Polymorphisms in genes involved in inflammatory pathways in patients with sudden sensorineural hearing loss

White Matter Hyperintensity in Patients with Sudden Sensorineural Hearing Loss

OBJECTIVE

To compare white matter hyperintensities (WMHs) on T2-weighted magnetic resonance imaging (MRI) of patients with sudden sensorineural hearing loss (SSNHL) and analyze subpopulations with age-matched controls.

METHODS

T2-weighted MRI scans of 150 patients with SSNHL were assessed for WMHs and compared with the data of 148 healthy age-matched adults. Assessments of WMHs included independent grading of deep white matter hyperintensities (DWMHs) and periventricular hyperintensities (PVHs). WMH severity was visually rated using the Fazekas and Mirsen scales by two independent observers.

RESULTS

Fazekas grades for PVHs (p < 0.001) and DWMHs (p < 0.001) of SSNHL patients were found to be significantly greater than those of healthy participants. The average Mirsen grades for DWMHs of healthy and SSNHL patients were evaluated to be 0.373 ± 0.550 and 2.140 ± 0.859, respectively. Mirsen grades for DWMHs of SSNHL patients were found to be significantly greater (p < 0.001) than those of healthy participants. The Mirsen scale was found to have higher sensitivity (p < 0.001) than the Fazekas scale in grading PVHs and DWMHs. No significant difference (p = 0.24) was found in specificities between the two scales.

CONCLUSIONS

Patients with sudden hearing loss have a much higher likelihood of having periventricular and deep white matter hyperintensities compared to age-matched controls. These findings indicate that sudden hearing loss patients are more likely to have microvascular changes in the brain, which may indicate a vascular and/or migraine origin to sudden sensorineural hearing loss.

The Roles Played by Blood Inflammatory Parameters in Sudden Sensorineural Hearing Loss

OBJECTIVE

The etiology of sudden sensorineural hearing loss (SSNHL) remains unknown; inflammation may be one cause. We retrospectively studied SSHNL cases in terms of the inflammatory parameters involved.

METHODS

We reviewed 169 SSNHL cases. The control group contained 132 patients with vocal cord polyps. The C-reactive protein (CRP) level, CRP/serum albumin (Alb) ratio, and neutrophil/lymphocyte ratio (NLR) were compared between the 2 groups. The relationships between these parameters and the time to treatment after SSHNL onset, hearing level, and therapeutic effects were also analyzed.

RESULTS

The CRP level, CRP/Alb ratio, and NLR were higher in SSNHL patients than in controls, but only the NLR differed significantly between the 2 groups. We found no significant differences between patients with different hearing levels, those evaluated at various times after SSNHL onset, and those with different outcomes.

CONCLUSION

The NLR is a reliable SSNHL diagnostic marker. The CRP level and CRP/Alb ratio are not useful indicators.

Associations between neutrophil-to-lymphocyte/platelet-to-lymphocyte and recovery in sudden sensorineural hearing loss

Aims: This study investigated the nonlinear associations between neutrophil-to-lymphocyte (NLR)/platelet-to-lymphocyte (PLR) and recovery rates in sudden sensorineural hearing loss (SSNHL). Methods: Total of 244 SSNHL patients were included. The primary outcome was recovery rate. Results: A nonlinear association was detected between NLR and recovery rate using the LOWESS method, with a knot of 3. Patients with NLR ≥3 had a higher recovery rate than NLR <3. Using the linear-spline function, NLR was significantly associated with high recovery rate when NLR was <3. However, when NLR was ≥3, this association became nonsignificant. The trend test showed a similar result. PLR was not associated with recovery rate. Conclusion: The association between NLR and recovery rate is nonlinear, with a knot of around three. PLR is not associated with recovery rate.

Comparison of Batroxobin Versus the Combination of Batroxobin and Intratympanic Dexamethasone Injection in the Treatment of Sudden Sensorineural Hearing Loss

Introduction: Sudden sensorineural hearing loss (SSNHL) manifests as an abrupt decline in hearing by at least 30 dB within a 3 day period. Intratympanic dexamethasone injection (ITDI) has gained recognition as a potential treatment for SSNHL. This study aims to investigate the efficacy of combining batroxobin with ITDI (Bat and ITDI) in treating SSNHL patients and its influence on peripheral blood inflammatory indicators. Methods: SSNHL patients were retrospectively categorized into the control group (treated with Bat) and the observation group (treated with Bat and ITDI). The study involved analyzing clinical baseline data, evaluating clinical efficacy, and comparing the total effective rates among SSNHL patients with different audiometric curve types in the observation group. Routine blood tests were performed on peripheral blood samples to calculate the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), and to determine C-reactive protein (CRP) levels. Adverse reactions and complications were closely monitored. Results: Following treatment, both groups displayed improvements in hearing, with the observation group exhibiting a significantly higher total effective rate (75.90%) than the control group (59.78%). For patients with 3 distinct types of sudden hearing loss (high-frequency, flat-frequency, total deafness), Bat and ITDI treatment demonstrated increased total effective rate for patients with different sudden hearing loss types (high-frequency, flat-frequency, and total deafness). Both groups experienced reduced peripheral blood CRP levels and the NLR/PLR values, with the observation group demonstrating lower values. Additionally, across the 4 audio metric subtypes, the levels of peripheral blood CRP, NLR, and PLR decreased in SSNHL patients, and the observation group had a lower incidence of adverse reactions compared to the control group. Conclusions: Bat and ITDI emerge as notably more effective for SSNHL patients, displaying potential for reducing peripheral blood inflammatory indicator levels and mitigating the incidence of adverse reactions or complications, thereby enhancing safety.

Indications of Effective Hyperbaric Oxygen Therapy Combined With Steroid Therapy for Sudden Hearing Loss

OBJECTIVE

This study evaluated the therapeutic effect of hyperbaric oxygen therapy (HBOT) combined with steroid therapy to treat sudden hearing loss and examined the index associated with excellent therapeutic effect.

METHODS

We included 109 patients with sudden hearing loss. Patients were divided into the HBOT combination group (59 sides) treated with HBOT and steroid therapy and HBOT noncombination group (50 sides) involving steroid therapy only. The recovery rate of each group was compared according to the severity of hearing loss. Blood samples were evaluated and inflammatory markers, such as neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR), were calculated and compared by severity. We evaluated the usefulness of inflammatory markers for predicting recovery rate, and calculated cutoff values were also evaluated.

