of effective value as an adaptive automation GLOC recovery system trigger. The rSO2 measure also showed that loss of blood oxygen is not the sole factor underlying performance deficits in GLOC. Tissue oxygen saturation retuned to baseline levels shortly after the centrifuge came to a complete stop following GLOC onset but the performance deficits continued for 55 sec after rSO2 returned to baseline. Cleared for Public Release Distribution Unlimited