Relative Hearing Levels and Types of Hearing loss among Four Selected Groups of Air Force Personnel.

摘要

Pure-tone air-conduction and bone-conduction audiometric tests were administered to 125 Air Force personnel. One group consisted of 25 non-noise-exposed men. The other three groups were noise-exposed individuals: Class A, 50 Class B (re AFR 160-3, 1956), and 25 Class C (500-2000 cps average of more than 15 db). Relative hearing levels of right and left ears within and between groups are presented. Results showed: good agreement between median and mean thresholds at almost all test frequencies; no significant differences between right and left ears within groups; that the Class Ann and A median and mean thresholds were within a few decibels of the American Standard reference normal; that the Class B group deviated from the Class A groups only at 3000, 4000, and 6000 cps; that, with the exception of Class B at 4000 and 6000 cps, the Class C group was significantly different from the other groups at all test frequencies; that approximately 13 percent of Class B and Class C groups had either conductive or mixed-type hearing loss, the remaining 87 percent being perceptive-type hearing loss; that 35 out of 75 individuals in Class B and Class C groups expressed a preference for an ear and of these 35 individuals, 25 chose the better ear correctly.