RESULTS

The HBOT combination group exhibited a higher overall recovery rate than the HBOT noncombination group, particularly in severe cases. However, there was no significant difference in the severity of hearing loss based on various inflammatory markers. NLR and PLR are useful for predicting the effect in patients treated with concomitant HBOT. By setting 2.43 and 146.67 as cutoff values for NLR and PLR, respectively, we observed that lower values resulted in better recovery rates.

CONCLUSION

The use of HBOT is effective for severe cases and early blood flow disorders with low NLR and PLR and less inflammation. When determining treatment, not only should the severity of hearing loss be considered, but also the NLR and PLR should be evaluated and examined based on the cutoff values.

Prognostic Correlation of Immune-Inflammatory Markers in Sudden Sensorineural Hearing Loss: A Retrospective Study

BACKGROUND

The mechanism of sudden sensorineural hearing loss (SSNHL) remains incompletely understood, but immune cell infiltration has been identified as a crucial component in the sickness. The patients with SSNHL may benefit from investigating markers related to inflammation.

METHODS

From April 2022 to 2023, 80 patients who were diagnosed with SSNHL in the Department of Otolaryngology at Yangzhou University's Clinical Medical College were enrolled in the SSNHL group. And patients were separated into effective and ineffective groups based on the degree to which their hearing had recovered prior to discharge. As the control group, 80 healthy volunteers were chosen from hospital's physical examination center. Neutrophils, lymphocytes, platelets, and white blood cells were counted. Additionally, quantified and statistically examined were the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and systemic immune inflammation index (SII). The risk variables for prognosis were identified using logistic regression models, and the prediction accuracy of the model was calculated using the receiver operating characteristic (ROC) curves.

RESULTS

The SSNHL group had higher levels of white blood cells, neutrophils, platelets, NLR, PLR, and SII than the control group. While the PLR lacked statistical significance, the NLR and SII of the patients in the ineffective group were noticeably higher than those in the effective group.

CONCLUSION

Patients with SSNHL exhibit inflammatory immune responses. Patients with SSNHL can have their prognosis determined by the simple peripheral blood indicators NLR and SII, particularly SII, which is significant for predicting prognosis and directing treatment.

Examination of the Relation Between Audiometric Configuration and Hematological Parameters in Idiopathic Sudden Sensorineural Hearing Loss

Among the hematological parameters, neutrophil/lymphocyte ratio (NLR) and platelet/ lymphocyte ratio (PLR) have been associated with inflammatory state, microvascular damage and ischemia. It is well-known that these ratios increase in idiopathic sudden sensorineural hearing loss (ISSHL). In ISSHL, different audiographic features may reflect different disease mechanisms. This study aimed to investigate whether there were differences in NLR and PLR among patient groups with different audiometric configurations. Patients meeting the study inclusion criteria were divided into four groups according to their audiogram configurations. Mean NLR and PLR values of the patient groups were compared among themselves and versus control group. The study was conducted with 166 participants. Mean NLR values were 3.07 ± 2.48, 3.30 ± 2.70, 5.24 ± 3.71, 3.57 ± 3.19 and 1.51 ± 0.68 for ascending, flat, descending and total/subtotal audiometric configuration groups and control group, respectively. Mean PLR values were 145.2 ± 126.7, 130.9 ± 57.8, 192.2 ± 94.4, 143.7 ± 70.8 and 94.1 ± 24.7 for ascending, flat, descending, total/subtotal audiometric configuration groups and control group, respectively. Both NLR and PLR were significantly greater in patients from all configuration groups than in control group (p < 0.05). In addition, the group with descending audiometric configuration showed significantly higher mean NLR and PLR compared to other audiometric configuration groups (p < 0.05). The highest level of inflammation was detected in the ISSHL patient group with high frequency hearing loss and descending audiographic configuration.

Serum Fibrinogen Level and Cytokine Production as Prognostic Biomarkers for Idiopathic Sudden Sensorineural Hearing Loss

OBJECTIVES

No clinically useful prognostic factors have been identified for idiopathic sudden sensorineural hearing loss (ISSNHL). The current study therefore sought to identify useful prognostic factors for idiopathic sudden sensorineural hearing loss from blood biomarkers while attempting to classify the pathogenic mechanism and formulate treatment strategies based on these results.

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary referral center.

METHODS

A total of 47 patients with acute phase ISSNHL were treated with steroid at an initial dose of 1 mg/kg/day and hyperbaric oxygen therapy and followed up for 6 months. Serum fibrinogen levels, peripheral blood mononu- clear cells (PBMCs), and interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α production levels from PBMCs were measured, after which patient's pre- and post- treatment hearing was compared.

RESULTS

In the overall cohort, the mean improvement level, mean recovery rate, and mean fibrinogen level was 20.3 dB, 46.2%, 292.0 mg/mL, respectively. The mean levels of IL-1β, IL-6, and TNF-α produced by peripheral blood mononu- clear cells cultured under lipopolysaccharide stimulation were 318.4, 498.1, and 857.6 pg/mL, respectively. High fibrinogen levels were associated with poor hearing progno- sis. Lipopolysaccharide-stimulated cytokine production by PBMCs did not correlate with hearing changes; however, the prognosis was significantly better in patients with low fibrinogen levels and high IL-1β levels produced by PBMCs than in other patients.

CONCLUSIONS

Our results suggest that patients with simple inflammatory-type ISSNHL responded well to standard therapy. Therefore, serum fibrinogen levels and PBMCs cytokine production may help determine the management of ISSNHL based on its pathogenic mechanism.

Correlation Between the Prognosis of Sudden Total Deafness and the Peripheral Blood Inflammation Markers

Objective

To analyze the correlation between prognosis of sudden total deafness (STD) and peripheral blood inflammation markers including white blood cell count (WBC), monocytes, neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), fibrinogen (FIB).

Methods

125 patients with STD who were hospitalized in our department from 2014 to 2019 were enrolled. The general physical conditions, clinical manifestations, pure tone audiometry, imaging examination, and peripheral blood inflammation markers were collected, and all patients were divided into effective and ineffective two groups according to the degree of hearing recovery at the time of discharge. Then binary logistic regression was used to analyze the correlation between multiple factors and prognosis, meanwhile the receiver operating characteristic (ROC) curve was used to evaluate the predictive value of the above prognostic factors.

Results

Compared with the ineffective group, patients in the effective group were younger and have higher PLR level and lower FIB levels. Age and PLR are independent prognostic factors. Taking age ≤ 56 years old, PLR >142.6 as the standard to predict the prognosis of patients with STD has the largest AUC with the potential effective rate reaching 78.1%.

