State Institution "O. S. Kolomiychenko Institute of Otolaryngology of the National Academy of Medical Sciences of Ukraine", Kiev
Introduction. In the diagnostics of disorders of the hearing analyzer an important place is taken by the objective methods of research. In many scientific researches the well-proven role of method of otoacoustic emission in the diagnostics of disorders of the hearing system, the first place is taken by the receptor part of the hearing analyzer. In view of the enough high percent of patients with a sensorineural hearing loss, reason of which is a lesion of the cochlea structures of the internal ear, the use of a DPОАЕ method is of a large practical value. It is known that at SHL of noise genesis largely the receptor part of the hearing analyzer suffers directly. The events of the last time in Ukraine actualized many problems of military medicine and made to apply more attentively to possible risk of appearance of acoustic trauma. The cases of damages of the hearing system can occur due to a mine-explosion and other variants of acoustic trauma. The influence of sounds of high intensity – acoustic trauma - can cause considerable damages in the hearing system. Therefore, studying indicators of otoacoustic emission for combatants with acoustic trauma, got in the zone of the anti-terroristic operation (АТО), is of great interest.
Aim of this work – to define changes in the state of the receptor part of the auditory analyzer based on the data of registration of DPОАЕ in persons with acoustic trauma, got in the zone of АТО, depending on the degree of disorders of the hearing the function.
Materials and methods. A basic group consisted of 50 patients with acoustic trauma, got in the zone of the АТО. A control group consisted of 15 healthy persons who had no complaints of the hearing and no contacts with sounds of high intensity and who, in the period of their examination had no disorders on the side of the hearing analyzer. Totally there were examined 65 persons. 50 combatants were selected with acoustic trauma and bilateral sensorineural disorders, descending abrupt type of the audiometric curve, with the most expressed increase of thresholds of hearing to tones 4, 6 and 8 кHz. The patients were divided into 2 groups by the degree of disorders of the hearing function: 1st group – 24 persons with the initial, unexpressed disorders of the hearing function, lesions mainly in the basal part of the cochlea; 2nd group – 26 persons with more expressed SHL, with the lesion in the mediobasal part of the cochlea accompanied by disorders of speech and supra-threshold audiometry. The research of otoacoustic emission (DPОАЕ) conducted with the use of the generally accepted methodology of the bandwidth of 1–6 кHz with the help of the analyzing system "Eclipse" of the "Interacoustics" Company.
Results. The studies with DPОАЕ on combatants with acoustic trauma showed the following data. The complete adequate answer to the otoacoustic emission at all frequency spectrum is registered only in 10,0 % cases, typical for the 1st group. In the majority of the examined patients with the registered DPОАЕ, a positive test was received partly, only when on one or a few of the investigated frequency bands an adequate answer was marked. During research of DPОАЕ in persons with acoustic trauma in the zone of the АТО, a certain peculiarity of the disorders was noted. Although from the data of a subjective audiometry (tone-frequency threshold and supra-threshold) for the examined patients the receptor lesions of the hearing system and decrease of the hearing function were found in first of all high-frequencies of the conventional range, especially in the zone of 4–8 кHz, from the DPОАЕ data we often registered the maintenance of the answer of external hair cells to higher frequencies, being absent at lower ones, or "selective" sensitiveness of "discordantly". The answer of the cochlea was mostly kept at the frequency of 4 кHz. We should mark that in occupational SHL of noise genesis, as a rule, during registration of DPОАЕ the generation in a high-frequency range suffers mostly. In 40,0 % examined patients DPОАЕ did not register at any frequencies, generally in combatants of the 2nd group, pointing to disorders of the cochlea function in such patients. Also, the absence of registration of DPОАЕ can show the severity of disorders in the hearing function. According to our data, patients with acoustic trauma had a considerable decrease of the intensity of answers to DPОАЕ in relation to a norm, more shown in the 2nd group. The amplitude of emission on all investigated frequencies in both groups was reliably lower as compared to the norm at all frequencies. Thus, amplitude of DPOAE was significantly different in groups 1 and 2 between themselves at the frequency 6000 Hertz. So, in the 1st group it was presented as (7,7 ± 0,6), and in the 2nd – (6,3 ± 0,6) dB. We should notice that the manifestations PSIV (phenomenon of speed-up increase of volume) in the 2nd group were more expressed in a way of discomfort and decreasing DP by the method of Lusher, that a showing disfunction of the receptor part of the hearing analyzer. Thus, the more expressed disorders by the data of DPОАЕ were seen in combatants of the 2nd group, which is significantly shown by the decrease of average meanings of the amplitude in DPОАЕ, especially at 6 кHz, where they differed not only according to the norm but also by indicators in the 1st group. The studies showed the expedience of research on DPОАЕ for combatants with acoustic trauma got in the zone of the АТО. The changes educed by means of the method of registration of otoacoustic emission in patients with combat acoustic trauma have an important significance for objectivities of early signs of sensorineural disorders, disorders in the receptor structures of the cochlea, in the first place. It will help in the timely setting of medical and preventive measures and prevention the progress of SHL in such patients.
Conclusions. 1. Patients with acoustic trauma, got in real combat situations, can have disorders in the receptor part of the hearing analyzer that is objectively confirmed by the data of the DPОАЕ. 2. The amplitudes of DPОАЕ in patients with combat acoustic trauma are significantly lower than the norm at all investigated frequencies, more shown in 2nd group. The amplitudes of DPOAE were significantly different in the group 1st and 2nd between themselves at the frequency 6000 Hertz – in the 1st group it was presented as (7,7 ± 0,6), and in the 2nd as (6,3 ± 0,6) dB. 3. The studies point to the expedience of examining the registration of DPОАЕ in patients with acoustic trauma, got in the zone of the АТО, and can help to early reveal disorders in the receptor part of the hearing analyzer in such patients.
Key words: sensorineural disorders of hearing, acoustic trauma, hearing analyzer, otoacoustic emission, DPOAE
ORCID ID of co-authors and their contribution to the preparation and writing of the article:
Shidlovskaya T.A. (ORCID ID 0000-0002-7894-359X) - Definition of the purpose and design of the study, registration of the OAU, analysis of OAU registration data, analysis of the obtained results, formation of conclusions;
Petruk L.G. (ORCID ID 0000-0002-1261-7054) - selection of patients for examination, conducting of clinical researches, review of literature on the subject of work, statistical processing of the obtained results in accordance with generally accepted methods of mathematical variation statistics, analysis of the obtained data, formation of conclusions, registration of the article.