Soluble intercellular adhesion molecule 1 and soluble vascular cell adhesion molecule 1 in sudden hearing loss. Otol Neurotol. 2008;29:470-474. [PMID: 18401280 DOI: 10.1097/mao.0b013e318170b650]

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.

Evaluation of von Willebrand factor and protein/creatinine ratio in idiopathic sudden hearing loss

OBJECTIVE

The objective of this study was to evaluate the levels of von Willebraund Factor (vWF) in plasma and the protein/creatinine ratio in urine in patients with idiopathic sudden acute hearing loss, which we think to be caused by epithelial dysfunction.

MATERIALS-METHODS

Thirty patients with a sudden hearing loss and thirty healthy individuals were included in the study. Before the treatment, blood and urine were collected from the patients and the control group to investigate the levels of the protein/creatinine ratio and the levels of vWF. The test results of the patients group were compared with those of the control group.

RESULTS

We found that the levels of vWF increased in the patient group, which was statistically significant (P<.05). The protein/creatinine ratio in the urine increased in the patient group, but this was not statistically significant (P>.05). In addition, we found that the vWF and urine protein/creatin ratio of the patients who benefited from treatment were lower than those who did not benefit.

CONCLUSIONS

This study showed that sudden sensorineural hearing loss may result from endothelial dysfunction. However, more studies that include more patients are needed in order to support this.

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.

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.

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.

Short-term effects of intravenous batroxobin in treatment of sudden sensorineural hearing loss: a propensity score-matched study

Background

Sudden sensorineural hearing loss (SSNHL) can cause great panic in patients. Whether it is advantageous to add intravenous batroxobin in the treatment of SSNHL remains to be determined. This study aimed to compare the short-term efficacy of therapy combined with intravenous batroxobin and that without intravenous batroxobin in SSNHL patients.

Methods

This retrospective study harvested the data of SSNHL patients hospitalized in our department from January 2008 to April 2021. The hearing levels on the admitted day (before treatment) and the discharge day were considered pre-treatment hearing and post-treatment hearing, respectively. The hearing gain was the difference value of pre-treatment hearing and post-treatment hearing. We used Siegel's criteria and the Chinese Medical Association of Otolaryngology (CMAO) criteria to evaluate hearing recovery. The complete recovery rate, overall effective rate, and hearing gain at each frequency were considered outcomes. Propensity score matching (PSM) was conducted to balance the baseline characteristics between the batroxobin group and the non-batroxobin group. Sensitivity analysis was carried out in flat-type and total-deafness SSNHL patients.

Results

During the study period, 657 patients with SSNHL were admitted to our department. Among them, a total of 274 patients met the enrolled criteria of our study. After PSM, 162 patients (81 in each group) were included in the analysis. Once the hospitalized treatment was completed, the patients would be discharged the next day. Logistic regression analysis of the propensity score-matched cohort indicated that both the complete recovery rates [Siegel's criteria, OR: 0.734, 95% CI: 0.368-1.466, p = 0.381; CMAO criteria, OR: 0.879, 95% CI: 0.435-1.777, p = 0.720] and the overall effective rates [Siegel's criteria and CMAO criteria, OR: 0.741, 95% CI: 0.399-1.378, p = 0.344] were not significantly different between the two treatment groups. Sensitivity analysis has shown similar results. For flat-type and total-deafness SSNHL patients, no significant difference was found in post-treatment hearing gain at each frequency between the two groups after PSM.

Conclusion

There was no significant difference in short-term hearing outcomes between treatment with batroxobin and treatment without batroxobin in SSNHL patients by Siegel's and CMAO criteria after PSM. Future studies for better therapy regimens of SSNHL are still needed.

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.

Autonomic Nervous Function in Patients with Sudden Sensorineural Hearing Loss and Its Association with Prognosis and Disease Severity

INTRODUCTION

Vascular disorder is considered one of the main mechanisms of sudden sensorineural hearing loss (SSNHL) due to the anatomy of the inner ear. One factor that can contribute to vascular disorder is impairment in the autonomic nervous system. This study aims to investigate autonomic function in patients with SSNHL and its association with prognosis and disease severity from January 2018 to October 2019.