Conclusions

Age and PLR are independent prognostic factors for patients with STD. The younger the age and the higher the PLR, the better the prognosis. Clinically, the prognosis of patients with STD can be evaluated by the patient's age and PLR level, which is of great significance to predict the prognosis of patients with STD.

Resveratrol Ameliorates Lipopolysaccharide-Induced Sudden Sensorineural Hearing Loss in In Vitro Model through Multitarget Antiapoptotic Mechanism Based on Network Pharmacology and Molecular Docking

Objective

To explore the effects of resveratrol (RSV) on hair cell apoptosis caused by sudden sensorineural hearing loss (SSNHL) and its effect on lipopolysaccharide-induced apoptosis of HEI-OC1 cells.

Methods

We used the network pharmacology method to screen molecules related to RSV for the treatment of SSNHL and analyzed these molecules and their enriched biological processes and signaling pathways through Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analysis. We selected hub genes related to apoptosis using protein-protein interaction (PPI) analysis for in vitro and molecular docking verification.

Results

Eighty overlapping genes were identified as potential targets for RSV treatment of SSNHL. Further GO analysis showed that the biological processes were mainly related to toxicity, cell proliferation, and lipopolysaccharide reactions. KEGG analysis showed that the AGE-RAGE signaling pathway in diabetic complications, Kaposi's sarcoma-associated herpesvirus infection, FoxO signaling pathway, PI3K-Akt signaling pathway, and other inflammatory signaling pathways were concentrated. AKT1, STAT3, JUN, TNF, TP53, MAPK3, CASP3, and VEGFA were screened as HUB genes using PPI analysis. The apoptosis-related proteins TNF, CASP3, AKT1, and TP53 were selected for in vitro experiments, which showed that mRNA was significantly different before and after RSV intervention, confirming that the corresponding protein receptors could bind well with RSV.

Conclusion

RSV mainly affects the prognosis of SSNHL through anti-inflammatory effects and may improve hair cell apoptosis caused by inflammatory factors through multitargeted interventions involving TNF, CASP3, AKT1, and TP53.

The association of genetic polymorphisms in interleukin-1 receptors type 1 and type 2 with sudden sensorineural hearing loss in a Taiwanese population: a case control study

Background

Sudden sensorineural hearing loss (SSNHL) is a disease with an unknown etiology; damage to the auditory nerve from inflammation due to viral infection or vascular incidents has been implicated. According to several studies, cytokines, including interleukins, are associated with SSNHL in terms of serum expression and genetic polymorphisms. Interleukin-1 (IL-1) plays a key role in inflammation and may be associated with SSNHL. This study analyzed the association of single nucleotide polymorphisms (SNPs) of IL-1 receptor (IL-1R) genes with SSNHL in Taiwan.

Methods

We conducted a case–control study involving 401 patients with SSNHL and 730 healthy controls. Four SNPs (IL-1R type 1 gene [IL1R1] [rs3917225 and rs2234650] and IL-1R type 2 gene [IL1R2] [rs4141134 and rs2071008]) were selected. The genotypes were determined using the TaqMan assay. The Hardy–Weinberg equilibrium (HWE) was tested for each SNP, and genetic effects were evaluated.

Results

The TT genotype of rs2234650 had an adjusted odds ratio (OR) of 2.988 (95% confidence interval [95% CI] 1.27–6.82) (P = 0.012) compared with the CC genotype in patients with SSNHL. The SNP rs2234650 was associated with SSNHL in the recessive model (TT vs. CC + CT, P = 0.0206, OR = 2.681). The CT genotype of rs4141134 had an adjusted OR of 3.860 (95% CI 2.01–7.44; P < 0.0001) compared with the TT genotype, in patients with SSNHL. The SNP rs4141134 was associated with SSNHL under the dominant model (CC + CT vs. TT, P < 0.0001, OR = 4.087).

Conclusion

These findings suggest that IL1R1 and IL1R2 gene polymorphisms may contribute to an increased risk of SSNHL in Taiwan.

Association between routine hematological parameters and sudden sensorineural hearing loss: A meta-analysis

OBJECTIVE

Recent studies have shown that chronic inflammation contributes to the development of sudden sensorineural hearing loss (SSNHL). Some hematologic parameters have also been linked to the prognosis of SSNHL. However, the prognostic value of such hematological factors is not conclusive. This study explored the association of routine hematological parameters with SSNHL.

METHODS

A systematic literature search was conducted in PubMed, Cochrane Library, Web of Science and Embase to identify eligible studies. Standardized mean deviation (SMD) and the 95% confidence interval (CI) were retried from relevant studies for analysis. Heterogeneity, subgroup, and publication bias analyses were performed.

RESULTS

A total of 18 studies involving 1505 SSNHL patients and 1466 healthy persons were enrolled in the final analysis. The study population included 699 responders and 458 non-responders to treatment. Pooled results revealed that the neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR) value in the SSNHL patient group were higher than in the healthy group (SMD = 1.05, 95% CI: 0.86,1.24, p < 0.001, SMD = 0.52, 95% CI: 0.26,0.78, p < 0.001, respectively). However, there was no significant difference in the mean platelet volumes (MPV) between the groups (SMD = 0.03, 95% CI: 0.44, 0.49, p = 0.91). Notably, NLR and PLR values were evidently higher in the unrecovered group than in the recovered group (SMD = -0.63, 95% CI: 1.02, -0.23, p = 0.002, SMD = -0.4, 95% CI: 0.76, -0.03, p = 0.03, respectively). However, the MPV value was similar in both groups (SMD = -0.35, 95% CI: 1.14,0.44, p = 0.38).

CONCLUSIONS

Our results show that NLR and PLR values can predict the onset and prognosis of SSNHL.

Predictor parameters for poor prognosis in patients with sudden sensorineural hearing loss: fibrinogen to albumin ratio vs C-reactive protein to albumin ratio

Introduction

Prognosis of sudden sensorineural hearing loss may be predicted using several parameters of laboratory blood analysis.

Objective

To identify and investigate the most significant indicator parameters related to the poor prognosis of sudden sensorineural hearing loss.

Methods

Eighty-eight patients were included, and three groups were constituted: non-recovery group with14 patients, recovery group with 33 patients and control group with 41 individuals. We compared fibrinogen-to-albumin ratio, C-reactive protein-to-albumin ratio, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, white blood cell and hemoglobin of the groups. Then, we investigated the most significant indicator parameters related to the poor prognosis of sudden hearing loss.

