Laboratory assessment of sudden sensorineural hearing loss: A case-control study

The Impact of Cardiovascular Risk Factors on the Incidence, Severity, and Prognosis of Sudden Sensorineural Hearing Loss (SSHL): A Systematic Review

Sudden sensorineural hearing loss (SSHL) is believed to be mainly idiopathic since the cause is not usually identified. Several recent studies have examined the role of cardiovascular risk factors in this disease. The aim of this systematic literature review is to investigate the possible association between acquired and inherited cardiovascular risk factors and the incidence, severity, and prognosis of SSHL. A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search of the PubMed database for the period between February 2010 and January 2023 was performed in order to retrieve eligible articles. The analytic cohort included 24 studies. Overall, this systematic review includes a total of 61,060 patients that were encompassed in these studies. According to most studies, the prevalence of dyslipidaemia, diabetes, and ultrasound indices of atherosclerosis was significantly higher in SSHL patients compared to controls. On the other hand, obesity, hypertension, and smoking did not seem to influence the risk of SSHL. Most studies suggest the presence of a correlation between a high cardiovascular risk profile and the risk of developing SSHL. The theory of microvascular impairment in the development of SSHL is indirectly supported by the findings of this review.

The Effect of Rivaroxaban in the Complementary Therapy of Sudden Sensorineural Hearing Loss

Background

Due to the importance of sudden sensorineural hearing loss (SSNHL) and the possible role of blood coagulation in its mechanism and the likely therapeutic effect of anticoagulants and also the lack of studies in this field, this study aimed to evaluate the effect of rivaroxaban (RXA) in the treatment of this disease.

Materials and Methods

The present double-blind randomized clinical trial study was performed on 34 patients with SSNHL. Patients were randomly divided into two groups. In the first group, in addition to corticosteroid therapy (CST), RXA 10 mg tablets were used daily for 10 days (RXA group), and in the second group, only CST (CST group) treatment was prescribed. Hearing recovery was then assessed and recorded according to the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) criteria.

Results

This study showed that the grade of hearing recovery in the RXA group (58.8%) was higher than the CST group (47.1%), but this difference was not significant (P value >0.05). Also, RXA treatment increased the odds of hearing recovery, and this difference was not statistically significant (odd ratio (95% confidence interval)(OR (95% CI): 2.327 (0.180-18.082); P value = 0.518). In contrast, delay to treatment, more increased PTA (pure tone average (PTA)), and having vertigo reduced the odds of hearing recovery by 0.138-, 0.019-, and 0.069-fold, respectively (P value <0.05).

Conclusion

According to the results of this study, although the percentage of hearing recovery was higher in the RXA group, in general, the results of the two treatments were not significantly different.

Contemporary Review of Idiopathic Sudden Sensorineural Hearing Loss: Management and Prognosis

Sudden sensorineural hearing loss (SSNHL) is a rapid decline in auditory function that needs urgent medical management. Although etiologic factors, including viral infections, autoimmune diseases, and vascular issues, contribute to the understanding of SSNHL, the condition remains unclear in most cases. Systemic steroids are often used as the first-line treatment because they reduce inner ear inflammation; however, there remains numerous discussions about the effectiveness of alternative treatments. To predict hearing recovery is crucial in patients' counseling with factors, including delayed treatment, vertigo, and other health conditions, which indicate poor prognosis. Herein, we review contemporary research on the treatment approaches and outcome predictions of SSNHL to establish important guidelines for physicians in evaluating and treating patients with SSNHL.

The potential relationship between uric acid and the recovery in sudden sensorineural hearing loss

OBJECTIVE

Serum uric acid is proven to be associated with chronic hearing loss, but its effect on Sudden Sensorineural Hearing Loss (SSNHL) is unclear. This study aims to evaluate the prognostic values of serum uric acid levels in SSNHL patients.

METHODS

The clinical records of SSNHL patients were retrospectively reviewed. Patients were divided into different groups based on hearing recovery and audiogram type, and uric acid levels were compared. Based on uric acid levels, patients were categorized into normouricemia and hyperuricemia groups, and clinical features and hearing recovery were evaluated. Univariate and multivariate analyses were performed to identify prognostic factors.

RESULTS

In total, 520 SSNHL patients were included in this study, including 226 females and 294 males. In female patients, 186 patients were included in the normouricemia group, and 40 patients were enrolled in the hyperuricemia group. Significant differences were observed in uric acid levels, Total Cholesterol (TC), rate of complete recovery, and slight recovery between the two groups. In male patients, 237 subjects were categorized into the normouricemia group, and 57 patients were included in the hyperuricemia group. The rate of complete recovery and slight recovery was lower in the hyperuricemia group compared to the normouricemia group. All patients were further divided into good recovery and poor recovery groups based on hearing outcomes. The uric acid levels, initial hearing threshold, rate of hyperuricemia, and TC were lower in the good recovery group than the poor recovery group both in female and male patients. Binary logistic regression results showed that uric acid levels, initial hearing threshold, and hyperuricemia were associated with hearing recovery.

CONCLUSION

Hyperuricemia might be an independent risk factor for hearing recovery in SSNHL patients. Serum uric acid and initial hearing threshold possibly affected the hearing outcome in males and females with SSNHL.

LEVEL OF EVIDENCE

Level 4.

The Role of Fibrinogen, Homocysteine and Metabolic Syndrome's Alterations in Sudden Sensorineural Hearing Loss (SSHL): A Narrative Review

Fibrinogen and homocysteine (HCY) are molecules known to play a role in vascular homeostasis, and their blood levels are often elevated in patients with metabolic syndrome. Recent evidence suggests that sudden sensorineural hearing loss (SSHL) may have a vascular origin. This has led many authors to advocate that fibrinogen, homocysteine, and metabolic syndrome (MetS) may play a direct role in SSHL. The aim of this brief review is to examine the role and influence of these molecules and MetS on the mechanisms of SSHL. Elevated fibrinogen levels have been associated with a worse prognosis in SSHL, possibly due to increased blood viscosity and decreased blood flow. Similarly, HCY has been associated with vascular damage, particularly in hyperhomocysteinemia, although the exact association with SSHL remains controversial. MetS has been demonstrated to function both as a causative factor and as a contributor to poorer recovery in cases of SSHL. However, although some studies suggest a possible role for these biomarkers and MetS in the prognosis and treatment of SSHL, specific therapeutic and preventive strategies based solely on these factors have yet to be developed. Given their potential role in prognosis and treatment and the global epidemic of metabolic syndrome, this issue needs to be analyzed comprehensively. Thus, further quality studies need to be conducted, even though it is difficult to determine the actual impact of MetS on the development of SSHL, as it is a multifactorial disease affecting multiple organs.