METHODS

We conducted a cross-sectional study involving 40 healthy controls and 55 subjects with SSNHL. We compared the autonomic function of controls and patients using heart rate variability (HRV). SSNHL patients were divided into improvement and no-improvement groups and into mild and severe groups according to pure-tone audiometry results.

RESULTS

The SSNHL group had significantly decreased total power (TP), low frequency (LF), and high frequency (HF) compared to the control group. However, there were no significant differences between the mild and severe groups. In the no-improvement group, LF was significantly higher and normalized HF was significantly lower than in the improvement group. According to a multiple logistic regression analysis, age and LF were significantly correlated with improvement.

CONCLUSION

This is the first study to evaluate the significance of HRV in patients with SSNHL, according to prognosis and disease severity. Further studies about the relationship between autonomic nervous system and SSNHL with larger sample size and prospective design are needed.

Coagulation States in Patients With Sudden Sensorineural Hearing Loss Evaluated by Thromboelastography

OBJECTIVE

The state of coagulation is controversial in patients with sudden sensorineural hearing loss (SSNHL). We used thromboelastography (TEG) to explore the relationships between blood coagulation parameters and SSNHL pathogenesis and recovery.

STUDY DESIGN

Prospective study.

SETTING

Affiliated Sixth People's Hospital, Shanghai Jiao Tong University.

METHODS

A total of 104 newly diagnosed patients with SSNHL and 29 matched healthy controls were recruited. Hearing assessments, TEG, and conventional coagulation tests (CCTs) were performed, followed by standard treatments and follow-up.

RESULTS

The TEG parameters of patients with SSNHL were in the normal range, but the group exhibited a significantly prolonged kinetic time (K; P = .004) and a smaller angle (P = .003) as compared with the controls. After grouping the patients with SSNHL according to audiograms and comparing them in pairs, we found that the differences were significant only when controls were compared with patients with low-frequency SSNHL (K, P = .023; angle, P = .04) and flat-type SSNHL (K, P = .017; angle, P = .014). Logistic regression analysis showed that neither TEG nor CCT parameters significantly affected hearing improvement after SSNHL treatment.

CONCLUSIONS

Although the K value and angle were significantly increased and significantly reduced, respectively, in the test group as compared with the control group, the state of coagulation in patients with SSNHL was still within the normal range. No CCT or TEG coagulation parameters (except the angle) differed significantly among patients in each group according to hearing recovery status, which suggested that the coagulation status does not determine the prognosis of patients with SSNHL.

Hearing Evaluation in Patients with Chronic Renal Failure: A 1 Year Cross-Sectional Study in a Tertiary Care Centre

(1) To study the prevalence of sensorineural hearing loss among chronic renal failure patients. (2) To study the correlation between degree of hearing loss and the duration of chronic renal failure. This cross sectional study was conducted in the department of Otorhinolaryngology and Head and Neck Surgery at KAHER's Jawaharlal Nehru Medical College and KLEs Dr. Prabhakar Kore Hospital and Medical Research Centre, Belagavi from January 2018 to December 2018. 60 ears (30 patients) with chronic renal failure were included in the study. All 60 ears were subjected to ENT examination, pure tone audiometry and measurement of glomerular filtration rate. Patients with type 2 diabetes mellitus, suppurative otitis media, and other known causes of sensorineural hearing loss were excluded. The prevalence of sensorineural hearing loss was calculated among the chronic renal failure patients. The correlation, if any, was studied by statistical analysis between SNHL and duration of chronic renal failure, as well as type and degree of hearing loss. Sensorineural hearing loss was seen in 51.67% of the 60 ears with 18.33% had mixed hearing loss (p < 0.0001). Robust correlation was seen between severity of SNHL and the duration of chronic renal failure. Positive correlation was seen between SNHL and age of the patient. High prevalence of SNHL was seen in the chronic renal failure patients. Long standing cases had tendency of worse hearing levels. Age of the patients also seemed to have a positive correlation with SNHL severity. While evaluating a chronic renal failure patient, auditory impairment should always be kept in mind.