Results

The mean hemoglobin, mean platelet-lymphocyte ratio and median white blood cell values did not significantly differ among three groups (p = 0.36, p = 0.86 and p = 0.79, respectively). A significant difference of median fibrinogen-albumin ratio, C-reactive protein-albumin ratio, neutrophil-to-lymphocyte ratio was evident among three groups (p < 0.001, p = 0.003 and p = 0.002, respectively). Median fibrinogen-albumin ratio, C-reactive protein-albumin ratio and neutrophil-to-lymphocyte ratio values were significantly greater in the non-recovery group, compared with the controls (p < 0.001, p = 0.003 and p = 0.005, respectively). Median fibrinogen-to-albumin ratio, C-reactive protein-to-albumin ratio and neutrophil-to-lymphocyte ratio were significantly greater in the recovery group, compared with the controls (p < 0.001, p = 0.013 and p = 0.005, respectively). Moreover, the median fibrinogen-albumin ratio was significantly greater in the non-recovery group compared with the recovery group (p = 0.017). However, no statistically significant difference of median C-reactive protein-albumin ratio, neutrophil-to-lymphocyte was evident between the non-recovery and recovery groups (p = 0.15).

Conclusion

Increased levels of fibrinogen-albumin ratio may be predictive for poor prognosis in patients with sudden sensorineural hearing loss.

Neutrophil-lymphocyte ratio as a valuable prognostic marker in idiopathic sudden sensorineural hearing loss

Background: Neutrophil-to-lymphocyte ratio (NLR) has emerged as a marker for degree of inflammation. Inflammation has been regarded as one of the causes of idiopathic sudden sensorineural hearing loss.Objectives: This study investigated the potential association between neutrophil-to-lymphocyte ratio (NLR) and prognosis in patients with idiopathic sudden sensorineural hearing loss (ISSNHL).Material and methods: This retrospective, case-control clinical trial analyzed data from 186 subjects diagnosed with ISSNHL and admitted to Kyung-Hee Medical Center between March 2016 and February 2019. Hematologic and audiometric parameters were measured.Results: NLR showed a linear correlation with hearing recovery in patients with ISSNHL, with hearing gain (dB) = 56.698 - 3.718 × NLR (r² = 0.451, p = .001). Hearing recovery at all frequencies was numerically higher in patients with low (<6.661) than higher (≥6.661) NLR at all frequencies and was significantly higher at 500, 1000, 2000, 3000, and 4000 Hz. Hearing thresholds at 250, 500, 1000, 2000, 3000, and 4000 Hz in the low NLR group were significantly lower after treatment.Conclusions and significance: The ability to recover from ISSNHL decreases as NLR increases. NLR may be a valuable prognostic marker in patients with ISSNHL.

Nutritional Mushroom Treatment in Meniere's Disease with Coriolus versicolor: A Rationale for Therapeutic Intervention in Neuroinflammation and Antineurodegeneration

Meniere's disease (MD) represents a clinical syndrome characterized by episodes of spontaneous vertigo, associated with fluctuating, low to medium frequencies sensorineural hearing loss (SNHL), tinnitus, and aural fullness affecting one or both ears. To date, the cause of MD remains substantially unknown, despite increasing evidence suggesting that oxidative stress and neuroinflammation may be central to the development of endolymphatic hydrops and consequent otholitic degeneration and displacement in the reuniting duct, thus originating the otolithic crisis from vestibular otolithic organs utricle or saccule. As a starting point to withstand pathological consequences, cellular pathways conferring protection against oxidative stress, such as vitagenes, are also induced, but at a level not sufficient to prevent full neuroprotection, which can be reinforced by exogenous nutritional approaches. One emerging strategy is supplementation with mushrooms. Mushroom preparations, used in traditional medicine for thousands of years, are endowed with various biological actions, including antioxidant, immunostimulatory, hepatoprotective, anticancer, as well as antiviral effects. For example, therapeutic polysaccharopeptides obtained from Coriolus versicolor are commercially well established. In this study, we examined the hypothesis that neurotoxic insult represents a critical primary mediator operating in MD pathogenesis, reflected by quantitative increases of markers of oxidative stress and cellular stress response in the peripheral blood of MD patients. We evaluated systemic oxidative stress and cellular stress response in MD patients in the absence and in the presence of treatment with a biomass preparation from Coriolus. Systemic oxidative stress was estimated by measuring, in plasma, protein carbonyls, hydroxynonenals (HNE), and ultraweak luminescence, as well as by lipidomics analysis of active biolipids, such as lipoxin A4 and F2-isoprostanes, whereas in lymphocytes we determined heat shock proteins 70 (Hsp72), heme oxygenase-1 (HO-1), thioredoxin (Trx), and γ-GC liase to evaluate the systemic cellular stress response. Increased levels of carbonyls, HNE, luminescence, and F2-isoprostanes were found in MD patients with respect to the MD plus Coriolus-treated group. This was paralleled by a significant (p < 0.01) induction, after Coriolus treatment, of vitagenes such as HO-1, Hsp70, Trx, sirtuin-1, and γ-GC liase in lymphocyte and by a significant (p < 0.05) increase in the plasma ratio-reduced glutathione (GSH) vs. oxidized glutathione (GSSG). In conclusion, patients affected by MD are under conditions of systemic oxidative stress, and the induction of vitagenes after mushroom supplementation indicates a maintained response to counteract intracellular pro-oxidant status. The present study also highlights the importance of investigating MD as a convenient model of cochlear neurodegenerative disease. Thus, searching innovative and more potent inducers of the vitagene system can allow the development of pharmacological strategies capable of enhancing the intrinsic reserve of vulnerable neurons, such as ganglion cells to maximize antidegenerative stress responses and thus providing neuroprotection.

Association between Uncoupling Protein 2 Gene Ala55val Polymorphism and Sudden Sensorineural Hearing Loss

OBJECTIVES

The pathology of sudden sensorineural hearing loss, which is known as sudden deafness (SD), remains unknown. The purpose of this study was to investigate the association between mitochondrial uncoupling protein 2 (UCP2) polymorphism and SD risk.

MATERIALS AND METHODS

We compared 83 patients suffering from SD and 2048 controls who participated in the Longitudinal Study of Aging at the National Institute for Longevity Sciences. Multiple logistic regression was used to calculate the odds ratios (ORs) for SD with a polymorphism of the UCP2 (rs660339) gene.