Endothelial Dysfunction and Metabolic Disorders in Patients with Sudden Sensorineural Hearing Loss

Sudden sensorineural hearing loss (SSNHL) is defined as a sensorineural hearing loss of 30 dB or greater on at least three contiguous audiometric frequencies occurring within a 72 h period. Although SSNHL is commonly encountered in clinical audiology and otolaryngology practice, its etiopathogenesis continues to be poorly understood. Scientific investigations have highlighted the vulnerability of cochlear microcirculation to blood flow alterations. Even mild hypoperfusion can lead to immediate dysfunction in the organ of Corti, given the heightened susceptibility of cochlear hair cells to hypoxia and ischemic damage. The purpose of this review paper is to present evidence of endothelial and vascular involvement in SSNHL and the risk factors, such as metabolic syndrome, that may negatively impact the inner ear's vascular supply, influencing the onset pattern, incidence, and prognosis of SSNHL. By addressing these variables, we can deepen our comprehension of the mechanisms underlying SSNHL and potentially uncover strategies for prevention.

Cardiovascular Risk Factors, Cerebral Small Vessel Disease, and Subsequent Risk of Stroke in Patients with Idiopathic Sudden Sensorineural Hearing Loss: Systematic Review and Meta-Analyses of the Current Literature

Vascular involvement in the pathophysiology of idiopathic sudden sensorineural hearing loss (iSSNHL) has been previously proposed. The objective of this study was to perform a systematic review of the current literature and conduct meta-analyses to evaluate associations between cardiovascular risk factors, cerebral small vessel disease, and subsequent stroke after presentation with iSSNHL. Three systematic literature reviews and meta-analyses were conducted using PubMed, Embase, and CINAHL. All studies investigating associations between iSSNHL and the cardiovascular risk factors: body mass index (BMI), diabetes mellitus, hyperlipidemia, hypertension, medical history of myocardial infarction (MI), smoking, the degree of white matter hyperintensities, and incidence of stroke were included. Adhering to the PRISMA guidelines, two independent reviewers reviewed the articles and assessed risk of bias. The cardiovascular risk factors of abnormal BMI, diabetes, hypertension, total cholesterol, low-density lipoprotein cholesterol, and a medical history of MI were significantly associated with iSSNHL. The adjusted hazard ratio of a higher degree of white matter hyperintensities was 0.70 (95% CI 0.44, 1.12). Patients with iSSNHL showed a higher risk of stroke compared to controls, with hazard ratios ranging from 1.22 up to 4.08. Several cardiovascular risk factors are more frequently present in patients with iSSNHL than in the general population. The degree of white matter hyperintensities does not appear to be increased in patients with iSSNHL, while the risk of stroke following ISSNHL is increased. Prospective studies with larger study populations are needed to confirm the associations between generalized cardiovascular disease and iSSNHL and to assess whether these patients benefit from cardiovascular risk management to prevent future cardiovascular and cerebrovascular disease.

Impact of environmental noise exposure as an inducing factor on the prognosis of sudden sensorineural hearing loss: a retrospective case-control study

Objective

The study aimed to evaluate the clinical characteristics and prognostic factors associated with unilateral sudden sensorineural hearing loss (SSNHL) related to environmental noise exposure before its onset.

Methods

A total of 50 unilateral SSNHL patients exposed to environmental noise before onset (case group) and 924 unilateral SSNHL patients without any exposure to obvious inducing factors before onset (control group) were enrolled between January 2018 and October 2022. We retrospectively analyzed differences between both groups using the chi-square test, Fisher's exact tests, independent t-tests, and Mann-Whitney U-tests as appropriate before and after propensity score matching (PSM) based on sex, age, and initial pure-tone average (PTA). Prognostic factors for the case group were analyzed using univariate and multivariate logistic analyses between the effective and ineffective groups.

Results

Before PSM, significant differences were noted in age, sex, time to treatment, the proportion of combined diabetes mellitus, initial PTA, hearing gain, the incidence of vertigo or aural fulness, the rate of vestibular dysfunction or inner ear MRI abnormalities, the effective rate, the glucose and homocysteine levels, and the proportion of audiogram curve types (P < 0.05) between both groups. After PSM, compared to the control group, a longer time to treatment (Z= -3.02, P < 0.05), higher final PTA (Z= -2.39, P < 0.05), lower hearing gain (Z= -3.46, P < 0.05), lower rate of vestibular dysfunction (χ² = 55.1, P < 0.001), and lower effective rate (χ² = 4.87, P < 0.05) were observed in the case group. There was a significant difference between the audiogram curve types in both groups (χ² = 14.9, P < 0.05). Time to treatment (95% confidence interval: 0.692-0.965, P < 0.05) and final PTA (95% confidence interval: 0.921-0.998, P < 0.05) were associated with the clinical outcomes for the case group.

Conclusion

Unilateral SSNHL patients exposed to environmental noise triggers before onset showed a poorer effective rate and a lower rate of vestibular dysfunction than those who were not. The time to treatment and final PTA were associated with the prognosis of these patients.

Limited Link of Common Blood Parameters with Tinnitus

Background: Tinnitus severity is generally assessed by psychometric and audiological instruments. However, no objective measure exists to evaluate the subjective discomfort and suffering caused by this hearing phenomenon. The objective of this work was to determine the possible blood parameters for diagnostics and therapy. Methods: We measured tinnitus distress by using the Tinnitus Questionnaire (TQ) and collected tinnitus-related audiological measures, namely the hearing threshold (HT), tinnitus loudness (TL), and sensation level (SL, i.e., the tinnitus loudness/hearing threshold at a tinnitus frequency). Blood samples were taken from 200 outpatients of the Tinnitus Centre of the Charité, and 46 routine blood count parameters were examined. The possible interactions were determined by (robust) linear models. Results: Tinnitus distress and audiological measurements were largely uncorrelated but could partly be predicted by selected blood parameters. First, the erythrocyte counts predicted tinnitus distress to a small extent. Second, the levels of vitamin D3 explained about 6% of tinnitus loudness and, age-dependently, the hearing threshold variability. Last, the levels of uric acid explained about 5% of the sensation level variability. Conclusions: Tinnitus is a multidimensional phenomenon. The marginal influences of blood markers suggest the possible roles of inflammation and oxidative stress produced by psychological or somatic burdens. Clinically, a vitamin D substitution (in older patients) might have a hearing-protective effect.