Serum Fibrinogen as a Prognostic Factor in Sudden Sensorineural Hearing Loss: A Meta-analysis

OBJECTIVE

High blood viscosity has been proposed as a mechanism for sudden sensorineural hearing loss (SSNHL); however, the relationship between blood markers of fibrinolysis or coagulation and severity or prognosis of SSNHL is still unclear. The aim of this study is to investigate the relationship between serum fibrinogen and SSNHL.

DATA SOURCES

PubMed and Scopus were searched for English language articles using the following keywords: SSNHL, sudden hearing loss, sudden deafness, idiopathic hearing loss or idiopathic sensorineural hearing loss, and fibrinogen.

STUDY SELECTION

The articles in the study related to SSNHL and provided data about the serum fibrinogen level.

DATA EXTRACTION

The data included patient profiles, fibrinogen level, recovery, and treatment modality.

DATA SYNTHESIS

Nineteen articles were selected. The aggregated data were analyzed using the random effect model. Two articles that included the fibrinogen level with recovery rates were analyzed for the relationship between the fibrinogen level and recovery.

CONCLUSIONS

The average fibrinogen level was 318 ± 8.5 mg/dl (mean ± standard error, within normal range). There was no difference in the fibrinogen level between SSNHL patients and the control group. The fibrinogen level of the recovery group was lower than that of the no recovery group. This showed that a high fibrinogen level was associated with poor prognosis, and it could be related to the severity of the pathological change rather than being the cause of the SSNHL. SSNHL includes various pathologies; therefore, the appropriate therapy should be selected based on each condition.

White matter lesions and sudden sensorineural hearing loss

Aim of this paper is to investigate the presence of White Matter Lesions (WMLs) in subjects affected by Sudden Sensorineural Hearing Loss (SSNHL) and possibly to evaluate the significance of WMLs in SSNHL patients. A total of 64 patients (cases) affected by SSNHL were included in this case-control study. Hearing tests were performed at SSNHL onset, after 7 days and after 30 days. Cerebral MRI sequences were performed to rule out retrocochlear pathology, and WMLs were evaluated if present. MRI control group included 32 subjects, without hearing loss, affected by pituitary adenoma, who underwent cerebral MRI of follow-up. WML presence in those affected by SSNHL resulted having a similar distribution to that of the control group; however, we observed complete hearing recovery in 42,9% of patients without WML and in 11,6% of patients with WML >1 (p = 0,017^*). The incidence of WML in patients with SSNHL was not different compared to that of the control group; however, MRI could have a prognostic role for SSNHL patients, as the presence of WMLs can been linked to a poorer hearing recovery rate.

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.

Plasma levels of endothelial cell-specific molecule-1 and pentraxin-3 in idiopathic sudden sensorineural hearing loss

OBJECTIVES

To evaluate the plasma levels of endothelial cell-specific molecule-1 (ESM-1) and pentraxin-3 (PTX-3) in patients with idiopathic sudden sensorineural hearing loss, and to compare the pre- and post-treatment levels in patients responsive and non-responsive to therapy.

METHODS

The study included 108 subjects: 51 with idiopathic sudden sensorineural hearing loss and 57 controls. For ESM-1 and PTX-3 analyses, blood samples were collected before and three months after treatment initiation in the idiopathic sudden sensorineural hearing loss group and once for the control group. Treatment response was evaluated three months after therapy initiation with pure tone audiometry, and the patients were divided into two groups: responsive and non-responsive to treatment.

RESULTS

Serum ESM-1 levels were significantly higher in the idiopathic sudden sensorineural hearing loss group than the control group, whereas the difference was not significant for PTX-3. In the responsive and non-responsive groups, ESM-1 and PTX-3 levels were not statistically different before and after treatment.

CONCLUSION

To our knowledge, this is the first study investigating plasma ESM-1 and PTX-3 levels in idiopathic sudden sensorineural hearing loss. Increased plasma ESM-1 levels may confirm endothelial dysfunction involvement in idiopathic sudden sensorineural hearing loss pathogenesis, which could be associated with vascular impairment.

