Immune-mediated inner-ear disorders in neuro-otology

Audiovestibular Dysfunction Related to Anti-Phospholipid Syndrome: A Systematic Review

Background: Anti-phospholipid syndrome (APS) has emerged as a significant issue in autoimmune diseases over recent decades. Its hallmark feature is thromboembolic events, potentially affecting any vascularized area including the microcirculation of the inner ear. Since the first case report of APS-related audiovestibular dysfunction described in 1993, numerous reports have explored the association between APS-related antibodies and audiovestibular dysfunction. These studies indicate a higher prevalence of APS-related antibodies in patients with sensorineural hearing loss compared to healthy controls. Unlike other idiopathic hearing loss disorders, audiovestibular dysfunction associated with APS may respond to appropriate treatments, highlighting the importance of timely recognition by clinicians to potentially achieve favorable outcomes. Therefore, this systematic review aims to consolidate current evidence on the characteristics, pathophysiology, assessment, and management of audiovestibular dysfunction linked to APS. Methods: This systematic review utilized electronic searches of the PubMed, Embase, ClinicalKey, Web of Science, and ScienceDirect online platforms. The initial search was performed on 27 January 2024, with the final update search completed on 20 June 2024. Results: Based on theoretical pathophysiology, anticoagulation emerges as a pivotal treatment strategy. Additionally, drawing from our preliminary data, we propose a modified protocol combining anticoagulants, steroids, and non-invasive brain stimulation to offer clinicians a novel therapeutic approach for managing these symptoms. Conclusions: Clinicians are encouraged to remain vigilant about the possibility of APS and its complex audiovestibular manifestations, as prompt intervention could stabilize audiovestibular function effectively.

Blood tests as biomarkers for the diagnosis and prognosis of sudden sensorineural hearing loss in adults: a systematic review

OBJECTIVE

Sudden sensorineural hearing loss is considered idiopathic in up to 90 per cent of cases. This study explored the role of blood tests as biomarkers for the diagnosis and prognosis of sudden sensorineural hearing loss.

METHOD

Two researchers filtered 34 papers into the final review. This review was pre-registered on the Prospero database and conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines.

RESULTS

Raised inflammatory markers are almost universal in sudden sensorineural hearing loss, suggesting an inflammatory or autoimmune process. The most useful biomarkers are neutrophil-lymphocyte ratio, platelet-lymphocyte ratio and fibrinogen level. Focused investigations should be deployed on a case-by-case basis to identify underlying metabolic, infective and autoimmune conditions.

CONCLUSION

A full blood count and coagulation screen (fibrinogen) is recommended in all cases of sudden sensorineural hearing loss. These are inexpensive, accessible and offer as much diagnostic and prognostic information as any other biomarker. There is emerging evidence regarding specific biomarkers for sudden sensorineural hearing loss prognosis, with heat shock protein-70, anti-endothelial cell antibody and prestin demonstrating potential; investigation of their validity through prospective, controlled research is recommended.

Sex differences in autoimmune inner ear disease treatment and audiological outcomes

OBJECTIVE

The primary objective of this study was to assess possible sex-related differences in AIED treatment. The secondary aim was to assess the long-term outcomes of treatment using pre- and post-treatment audiometry and speech discrimination scores.

METHODS

Adult patients with a diagnosis of AIED who were treated for their condition at the senior author's (RTS) practice from 2010 to 2022 were included in this study. Patients were grouped as males or females for further analysis and comparison. Data included past medical history, medication use, surgical history and social history. Air-conduction thresholds (500 to 8000 Hz) were collected and averaged into discrete variables for pre- and post-treatment. The change (∆) and percent change (%∆) of these variables following therapy were analyzed. Speech discrimination score (SDS) testing results were taken at the same time points as pure tone averages, and patients were sub-stratified based on evidence of improvement in SDS and compared accordingly.