RESULTS

Under the additive model of inheritance, UCP2 polymorphisms showed significant association with a SD risk. The OR was 1.468 (95% confidence interval, 1.056-2.040) with an adjustment for any past history, such as diabetes, dyslipidemia, or hypertension, and for age and sex.

CONCLUSION

Our results imply that the UCP2 (rs660339) polymorphism has a significant association with the risk of developing SD.

Selected Blood Inflammatory and Metabolic Parameters Predicted Successive Bilateral Sudden Sensorineural Hearing Loss

Objectives

To explore whether peripheral inflammatory, metabolic, and hemostatic parameters could predict the pathogenesis of successive bilateral sudden sensorineural hearing loss (SSNHL).

Methods

This study reviewed 33 patients with successive bilateral SSNHL and 215 patients with unilateral SSNHL. Clinical characteristics and hematological parameters were compared, including the inflammatory markers (like neutrophil lymphocyte ratio (NLR), monocyte lymphocyte ratio (MLR), and platelet lymphocyte ratio (PLR)) and metabolic features (including hypertension, triglyceridemia, dyslipidemia, and hyperglycemia), as well as hemostatic indices (including prothrombin time (PT), activated partial thromboplastin time (APTT), and fibrinogen).

Results

In the successive bilateral SSNHL group, older average onset age (48.67 ± 15.36 vs. 42.71 ± 13.58, p < 0.05), higher male to female ratio (18 : 15 vs. 112 : 103, p > 0.05), and poorer therapeutic efficacy (12% vs. 59%, p < 0.01) were observed than those in the unilateral SSNHL group. Compared to the unilateral SSNHL group, NLR, MLR, and PLR in the successive bilateral SSNHL group were significantly higher (NLR: 5.72 ± 2.23 vs. 4.45 ± 2.82, p = 0.01; MLR: 0.25 ± 0.15 vs. 0.17 ± 0.11, p < 0.01; PLR: 190.70 ± 69.79 vs. 148.18 ± 65.67; p < 0.01); the LDL level was significantly higher; yet, the HDL level was significantly lower (LDL: 3.79 ± 0.53 vs. 3.49 ± 0.74; HDL: 1.33 ± 0.32 vs. 1.44 ± 0.26; p < 0.05 for both); fibrinogen was significantly higher (4.03 ± 0.47 vs. 3.70 ± 0.65; p < 0.01). Logistic regression analysis demonstrated that the risk factors for successive bilateral SSNHL included age, NLR, MLR, PLR, LDL, HDL, diabetes, and fibrinogen. However, only NLR, MLR, PLR, diabetes, LDL, and HDL independently predicted successive bilateral SSNHL.

Conclusion

Selected blood inflammatory markers combined with metabolic parameters were positively correlated with successive bilateral SSNHL.

Recovery From Sudden Sensorineural Hearing Loss May Be Linked to Chronic Stress Levels and Steroid Treatment Resistance

Purpose This article investigates the possible connections between the level of chronic stress and success of steroid therapy in patients with sudden sensorineural hearing loss (SSNHL). Method A single-center, retrospective, longitudinal cohort study on 55 patients in a tertiary referral otology center was examined. Patients diagnosed with SSNHL between 2014 and 2017 were asked to complete a Measure of Perceived Stress (Brajac, Tkalcic, Dragojević, & Gruber, 2003 ) questionnaire. Inclusion criteria were patients > 18 years of age, SSNHL diagnosed within 4 previous weeks, completed steroid treatment, and complete documentation. Results There were 30 patients (55%) that showed significant improvement in their pure-tone audiogram (PTA) hearing threshold average (≥ 15 dB) after steroid treatment. Two-step cluster analysis identified 3 clusters based on average PTA hearing threshold recovery and average Measure of Perceived Stress scores. The difference between pretreatment and posttreatment hearing levels was significantly higher in the cluster with moderate stress compared to clusters with mild and high stress levels (Kruskal-Wallis test, Friedman test, p < .001). There were no significant differences in average PTA hearing threshold recovery after steroid therapy between groups of patients with mild and severe stress. Conclusion Patients with moderate stress levels show significantly better results after steroid treatment for SSNHL than patients with low or high stress levels.

Role of viral infection in sudden hearing loss

According to a recent epidemiological survey, the incidence of sudden sensorineural hearing loss (SSNHL) is increasing yearly. The cause of SSNHL is of great interest in research. To date, viral infection, vascular occlusion, abnormal cellular stress responses within the cochlea, and immune-mediated mechanisms are considered the most likely etiologies of this disease. Among these etiologies, the relationship between viral infection and sudden deafness has been unclear. In this review, we mainly discuss the viral hypothesis of SSNHL. There is little research proving or clearly indicating the pathogenesis of this disease. Further research is needed to elucidate the precise etiopathogenesis to better understand SSNHL and establish more suitable treatment to help restore hearing in affected patients.

Genetic Polymorphisms and Susceptibility to Sudden Sensorineural Hearing Loss: A Systematic Review

BACKGROUND

Recently, genetic factors have been considered as an important risk factor for sudden sensorineural hearing loss (SSNHL). Many studies analyzed the association between SSNHL and polymorphisms. However, most of them gave inconclusive results. Key Message: We performed a systematic review to find out the association between polymorphisms and susceptibility to SSNHL. Finally, 47 studies involving 5,230 SSNHL patients and 68 genes were included for analysis and discussion of results. Polymorphisms in 26 genes have been suggested to be correlated with the susceptibility to SSNHL.

SUMMARY

Although a great number of studies support that polymorphisms in genes are associated with susceptibility to SSNHL, we need large multicenter studies, which evaluate multiple single nucleotide polymorphisms in SSNHL patients, to find real genetic risk factors for susceptibility to SSNHL. This is very helpful in designing more effective prevention and treatment strategies for patients with SSNHL.

Inflammatory cytokines and mononuclear cells in sudden sensorineural hearing loss

OBJECTIVE

This study evaluated tumour necrosis factor-α, interleukins 10 and 12, and interferon-γ levels, peripheral blood mononuclear cells, and clusters of differentiation 17c and 86 expression in unilateral sudden sensorineural hearing loss.

METHODS

Twenty-four patients with unilateral sudden sensorineural hearing loss, and 24 individuals with normal hearing and no history of sudden sensorineural hearing loss (who were attending the clinic for other problems), were enrolled. Peripheral blood mononuclear cells, and clusters of differentiation 11c and 86 were isolated and analysed. Plasma and supernatant levels of tumour necrosis factor-α, interferon-γ, and interleukins 10 and 12 were measured.

