Correlation of NIRS Determined Cerebral Oxygenation with Severity of Pilot +Gz Acceleration Symptoms
Pilots commonly experience decreased peripheral vision, confusion & disorientation, and/or unconsciousness when exposed to high +Gz acceleration. We correlated NIRS determined ΔHb, ΔHbO2, and ΔTotalHb with the resultant +Gz stress symptoms that subjects reported after experiencing a 6 to 10 +Gz amplitude pulse. During the hyperemic response phase following the +Gz pulses, an increase of the averaged peak values of ΔHbO2 and ΔTotalHb as a function of the severity of the subjects’ symptoms was observed. Significant increases were found for the averaged peak values of ΔHbO2 and ΔTotalHb between high vision loss, confusion and disorientation while remaining conscious (A-LOC), and unconsciousness (G-LOC). The results suggest that the confusion and disorientation associated with A-LOC is physiologically based and that A-LOC is an intermediate +Gz stress symptom between high peripheral vision loss and G-LOC. Like G-LOC, pilots who experience A-LOC symptoms momentarily do not have full control of their aircraft.
Key wordsA-LOC Cerebral oxygenation +Gz acceleration +Gz stress G-LOC (G-induced loss of consciousness) NIRS (Near-Infrared Spectroscopy)
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