Comparison between pure tone audiometry and auditory brain-stem response threshold in patients with presbycusis in co-morbid with arterial hypertension and diabetes mellitus : a prospective study of 56 patients aged ≥50years old.

Background: Presbycusis is age-related bilateral sensorineural hearing loss, with course acceleration highly influenced by comorbidities including arterial hypertension (AH) and diabetes mellitus (DM). Two major diagnostic approaches used include pure tone audiometry (PTA) and audiometry brain-stem response (ABR).Comparative studies regarding change in PTA and ABR threshold without age limit and co-morbidities’ consideration have been published. However, literature has no reports regarding aforementioned concerns. Objective: In this prospective study, we aimed to ascertain and correlated the relationship between PTA and ABR thresholds in patients with presbycusis in co-morbid with arterial hypertension and diabetes mellitus, either alone or combined. Methods: In this study, 56 patients comprised of 35 females and 21 males, with mean age 64.71± 9.3(50-83) met study criteria. Depending on associated co-morbidities, the cohort was divided into 4groups, thus: group I (presbycusis alone, n=21), group II (presbycusis and DM, n=12), group III (presbycusis and AH, n=14) group IV (presbycusis and DM/AH, n=9) respectively. PTA and ABR thresholds were obtained and analysed. The statistical data analysis was performed using ANOVA-ONEWAY (SPSS-IBM), and p-value (≤0.05) was considered significant. Results: In this study, ABR and PTA threshold difference between ears was not statistically significant. The comparison between the mean threshold difference of ABR and PTA in group I and II was significant at each frequency, while group III exhibited a significant difference at high frequency only. However, group IV showed no significant difference between ABR and PTA thresholds. We also found that the mean difference in decibel was different in each group. In group I the mean difference decibel was < 20dB at high frequency and >20dB at 0.5 and 1 kHz. Group II showed a mean difference < 20dB at all frequency range. In group III we found mean difference between the two tests <20dB at 4, 8 and 2-4 kHz and >20dB at 0.5, 1, and 2 kHz. Finally in group 4 the mean threshold difference was >20dB at each frequency. Conclusion: There was a positive relationship between the ABR and PTA threshold, which appear to be insignificant in presbycusis patients with both AH and DM; this finding may be related to synergic effects of the two chronic illnesses on the cochlea.