Study of otoacoustic emissions in workers of various professional groups of the coal industry

Noise influence takes one of the leading roles in the development of sensorineural hearing loss (SHL). At the same time professional deafness steadily occupies the 5th place in the structure of occupational diseases in Ukraine over the past few years. Of special importance is the problem of pre-clinical and early diagnosis of occupational hearing deterioration, in sense of timely prophylactic and rehabilitation measures in “risk group” workers. The objective research methods play an important role in the diagnosis of auditory analyzer state. Many scientific studies have shown the diagnostic effectiveness of method of otoacoustic emissions recording in the early diagnosis of lesions of receptor part of auditory analyzer. It is known that SHL of noise genesis largely affects the receptor part of the auditory analyzer, for which the OAE method has great practical diagnostic significance. Objective: to study informativity indicators of otoacoustic emission for the diagnosis of sensorineural hearing loss in various occupational groups of coal workers in Ukrainian mines. Materials and Methods: Auditory function of 87 workers of the coal industry (drifters, miners and longwall miners) with different levels of industrial noise and hygienic conditions in their workplaces was: 28 studied drifters (group 1), 25 miners (group 2) and 34 longwall miners (group 3). Work experience in noise in these groups was 17,9±1,0; 23,1±1,0 and 22,2±2,0 accordingly. Noise ratio in drifters was 93,6±4,9 dBA, in miners ? 92,9±5,5 dBA and in longwall miners ? 86,5±6,04 dBA accordingly, while the maximum permitted level is 80 dBA. The research was conducted on the analyzing system "Eclipse" "Interacoustics" (Denmark). All patients underwent registratiov of the caused OAE at frequency distortion product (DPOAE) at frequencies 1-6 kHz. The results were rated using variation statistics Student's test. Results: The most prominent violation of the receptor part of the auditory analyzer according to the OAE among all the examined workers of different professional groups of the coal industry was found in drifters, miners had less pronounced violations and the least significant ones were in longwall miners. At the same time in 42,9% drifters caused OAE at frequency distortion products was not recorded on any of the investigated frequencies.Received averages of OAE amplitude in the studied frequencies differed significantly in drifters not only from the norm, but also from that in the group of longwall miners in the 4-6 kHz region. The most prominent disorders according to the speech and above-threshold audiometry were found in drifters and miners, testifying to violations in the receptor part of the auditory analyzer. Conclusions: In all occupational groups of coal industry workers according to OAE data, more pronounced violations were found in the frequency distortion products in the 4-6 kHz. This is evidenced by significant decrease of OAE amplitudes averages, especially pronounced in 4 and 6 kHz, where they significantly differ from the norm and from the indicators in the group of longwall miners; and OAE registration was absent in the drifters. The identified differences in OAE indicators and dysfunction severity in the receptor structures of the auditory analyzer, obviously, could be explained by the nature of industrial noise and hygienic working conditions in the workplaces of the studied workers of coal industry.