RESULTS

There were no significant differences with respect to age and gender. Monocyte population, mean tumour necrosis factor-α level and cluster of differentiation 86 expression were significantly increased in the study group compared to the control group. However, interferon-γ and interleukin 12 levels were significantly decreased. The difference in mean interleukin 10 level was not significant.

CONCLUSION

Increases in tumour necrosis factor-α level and monocyte population might play critical roles in sudden sensorineural hearing loss. This warrants detailed investigation and further studies on the role of dendritic cells in sudden sensorineural hearing loss.

Neutrophil-to-Lymphocyte Ratio and Platelet-to-Lymphocyte Ratio in Patients with Sudden Sensorineural Hearing Loss

OBJECTIVE

Sudden sensorineural hearing loss (SSNHL) is a common acute disease with an incidence of 0.5-2/10,000. This study aimed to determine whether the neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR) could be indicators for SSNHL.

METHODS

A total of 60 confirmed cases of SSNHL and 60 healthy volunteers were included in this study. Peripheral blood NLRs and PLRs were compared between these groups. The SSNHL patients were divided into two groups, according to therapeutic effect: an effective group and an ineffective group. Peripheral blood NLRs and PLRs before and after treatment were compared between these two groups.

RESULTS

The average NLRs and PLRs of these patients were both significantly higher than in controls. The average NLRs and PLRs of the ineffective group were both significantly higher than those of the effective group.

CONCLUSION

Peripheral blood NLR and PLR could be used as a convenient, reliable, and cost-effective indicator to predict the prognosis of SSNHL.

Is the C-reactive protein/albumin ratio a prognostic and predictive factor in sudden hearing loss?

Introduction

Sudden hearing loss is a significant otologic emergency. Previous studies have revealed a coexistence of sudden hearing loss with chronic inflammation. The predictive importance of C-reactive protein/albumin values as a prognostic factor has been shown in various inflammatory and tumoral conditions.

Objectives

The aim of this study was to determine whether the C-reactive protein/albumin ratio in sudden hearing loss can be used for prognostic purposes and whether there is a relationship between the neutrophil/lymphocyte ratio and the C-reactive protein/albumin ratio.

Methods

A retrospective examination was made of 40 patients diagnosed with idiopathic sudden hearing loss and a control group of 45 healthy subjects. The pure tone averages of all the patients were determined on first presentation and repeated at 3 months after the treatment. The patients were separated into 2 groups according to the response to treatment. The neutrophil/lynphocyte ratio and the C-reactive protein/albumin ratios were calculated from the laboratory tests.

Results

The patients included 16 females and 24 males with a mean age of 44.1 ± 14.2 years and the control group was composed of 23 females and 22 males with a mean age of 42.2 ± 13.8 years. The mean C-reactive protein/albumin ratio was 0.95 ± 0.47 in the patient group and 0.74 ± 0.13 in the control group. The difference was statistically significant (p = 0.009). The mean C-reactive protein/albumin ratio was 0.79 ± 0.12 in the response to treatment group and 1.27 ± 0.72 in the non-response group, with no significant difference determined between the groups (p = 0.418). The mean neutrophil/lymphocyte ratio was 3.52 ± 3.00 in the response to treatment group and 4.90 ± 4.60 in the non-response group, with no statistically significant difference determined between the groups (p = 0.261).

Conclusion

C-reactive/albumin ratio was significantly higher in patients with sudden hearing loss than in the control group. Although C-reactive protein/albumin ratio was found to be lower in sudden hearing loss patients who responded to treatment compared to those who did not, the difference between two groups was not statistically significant.

Differences in platelet-related parameters among patients with audiographically distinct sudden sensorineural hearing loss: A retrospective study

We explored possible relationships between sudden sensorineural hearing loss (SSNHL) in patients differing in terms of audiographic data and the levels of vascular markers in routine blood data.We included 37 patients with low-frequency SSNHL (LF-SSNHL), 28 with high-frequency SSNHL (HF-SSNHL), 32 with all-frequency SSNHL (AF-SSNHL), 32 with total-deafness SSNHL (TD-SSNHL), and 31 age- and sex-matched healthy controls. Peripheral venous blood samples were collected, and routine blood parameters including platelet and lymphocyte count, mean platelet volume (MPV), and platelet-to-lymphocyte ratio (PLR) were measured. Each group was divided into recovery subgroup and unrecovery subgroup in accordance with hearing level after 1 month therapy, then compared the difference of platelet and lymphocyte count, MPV, and PLR between the 2 subgroups.No significant difference was observed between platelet count of all SSNHL patients and control group (all P > .05). MPV of AF-SSNHL and TD-SSNHL, PLR of all SSNHL patients were significantly higher than those of control group (all P < .05), while lymphocyte count of all audiographically distinct SSNHL patients was significantly lower than that of control group (all P < .05). However, the difference of platelet count, lymphocyte count, MPV, and PLR among audiographically distinct SSNHL patients was not significant (all P > .05). In HF-SSNHL patients, lymphocyte count of unrecovery subgroup was significantly lower, while MPV and PLR of the unrecovery subgroup were significantly higher than those of recovery subgroup (all P < .05). In AF-SSNHL patients, MPV of the unrecovery group was significantly higher than that of recovery subgroup (P < .05).Lymphocyte count, MPV, and PLR may be relative to SSSNHL, but they could not be used to distinct SSNHL audiographically. Lower lymphocyte, higher MPV, and PLR may be indicative for the prognosis of HF-SSNHL patients; higher MPV may be related to bad treatment outcome of AF-SSNHL patients.

Endothelial Dysfunction in Idiopathic Sudden Sensorineural Hearing Loss: A Review

An endothelial dysfunction has been described in idiopathic sudden sensorineural hearing loss (ISSHL) patients. The purpose of our review was to: i) identify, evaluate and review recent research about cardiovascular risk factors involvement and signs of endothelial dysfunction in ISSHL; ii) implication of these discovering in clinical practice and future research. A Medline literature search was conducted to identify any study on the involvement of endothelial dysfunction in ISSHL, published in the English language in the last decade. The following MEDLINE search terms were used: sudden sensorineural hearing loss (SSHL) and endothelial dysfunction (text words). Additional studies were identified by hand searching the references of original articles and review articles. Studies were not excluded on the basis of the qualitative or quantitative definitions of SSHL, treatment regimens, or outcome measures. Data were extracted from included papers by a reviewer. Information on the patients, investigations, methods, interventions, and outcomes were systematically analyzed. Characteristics and results of all included studies were reviewed systematically. High levels of adhesion molecules, hyperhomocysteinemia and lower folate levels, unbalanced oxidative status, a lower value of flow-mediated dilatation of brachial artery and a reduced percentage of circulating endothelial progenitor cells in patients affected by ISSHL support the hypothesis that this syndrome should be considered as a microcirculation disorder based on endothelial dysfunction and drive clinicians to implement all the traditional strategies used for preventing cardiovascular events, to also reduce the likelihood of ISSHL occurrence.