Association between Chronic Kidney Disease and Sudden Sensorineural Hearing Loss: A Longitudinal Follow-Up Studies Using ICD-10 Codes in a National Health Screening Cohort

This study aims to investigate the association between chronic kidney disease (CKD) and sudden sensorineural hearing loss (SSNHL) using a population-based cohort study. We used data from the Korean National Health Insurance Service-Health Screening Cohort. Participants were selected based on diagnosis and treatment codes, and CKD participants were 1:4 matched with control participants. Covariates, including demographic and lifestyle factors, and comorbidities were considered in the analysis. We calculated the incidence rate and hazards ratio of SSNHL. A total of 16,713 CKD participants and 66,852 matched controls were enrolled. The CKD group had a higher incidence rate of SSNHL compared to the control group at 2.16 and 1.74 per 1000 person-years, respectively. The CKD group exhibited a higher risk for SSNHL compared to the control group with adjusted HR 1.21. In the subgroup analysis, the presence of cardiovascular risk factors was associated with a diminished effect of CKD on the risk of developing SSNHL. This study provides strong evidence of an association between CKD per se and an increased risk of SSNHL even after adjusting for various demographic and comorbidity factors. The findings suggest that CKD patients may require more comprehensive monitoring for hearing loss.

Etiological analysis of patients with sudden sensorineural hearing loss: a prospective case-control study

Sudden sensorineural hearing loss (SSNHL) is a multifactorial emergency disease. Until now, the etiology of SSNHL is still unknown. Previous studies regarding the etiology of SSNHL are clinical studies depending on clinical data collection and analysis. Due to the insufficient sample size or various selective bias in clinical studies, the results of these studies may be inaccurate. This prospective case-control study aimed at exploring the possible etiology and risk factors of SSNHL. We enrolled 255 SSNHL patients and 255 sex-, age- and residence-matched non-SSNHL subjects in the control group. Our study shows that there was no significant difference in the prevalence of comorbidities including hypertension and diabetes, as well as the incidence of smoking and drinking habits between the case and control groups (P > 0.05). In addition, the peripheral blood white blood cell count, neutrophil count, platelet-to-lymphocyte ratio (PLR) and fibrinogen level of the case group were significantly higher than those in the control group (P < 0.05). These findings suggest smoking, drinking, hypertension and diabetes may not be related to the onset of SSNHL. However, hypercoagulable state and inner ear vascular microthrombosis related to an elevated fibrinogen level might be the risk factors of the disease. In addition, inflammation play an important role of SSNHL onset.Trial Registration: Chinese Clinical Trial Registry. Registration number: ChiCTR2100048991.

Cardiovascular Risk Factors in Patients With Sudden Sensorineural Hearing Loss: A Systematic Review and Meta-Analysis

OBJECTIVE

The interruption of vascular supply to the inner ear is one of several proposed etiologies of sudden sensorineural hearing loss (SSNHL). The increased presence of cardiovascular risk factors may predispose patients to SSNHL through this pathway. This systematic review and meta-analysis studies the presence of cardiovascular risk factors in patients diagnosed with SSNHL.

DATA SOURCES

Databases included PubMed/Medline, OVID, EMBASE, Cochrane, and Web of Science.

REVIEW METHODS

Inclusion criteria included studies featuring SSNHL patients presenting with 1+ cardiovascular risk factors. Exclusion criteria included case reports and studies without outcome measures. Two investigators independently reviewed all manuscripts and performed quality assessments using validated tools.

RESULTS

Of 532 identified abstracts, 27 studies met inclusion criteria (19 case-control, 4 cohorts, 4 case series). Of these, 24 underwent meta-analysis encompassing a total of 77,566 patients (22,620 SSNHL patients, 54,946 matched controls). The mean age was 50.43 years. SSNHL patients were more likely to have concomitant diabetes (odds ratio [OR] 1.61 [95% confidence interval [CI]: 1.31, 1.99; p < .00001]) and hypertension (OR 1.5 [95% CI: 1.16, 1.94; p = .002]). An increased standard mean difference of total cholesterol of 11.09 mg/dL (95% CI; 3.51, 18.67; p = .004) was noted in the SSNHL group compared with the controls. No significant differences in smoking, high-density lipoprotein, triglycerides, or body mass index were detected.

CONCLUSION

Patients presenting with SSNHL have a significantly higher risk of concomitant diabetes, hypertension, and higher total cholesterol in comparison to matched controls. This may indicate a higher cardiovascular risk profile in this population. More prospective and matched cohort studies are needed to understand the role of cardiovascular risk factors in SSNHL.

Inflammatory Indicators in Peripheral Blood in Sudden Sensorineural Hearing Loss Patients With Different Audiogram Shapes

Objective: A retrospective study was conducted to explore the immune-inflammatory responses in sudden sensorineural hearing Loss (SSNHL) patients with different audiogram shapes. Methods: One hundred and ten inpatients with SSNHL were assigned to 4 subgroups according to the audiogram shape and treated with systemic methylprednisolone. The numbers of white blood cells, neutrophils, lymphocytes, platelets, and monocytes were counted. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and the monocyte-to-lymphocyte ratio (MLR) were calculated and statistically analyzed. Results: Neutrophil-to-lymphocyte ratio, MLR, and systemic immune index (SII) of SSNHL patients were significantly higher than the control group, while PLR was not statistically significant. There were no statistical differences in NLR, PLR, MLR, and SII among the 4 subgroups. Conclusion: Immune-inflammatory response may be a common pathogenesis in all SSNHL patients with different audiogram shapes. The predictive value of these hematologic markers needs further research in the future.

The relationship between serum homocysteine levels and sudden sensorineural hearing loss: a meta-analysis

OBJECTIVE

There was disagreement over the association between serum/plasma homocysteine (HCY) levels and sudden sensorineural hearing loss (SSNHL). Through the use of a meta-analysis, this study aims to determine whether there is a significant difference in serum homocysteine levels between the SSNHL group and the control group.

DESIGN

The Cochrane Library, EMBASE, and PubMed databases were all thoroughly searched. The two independent reviewers thoroughly examined the initially searched articles. The data results were calculated by standard mean difference (SMD) or odds ratios (OR). Review Manager (version 5.3) was applied to statistical data.

STUDY SAMPLE

There were 766 participants in the 6 trials with continuous outcomes that were part of the meta-analysis A. In addition, meta-analysis B, which included 961 people, contained a total of 3 studies with dichotomous results.

RESULTS

Both meta-analyses revealed the same conclusion that serum/plasma HCY levels in the SSNHL patients are higher than those in the controls (SMD 0.41, 95 % confidence interval (CI) 0.11 to 0.72, P < 0.01; OR 3.27, 95 % CI 2.16 to 4.94, P < 0.01).

CONCLUSION

This study demonstrated that the SSNHL patients' serum/plasma HCY levels were greater than those of the control group.

Cardiovascular Risk and Sudden Sensorineural Hearing Loss: A Systematic Review and Meta-Analysis

OBJECTIVES/HYPOTHESIS

It was previously suggested that patients with idiopathic sudden sensorineural hearing loss (ISSNHL) have a higher risk of cardiovascular disease. The aim of this study is to determine if ISSNHL patients have an increased cardiovascular risk by means of a systematic review and meta-analysis.

