We examined the immediate and long-term impacts of military aircraft noise exposure on noise-induced hearing loss (NIHL) in fighter pilots and ground staff. We recruited 40 pilots, 40 ground staff, and 136 age-matched controls; all participants underwent hearing tests, including conventional pure-tone audiometry (PTA) (0.25-8.0 kHz), extended high-frequency (EHF) audiometry (9.0-18.0 kHz), and distortion-product otoacoustic emission (DPOAE) as a recent reference. A subsequent hearing test immediately after flight-mission noise exposure was requested. The results revealed higher recent hearing thresholds in pilots and ground staff than in controls. Threshold shifts at many octave band frequencies were also significantly elevated in ground staff. The grouped frequency threshold was significantly elevated in the 4-8 kHz high-frequency range. After a single flight-mission noise exposure, both ground staff and pilots showed decreased signal-to-noise ratios for DPOAE (1-8 kHz), whereas only ground staff showed significantly elevated left-ear hearing thresholds at 3, 11.2, and 12.5 kHz by conventional and EHF PTA. Fighter pilots and ground staff serve in hazardous noise-exposed environments that cause hearing damage and subsequent NIHL, but ground staff may be more vulnerable. A comprehensive hearing conservation program should be implemented to protect high-risk service members, and especially ground staff, from high-intensity noise exposure.
Keywords: distortion-product otoacoustic emissions (DPOAEs); extended high-frequency (EHF) audiometry; fighter aircraft; ground staff; military noise; noise-induced hearing loss (NIHL); pilot; pure-tone audiometry (PTA); signal-to-noise ratio (SNR).