Noise-induced hearing loss

ABSTRACT

A total number of 225 noise exposed subjects chosen from different places in the Spinning and Weaving Factory of Assiut and the Red Sea Phosphate Mines and fifty non-exposed subjects were chosen as controls. All the subjects were subjected to clinical and audiometric examination. Statistical analysis was done on the results of the work and reveled that There was no pre-employment audiograms included within the fields of the workers. The noise-induced hearing loss is directly proportional to noise level and length of exposure. The threshold of hearing of our controls was found to be higher than other presbyacusis data pointing to the importance of sociocusis factor in Egypt. The maximum hearing loss occurs at 4 KHz followed by the other frequencies, and the major hearing loss occurs after 10 years. Although the maximum permissible noise level is 90 dB, we noticed that exposure to noise level of 80-90 dB was harmful