The Expression of TNFα, IL-6, IL-2 and IL-8 in the Serum of Patients with Idiopathic Sudden Sensorineural Hearing Loss: Possible Prognostic Factors of Response to Corticosteroid Treatment

Introduction: Idiopathic sudden sensorineural hearing loss (ISSNHL) remains one of the major unsolved otologic emergencies. A viral infection, a systemic inflammatory disorder, as well as physical, mental and metabolic stress can trigger an innate immune response in the inner ear resulting in ISSNHL. Proinflammatory cytokines play a central role in this cochlear immunological cascade. Objective: To examine the expression of proinflammatory cytokines in the serum of patients with ISSNHL in correlation with the therapeutic outcome of intravenous administration of corticosteroids. Method: Forty-three patients primarily diagnosed with ISSNHL underwent intravenous corticosteroid treatment for 8 days. The expression of tumor necrosis factor-α (TNFα), interleukin-6 (IL-6), interleukin-2 (IL-2) and interleukin-8 (IL-8) was detected with the use of enzyme-linked immunosorbent assay in serum specimens on the 1st and 8th day of treatment and it was correlated with the treatment outcome. Results: TNFα reduction and IL-6 increase strongly correlate with a good therapeutic result [χ2(2) = 13.12, p = 0.001 and χ2(2) = 16.78, p = 0.0001]. IL-8 increase reflects negatively on the outcome, however, not in a statistically significant way. No association was established between IL-2 variations and the therapeutic outcome. Conclusions: TNFα and IL-6 can be used as prognostic factors for the treatment outcome, whereas the prognostic value of IL-8 requires further statistical confirmation.

Sleep Disturbance and Altered Expression of Circadian Clock Genes in Patients With Sudden Sensorineural Hearing Loss

The cause of sudden sensorineural hearing loss (SSNHL) remains unclear and therefore it is often considered as idiopathic. Sleep disturbance has been linked to SSNHL and circadian rhythm disruption, but the link between circadian rhythm disruption and SSNHL has never been investigated.In this study, we surveyed the sleep quality of 38 patients with SSNHL using a simple insomnia sleep questionnaire. The expression of circadian clock genes in peripheral blood (PB) leukocytes from 38 patients with SSNHL and 71 healthy subjects was accessed using real-time quantitative reverse transcriptase-polymerase chain reaction and validated using immunocytochemical staining.We found that 61.8% of patients with SSNHL suffered from insomnia before the insult of hearing loss. Besides, significantly decreased expression of PER1, CRY1, CRY2, CLOCK, BMAL1, and CKlε was found in PB leukocytes of patients with SSNHL when compared with healthy subjects. SSNHL patients with vertigo had significantly lower expression of CRY1 and CKlε than patients without vertigo symptoms. Our results imply the association of sleep disturbance and disrupted circadian rhythm in SSNHL.

Hyperbaric Oxygen Treatments Attenuate the Neutrophil-to-Lymphocyte Ratio in Patients with Idiopathic Sudden Sensorineural Hearing Loss

Objective

Hyperbaric oxygen therapy (HBOT) is a promising treatment in the management of idiopathic sudden sensorineural hearing loss (ISSNHL), but the specific mechanisms of HBOT in ISSNHL are still unclear. The curative effects of HBOT in many diseases are related to the attenuation of inflammatory response. The neutrophil-to-lymphocyte ratio (NLR) is a new inflammatory marker that can be assessed quickly. We investigated the relationship between HBOT and the inflammatory response in ISSNHL using the NLR.

Study Design

Case series with chart review

Setting

Tertiary teaching and research hospital

Subjects and Methods

Between December 2007 and December 2013, 41 ISSNHL patients who underwent HBOT, 45 ISSNHL patients who did not undergo HBOT, and 14 healthy control subjects who underwent HBOT were included in the study. NLRs were assessed at 2 time points: at baseline (pretreatment) and on day 1 after 10 sessions of HBOT (posttreatment). Audiometric testing was performed at the above 2 time points.

Results

The mean post-HBOT NLRs, neutrophil, and white blood cell count values of the ISSNHL patients were significantly lower than their pretreatment values ( P < .001). Compared with the ISSNHL patients who did not undergo HBOT, the posttreatment NLR levels of the ISSNHL patients who underwent HBOT were much lower ( P = .036). Higher relative hearing gains were significantly associated with a greater reduction in the NLR after HBOT ( r = −0.885, P = .001).

Conclusions

The beneficial effect of HBOT on ISSNHL may be mediated at least in part by a decrease of inflammation.

The association between hearing impairment and polymorphisms of genes encoding inflammatory mediators in Japanese aged population

BACKGROUND

Aging process is accompanied by a chronic sub-clinical systemic inflammation. This study aimed to assess the association between hearing impairment and polymorphisms of genes encoding cytokines deeply-committed to the inflammatory response and immune homeostasis in an elderly Japanese population. Data were collected in the Longitudinal Study of Aging surveyed biennially between 1997 and 2010. The participants without any missing information at baseline were 1,957 individuals, and the gross accumulated number of 8,675 subjects (40-89 years of age) was analyzed. Two hearing impairment criteria were taken as the better ear pure-tone average (PTABE) greater than 25 dB and greater than 40 dB. We analyzed cumulative data using generalized estimating equations to investigate the effect of 9 polymorphisms, namely, tumor necrosis factor (TNF) α, rs1800630; TNF receptor super family (TNFRSF) 1B, rs1061624; interleukin (IL)-1A, rs1800587; IL-1B, rs16944; IL-4R, rs1801275; IL-6, rs1800796; IL-10, rs1800872; IL-1 receptor-associated kinase 1 (IRAK1), rs1059702; C reactive protein (CRP), rs1130864.