Evaluation of Serum Endocan Levels in Sensorineural Hearing Loss

OBJECTIVES

The aim of this study was to reveal the possible role of endothelial dysfunction in sensorineural hearing loss (SNHL) by determining the serum endocan levels of patients with varying degrees of SNHL.

MATERIALS AND METHODS

Patients with documented SNHL and healthy controls were included in the study, whereas those with a known history of chronic inflammatory condition were excluded. In addition, a recent history of use of glucocorticoids, nonsteroid anti-inflammatory drugs, or any ototoxic medications was also considered as an exclusion criterion due to its potential impact on endocan synthesis and metabolism. Following overnight fasting, blood samples were collected, and serum endocan levels were measured. For statistical analysis of the data, PASW Statistics for Windows version 18 was used.

RESULTS

The comparison of the subgroups yielded no statistically significant difference between the control and mild-to-moderate SNHL groups. Despite the increase in hearing loss, the difference between the endocan levels in these patients did not increase proportionately and was not statistically significant (p>0.05). The patients in the severe SNHL group had a higher level of serum endocan than those in other groups, and the difference was statistically significant (p<0.05).

CONCLUSION

The serum endocan levels failed to show a proportionate increase with increasing degree of SNHL, indicating that there is no precise association between SNHL and serum endocan levels. The serum endocan levels of patients with SNHL did not significantly differ from those of the healthy controls.

Italian survey on benign paroxysmal positional vertigo

Benign paroxysmal positional vertigo (BPPV) is the most common type of peripheral vertigo. BPPV often relapses after the first episode, with a recurrence rate between 15% and 50%. To date both the aetiopathogenetic processes that lead to otoconia detachment and the factors that make BPPV a relapsing disease are still unclear, but recent epidemiological studies have shown a possible association with cardiovascular risk factors. The aim of the present study (Sesto Senso Survey) was to evaluate in the Italian population through an observational survey, the main demographic and clinical characteristics of patients with BPPV (first episode or recurrent) with particular focus on the potential cardiovascular risk factors. The survey was conducted in 158 vestibology centres across Italy on 2,682 patients (mean age 59.3 ± 15.0 years; 39.1% males and 60.9% females) suffering from BPPV, from January 2013 to December 2014. The results showed a high prevalence of cardiovascular risk factors such as high blood pressure (55.8%), hypercholesterolaemia (38.6%) and diabetes (17.7%), as well as a family history of cardiovascular disease (49.4%). A high percentage of patients also had hearing loss (42.9%), tinnitus (41.2%), or both (26.8%). The presence of hypertension, dyslipidaemia and pre-existing cardiovascular comorbidities were significantly related to recurrent BPPV episodes (OR range between 1.84 and 2.31). In addition, the association with diabetes and thyroid/autoimmune disease (OR range between 1.73 and 1.89) was relevant. The survey results confirm the significant association between cardiovascular comorbidities and recurrent BPPV and identify them as a potential important risk factor for recurrence of BPPV in the Italian population, paving the way for the evaluation of new therapeutic strategies in the treatment of this disease.

Association between endothelial dysfunction and otoneurological symptoms in children with sickle cell disease

OBJECTIVE

To evaluate the association between endothelial dysfunction and otoneurological symptoms and vaso-occlusive phenomena in children with sickle cell disease (SCD).

METHODS

Cross-sectional study with 54 children, aged between 6 and19 years of age, of whom 28 had genotype SS and 26 apparently healthy (AA genotype) whose parents or guardians, or the children themselves, filled out a questionnaire designed to assess their otoneurological symptoms. All the individuals were submitted assessment of endothelial function by flow-mediated dilation (FMD) percentage with reactive hyperemia of brachial artery Doppler.

