@article{ref1,
title="On Tracking the Course of Cerebral Oxygen Saturation and Pilot Performance During Gravity-Induced Loss of Consciousness",
journal="Human factors",
year="2009",
author="Tripp, Lloyd D. and Warm, Joel S. and Matthews, Gerald and Chiu, Peter Y. and Bracken, R. Bruce",
volume="51",
number="6",
pages="775-784",
abstract="Objective: The aim of this study was to track the course of cerebral tissue oxygen saturation (rSO<sub>2</sub>) and pilot performance during an episode of gravity-induced loss of consciousness (GLOC). Background: GLOC, a major problem facing pilots of high-performance aircraft, is brought about by a sudden reduction in rSO<sub>2</sub> as a result of increased +Gz force. It consists of 24 s of complete functional impairment followed by a prolonged period of performance recovery. This study tested the hypothesis that delayed recovery in GLOC is caused by a slow return of rSO<sub>2</sub> following removal of the g-force that induced the episode. Method: GLOC was induced in U.S. Air Force personnel via a centrifuge with math and tracking tasks emulating flight performance. A near-infrared spectroscopy unit provided the rSO<sub>2</sub> measure.  Results: Declines in rSO<sub>2</sub> from baseline pinpointed when pilots would cease active flight control and when GLOC would set in. Counter to expectation, rSO<sub>2</sub> returned to baseline levels shortly after the centrifuge came to a complete stop following GLOC onset. Nevertheless, performance deficits continued for 49.45 s thereafter. Conclusion: The prolonged performance recovery time in GLOC cannot be attributed to delays in the return of rSO<sub> 2</sub>. This finding explains why previous ergonomic efforts to shorten the duration of GLOC episodes by increasing the rate of return of rSO<sub> 2</sub> have not been fruitful. Evidently, another approach is needed.  Application: Such an approach might use the close linkage between loss of rSO<sub>2</sub>, performance deterioration, and GLOC onset to develop a warning system that would permit pilots to take effective action to avoid GLOC incapacitation.<p />",
language="",
issn="0018-7208",
doi="10.1177/0018720809359631",
url="http://dx.doi.org/10.1177/0018720809359631"
}