METHODS

A systematic literature review was performed using PubMed, Embase, Cochrane Libraries and Web of Science. Studies with a clear definition of ISSNHL, investigating an association between traditional vascular risk factors and ISSNHL were included. Adhering to Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, two reviewers extracted the data, assessed the risk of bias and performed the analysis of the collected evidence.

RESULTS

Nineteen case-control studies and two cohort studies were included (102,292 patients). Individual studies argued for higher prevalence of hypercholesterolemia, diabetes mellitus (DM) and higher blood pressure (HBP) in ISSNHL patients with a range of odds ratios (ORs) from 1.03 to 19. Pooled analysis of adjusted ORs revealed a significantly increased risk of ISSNHL for patients with hypertriglyceridemia (OR 1.54; 95% confidence interval [CI] 1.18-2.02) and high levels of total cholesterol (TC) (OR 2.09; 95% CI 1.52-2.87 after sensitivity analysis), but not for HBP, DM, or high levels of low- and high-density lipoproteins.

CONCLUSION

An association between higher vascular risk profile and ISSNHL seems apparent in high levels of triglycerides (TG) and TC, but more studies are needed to confirm this hypothesis due to the high levels of data heterogeneity in the literature.

LEVEL OF EVIDENCE

NA Laryngoscope, 133:15-24, 2023.

Comorbidities and laboratory changes of sudden sensorineural hearing loss: a review

Sudden sensorineural hearing loss (SSNHL) is defined as an abrupt hearing loss of more than 30 dB in three contiguous frequencies within 72 h. It is an emergency disease requiring immediate diagnosis and treatment. The incidence of SSNHL in Western countries' population is estimated between 5 and 20 per 1,00,000 inhabitants. The etiology of SSNHL remains unknown. Due to the uncertainty of the cause of SSNHL, at present, no specific treatment targets the cause of SSNHL, resulting in poor efficacy. Previous studies have reported that some comorbidities are risk factors for SSNHL, and some laboratory results may provide some clues for the etiology of SSNHL. Atherosclerosis, microthrombosis, inflammation, and the immune system may be the main etiological factors for SSNHL. This study confirms that SSNHL is a multifactorial disease. Some comorbidities, such as virus infections, are suggested to be the causes of SSNHL. In summary, by analyzing the etiology of SSNHL, more targeting treatments should be used to achieve a better effect.

Characteristics and prognostic analysis of simultaneous bilateral sudden sensorineural hearing loss

Objective

To evaluate the clinical characteristics of simultaneous bilateral sudden sensorineural hearing loss (Si-BSSNHL) as well as its prognostic factors.

Methods

Patients with Si-BSSNHL who were admitted to the Department of Otology Medicine between December 2018 and December 2021 were enrolled in the case group. Propensity score matching (PSM) for sex and age was used to select the control group, which included people who had unilateral sudden sensorineural hearing loss (USSNHL) during the same time period. Hearing recovery, audiological examinations, vestibular function assessments, laboratory tests, and demographic and clinical manifestations were analyzed for intergroup comparisons. Binary logistic regressions were used for both univariate and multivariate analyses of Si-BSSNHL prognostic factors.

Results

Before PSM, the Si-BSSNHL and USSNHL groups differed significantly (p < 0.05) in terms of time from onset to treatment, initial pure-tone average (PTA), final PTA, hearing gain, audiogram curve type, proportion of tinnitus, high-density lipoprotein level, homocysteine level, and effective rate. After PSM, significant differences were also observed in time from onset to treatment, initial PTA, final PTA, hearing gain, total and indirect bilirubin levels, homocysteine level, and effective rate between the two groups (p < 0.05). There was a significant difference in the classification of therapeutic effects between the two groups (p < 0.001). For prognostic analysis, the audiogram curve type was significantly different between the effective group and the ineffective groups of Si-BSSNHL (p = 0.01), in which the sloping type was an independent risk factor for the prognosis of the right ear in Si-SSNHL (95% confidence interval, 0.006-0.549, p = 0.013).

Conclusion

Patients with Si-BSSNHL had mild deafness, elevated total and indirect bilirubin and homocysteine levels, and poorer prognosis than those with USSNHL. Audiogram curve type was linked to the therapeutic effect of Si-BSSNHL, and the sloping type was an independent risk factor for a poor prognosis in the right ear of Si-SSNHL.

Vestibular assessment in sudden sensorineural hearing loss: Role in the prediction of hearing outcome and in the early detection of vascular and hydropic pathomechanisms

Introduction

Predicting hearing outcome in sudden sensorineural hearing loss (SSNHL) is challenging, as well as detecting the underlying pathomechanisms. SSNHL could be associated with vestibular damage since cochleo-vestibular structures share the same vascularization, along with being in close anatomical proximity. Whereas viral inflammations and autoimmune/vascular disorders most likely represent the involved aetiologies, early-stage Menière's disease (MD) can also present with SSNHL. Since an early treatment could beneficially influence hearing outcome, understanding the possible etiology plays a pivotal role in orienting the most appropriate treatment. We aimed to evaluate the extent of vestibular damage in patients presenting with SSNHL with or without vertigo, investigate the prognostic role of vestibular dysfunctions on hearing recovery and detect specific lesion patterns related to the underlying pathomechanisms.

Methods

We prospectively evaluated 86 patients with SSNHL. Audio-vestibular investigation included pure-tone/speech/impedance audiometry, cervical/ocular-VEMPs, vHIT and video-Frenzel examination. White matter lesions (WML) were evaluated on brain-MRI. Patients were followed-up and divided into "SSNHL-no-vertigo," "SSNHL+vertigo" and "MD" subgroups.

Results

Hearing was more impaired in "SSNHL+vertigo" patients who exhibited either down-sloping or flat-type audiograms, and was less impaired in "MD" where low frequencies were mostly impaired (p < 0.001). Otolith receptors were more frequently involved than semicircular canals (SCs). Although the "SSNHL-no-vertigo" subgroup exhibited the lowest vestibular impairment (p < 0.001), 52% of patients developed otolith dysfunctions and 72% developed nystagmus. Only "MD" subjects showed anterior SC impairment and upbeating spontaneous/positional nystagmus. They more frequently exhibited cervical-VEMPs frequency tuning (p = 0.036) and ipsilesional spontaneous nystagmus (p < 0.001). "SSNHL+vertigo" subjects presented with more frequently impaired cervical-VEMPs and posterior SC and with higher number of impaired receptors (p < 0.001). They mainly exhibited contralesional spontaneous and vibration-induced nystagmus (p < 0.05) and only they showed the highest WML score and "vascular" lesion patterns (p < 0.001). Concerning the outcomes, hearing was better in "MD" and worse in "SSNHL+vertigo" (p < 0.001). Hearing recovery was mostly affected by cervical-VEMPs impairment and the number of involved receptors (p < 0.05). Patients with "vascular" lesion patterns presented with the highest HL degree and WML score (p ≤ 0.001), while none of them exhibited a complete hearing recovery (p = 0.026).