RESULTS

Otoneurological symptoms (tinnitus and/or vertigo) predominated in the SCD group (46.4 vs. 15.4%; p = 0.006). A negative correlation was observed between FMD percentage and time of evolution of vertigo SCD (r = -0.432; p = 0.022) and the linear regression analysis demonstrated that for every reduction in FMD percentage there was an increase in time of evolution of vertigo of 1.79 months (β = -1.79; p = 0.022). The positive correlation between episodes of painful crisis and time of evolution of vertigo (r = 0.3; p = 0.04).

DISCUSSION

The presence of vascular endothelial damage in the labyrinthine artery in patients with SCD is capable of compromising the semicircular canals, shown by clinical expression of otoneurological symptoms, such as vertigo. In the present study, an association was observed between endothelial dysfunction with otoneurological symptoms and otoneurological symptoms and vaso-occlusive phenomena in SCD.

A comprehensive study of oxidative stress in sudden hearing loss

Little is known about the association between idiopathic sudden sensorineural hearing loss (ISSNHL) and oxidative stress. We investigated changes in a wide range of oxidants and antioxidants to create a comprehensive picture of oxidative imbalance. In the peripheral blood of 50 ISSNHL patients and 50 healthy subjects, total oxidant status (TOS), total antioxidant status (TAS), paraoxonase (PON), thiol/disulphide levels were measured. Moreover, a global oxidative stress index, reflecting both oxidative and antioxidant counterparts, was also calculated. One-way analysis between oxidative markers and severity of hearing loss were evaluated. The ISSNHL patients showed significantly higher TOS levels than controls (6.02 ± 3.17 vs. 4.5 ± 2.22; p = 0.018). The oxidative index was also significantly higher in patients than controls (0.39 ± 0.19 vs. 0.3 ± 0.14; p = 0.035). TAS, PON, native thiol, and total thiol were not altered. There was no statistical significance between oxidative markers and severity of hearing loss. The binary logistic regression model revealed that disulphide and TOS were associated with ISSNHL. There are alterations in a wide array of oxidants and antioxidants, with balance shifting toward increased oxidative stress in ISSNHL. Our findings may suggest endothelial dysfunction in ISSNHL etiopathogenesis.

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.

High Total Cholesterol in Peripheral Blood Correlates with Poorer Hearing Recovery in Idiopathic Sudden Sensorineural Hearing Loss

Idiopathic sudden sensorineural hearing loss (ISSHL) is a common otologic emergency whose cause is still unclear. The importance of blood lipids in the pathogenesis of ISSHL is widely reported in literature. In fact elevated levels of low density lipoprotein cholesterol (LDL), total cholesterol (TC) and apolipoprotein B (Apo-B) have been proposed as risk factors for this pathology. No correlation has been described between serum lipid parameters and the prognosis of ISSHL. Aim of the present study was to identify prognostic factors associated with hearing recovery in a group of patients affected by ISSHL. Ninety-four patients with the diagnosis of ISSHL hospitalized between March 2013 and October 2014 were included in this study. Patients' blood sampling and hearing assessments were carried out. Patients were divided into two groups as "recovered" and "unrecovered", according to their response to the treatment. We found a statistically significant higher level of total cholesterol in the unrecovered group compared to the recovered one (p = 0.03). None of the other routine laboratory parameters have shown a statistically significant difference between the patients successfully treated and patients with poor outcomes. Total cholesterol concentrations may be a prognostic factor for recovery in ISSHL and should be assessed together with routine tests in patients with this condition. The other routine laboratory parameters seem to have no effect on the development and prognosis of this pathology.

The relationship between serum lipids and sudden sensorineural hearing loss: a systematic review and meta-analysis

Background

Sudden sensorineural hearing loss (SSNHL) is a relatively common condition that is usually of unknown etiology. A number of individual studies have investigated the association between various serum lipids and SSNHL; however, the findings have been inconsistent. In an attempt to obtain more definitive information on the relationship between serum lipids and SSNHL, we carried out a systematic review and meta-analysis.

