Distortion product otoacoustic emissions among the patients suffering diabetes mellitus type II with hearing impairment
Authors: Shidlovskaya Tetiana A. , Navalkivska Nadiya Ya. 
Published: March 2020

Topicality: Objective research methods of the auditory analyzer are of great importance in diagnosis sensorineural disorders of auditory function, treatment of such diseases and solving a number of expert questions. While diagnosis the damage of auditory system, especially the receptor part of the auditory analyzer the method of the caused OAE on the frequency distortion product (DPOAE) plays a significant role. Quite often at sensorineural hearing loss of different genesis is observed an affection of cochlea structures of the inner ear. Diabetes mellitus (DM) is one of the most acute medical and social problems. According to the latest data, there are 463 million adults with diabetes mellitus in the world; accounting for 9.3% of the world's total population, meaning that 1 among 11 people suffers from diabetes (IDF Diabetes Atlas 9th edition, 2019). Among patients with diabetes, according to various authors, there are disorders in the auditory analyzer.
Purpose: to determine changes in the condition of the receptor part of auditory analyzer according to the OAE registration of the frequency of distortion products among patients with diabetes mellitus type II with impaired auditory function.
Materials and methods: 17 patients with diabetes mellitus type II were examined, who, according to subjective audiometry, revealed impairments of auditory function of the I-II degree. The control group consisted of 15 healthy normal-hearing persons who did not report hearing impairment, had no elevated blood sugar levels. 32 persons were examined in total. The registration of the caused OAE at frequency of distortion product (DPOAE) was conducted on the analyzing system "Eclipse" "Interacoustics" (Denmark) at frequencies 1-6 kHz. Statistical processing of the obtained results was carried out according to the conventional methods of mathematical variation statistics using the STATISTICA software package. The average value of indicators was calculated - magnitude
(M) and its error (+- m). The probability of changes and differences between the comparative values was estimated by the criterion for the reliability of the difference (t) according to the Student's table.
Results and discussion: We have selected for the analysis patients with diabetes mellitus type II, who according to subjective audiometry revealed impaired auditory function. Patients also reported otologic complaints of hearing loss, periodic or persistent subjective ear noise.
As a result of the OAE researches at frequency distortion products, the following data were obtained. A full adequate response of the otoacoustic emission across all frequency spectrums was reported in only 3 patients (9.4% of cases) on the one hand. The majority of the observed patients in whom the OAE was registered received a partially positive test (68.7%). In 7 patients (21.8%) the OAE response was not registered. The absence of OAE response or a partially positive registration in 90.6% of the observed patients indicated violation function of the cochlea in such patients. The DPOAE (response intensity) emission amplitude at all tested frequencies (1-6 kHz) in patients with diabetes mellitus type II was significantly (P<0.01) lower than the norm at all frequencies. Particularly pronounced such a decrease is in the area of 4 kHz, where the amplitude of the OAE response was 5.9±0.2 dB at a norm of 9.4±0.5 dB. Therefore, in patients with diabetes mellitus type II with hearing impairment, there are changes in the receptor part of the auditory analyzer, which is confirmed by the data of objective examination methods.
The changes we have identified in the OAE indicators may express the affection of the receptor structures of the auditory analyzer among patients with diabetes mellitus type II with impaired auditory function. The information obtained on the OAE indicators provides the detection of early violations and the objective ascertainment of changes in the receptor part of the hearing analyzer in diabetes mellitus type II.
Conclusions:
1. OAE data on the frequency of distortion products in patients with diabetes mellitus type II objectively confirm the presence of violations in the auditory receptor.
2. In patients with diabetes mellitus type II, the OAE amplitude at the frequency of distortion products is significantly lower than normal at all tested frequencies (1-6 kHz). Particularly pronounced such a decrease is in the area of 4 kHz, where the amplitude of the OAE response was 5.9±0.2 dB at a norm of 9.4±0.5 dB.
3. The conducted researches prove the expediency of examination by the method of registration of OAE of patients with diabetes mellitus type II, since it promotes the early detection of violation in the receptor structures of the auditory analyzer in such patients.
4. The use of the method of recording otoacoustic emissions in the examination of patients with type II diabetes is important for the objectification of early signs of sensorineural hearing impairment in this contingent.