Evaluation of the changes in the hearing system over the years among patients with OSAS using a CPAP device

Oxidative Stress in Obstructive Sleep Apnea Syndrome: Putative Pathways to Hearing System Impairment

INTRODUCTION

OSAS is a disease that affects 2% of men and 4% of women of middle age. It is a major health public problem because untreated OSAS could lead to cardiovascular, metabolic, and cerebrovascular complications. The more accepted theory relates to oxidative stress due to intermittent hypoxia, which leads, after an intense inflammatory response through multiple pathways, to endothelial damage. The objective of this study is to demonstrate a correlation between OSAS and hearing loss, the effect of the CPAP on hearing function, and if oxidative stress is also involved in the damaging of the hearing system.

METHODS

A review of the literature has been executed. Eight articles have been found, where seven were about the correlation between OSAS and the hearing system, and only one was about the CPAP effects. It is noted that two of the eight articles explored the theory of oxidative stress due to intermittent hypoxia.

RESULTS

All studies showed a significant correlation between OSAS and hearing function (p < 0.05).

CONCLUSIONS

Untreated OSAS affects the hearing system at multiple levels. Oxidative stress due to intermittent hypoxia is the main pathogenetic mechanism of damage. CPAP has no effects (positive or negative) on hearing function. More studies are needed, with the evaluation of extended high frequencies, the execution of vocal audiometry in noisy environments, and the evaluation of potential biomarkers due to oxidative stress.

Obstructive Sleep Apnea and Sensorineural Hearing Loss: A Systematic Review and Meta-analysis

OBJECTIVES

To evaluate the associations between obstructive sleep apnea (OSA) and sensorineural hearing loss (SNHL) and the effects of continuous positive airway pressure (CPAP) therapy on SNHL.

DATA SOURCES

Ovid Medline, Embase, and Scopus databases.

REVIEW METHODS

A systematic search was done for studies investigating relationships between OSA and SNHL in adults, with manual searches for additional references. The final update was done on December 22, 2021. The Risk of Bias Assessment Tool for Nonrandomized Studies was applied for quality assessments.

RESULTS

The 20 included studies had a total of 34,442 participants (66% male; mean age, 46.6 years). The OSA group had a significantly worse mean hearing threshold level (HTL) than the control group for midfrequency ranges (500, 1000, 2000 Hz; mean difference, 4.00 dB; 95% CI, 2.40-5.61) and high-frequency ranges (4000, 8000 Hz; mean difference, 6.24 dB; 95% CI, 2.99-9.49). An association between OSA and SNHL was found. When compared with controls, patients with OSA had an odds ratio of 1.52 (95% CI, 1.12-2.06) for midfrequency hearing impairment and 1.19 (95% CI, 1.05-1.34) for high-frequency hearing impairment. However, we did not find significant improvements in midfrequency HTL after CPAP therapy.

CONCLUSIONS

HTL was significantly poorer among participants with OSA (especially in severe cases) than non-OSA controls. Studies on patients with OSA with SNHL treated with CPAP did not show significant improvements in midfrequency HTL. Further studies are warranted on these issues.

CPAP Treatment Improves Pure Tone Audiometry Threshold in Sensorineural Hearing Loss Patients with Sleep-Disordered Breathing

This article investigates the effects of continuous positive airway pressure (CPAP) on hearing impairment in sensorineural hearing loss (SNHL) patients with sleep-disordered breathing (SDB). This retrospective and observational study took place from September 2016 to February 2021, accumulating 77 subjects with SNHL and SDB (60.7 ± 11.1 years). Of which, 28 received CPAP treatment (63.0 ± 8.5 years). In our methodology, hearing thresholds at low, medium, high, and average frequencies are assessed by pure-tone audiometry at baseline (BL), three (3 m), six (6 m), and 12 (12 m) months. Our results show that the BL of at least three frequencies in all subjects is positively associated with old age, males, smoking, alcohol, coronary artery disease, hypertension, and apnea-hypopnea index [AHI] (all p < 0.05). Moreover, low, medium, and average frequencies are negatively correlated at CPAP-6 m (-5.60 ± 2.33, -5.82 ± 2.56, and -5.10 ± 2.26 dB; all p < 0.05) and CPAP-12 m (-7.97 ± 2.74, -8.15 ± 2.35, and -6.67 ± 2.37 dB; all p < 0.01) against corresponding measures of CPAP-BL. High, medium, and average frequencies positively correlated with age (p < 0.001 for high and average frequencies and <0.01 for medium frequencies). We conclude that in SNHL patients with SDB, hearing thresholds at low and medium frequencies improves under CPAP use after six months, which persists at least to the end of one year.