Methods

Medline, the Cochrane Library, and EMBASE were searched using the following key words: lipid, cholesterol, triglyceride, fat, serum, blood, sudden hearing loss, hearing loss, hearing disorders. Randomized controlled trials, prospective cohort studies, and retrospective case-control studies involving patients with SSNHL and healthy controls that examined the relationship (reported as odds ratios [OR]) between lipid profiles and SSNHL were included. Primary outcomes were total cholesterol and low-density lipoprotein cholesterol (LDL-C) concentrations. Secondary outcomes were triglyceride, high-density lipoprotein cholesterol, and lipoprotein(a) concentrations.

Results

A total of 6 case-control studies were included in this systematic review/meta-analysis. The total number of participants ranged from 30 to 250 in the case group and from 43 to 271 in the control group. Meta-analysis revealed no significant difference in total cholesterol levels between the case and control groups (pooled OR = 1.79, 95% confidence interval [CI] = 0.98 to 3.26, P = 0.057). Likewise, meta-analysis revealed no significant difference in LDL-C concentrations between the case and control groups (pooled OR = 1.15, 95% CI = 0.64 to 2.07, P = 0.639). Since there were an insufficient number of studies reporting data for the secondary outcomes, meta-analysis was not possible.

Conclusions

Our results do not provide evidence for serum lipids being associated with SSNHL, nor do they definitively rule out such an association. Additional studies are needed to ascertain the relationship, or lack thereof, between serum lipids and SSNHL.

High fibrinogen in peripheral blood correlates with poorer hearing recovery in idiopathic sudden sensorineural hearing loss

Objectives

We used hearing tests and peripheral blood sample analyses to characterize the pathology of idiopathic sudden sensorineural hearing loss (ISSNHL) and to identify possible prognostic factors for predicting recovery of hearing loss.

Study Design

A retrospective, multicenter trial was conducted.

Methods

Two hundred three patients examined within 7 days after the onset of ISSNHL received prednisone with lipo-prostaglandin E1. Pure-tone auditory tests were performed before and after treatment with these drugs. Blood tests were performed on blood samples collected during the patients’ initial visit to our clinic.

Results

In all patients, elevated white blood cell (WBC) counts, fasting blood sugar levels, HgbA1c, and erythrocyte sedimentation rate (ESR) significantly correlated with high hearing threshold measurements obtained on the initial visit. High fibrinogen levels, WBC counts, ESR, and low concentrations of fibrinogen degradation products (FDP) were associated with lower hearing recovery rates. Additionally, different audiogram shapes correlated with different blood test factors, indicating that different pathologies were involved.

Conclusions

High fibrinogen levels measured within seven days after ISSNHL onset correlated with poorer hearing recovery. This may be a consequence of ischemia or infections in the inner ear. The high WBC counts also observed may therefore reflect an immune response to inner ear damage induced by ischemic changes or infections. Our data indicate that therapeutic strategies should be selected based on the timing of initial treatment relative to ISSNHL onset.

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.

Correlations of inflammatory biomarkers with the onset and prognosis of idiopathic sudden sensorineural hearing loss

HYPOTHESIS

We investigated whether inflammatory biomarkers and stress are involved in the pathophysiology of idiopathic sensorineural hearing loss (ISHL).

STUDY DESIGN

Individual cohort study.

SETTING

Two tertiary centers.

PATIENTS

Forty-three ISHL and 10 non-ISHL patients seen in our ENT departments from 2004 to 2010 within a week from the onset of new symptoms and without steroid administration before visiting our departments.

INTERVENTION

Multiple audiologic evaluations, blood tests including leukocyte counts, natural killer cell activity (NKCA), interleukin 6 (IL-6), tumor necrosis factor, high-sensitivity CRP (hCRP), and the General Health Questionnaire were used to evaluate the systemic stress and inflammatory response.

MAIN OUTCOME MEASURES

Correlations between biomarkers and ISHL severity and prognosis were evaluated by statistical analysis.

RESULTS

In the ISHL patients, a neutrophil count above the reference range was associated with severe hearing loss and poor prognosis, and was accompanied by low NKCA and high IL-6. In the non-ISHL patients, these associations were not present. The abnormal neutrophil count was independent of preexisting vascular diseases. The abnormal counts responded to treatment and decreased into the reference range.

