Verbal communication intelligibility in oxygen-helium, and other breathing mixtures, at low atmospheric pressures

Author / Creator

Cooke, Julian P

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Summary

A total of 13 simulated flights with 25 subjects with 4 chamber operators were performed using some 8,300 numbers and words and 2,200 words in sentences to help evaluate communication intelligibili...

A total of 13 simulated flights with 25 subjects with 4 chamber operators were performed using some 8,300 numbers and words and 2,200 words in sentences to help evaluate communication intelligibility in oxygen at 5 and 2.5 psia, in oxygen-and-nitrogen at 7 psia, in oxygen-and-helium at 7 psia, and to compare these findings with those obtained in room air at ground level. Three-way communication was carried out between chamber subjects and ground level operators in room air.

No statistically significant differences could be detected in test results when either words within sentences or random numbers were employed, but unrelated words resulted in statistically significant differences in some cases. Also, the effects due to tiring or lack of alertness create as many problems in room air as do the reduced pressures if subjects are alert. More errors result between subjects in test environments than between subjects and operators, in which case phone communication equipment is necessary. Most errors are of the rhyming type.

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