Conclusions

Our data suggest that vestibular evaluation in SSNHL can provide useful information on hearing recovery and underlying aetiologies.

Role of Blood Investigations in Idiopathic Unilateral Sensorineural Hearing Loss

Majority of unilateral sensorineural hearing loss are idiopathic. Hence, outcome depends on factors which are associated with nature of disease and its treatment. These can be sudden or progressive. Various studies are done to evaluate the association in sudden variety, however causality still lacks evidence. There are limited studies regarding progressive variety and its outcome. A prospective study of 40 patients with idiopathic unilateral SNHL was carried out which attempts at identifying factors associated with either disease severity or its prognosis. A significant association was seen between distribution of random blood sugar and post treatment improvement in patients with sudden USNHL (p = 0.045). No significant association was seen with other blood parameters to treatment outcome in sudden SNHL, and severity of progressive SNHL to any blood parameters. Elevated blood sugar may affect a negative effect on treatment outcome in unilateral ISSNHL. There is scarcity of evidence in scientific literature related to "Unilateral Idiopathic Progressive Sensorineural Hearing Loss" for any association/correlation with nature of disease.

Metformin Reduces the Incidence of Sensorineural Hearing Loss in Patients With Type 2 Diabetes Mellitus: A Retrospective Chart Review

Introduction and objectives

Acquired sensorineural hearing loss (SNHL) has become a critical societal issue in recent years. SNHL is considered a risk factor for type 2 diabetes mellitus (T2DM). Metformin is commonly used to treat T2DM. However, its effects on SNHL have not been reported yet. Hence, this study aimed to evaluate the association between the use of metformin and SNHL incidence.

Patients and methods

In this retrospective matched-cohort study, the medical records of 1219 patients with T2DM aged >18 years from our hospital’s inpatient database from January 1, 2012, to December 31, 2019, were examined, and matched cohorts were generated (76 patients receiving metformin and 76 not receiving metformin). A multivariable logistic regression analysis was performed to investigate the factors influencing the incidence of SNHL.

Results

After adjustment by propensity matching, multivariable logistic regression analysis revealed that the non-use of metformin increased the risk of developing SNHL (odds ratio, 0.26; 95% confidence interval, 0.07-0.93; p = 0.03).

Conclusions

This study demonstrated an association between the use of metformin and a reduced incidence of SNHL among patients with T2DM.

Predictive factors of acute sensorineural hearing loss in adult Japanese patients for clinical application by primary care doctors: a cross-sectional study

Background

Several methods are used for hearing loss screening; however, their benefits are uncertain. In this study, we aimed to determine the predictive factors of acute sensorineural hearing loss for clinical application by primary care doctors.

Methods

This retrospective, cross-sectional study included 365 patients with acute sensorineural hearing loss without prior therapy. The patients’ clinical data, demographic information, and medical histories were obtained, and they were asked about comorbidities. In addition, we assessed lifestyle factors such as stress level, alcohol consumption, marital status, and socioeconomic level. Logistic regression analysis was performed to investigate the diagnostic predictive ability of the selected factors associated with acute sensorineural hearing loss. The hearing levels of all patients were evaluated using pure tone audiometry.

Results

We identified significant predictive factors for acute sensorineural hearing loss. The absence of hyperacusis was a predictive factor for sudden sensorineural hearing loss. Younger age, female sex, and marital status were predictive factors for acute low-tone hearing loss. High body mass index, high socioeconomic level, low alcohol consumption, high stress level, hyperacusis, and vertigo/dizziness were predictive factors for Ménière’s disease. High body mass index and ear fullness were predictive factors for perilymph fistula. Low stress level was a predictive factor for acoustic tumours.

Conclusions

Our findings can be used to distinguish between the types of acute sensorineural hearing loss. Symptoms, physical status, and lifestyle factors identified during this study are useful markers for predicting acute sensorineural hearing loss occurrence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-022-01830-8.

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.

Vascular mechanisms in acute unilateral peripheral vestibulopathy: a systematic review

Acute unilateral peripheral vestibulopathy (AUPVP) is a frequent cause of vestibular loss. Several aetiologies have been proposed, but the exact mechanism remains unknown. The aim of this study is a systematic analysis of the literature evaluating the vascular aetiology of AUPVP. A systematic literature search was performed in PubMed, Cochrane Library and Embase, including articles published from January 1^st, 2010 to November 30^th, 2020. Two reviewers independently selected articles investigating a link between AUPVP and vascular disease. The following information was extracted: year of publication, country, level of evidence, assessed vascular risk factors and number of patients. A total of 450 articles was obtained. Eleven articles were retained with 100% agreement between the two reviewers. In a pooled population of 805 patients, the main results were the higher neutrophil to lymphocyte ratio and higher prevalence of vascular risk factors among AUPVP patients. A meta-analysis was not performed because the studies were too heterogeneous in terms of methodology. Indirect arguments for vascular mechanisms in AUPVP were found. These findings indicate that larger prospective well-controlled studies are needed to clarify the vascular aetiology of AUPVP.

Association of the prognosis and severity of idiopathic sudden sensorineural hearing loss with cervical ultrasonographic findings

OBJECTIVE

The aim of this study was to investigate the association of the prognosis and severity of idiopathic sudden sensorineural hearing loss (ISSNHL) with cervical ultrasonographic findings suggestive of cardiovascular risk.

METHODS

Seventy-four inpatients with ISSNHL were included in our study. Cervical ultrasonography was performed to evaluate the common carotid artery (CCA), internal carotid artery (ICA), and vertebral artery (VA). The peak systolic velocity, end diastolic velocity, intima-media thickness, pulsatility index (PI), and resistance index (RI) were evaluated. We investigated the relationship of these variables with the severity and prognosis of ISSNHL.

RESULTS

ICA-PI, ICA-RI, and CCA-RI were significantly higher in patients with poor hearing prognosis than in those with good prognosis. The variables of VA were not related to the prognosis of ISSNHL. There were no statistically significant differences between ISSNHL severity and cervical ultrasonographic findings.

CONCLUSIONS

We found that PI and RI might be prognostic factors for ISSNHL.

Association Between Sudden Sensorineural Hearing Loss and History of Statin Use: A Nested Case-Control Study

OBJECTIVE

The effect of statin on sudden sensorineural hearing loss (SSNHL) remains unclear. Thus, this study aimed to investigate the association between prior statin use and SSNHL.

STUDY DESIGN

A nested case-control study.

SETTING

Participants aged ≥40 years were enrolled from the 2002-2015 Korean National Health Insurance Service-Health Screening Cohort.

