抄録
From 1970 through 1980, 228 airplane crew who failed to satisfy criteria for physical examination for airplane crew were studied.
Of the 228 crew 65 were successfully followed up over 5 year periods as to the changes of hearing threshold.
Their hearing threshold deteriorated about 10 dB at 2 kHz and 3 kHz in 10 years. The hearing loss in left ear was more frequently found than in the right.
Because noise level (Leq) in cockpit was found to be about 90 dB, the noise did not seem to have caused the hearing loss. The authors presumed that hearing loss in cockpit crew might be either due to head phone sound from which the aircrew hear ATC (Air Traffic Control) from the control tower or to an individual hypersusceptibility.
