Endocrine Abstracts

Purpose: Hyperinsulinemia is the metabolic change, which is related to the cochleovestibular diseases the most. It is thought that undiagnosed deafness is highly probable in individuals with prediabetic hyperinsulinemia. We aimed at investigating the results of hearing function test in hyperinsulinemic individuals.

Material and Method: 164 patients were included in the study, which was designed as a prospective research, 76 of which were in case group and 88 of which were in the control group. 76 patients who were between 18 and 64 years of age and with insulin resistance (HOMA-IR≥2.5) comprised the case group of the study and 88 patients with HOMA-IR values <2.5 comprised the control group. All patients were administered the 75 gr OGTT chemical analysis (lidip panel, creatinine, fasting serum glucose and fasting serum insulin level), hormonal analysis (TSH and sT4), audiological assessment, electrocochleography (EcochG) and transient evoked otoacoustic emissions (TEOAE) test.

Findings: The pure sound audiometry threshold values at the 500, 1000, 2000 and 4000 Hz for both ears were found higher in the patients in the case group than the patients in the control group (P<0.01). A positive correlation was found between HbA1c and right ear 500, 1000, 4000 and 8000 Hz threshold values and left ear 2000, 4000, 6000 and 8000 Hz threshold values (P<0.05). A negative correlation was found between HbA1c and speech recognition (P<0.01). The right ear 1.00 and 2.83 kHz TEOAE measurements in the individuals with normal glucose tolerance (NGT) were found higher than the patients with impaired glucose tolerance (IGT); and the 1.42 kHz TEOAE measurements and reproducibility were found higher than the patients with impaired fasting glucose (IFG) (P=0.013, P=0.035, P=0.031). The left ear 1.00 kHz and the 1.42 kHz TEOAE measurements of the IGT patients were found lower than the IFG and NGT patients (P=0.004, P=0.006).

Conclusion: In our study, it was shown that hearing loss developed in hyperinsulinemic cases and prediabetic conditions (IFG/IGT) were related with hearing function impairment. Based on the data of our study, pure sound audiometry and speech recognition scores are recommended in metabolism related hearing loss studies, as electrocochleography does not make an additional contribution, although they are not practical.