Distortion product otoacoustic emissions as a health surveillance technique for hearing screening in workers in the steel manufacturing industry

Abstract

BACKGROUND : Distortion product otoacoustic emissions (DPOAEs) are a promising screening technique for the early detection of subtle noise-induced cochlear function changes. OBJECTIVES : To determine the applicability of DPOAEs as a health surveillance technique for the early detection of noise-induced hearing loss (NIHL) in workers at a steel manufacturing industry. METHODS : DPOAE measurements were recorded in 20 participants with no history of occupational noise exposure and 20 participants exposed to noise in the steel manufacturing industry. Participants were not exposed to noise for at least 48 hours prior to testing. All participants were male, with normal audiometric thresholds of ≤15 dB HL. The DPOAE presence and response levels for different frequencies were compared between the two groups. The study further evaluated the shortterm test-retest repeatability of DPOAE measurements. RESULTS : The noise-exposed group had significantly lower DPOAE response amplitudes than the control group for all the tested frequencies: p<0.001 at 2002 to 4004 Hz; p=0.01 and p=0.001 at 6348 and 7996 Hz, respectively, suggesting early outer hair cell damage in the noise-exposed group. DPOAEs showed good reproducibility. CONCLUSION : DPOAEs appear to be a sensitive technique for detecting noise-induced subtle cochlear function changes. DPOAEs could be used as a health surveillance technique in conjunction with pure tone audiometry for the early detection of NIHL in the steel manufacturing industry.