Auditory Deficits in Patients With Mild and Moderate Obstructive Sleep Apnea Syndrome: A Speech Syllable Evoked Auditory Brainstem Response Study

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.

The correlation between the body shape and otolithic function in patients with obstructive sleep apnea

OBJECTIVE

To identify the typical pattern of changes of vestibular-evoked myogenic potentials (VEMPs) and explore the relationship between VEMPs and the anthropometry factors in patients with obstructive sleep apnea (OSA).

METHODS

Patients diagnosed as OSA after overnight polysomnography (PSG) tests were enrolled as the study group. Healthy volunteers were recruited as the control group. Anthropometry data of the body shape and VEMPs results were collected completely. The correlation analysis was conducted among those parameters.

RESULTS

Forty-nine patients with OSA who were diagnosed in the Therapy Center of Sleep-disordered Breathing in our hospital and sex- and age-matched healthy controls as well. Significant changes in ocular and cervical VEMPs (oVEMP and cVEMP) in the study group were observed, which were reduced response rates, elevated thresholds, decreased amplitudes, and prolonged first wave latencies. In oVEMP, the first wave (n1) latency was significantly correlated with weight, body mass index (BMI), neck circumference, waist circumference, hip circumference, and apnea hypopnea index (AHI). In a tentative application, combined use of BMI and oVEMP n1 latency increased the detection rate during OSA screening prior to PSG.

CONCLUSION

OSA can negatively affect function of otolithic organs and their pathways. The first wave latency of the VEMPs waveform may be another important parameter to define peripheral nervous system lesions caused by systemic diseases as OSA.

Evaluation of auditory system in obstructive sleep apnea patients

OBJECTIVES

Obstructive sleep apnea (OSA) has been associated with auditory dysfunction both to the cochlear and higher auditory pathways. However, available literatures presented conflicting results. We aimed to study the impact of OSA severity and their polysomnography parameters on hearing function.

MATERIALS AND METHODS

A total of 44 patients were included after evaluation for sleep disorders and were divided into four groups in accordance with apnea-hypopnea index (AHI). Pure tone audiometry (PTA), distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) were compared in commensurate with the severity of AHI. Polysomnography oximetry parameters of oxygen desaturation index, mean SPO2, minimum SPO2 and percent SPO2 < 90% were correlated with their respective PTA, DPOAE and ABR results.

RESULTS

There was no significant change in the PTA, DPOAE and ABR results in connection with AHI severity. However, we found significant correlations between mean SPO2 and percent SPO2 < 90% with ABR wave I, III and V absolute latencies. Minimum SPO2 was also significantly correlated with wave III peak latency changes.

CONCLUSIONS

Mean SPO2, percent SPO2 < 90% and minimum SPO2 could be key prognostic indicators of central auditory dysfunction in OSA patients. These parameters should be explored further as indicators of OSA severity rather than utilizing AHI alone. The hypoxic burden derived could be a better predictor of auditory function abnormalities rather than one derived from AHI.

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.

Uneven Effects of Sleep Apnea on Semicircular Canals and Otolithic Organs

OBJECTIVE

This study aimed to explore how obstructive sleep apnea (OSA) affects the function of each vestibular organ and to identify the correlations among them.

METHODS

A prospective study was conducted involving 32 healthy controls and 64 patients with OSA. The objective detection methods of the utricle and saccule are vestibular-evoked myogenic potentials (VEMPs). A combination of the caloric test and video head impulse test (vHIT) was used to comprehensively evaluate the objective function of semicircular canals.

RESULTS

Elevated thresholds (p < 0.001), decreased waveform amplitudes (p < 0.001), prolonged first wave latencies (p < 0.001), and shortened first interpeak latencies (p < 0.001) were observed in both ocular VEMP (oVEMP) and cervical VEMP (cVEMP). A significant difference was found in the caloric test comparison (χ² = 4.030, p = 0.045) but not in the vHIT. The intergroup comparison of normal rates among the VEMPs, caloric test, and vHIT groups showed a significant difference (p < 0.001).

CONCLUSION

The impairment of vestibular function in patients with OSA was uneven and biased. More attention should be given to vestibular dysfunction in the diagnosis and treatment of OSA.

Characteristic manifestation of ocular and cervical vestibular evoked myogenic potentials findings in severe obstructive sleep apnea patients

BACKGROUND

Studies of saccular and utricular function in patients with obstructive sleep apnea (OSA) are rare. We noticed that some OSA patients also had positive results in vestibular function tests, and this inspired our interest in exploring the vestibular function patterns of OSA patients.

OBJECTIVES

To investigate otolithic organ function in severe OSA patients who lack vestibular symptoms and systemic disease.

MATERIAL AND METHODS

32 patients (64 ears) with severe OSA and 22 healthy controls (44 ears) were enrolled. The ocular and cervical vestibular-evoked myogenic potentials (oVEMP and cVEMP) and the caloric test were recorded and analyzed.

RESULTS

The response rates of oVEMP (73.4%) and cVEMP (82.8%) in patients with severe OSA were significantly lower than those in controls. In oVEMP, elevated thresholds (p = .002), decreased n1-p1 amplitudes (p < .001), prolonged n1 latencies (p < .001) were observed. In cVEMP, the elevation of thresholds (p < .001), decrease in p1-n1 amplitudes (p < .001), and n1-p2 amplitudes (p < .001), prolongation of p1 latencies (p = .003) were observed. No significant difference in the caloric test was found between the two groups.

