Analyses of hearing loss induced by ship noise among sailors

Abstract

Objective To investigate the features of hearing loss induced by ship noise among sailors.Methods One thousand sailors,among whom 563 of them were from the deck department and 437 were from the engine department,received hearing tests.Results Of pure tone audiometry detection were evaluated,analyzed and compared.Results For hearing damage at various frequencies,hearing loss at 4 kHz was the most common.The rate of hearing loss at high frequency was greater than that at audio frequency,which conformed to the features of noise-induced hearing loss (NIHL).The longer the sea service of sailors was and the longer they exposed to ship noise,the greater hearing damage they would sustain.For instance,the rate of hearing loss for sailors with 31 years of sea service or longer would reach as high as 35.2％.Statistical differences could be seen in the severeness of hearing damage among different groups of sailor with different length of sea service (P ＜ 0.01).There was statistical significance in the rate of hearing loss,when comparisons were made between the engine department sailors (21.1％) and the deck department sailors (11.4％) (P ＜ 0.01).The rate of hearing loss for the sailors wearing ear plugs frequently was much lower than those not wearing them,also with statistical significance (P ＜ 0.01).Conclusions Due to the high rate of hearing loss among sailors,the application of ear plugs could alleviate noise-induced hearing loss to some extent.It is of practical importance to develop and adopt highly effective,convenient and nontoxic intervention measures or devices against noiseinduced hearing loss. Key words: Noise-induced hearing loss; Audiometry; Pure-tone detection; Sailors