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COUNTERING +Gz ACCELERATION LOSS OF CONSCIOUSNESS: HEMODYNAMIC APPROACHES AND ADAPTIVE AUTOMATION

TRIPP, LLOYD Dale, JR.
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1181179663

Abstract Details

2007, PhD, University of Cincinnati, Arts and Sciences : Psychology.
Gravity-induced loss of consciousness (GLOC) is a major psychophysiological threat to pilots of high-performance aircraft that has resulted in substantial loss of life and equipment (Albery &Van Patten, 1991). It is brought about by a sudden reduction in cerebral blood flow and subsequent decrease in cerebral tissue O2 as a result of increased +Gz force (McKinley, Tripp, Bolia, & Roark, 2005). During such episodes, pilots are totally incapacitated for 24 sec. They are unconscious for half of that time (the absolute incapacitation period) and confused for the remainder (the relative incapacitation period; Whinnery, Burton, Boll, & Eddy, 1987). In addition, evidence is available to indicate that cognitive and psychomotor functions are compromised several sec prior to the onset of unconsciousness and for 55.50 sec after confusion subsides (Tripp et al., 2006). Using centrifuge simulators to induce GLOC and math and tracking tasks to emulate flight performance, three experiments were conducted to determine if reductions in the rate of G-suit deflation (Experiment 1), the application of supplementary sensory stimulation (Experiment 2), and the employment of negative Gz offset profiles (Experiment 3) could be of effective value in reducing the duration of the GLOC epoch. All three experiments produced statistically significant reductions in the duration of the epoch, but these reductions were too small to be of practical utility in an operational setting. Experiment 3 also featured the use of near-infrared cerebral oximetry to track the course of cerebral tissue O2 levels in a GLOC-inducing experimental session. The results indicated that O2 levels dropped precipitously from baseline after the onset of Gz acceleration with performance deterioration beginning and GLOC appearing when the O2 levels fell to 95 percent and 80 percent of baseline, respectively. Cerebral oxygen levels rose quickly after the termination of acceleration and returned to baseline well before participants’ performance efficiency returned to pre-GLOC levels. These results indicate that cerebral O2 levels may serve as critical landmarks for alerting the pilot that loss of consciousness is approaching and for triggering an adaptive automation system to assume flight control while the pilot is incapacitated.
Dr. Joel Warm (Advisor)
103 p.
Psychology, Cognitive
Gravity induced loss of consciousness; cerebral tissue oxygen saturation cognitive tasks;

Recommended Citations

Citations

  • TRIPP, JR., L. D. (2007). COUNTERING +Gz ACCELERATION LOSS OF CONSCIOUSNESS: HEMODYNAMIC APPROACHES AND ADAPTIVE AUTOMATION [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1181179663

    APA Style (7th edition)

  • TRIPP, JR., LLOYD. COUNTERING +Gz ACCELERATION LOSS OF CONSCIOUSNESS: HEMODYNAMIC APPROACHES AND ADAPTIVE AUTOMATION. 2007. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1181179663.

    MLA Style (8th edition)

  • TRIPP, JR., LLOYD. "COUNTERING +Gz ACCELERATION LOSS OF CONSCIOUSNESS: HEMODYNAMIC APPROACHES AND ADAPTIVE AUTOMATION." Doctoral dissertation, University of Cincinnati, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1181179663

    Chicago Manual of Style (17th edition)

ucin1181179663
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This open access ETD is published by University of Cincinnati and OhioLINK.