METHODS

A total of 5876 patients with SSNHL were matched with 23,504 control participants for age, sex, income, and region of residence. History of statin use for 2 years before SSNHL onset was investigated between the groups. The odds ratios (ORs) of the length of statin use for SSNHL stratified by age, sex, income, and region of residence were analyzed with conditional logistic regression. Dyslipidemia, total cholesterol, blood pressure, blood glucose, hemoglobin, obesity, smoking, alcohol consumption, and Charlson Comorbidity Index score were adjusted. The adjusted variables were subjected to subgroup analyses.

RESULTS

The SSNHL group had a longer duration of statin use than the control group (mean [SD], 81.9 [197.7] days vs 72.7 [188.0] days; P = .001). However, statin use was not associated with SSNHL after adjusting for the confounders (adjusted OR, 1.04; 95% CI, 0.98-1.11; P = .245). There was a positive correlation between statin use and SSNHL in the crude model (crude OR, 1.10; 95% CI, 1.04-1.16; P = .001). However, there was no association between statin use and SSNHL in all subgroup analyses.

CONCLUSION

Previous statin use was not associated with SSNHL.

Risk of Stroke and Myocardial Infarction After Sudden Sensorineural Hearing Loss: A Meta-Analysis

OBJECTIVES/HYPOTHESIS

The pathophysiology of idiopathic sudden sensorineural hearing loss (ISSNHL) is still unknown, but labyrinthine artery infarction has been proposed. The objective of this study was to perform a systematic review and conduct a meta-analysis assessing the risk of developing stroke and myocardial infarction after presentation with ISSNHL.

METHODS

A systematic literature review was conducted using Pubmed, Embase, Web of Science, and Cochrane Libraries. All studies investigating an association between ISSNHL and stroke and/or myocardial infarction (MI) were included. Adhering to the MOOSE guideline, two independent reviewers extracted data, assessed risk of bias, and evaluated the relevance and quality of evidence.

RESULTS

Three observational studies evaluating the risk of stroke in ISSNHL were included (n = 6,521 patients). All individual study results indicated an increased relative risk of stroke after ISSNHL (unadjusted relative risk range 1.21-1.63). Pooled adjusted hazard ratios revealed a 1.42-fold increased risk of stroke after ISSNHL (hazard ratio [HR] 1.42; 95% confidence interval [CI] 1.15-1.75, I² = 55%). Subgroup analysis of one study demonstrated that the increased risk is only present in adults aged above 50 years (HR 1.23; 95% CI 1.07-1.42). Five observational studies evaluating the risk of MI in patients with ISSNHL were included (n = 61,499 patients). Pooled analyses demonstrated that ISSNHL was not associated with MI (HR 1.08, 95% CI 0.87-1.34).

CONCLUSION

ISSNHL may be an independent risk factor for the subsequent development of stroke especially in a subgroup of elderly patients. More studies are needed to confirm this association and to assess whether such patients would benefit from cardiovascular risk assessment and management to prevent future strokes. Laryngoscope, 131:1369-1377, 2021.

Biomarkers Suggesting Favorable Prognostic Outcomes in Sudden Sensorineural Hearing Loss

Sudden sensorineural hearing loss (SSNHL) is a medical emergency, making detailed examination to determine possible causes and early treatment important. However, etiological examinations in SSNHL do not always reveal a cause, and several factors have been found to affect treatment outcomes. Various studies are being performed to determine the prognosis and effects of treatment in patients who experience sudden hearing loss, and to identify biomarkers associated with this condition. Embase, PubMed, and the Cochrane database were searched using the key words SSNHL, prognostic, and biomarker. This search identified 4 articles in Embase, 28 articles in PubMed, and 36 in the Cochrane database. Of these 68 articles, 3 were duplicates and 37 were unrelated to the research topic. After excluding these articles, the remaining 28 articles were reviewed. Factors associated with SSNHL were divided into six categories: metabolic, hemostatic, inflammatory, immunologic, oxidative, and other factors. The associations between these factors with the occurrence of SSNHL and with patient prognosis were analyzed. Low monocyte counts, low neutrophil/lymphocyte ratio (NLR) and monocyte/high-density lipoproteins (HDL) cholesterol ratio (MHR), and low concentrations of fibrinogen, platelet glycoprotein (GP) IIIa, and TNF-α were found to be associated with good prognosis. However, these factors alone could not completely determine the onset of and recovery from SSNHL, suggesting the need for future basic and clinical studies.

Sudden Sensorineural Hearing Loss Associated with Nutritional Anemia: A Nested Case-Control Study Using a National Health Screening Cohort

Previous studies have suggested an association of anemia with hearing loss. The aim of this study was to investigate the association of nutritional anemia with sudden sensorineural hearing loss (SSNHL), as previous studies in this aspect are lacking. We analyzed data from the Korean National Health Insurance Service-Health Screening Cohort 2002-2015. Patients with SSNHL (n = 9393) were paired with 37,572 age-, sex-, income-, and region of residence-matched controls. Both groups were assessed for a history of nutritional anemia. Conditional logistic regression analyses were performed to calculate the odds ratios (ORs) (95% confidence interval, CI) for a previous diagnosis of nutritional anemia and for the hemoglobin level in patients with SSNHL. Subgroup analyses were conducted for age and sex. Age, sex, income, and region of residence were stratified. Obesity, smoking, drinking alcohol, systolic/diastolic blood pressure, fasting blood glucose, total cholesterol, and the Charlson Comorbidity Index were considered in the regression models. Nutritional anemia was present in 4.8% (449/9393) of patients with SSNHL and 4.0% (1494/37,572) of controls (p < 0.001). The SSNHL group demonstrated 1.20-fold higher odds for nutritional anemia (95% CI = 1.08-1.34, p = 0.001). Hemoglobin levels were not associated with SSNHL. In subgroups <60 years old, there was a consistent positive association of nutritional anemia with SSNHL (adjusted OR = 1.55, 95% CI = 1.11-2.15, p = 0.010 for men <60 years old, and adjusted OR = 1.22, 95% CI = 1.02-1.45, p = 0.028 for women <60 years old). Nutritional anemia, but not hemoglobin level, was associated with an increased risk of SSNHL.

Metabolic syndrome and idiopathic sudden sensori-neural hearing loss

The purpose of this study was to evaluate the association between the presence of Metabolic Syndrome (MetS) and idiopathic sudden sensorineural hearing loss (ISSHL) and the impact of MetS on recovery of patients with ISSHL. 39 Patients with ISSHL and 44 controls were enrolled in this study. Demographic, clinical characteristics and hearing recovery were evaluated. MetS was defined according to the diagnostic criteria of International Diabetes Federation (IDF) consensus definition. Patients affected by ISSHL presented a body mass index (BMI), waist circumference, waist hip ratio (WHR), fasting glucose and blood pressure significantly higher compared to controls. Considering patients with central obesity, 5 controls and 15 ISSHL patients met the criteria of MetS. According to Siegel criteria, a complete or partial recovery was observed in 60% of patients with MetS and in 91,66% of patients without MetS. MetS was associated with ISSHL and this association negatively influenced the hearing recovery of these patients.

