Neurobehavioral Effects of Carbon Monoxide (CO) Exposure in Humans Protocol 1.
Final rept. 1981-1982,
ARMY MEDICAL BIOENGINEERING RESEARCH AND DEVELOPMENT LAB FORT DETRICK MD
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The neural and behavioral effects of acute low level carbon monoxide exposure are not well known but have been reported to produce sensory and vigilance deficits. Stage one of this research program is to establish a reliable paradigm for the measurement of CO effects. During stage two concentration-effects functions are to be established. Stage three is concerned with the evaluation of the concentration effects functions in an actual field Army training setting. A total of 92 subjects were used in this double-blind study, 47 air-exposed controls and 45 subjects exposed to 200 ppm CO for 1.5 hours. In the confirmatory analyses CO did not affect any behavioral measure. Alpha-band EEG power may have been affected by this level and duration of CO exposure. Although the trends were subjectively reliable for each of two tasks on both EEG sites in both halves of the sample and in the total group, the effect did not reach statistical significance. Vigilance, alpha-band EEG power and theta-band EEG power had significant trends across time. Apparently unless CO has some non-hypoxic effect, no cosistent vigilance decrement should occur until COHb reaches about 13. There might be specific but minor effects as low as 7 COHb. Since these figures were based upon extrapolations, they are subject to considerable error.