Audiological Profile of OSA Patients: The Effect of Chronic Nocturnal Intermittent Hypoxia on Auditory Function; A Pilot Study

Objective: The objective of this study was to investigate whether there is any positive or negative correlation between inner ear function and obstructive sleep apnea (OSA). Methods: The study included 35 patients diagnosed with moderate or severe OSA and a control group consisting of 25 healthy individuals. Pure-tone audiometry, tympanometry, transient evoked otoacoustic emissions (TEOAE), distortion product otoacoustic emissions (DPOAE) and auditory brainstem response (ABR) tests were performed, evaluated and compared between the two groups. Results: The air-conduction thresholds at 1000, 4000 and 8000 Hz were higher in OSA patients compared to the controls (P < 0.05). Biauricular wave I and wave V latencies in the OSA group were longer than in the control group, but were still within reference values (1.60 ± 0.45 vs 1.43 ± 0.16 ms, P < 0.001; 5.52 ± 0.70 vs 5.47 ± 0.19 ms, P < 0.001). There was a significant difference in the wave I–V interval between the two groups (4.17 ± 0.36 vs 4.03 ± 4.03 ± 0.16 ms, P < 0.006). An analysis of TEOAE signal-to-noise ratio (SNR) mean values revealed a significant difference between the target OSA group and the control group at 1.00 kHz, 1.42 kHz, 2.00 kHz, 2.83 kHz and 4.00 kHz (P < 0.001). An analysis of DPOAE SNR mean values revealed a significant difference between OSA patients and the control group at all tested frequencies (P < 0.027 for 500 Hz; P < 0.001 for 1000 to 8000 Hz). Conclusion: There is a positive correlation between inner ear function and OSA. High-frequency hearing loss was detected in adults with OSA. The results of otoacoustic emissions showed damage of the cochlear receptor cells.