CONCLUSION

Neutrophil counts above the reference range of a facility will be a useful indicator of poor prognosis of ISHL. Synchronism of different types of NF-κB activation pathways could be required to cause severe ISHL. An NKCA decrease, an acute neutrophil count increase, and an IL-6 increase can induce NF-κB activation in the cochlea and cause severe ISHL. Further epidemiologic surveys should be conducted to evaluate whether stressful life events increase the risk of severe ISHL onset.

Endothelial function and cardiovascular risk in patients with idiopathic sudden sensorineural hearing loss

OBJECTIVE

To evaluate cardiovascular risk factors and pre-clinical atherosclerosis in subjects affected by idiopathic sudden sensorineural hearing loss (ISSHL).

METHODS

In this study, 29 ISSHL patients and 29 healthy controls were evaluated. All of the patients underwent a complete audiovestibular and clinical evaluation. Carotid intima-media thickness (C-IMT) and flow-mediated dilation (FMD) of the brachial artery were assessed as early markers of atherosclerosis.

RESULTS

Our results showed that FMD was significantly lower in the ISSHL patients than in the controls (5.6 ± 1.6% vs. 7.7 ± 3.7%, p < 0.01). Moreover, the total cholesterol and low density lipoprotein cholesterol were significantly higher in the ISSHL patients than in the controls (p < 0.05). The two groups did not differ with regards to C-IMT and other cardiovascular risk factors. Vestibular involvement was shown to be associated with lower FMD values (4.1 ± 1.7% vs. 5.8 ± 1.5%, p < 0.05). No relationship was found between C-IMT and vestibular involvement. Finally, multiple logistic regression highlighted the finding that only FMD values seemed to predispose individuals to developing ISSHL (p = 0.03, OR: 1.4).

CONCLUSIONS

ISSHL seemed to be associated with vascular endothelial dysfunction and an increased cardiovascular risk, which supports the hypothesis of a vascular aetiology for this disease.

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

Although the etiology of idiopathic sudden sensorineural hearing loss (SSNHL) remains unclear, the pathologically increased permeability of blood vessels, elucidated by gadolinium-enhanced magnetic resonance imaging (MRI), suggests the involvement of inflammation. Because SSNHL is considered a multifactorial disease, possibly caused by interactions between genetic factors and environmental factors, the authors investigated the associations of polymorphisms of inflammatory mediator genes with susceptibility to SSNHL. The authors compared 72 patients affected by SSNHL and 2010 adults (1010 men and 1000 women; mean age 59.2 years; range 40-79) who participated in the National Institute for Longevity Sciences Longitudinal Study of Aging. Multiple logistic regression was used to obtain odds ratios (ORs) for SSNHL in subjects with polymorphisms in the genes IL-6 C - 572G, IL-4R G1902A, IL-10 A - 592C, TNFα C - 863A, TNFRSF1B G593A, VEGF C936T, VEGF C - 2578A, and VEGF G - 1154A, with adjustment for age, gender, and any history of hypertension, diabetes, or dyslipidemia. The per-allele OR for the risk of SSNHL in subjects bearing IL-6 C - 572G was 1.480 (95% confidence interval [CI], 1.037-2.111) in model 1 (no adjustment), 1.463 (CI, 1.022-2.094) in model 2 (adjusted for age and gender), and 1.460 (CI, 1.016-2.097) in model 3 (adjusted for age, gender, and a history of hypertension, diabetes, or dyslipidemia). Under the dominant model of inheritance, the ORs were 1.734 (CI, 1.080-2.783) in model 1, 1.690 (CI, 1.050-2.721) in model 2, and 1.669 (CI, 1.035-2.692) in model 3. The remaining seven polymorphisms failed to show any associations with the risk of SSNHL. These data need to be confirmed on larger series of patients. In conclusion, the IL-6 C - 572G polymorphism is associated with a risk of SSNHL. Because permeability of blood vessels in the inner ear is frequently increased in patients with SSNHL, inflammation of the inner ear might be involved.

Systematic review and meta-analysis of the risk factors for sudden sensorineural hearing loss in adults

OBJECTIVES/HYPOTHESIS

To review the medical literature evidence of potential risk factors for sudden sensorineural hearing loss (SSNHL) in the adult general population.