Sudden sensorineural hearing loss: What factors influence the response to therapy?

The standard treatment of Sudden Sensorineural Hearing Loss is based on oral steroids. In addition, intratympanic steroid is currently used in patients who fail to respond to oral treatment. The aim of the present study was to evaluate, in patients affected by SSHL, factors that influence the response to systemic and intratympanic steroid treatment. A retrospective analysis was conducted on 149 patients, all treated with systemic steroids. Moreover, patients not responsive to systemic therapy were treated with intratympanic steroids as salvage therapy. Auditory gain was assessed through the recovery rate at the discharge and after 30 days. Statistical analysis demonstrated that patients with delayed treatment and down-sloping auditory curve presented a poor recovery. Linear and stepwise regression showed that hypertriglyceridemia and hyperglycemia were negative prognostic factors. The prognosis of SSHL is affected by hyperglycemia and hypertriglyceridemia suggesting that a microvascular dysfunction within the cochlea could impair hearing recovery. Intratympanic steroid treatment was used as salvage treatment, however in patients with poor prognostic factors or at risk for side effects, it could be used in association with systemic treatment.

Plasma Serotonin is Elevated in Adult Patients with Sudden Sensorineural Hearing Loss

Background The roles of thrombophilia and cardiovascular risk factors in sudden sensorineural hearing loss (SSNHL) remain controversial. Cochlear microthrombosis and vasospasm have been hypothesized as possible pathogenic mechanisms of SSNHL. This article investigates the circulating serotonin and homocysteine levels besides thrombophilia screening in patients with idiopathic SSNHL.

Methods A total of 133 SSNHL patients and age- and sex-matched controls were investigated (discovery cohort). Measurement included common inherited natural coagulation inhibitors, factor VIII, von Willebrand factor (VWF), antiphospholipid antibodies, homocysteine, and serotonin (whole blood, platelet, and plasma) levels, along with frequent relevant genetic variants. A validation cohort (128 SSNHL patients) was studied for homocysteine and serotonin levels.

Results and Conclusion In the discovery cohort, 58.6% of patients exhibited thrombophilia, of which most had a low to moderate titers of antiphospholipid antibodies and high levels of factor VIII/VWF. Twenty-seven patients (20%) had mild-to-moderate hyperhomocysteinemia or were homozygous for the methylenetetrahydrofolate reductase (MTHFR) C677T mutation. Regarding serotonin, SSNHL patients had elevated whole blood levels that remained within the normal range and normal platelet content. However, approximately 90% patients of both cohorts had elevated plasma serotonin. Elevated plasma serotoninemia was accompanied by serotonylation of platelet rhoA protein. This study shows that increased plasma serotonin appears as a biomarker of SSNHL (specificity: ∼96%, sensitivity: ∼90%) and could participate in the pathophysiology of SSNHL.

Association of carotid intima-media thickness with the risk of sudden sensorineural hearing loss

Cardiovascular factors are associated with the pathophysiological features and risk of sudden sensorineural hearing loss (SSNHL). However, little is known about the link between carotid intima-media thickness (IMT), SSNHL risk, and their respective treatment outcomes. In this study, we retrospectively reviewed 47 SSNHL cases and 33 control subjects from a single medical center and compared their demographic data and clinical characteristics, including their carotid IMT and audiological data. Of the 80 enrolled subjects, the proportion of those with high carotid IMT was greater in the SSNHL group (53.2%) than in the control group (21.2%), with an odds ratio (OR) of 4.22 (95% confidence interval (CI) [1.53–11.61], P = 0.004). Notably, high carotid IMT was more common in female SSNHL patients than females in the control group (54.2% vs. 12.5%; OR, 8.27 (95% CI [1.53–44.62]), P = 0.008), particularly in female patients ≥50 years of age (75% vs. 25%; OR, 9.0 (95% CI [1.27–63.9]), P = 0.032). The multivariate regression analyses showed the association between high carotid IMT and SSNHL with an adjusted OR of 4.655 (95% CI [1.348–16.076], P = 0.015), particularly in female SSNHL patients (adjusted OR, 9.818 (95% CI [1.064–90.587], P = 0.044). The carotid IMT was not associated with the treatment outcomes of SSNHL. Our results indicate that early-stage atherosclerosis may be associated with SSNHL, particularly in female patients more than 50 years old.

The Prognostic Value of Circulating Inflammatory Cell Counts in Sudden Sensorineural Hearing Loss and the Effect of Cardiovascular Risk Factors

OBJECTIVES

Recent studies suggest that elevated neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) are poor prognostic factors in sudden sensorineural hearing loss (SSNHL). We aimed to investigate the accuracy of this hypothesis by taking into account the effect of cardiovascular risk (CVR) factors.

METHODS

Medical records of 122 patients with SSNHL were reviewed retrospectively and grouped into 2 as; patients without CVR (group 1; n = 68) and patients having CVR (group 2; n = 54). Moreover, 60 control cases who did not have SSNHL were also included and grouped into 2 as; group 3 (n = 30) with CVR and group 4 (n = 30) healthy controls without having SSNHL or CVRs. Neutrophil (N), lymphocyte (L), platelet (Plt), NLR, and PLR between the groups and their relationship with the severity of hearing loss, recovery rates, and audiogram configurations were analyzed.

RESULTS

The highest N and NLR values were in group 1 and were significantly higher than the values of group 4 (P < .05, P < .01). There was no significant relationship between the groups in terms of L, Plt, or PLR values. The highest NLR and PLR values were determined in SSNHL patients with mild hearing loss, complete recovery, and up-sloping audiogram configuration (P > .05).

CONCLUSIONS

Elevated levels of N and NLR may be considered as strong laboratory findings showing an inflammatory response in the diagnosis of SSNHL, but the presence of CVR factors does not seem to increase the inflammatory response in SSNHL as expected. In patients with SSNHL, NLR and PLR elevation may indicate better prognosis.

Analysis of Clinical and Laboratory Findings of Idiopathic Sudden Sensorineural Hearing Loss

Idiopathic sudden sensorineural hearing loss (ISSNHL) is an emergency disease requiring immediate diagnosis and treatment. The incidence of ISSNHL in the Western countries’ population was estimated to 5–20 per 100,000 inhabitants. The etiology of ISSNHL remains unknown. Its pathogenesis is most often suggested to be due to a disturbed microcirculation and infection. Previous studies have reported that comorbidities, including hypertension, diabetes mellitus (DM), and hyperfibrinogenemia are risk factors of ISSNHL. This study aimed at investigating the clinical characteristics, laboratory parameters and comorbidities of patients with ISSNHL. Our study suggests that the annual incidence of ISSNHL in China mainland is 19 per 100 000. The clinical characteristics and prevalence of comorbidities of ISSNHL patients are different according to age distribution and hearing results. Moreover, the patients with vertigo, hypertension, DM and high TG suffered more often from severe hearing loss compared with the counterparts. This indicates that the cardiovascular and metabolic diseases (hypertension and hyperlipidemia) appeared to be closely associated with the occurrence and severity of ISSNHL.

