Evaluation of Contralateral Suppression of Otoacoustic Emissions, Middle Ear Mechanics, and Hearing in Renal Transplant Patients via Otoacoustic Emissions and Ear Mechanics.

The stria vascularis, which is located in the cochlea of the inner ear, and the renal tubules contain similar anatomical, physiological, immunological, and pathological properties. Therefore, nephrotoxic drugs; electrolyte imbalances; and biochemical, immunological, osmotic, and vascular differences may affect the middle and inner ear and the central pathways. We evaluated the middle ear mechanisms, inner ear functions, and hearing thresholds of 30 renal transplant (RT) recipients (60 ears); 30 healthy volunteers (60 ears) served as the control group. All patients underwent an audiological assessment by means of pure-tone audiometry, otoacoustic emission (OAE), and contralateral suppression of transient-evoked OAE measurements. The mean follow-up after transplant was 6.8 ± 6.1 years (range: 1-20 years). Hearing for the four frequency averages between the two groups was significantly different (P = 0.002). When the cochlea's outer hair cells were evaluated, the signal-to-noise ratio was significantly lower at frequencies of 1000 and 1400 Hz in the RT group versus the control group (P <0.001 and P = 0.008, respectively). When frequency-specific suppressions were assessed, there was no significant suppression at any frequencies in the RT group, but significantly lower suppression was found at all frequencies in the control group (P <0.001 for all frequencies). These results support the presence of auditory dysfunction in RT recipients. Low levels of OAE support our conclusion that RT recipients are prone to cochlear dysfunction. Therefore, audiometric evaluations should be conducted before and after RT, and the recipients should be informed about possible otological involvement.