CONCLUSIONS AND SIGNIFICANCE

Disappearance or impairment of VEMPs could be observed in patients with severe OSA, and reflects different degrees of impairment in the utricle and saccule.

miR-126a-3p targets HIF-1α and alleviates obstructive sleep apnea syndrome with hypertension

The obstructive sleep apnea syndrome (OSAS) is a common sleep-related breathing disorder and an important cause of refractory hypertension. MicroRNAs (miRNAs) are involved in the development of hypertension, but their role in OSAS with hypertension (OSAS-hypertension) has been little studied. Evidence indicates that miR-126a-3p expression is lower in patients with OSAS-hypertension compared with the patients with OSAS alone. However, its role in the pathogenesis of OSAS-hypertension remains unclear. Therefore, this study aims to investigate the role of miR-126a-3p in OSAS-hypertension and to determine whether HIF-1α is involved in this process. Sprague Dawley rats were exposed to chronic intermittent hypoxia (CIH) for 8 weeks to induce OSAS-hypertension. Rat aortic smooth muscle cells (A7r5) were cultured under hypoxia as an in vitro model. Our results showed that rats exposed to 8 week CIH exhibited decreased miR-126a-3p and increased HIF-1α expression. Furthermore, administration of recombinant adeno-associated virus expressing miR-126a-3p (rAAV-miR-126a) counteracted the CIH-induced systolic blood pressure upregulation, oxidase stress, inflammation, and heart and abdominal aorta vascular remodeling. Moreover, the mechanism was associated with its targeted suppression of HIF-1α. These findings suggest that miR-126a-3p might be a novel potential therapeutic target for the treatment of OSAS-hypertension.

The relationship between the findings of vestibular evoked myogenic potentials and severity of obstructive sleep apnea syndrome

PURPOSE

Our study aimed to evaluate the effects of chronic hypoxic state in Obstructive Sleep Apnea Syndrome (OSAS) on brainstem pathways using Vestibular Evoked Myogenic Potential (VEMP) test and to investigate the presence of new markers likely to be correlated with the severity of the disease.

METHODS

The study was planned as prospective and double blind. A total of 60 patients (120 ears) diagnosed with mild, moderate and severe OSAS were included in the study and the patients are grouped as 20 patients in each group. Twenty volunteer healthy individuals (40 ears) shown to be without OSAS were included in the study. VEMP measurements were made in 60 study group patients (120 ears) and in 20 healthy controls (40 ears). The groups were compared in terms of variables such as the acquisition rate of oVEMP and cVEMP waves, interval between the waves, latency and amplitude of the waves. p < 0.05 values were considered as significant.

RESULTS

The results of cVEMP test showed that the rate of wave acquisition in the moderate and severe OSAS groups was significantly lower than the control group and mild OSAS groups (p = 0.008). There was no difference between the control group and the mild OSAS group in terms of the rate of obtaining the wave (p > 0.05). In the moderate and severe OSAS groups, P1N1 amplitude and N1P2 amplitude values were found to be significantly lower than the mild OSAS group (p = 0.007 and p = 0.017, respectively). In the oVEMP test, there was no significant difference between the mild OSAS group and the control group in terms of the wave yield (p > 0.05); however, it was found that the rate of wave acquisition in the moderate and severe OSAS groups was significantly lower than the mild OSAS group (p = 0.041). There was inverse correlation between the N1P2 interval and P1N1 amplitude value and AHI in simple regression analysis and multiple regression analysis (p = 0.012 and p = 0.021; p = 0.009 and p = 0.040, respectively).

CONCLUSION

The negative effects of chronic intermittent hypoxia related with OSAS on the brainstem and vestibular system can be demonstrated by VEMP tests. Especially, the inability to obtain the wave is the most important finding showing this situation. Also, we think that N1P2 interval and P1N1 amplitude markers can be used to detect the subclinical negative effect of chronic hypoxia on vestibular nuclei in the brainstem.

Inner ear function in patients with obstructive sleep apnea

OBJECTIVE

Because of their high metabolic activity and low-resting oxygen tension, the organs of the inner ear are vulnerable to hypoxia, a condition that occurs repetitively in obstructive sleep apnea-hypopnea syndrome (OSAHS). The present study aimed to investigate the inner ear function of patients with OSAHS.

METHODS

A total of 58 patients with OSAHS (116 ears) and 20 adults without OSAHS were enrolled in the present study. The clinical features, such as air-conduction thresholds, auditory brainstem response (ABR, 11 times/s and 51 times/s stimulation rates), and distorted products otoacoustic emission (DPOAE), were evaluated and compared between these two groups.

RESULTS

Air-conduction thresholds at 4 kHz and 8 kHz were higher in patients with OSAHS compared with controls (P < 0.001). At the rate of 11 times per second, biauricular wave I latencies and wave V latencies in the OSAHS group were longer than those in the control group (1.51 ± 0.13 vs. 1.33 ± 0.07 ms, P < 0.001; 5.65 ± 0.23 vs. 5.53 ± 0.23 ms, P = 0.0016). At the rate of 51 times per second, biauricular wave I latencies and wave V latencies in the OSAHS group were longer than those in the control group (1.64 ± 0.12 vs. 1.44 ± 0.06 ms, P = 0.0001; 5.92 ± 0.26 vs. 5.80 ± 0.18 ms, P = 0.0077). However, there was no significant difference in the wave I and wave V interval between these two groups (P = 0.10). DPOAE amplitude was significantly reduced in OSAHS patients, although no hearing loss was observed.

CONCLUSION

High-frequency hearing loss was detected in adults with severe OSAHS, and wave I latencies and wave V latencies of ABR were prolonged.