Metabolic syndrome components and sudden sensorineural hearing loss: a case-control study

PURPOSE

Cardiovascular risk factors, including metabolic syndrome (MetS) components, were reported as possible risk factors of sudden sensorineural hearing loss (SSNHL). The objective of this study was to evaluate the relationship between MetS (and its components) and SSNHL.

METHODS

Eighty-one SSNHL patients and 243 sex-, aged-matched controls participated from January 2018 to July 2019. The participants included 176 (54.3%) men and 148 (45.7%) women. The correlation between Mets components, total cholesterol, low-density lipoprotein-cholesterol, and the onset of SSNHL was analyzed using used multivariate conditional logistic regression analysis.

RESULTS

A total 12 patients (14.8%) with SSNHL and 27 subjects (11.1%) in control group had MetS (p > 0.05). The rate of low levels of high-density lipoprotein-cholesterol (HDL-C), hypertriglyceridemia, and hypertension was significantly higher in the SSNHL group than those in the control group (p < 0.05). A trend of odds SSNHL was observed with increasing the number of MetS components (p < 0.001). The multivariable analysis revealed that the rate of hypertriglyceridemia and low HDL-C concentration was significantly higher in the SSNHL groups compared to the controls.

CONCLUSIONS

Hypertriglyceridemia and low levels of HDL-C may be important factors in the pathogenesis of SSNHL, and should be assessed during the investigation of patients with this condition.

Herpes zoster does not increase the risk of sudden sensory neural hearing loss: a longitudinal follow-up study using a national sample cohort

Objective: This study aimed to investigate the risk of sudden sensorineural hearing loss (SSNHL) in Herpes zoster patients from a representative population cohort.Design: A longitudinal follow-up studyStudy sample: Data were obtained from the Korean National Health Insurance Service-National Sample Cohort for the period from 2002 to 2013. We matched 61,702 subjects in the Herpes zoster group with subjects in a control group (246,808 subjects with no history of Herpes zoster) based on demographic factors (age, sex, income, and region of residence) and medical history (diabetes, dyslipidemia, and hypertension). The crude (simple) and adjusted hazard ratios (HRs) for Herpes zoster with SSNHL were analysed using the Cox-proportional hazard model.Results: Only 0.5% (338/61,364) of the Herpes zoster group and 0.7% (1664/245,144) of the control group showed SSNHL. The Herpes zoster group did not exhibit a higher rate of SSNHL (adjusted HR = 0.81, 95% CI = 0.72-0.91, p < 0.001) than the control group. In subgroup analyses, no age subgroups showed a significant risk of SSNHL in the Herpes zoster group.Conclusions: After adjusting for confounding factors, the risk of SSNHL did not increase in the Herpes zoster group compared with the control group.

Assessment of Oxidative Stress in Patients with Sudden Hearing Loss: A Non-randomized Prospective Clinical Study

The etiology of sudden hearing loss (SHL) has not been fully elucidated. Previous studies claimed that different etiological factors may play a role in the pathogenesis of SHL. The aim of the present study is to investigate the presence of oxidative stress (OS) in SHL cases using thiol-disulfide balance. In addition, total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI) and lipid hydroperoxide levels (LOOH) were investigated. A total of 30 cases (15 female, 15 male, mean age 48.9 ± 8.1 years, age range: 36-68 years) were included in the study. Thiol and disulfide amounts, thiol/disulfide ratios, TOS, TAS, OSI and LOOH scores of the case group and control group were compared. Native thiol (SH) and total thiol (SH + SH) values were significantly lower in the SHL group than in the control group (p = 0.028 and p = 0.044, respectively). The LOOH value, TOS value and OSI value were significantly higher in the SHL group than in the control group (all p values < 0.05). The TAS value was significantly lower in the SHL group than in the control group (p = 0.0001). The present study has presented that the thiol-disulfide balance was impaired in SHL cases. OS may play a role in the development of SHL.

Update on consensus on diagnosis and treatment of idiopathic sudden sensorineural hearing loss

INTRODUCTION

Idiopathic sudden sensorineural hearing loss (ISSNHL) is a sudden, unexplained unilateral hearing loss.

OBJECTIVES

To update the Spanish Consensus on the diagnosis, treatment and follow-up of ISSNHL.

MATERIAL AND METHODS

After a systematic review of the literature from 1966 to March 2018, on MESH terms «(acute or sudden) hearing loss or deafness», a third update was performed, including 1508 relevant papers.

RESULTS

Regarding diagnosis, 11ISSNHL is clinically suspected, the following diagnostic tests are mandatory: otoscopy, acumetry, tonal audiometry, speech audiometry, and tympanometry, to discount conductive causes. After clinical diagnosis has been established, and before treatment is started, a full analysis should be performed. An MRI should then be requested, ideally performed during the first 15 days after diagnosis, to discount specific causes and to help to understand the physiopathological mechanisms in each case. Although treatment is very controversial, due to its effect on quality of life after ISSNHL and the few rare adverse effects associated with short-term steroid treatment, this consensus recommends that all patients should be treated with steroids, orally and/or intratympanically, depending on each patient. In the event of failure of systemic steroids, intratympanic rescue is also recommended. Follow-up should be at day 7, and after 12 months.

CONCLUSION

By consensus, results after treatment should be reported as absolute decibels recovered in pure tonal audiometry and as improvement in speech audiometry.

Causes of hyperhomocysteinemia and its pathological significance

In the last 10 years, homocysteine has been regarded as a marker of cardiovascular disease and a definite risk factor for many other diseases. Homocysteine is biosynthesized from methionine through multiple steps and then goes through one of two major metabolic pathways: remethylation and transsulfuration. Hyperhomocysteinemia is a state in which too much homocysteine is present in the body. The main cause of hyperhomocysteinemia is a dysfunction of enzymes and cofactors associated with the process of homocysteine biosynthesis. Other causes include excessive methionine intake, certain diseases and side effects of some drugs. Hyperhomocysteinemia is a trigger for many diseases, such as atherosclerosis, congestive heart failure, age-related macular degeneration, Alzheimer's disease and hearing loss. There are many studies showing a positive relationship between homocysteine level and various symptoms. We speculate that a high level of homocysteine can be the sole reason or an aggravating factor in numerous diseases for which causal links are not fully understood.