STUDY DESIGN

Systematic review of prospective and retrospective studies; meta-analysis of case-controlled studies.

METHODS

Three researchers independently reviewed MEDLINE (January 1, 1950-November 30, 2010), Embase (January 1, 1980-November 30, 2010), and Evidence-Based Medicine Reviews databases in addition to conducting a manual reference search. Randomized controlled trials, prospective cohort studies, consecutive/nonconsecutive case series, and retrospective reviews in which a clear definition of SSNHL was stated were included in the study. Researchers individually extracted data regarding patient information and the presumed risk factors. Discrepancies were resolved by mutual consensus.

RESULTS

Twenty-two articles met the inclusion criteria. Cardiovascular risk factors (smoking, increased alcohol consumption) appeared to be associated with a higher risk of developing SSNHL. A low level of serum folate may also be implicated as a risk factor. Factor V Leiden and MTHFR gene polymorphisms were found to occur more frequently in patients with SSNHL in several studies, suggesting these inherited prothrombophilic mutations could be independent risk factors of SSNHL.

CONCLUSIONS

Acquired and inherited cardiovascular risk factors appeared to be associated with an increased risk of developing SSNHL.

Endothelial progenitor cells in sudden sensorineural hearing loss

CONCLUSIONS

Endothelial progenitor cells (EPCs) are a unique subtype of circulating cells with properties similar to those of embryonal angioblasts. They have the potential to proliferate and to differentiate into mature endothelial cells. EPCs are reduced in patients with vascular risk factors due to a decreased mobilization, an increased consumption at the site of damage or a reduced half-life. The results of this study confirm the existence of an endothelial dysfunction in patients with sudden sensorineural hearing loss (SSHL) and support the vascular involvement in the pathogenesis of the disease.

OBJECTIVE

The aim of this study was to evaluate the concentration of EPCs in patients affected by SSHL.

METHODS

Twenty-one patients affected by SSHL were evaluated. The number of EPCs was analyzed by flow cytometry analysis of peripheral blood CD34+KDR+CD133+ cells.

RESULTS

Circulating levels of EPCs were significantly lower in SSHL patients compared with controls. In particular, CD34+KDR+ cells and CD34+CD133+KDR+ cells were significantly reduced (p < 0.05).

The role of soluble adhesion molecules and cytokines in sudden sensorineural hearing loss

OBJECTIVE

The underlying pathology of sudden sensorineural hearing loss (SSNHL) is still not completely understood. Inflammatory and vascular factors are part of the present discussion. The aim of this study was to learn more about the possible role of adhesion molecules and cytokines in patients with SSNHL. These molecules are thought to contribute to endothelial dysfunction.

STUDY DESIGN

Case-control study with planned data collection.

SETTING

Tertiary referral center.

SUBJECTS AND METHODS

Blood samples of 35 patients presenting with SSNHL of more than 30 dB in at least 3 contiguous frequencies were compared to a gender- and age-matched control group of normal-hearing subjects. Levels of the soluble adhesion molecules intercellular adhesion molecule (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), endothelial selectin (E-selectin), and concentration of interleukin 6 (IL-6), interleukin 8 (IL-8), and monocyte chemoattractant protein 1 (MCP-1) were measured using established enzyme-linked immunosorbent assays. These parameters as well as fibrinogen and lipid values were statistically analyzed.

RESULTS

Levels of soluble ICAM-1, VCAM-1, E-selectin, IL-6, IL-8, and MCP-1 were not significantly elevated in patients with SSNHL. The clinical chemistry and hematologic determinations showed no significant differences between patients and control subjects.

CONCLUSION

This study revealed no association concerning SSNHL and typical vascular risk factors such as lipids and fibrinogen. Soluble adhesion molecules were not elevated in the SSNHL group. The role of endothelial dysfunction represented by increased levels of soluble adhesion molecules in the pathogenesis of SSNHL remains unclear. Further studies are necessary to elucidate the vascular etiology of SSNHL.