Screening for NIHL among Military Personnel in Eastern Province of Saudi Arabia

Abstract

Objectives: Study the effect of noise exposure on the hearing sensitivity of the screened study subjects, analyze the questionnaire for noise exposure, and compare between hearing impairment in different noise exposure categories. Methods: A total of 1879 subjects were evaluated and a noise exposure survey was completed by the study group. Screening air conduction pure tone audiogram was done for each participant. Patients who did not pass the screening were referred to the ear, nose, and throat and audiology unit for further evaluation: complete history, otological examination, pure tone audiometry, tympanometry and distortion product otoacoustic emissions (DPOAEs). Results: The study group’s average duration of duty was 10.26 ± 8.06 years. Of the study group, 33.9% were cigarette smokers. A total of 188 subjects out of 1879 (10%) did not pass the screening air conduction pure tone audiogram and they were referred to the audiology clinic. The mean emission amplitude across the DPOAEs measured frequencies in noise-induced hearing loss (NIHL) patients at high frequencies were significantly lower than that of the low frequencies. Also it was noticed that as the hearing loss increases at high frequencies region with the NIHL the DPOAEs amplitude decreases. Conclusions: Ten percent of the high-risk noise exposed subjects had high frequency hearing loss which can be minimized by using hearing protective devices during exposure to intense noise level. Reduction in the emission amplitude of DPOAEs at high frequencies region was significant in comparison with that of the low frequencies. These differences can be attributed to the hearing loss and the patho-physiologic mechanism at the level of outer hair cells encountered in those patients.