Introduction: Registration of otoacoustic emission is the general objective method in diagnostics of receptor defeats of the auditory system, first of all the organ of Corti outer hair cells. At an acutrauma the receptive field of auditory system suffers.
The purpose: to determine the possible prognostic criteria of progression of perceptual hearing disorders according to distortion-product otoacoustic emission (DPOAE) in servicemen who received acutrauma in real combat conditions.
Material and methods: In the this work indicators for distortion-product otoacoustic emission (DPOAE) in servicemen who received acutrauma in the area of the joint forces operation have been investigated.
We had examined 2 groups of people: 1st group – 30 persons who had shown improvement in auditory function and general condition after treatment, 2nd group – 30 persons in whom disease progression had observed, they had no positive dynamics after treatment.
The investigation of otoacoustic emission (OAE) was conducted by analyzing system “Eclipse” of the “Interacoustics” Company (Denmark). Was used the generally accepted methodology. The recording has performed in the frequency band (1 - 6) kHz.
Results. The complete adequate response of OAE across the entire frequency spectrum has been registered in only one patient with combat acutrauma from group 1. In most of the surveyed patients in whom the OAE was registered, a partially positive test was obtained as already mentioned. The response was considered as registered when the signal-to-noise ratio exceeded or was equal to 3 dB. The decision on a partially positive test was made when only one or more of the tested frequency bands had an adequate response. A positive response was registered in 42.6% of fighters of group 1 and 31.25% of group 2. According to our data, in patients of group 1 in 57.4% of cases the DPOAE was not registered at any of the frequencies, the same situation in patients of group 2 were in 68.75%.
Thus in group 1 positive, including in part, the DPOAE was recorded at one frequency in 16.7% of cases, at twо frequencies - at 18.5%, at three frequencies - 7.4% and at four frequencies -1 . 8%. In group 2, a positive test was registered at one frequency in 16.7% of cases, at twо frequencies - 4.2% at three frequencies - 6.2%. At four frequencies, a positive test (complete response) was not registered in any patient of group 2. We analyzed at which frequencies the response was most often recorded with partially positive DPOAE results in surveyed patients. The corresponding percentages were calculated from the total number of received responses.
At the same time, in patients of group 1 partial response of DPOAE have been registered more often than in group 2. In group 1, DPOAE was recorded at frequencies of 1 kHz in 52.2% of cases, 2 kHz - 34.8%, 4 kHz - 78.3%, 6 kHz - 21.7%. In persons from group 2, with a progressive course of sensorineural hearing loss, the DPOAE response was observed at frequencies of 1 kHz - 38.5%, 2 kHz - 46.1%, 4 kHz - 53.8%, 6 kHz - 23.1%.
Thus, in both groups, the DPOAE response have been most often recorded at 4 kHz: (78.3%) and (53.8%), respectively. It is followed by the frequency of registration in 1 group with a frequency of 1 kHz (52.2%), and in group 2 with 2 kHz (46.1%).
Thus, registration of the DPOAE will promote objectification of sensorineural hearing loss course at a combat acutrauma.
Conclusions:
The conducted researches have shown the importance of DPOAE definition at patients with a combat acutrauma that promotes timely and objective detection of receptor structures defeats of the auditory system at such patients.
The results of DPOAE registration can be used to predict the course of sensorineural hearing loss and assess adverse factors in combat acutrauma.
Complete absence of registration of DPOAE at servicemen with a combat acutrauma can serve as an objective sign of prognostically unfavorable course of sensorineural hearing loss at such patients.
Sensorineural hearing loss amplifies neural coding of envelope information in the central auditory system of chinchillas
