The effect of prolonged mild anoxia on speech intelligibility

Abstract

"1. Using the method and materials employed in an earlier study in collaboration with C. P. Seitz [see 20: 3130], twelve subjects were tested for their ability to perceive standard speech sounds at four periods during an eight-hour exposure to mild anoxia encountered at an altitude of approximately 10,000 ft., simulated in a nitrogen dilution chamber. 2. The decrement in speech intelligibility at altitude was very slight and unreliable at the 3/4 hr. period; it was nearly reliable at the 2¼ hr. and 4 3/4 hr. periods; but there was a marked lessening of the altitude effect at the last period, 6 3/4 hrs. after entering the chamber." Psychological factors such as wandering of attention and boredom are suggested as explanations of the apparent losses in efficiency, although some physiological consequences of altitude changes are indicated by enlarged angioscotoma during prolonged exposure to increased altitude. (PsycInfo Database Record (c) 2025 APA, all rights reserved)