RESULTS

The odds ratios for the hearing impairment (PTABE >25 dB) risk under additive genetic model were significant in TNF-α rs1800630 and TNFRSF1B rs1061624, which were respectively 1.172 (confidence interval [CI]: 1.005-1.367), 1.211 (CI: 1.053-1.392) in model after adjustment for possible confounders. Using the criterion of PTABE >40 dB as disabling hearing impairment, the association remains significant in TNFRSF1B rs1061624, but not in TNF-α rs1800630. No other polymorphisms showed a significant association.

CONCLUSIONS

The present population-based cohort study demonstrated that TNF-α rs1800630 and TNFRSF1B rs1061624 contributed to the incremental risk of hearing impairment in the elderly. TNF-α and TNF receptor interactions play a pivotal role in the pathogenesis of the inflammatory response, and also cause programmed cell death and cell proliferation. The present observation implied the signalling cascades of TNF were involved in ear aging.

Neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio: novel markers for diagnosis and prognosis in patients with idiopathic sudden sensorineural hearing loss

Background. We aim to provide useful evidence about the association of neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) with idiopathic sudden sensorineural hearing loss (ISSNHL) and its possibility of emerging as a cheap, reliable, and independent prognostic marker of ISSNHL. Methods. 348 patients diagnosed with ISSNHL were included in our retrospective data analysis. Blood samples and the hearing assessments of the patients were carried out. Then, the patients were divided into 2 groups as “recovered” and “unrecovered” according to their response to the treatment. Results. Both mean NLR and PLR values of the ISSNHL patients were significantly higher than the control group (both P < 0.001). The NLR value was 5.98 ± 4.22 in the unrecovered group and 3.50 ± 3.38 in the recovered group (P < 0.001). After adjustment in a binary logistic regression model, only NLR value was associated with the recovery of ISSNHL (P = 0.001). Discussion. We demonstrated for the first time that NLR and PLR values were significantly high in ISSNHL patients. Also the NLR level might be taken into account as a novel potential marker to predict the patients' prognosis in terms of recovery.

Cause of idiopathic sudden sensorineural hearing loss: The stress response theory

The stress response theory is a relatively new concept about the cause of idiopathic sudden sensorineural hearing loss (ISHL). A number of possible etiologies have been proposed in the literature, as discussed in this paper, but each proposed etiology has been both supported and refuted in the literature. However, the stress response theory can integrate hypotheses that have been advocated so far. The word “stress” refers to a constellation of physical and psychological stimuli including systemic viral and bacterial illness, systemic inflammatory disorders, and physical, mental or metabolic stress. Numerous studies have demonstrated adverse effects of systemic stress on health. Stress causes changes in the immune system and cytokine network through activation of the hypothalamus-pituitary-adrenal axis and the sympathetic nervous system. Several types of catecholamine and cytokine receptors are in the cochlea cells other than capillary cells, and then they can respond to systemic stressors. However, there are few studies examining how systemic stress is associated with cochlear dysfunction. The stress response theory addresses this question. In the theory, a variety of stressors and risk factors contribute to the onset of ISHL in varying degrees. The lateral wall of the cochlea has very unique responses to systemic stressors. It plays a critical role in causing ISHL. Systemic stressors converge at the lateral wall and trigger pathological activation of nuclear factor κ-light-chain-enhancer of activated B cells, a transcriptional factor known as a stress sensor. This activation enhances local expression of genes associated with immune and inflammatory system, resulting in cochlear dysfunction. We review the original stress response theory advocated by Adams et al and the integrative stress response theory that integrates our knowledge about the etiologies of ISHL so far.

Acute-phase inflammatory response in idiopathic sudden deafness: pathogenic implications

The acute-phase inflammatory response in the peripheral bloodstream can be an expression of transient cerebral ischaemia in idiopathic sudden deafness. For this, a neurological and otorhinolaryngological examination of each patient, performing tests on audiometry, and tympanometry, haemogram, and cranial magnetic resonance were performed. The acute-phase inflammatory response manifests as an increased neutrophil/lymphocyte ratio that is detected 48–72 hours after the appearance of sudden deafness. This study shows that there is an acute-phase response in the peripheral bloodstream with an increased neutrophil/lymphocyte ratio as an expression of an inflammatory process that can be caused by transient cerebral ischaemia in sudden deafness. In addition, the increased neutrophil/lymphocyte ratio can rule out a viral origin of sudden deafness, since a viral infection lowers the neutrophil count and increases the lymphocyte count, thus reducing the neutrophil/lymphocyte ratio. These findings aid in understanding the pathogenic mechanisms involved in sudden deafness and offer better treatment to the patient.

Polymorphisms in genes involved in oxidative stress response in patients with sudden sensorineural hearing loss and Ménière's disease in a Japanese population

The etiologies of idiopathic sudden sensorineural hearing loss (SSNHL) and Ménière's disease remain unclear. Recently, accumulating evidence has demonstrated that oxidative stress is related to the pathology of inner ear disease. Because genetic factors may contribute partly to the etiologies of SSNHL and Ménière's disease, we investigated the associations between genetic polymorphisms located in oxidative stress response genes and susceptibility to SSNHL and Ménière's disease. We compared 84 patients affected by SSNHL, 82 patients affected by Ménière's disease, and 2107 adults (1056 men and 1051 women; mean age, 59.2 years; range, 40-79 years) who participated in the National Institute for Longevity Sciences, Longitudinal Study of Aging. Multiple logistic regression was used to calculate odds ratios for SSNHL and Ménière's disease in individuals with polymorphisms in the genes glutathione peroxidase 1 (GPX1) (Pro198Leu, rs1050450), paraoxonase 1 (PON1) (Gln192Arg, rs662; and Met55Leu, rs854560), PON2 (Ser311Cys, rs7493), and superoxide dismutase 2 (SOD2) (Val16Ala, rs4880), with adjustment for age and gender. No significant differences in the distribution of the genotypes at these polymorphisms were observed among individuals with SSNHL and Ménière's disease and controls. No significant risk for SSNHL and Ménière's disease was observed in the additive genetic model, regardless of moderating variables. The C allele of SOD2 (rs4880) was more frequent in Ménière's disease cases with a hearing level over 50 dB compared with cases with a hearing level below 50 dB, suggesting that this polymorphism is associated with progression of a hearing loss in Ménière's disease. In conclusion, no significant associations between the polymorphisms of GPX1, PON1, PON2, and SOD2 and risk of SSNHL and Ménière's disease were observed in this Japanese case-control study.