The assessment of the hearing functions of the patients with diabetes mellitus by the means of high frequency audiometry

DM is a chronic disease of the metabolism that can affect a number of systems at different periods. Many studies have been carried out for so long in an attempt to explain the likely connection between the complications such as nephropatia, retinosis and neuropathy and sensinoneural hearing loss of DM with a high rate of morbidity and mortality.The aim of our study is to assess the hearing functions of type II DM patients between the ages of 40 and 60 through high frequency audiometry and to compare them with the audiometric thresholds in the normal control group. The study was conducted at the Otorhinolaryngology Department of Ahmet Necdet Sezer Research and Application Hospital, Afyon Kocatepe University between May and October 2011. Fitting the criteria, 50 type II patients with DM (100 ears) and 45 healthy control individuals (90 ears) were included in the study for assessment. The demographic features of the DM patients such as the period of disease, treatment employed, age, gender and occupation, their VKI?s and smoking habits were taken down. In addition, the recent HbA1c value available and existence of retinopathy was recorded after a scan of the patients? files was done. High frequency audiometry and audiometric threshold values were identified in all groups. The analysis of all this data was carried out using SPSS 16.0 program and if the bicuspid p value is <0,05, it was statistically regarded as meaningful.Of the 50 patients in the study, 18 (36 %) were males and 32 (64 %) were females, while, in the control group, there were 17 (37.8 %) males and 28 (62,2 %) females. In the patient group, the age range was 40 to 58 and average of age was 50,34±5,02. In the control group, however, the ages ranged between 40 and 60 and ages averaged about at 48,33±5,66. The groups were similar in age, gender, VKI, smoking habits and occupational distribution (p>0.05). The period of disease for the patient group was found to be 7,09±7,19 (1-30) years on average and HbA1c values were running around % 8,14±1,85. 18 patients (36 %) had retinopathy and 22 (44 %) had additional disease.A meaningful discrepancy with the values of SSO, KAE and KAS was detected in all the frequency thresholds but 16.000 Hz (p>0.05) within the study groups (p<0.05). When the audiogram values of the groups related to their right and left ears were compared, neither group had any meaningful discrepancy between them (p>0.05). In the patient group there was no meaningful correlation when HbA1c averages, the ways and durations of treatment, the existence and degree of retinopathy, existence of an additional disease other than HT and audiometric thresholds were examined through correlation analysis. When the relationship between audiometric thresholds and existence of HT was studied with the correlation analysis, high frequency thresholds particularly above 8000 and the existence of HT were meaningfully correlated. In the light of these findings, cases were compared in three groups, those only with DM, the ones with an additional HT and the controls. While, during the assessment of patients with diabetes, hearing loss was identified between the frequencies at or below 4000 HZ and 12000 Hz, diabetes accompanied by the existence of HT caused hearing loss in all frequencies but 16000 Hz. There is a fall in KAS for patients with DM whether there is an additional disease or not. When a patient with tonal audiometry and normal hearing and high frequency audiogram values related to control groups were compared, the meaningful discrepancy was found at 12000 Hz frequency hearing threshold and KAS values (p<0.05).In conclusion, there is a meaningful fall in the audiometric thresholds of DM patients at all frequencies but 16000 Hz compared to healthy individuals. The fall in the hearing threshold of 12000 Hz and KAS is an early symptom of diabetic hearing loss. The existence of HT is a major factor that increases hearing loss of patients with diabetes.