RESULTS

One hundred eighty-four patients (78 male/106 female) were included in this study. The mean age of the male participants was 57.18 ± 15.92 years, and the mean age of the female participants was 53.49 ± 16.04 years (p = 0.220). Comorbid autoimmune disease (AD) was more prevalent in females than in males (38.7 % vs. 16.7 %, p = 0.001). Of the patients treated with oral steroids, females received significantly more courses than males (2.554 ± 2.078 vs. 1.946 ± 1.301, p = 0.020). However, the average duration of oral steroids used per trial did not differ significantly between males and females (21.02 ± 18.05 vs. 20.62 ± 7.49, p = 0.135). Audiological results demonstrated that the change (∆) in pure tone average (PTA) at 0.5, 1, 2, and 3 kHz (-4.21 ± 6.394 vs. -3.91 ± 6.105) and high-frequency pure tone average (HFPTA) at 4, 6, and 8 kHz (-4.55 ± 6.544 vs. -2.19 ± 6.842) was not significantly different between the sexes following treatment (p = 0.376 and p = 0.101, respectively). Similarly, the percentage change (%∆) in PTA (-13.17 % vs. -15.01 %) and HFPTA (-8.50 % vs. -6.76 %) also did not differ significantly between males and females (p = 0.900 and p = 0.367, respectively). One hundred-five (57.1 %) patients qualified for the SDS improvement subgroup for analysis, with 50 (47.6 %) being male and 55 (51.9 %) being female (p = 0.159). The change (∆) in SDS (15.12 ± 21.159 vs. 10.62 ± 19.206) and the percentage change (%∆) in SDS (16.71 % vs. 12.40 %) also showed no significant difference between male and female patients (p = 0.312 and p = 0.313, respectively).

CONCLUSION

AIED is not a uniform condition regarding clinical presentation, audiological findings or progression, nor is its treatment straightforward. The utilization and duration of cytotoxic medications, as well as PTA and SDS findings, did not differ between the sexes. However, significantly more courses of oral steroids were prescribed to females than males. Sex as a biological variable and its implications in the pathogenesis and treatment of AIED warrant further study.

Disease-Modifying Antirheumatic Drugs in the Treatment of Autoimmune Inner Ear Disease: A Systematic Review and Meta-Analysis of Auditory and Vestibular Outcomes

OBJECTIVE

To answer the following question: In patients with primary autoimmune inner ear disease (AIED), (population) what impact do disease-modifying antirheumatic agents (DMARDs) (intervention) when compared with no treatment or corticosteroids (comparison) have on auditory and vestibular outcomes (outcome)?

STUDY DESIGN

Systematic review and meta-analysis.

DATA SOURCES

According to PRISMA guidelines, PubMed, Scopus, CINAHL, and Cochrane Library databases were searched from inception to March 10, 2022.

STUDY SELECTION

Studies of patients receiving DMARDs for the treatment of AIED were selected for review. Case reports, phase I/II trials, studies of patients with secondary AIED, and studies of AIED patients receiving solely corticosteroids were excluded.

DATA EXTRACTION

Primary outcomes were pure-tone audiometry and speech discrimination scores at baseline and after DMARD treatment. Secondary outcomes were rates of subjective audiovestibular complaints and rates of adverse reactions. No objective vestibular outcomes underwent meta-analysis.

DATA SYNTHESIS

Mean differences were calculated using RevMan 5.4. Heterogeneity was assessed with the Q test and I2 statistic. Pooled prevalence rates of audiovestibular symptoms were expressed as a percentage with 95% confidence intervals.

RESULTS

Ten studies with a total of 187 patients were included. Treatments included methotrexate, etanercept, azathioprine, anakinra, cyclophosphamide, rituximab, and infliximab. Mean treatment duration was 10.8 ± 22.2 months and mean follow-up was 13.7 ± 8.1 months. The pure-tone audiometry and speech discrimination scores mean differences between baseline and post-DMARD were -2.1 [-4.1, -0.1] dB and 13.9 [8.5, 19.4] %, respectively. Seven studies reported 38 adverse events, four of which were classified as serious.

CONCLUSION

DMARDs showed statistically significant improvement in auditory outcomes, as well as subjective symptoms, with relatively low rates of adverse events. They warrant further exploration to better compare with corticosteroids.

Autoimmune Vestibulopathy—A Case Series

Autoimmune inner ear disease (AIED) is a rare clinical entity. Its pathogenicity, heterogenous clinical presentation in the context of secondary systemic autoimmune disease and optimal treatment avenues remain poorly understood. Vestibular impairment occurring in the context of AIED is rarely subject to detailed investigation given that the auditory symptoms and their responsiveness to immunosuppression are the focus of the few proposed diagnostic criteria for AIED. We present three cases of vestibulopathy occurring in the context of autoimmune inner ear conditions, including the first known report of autoimmune inner ear pathology arising with a temporal association to administration of the Pfizer-BioNTech SARS-CoV2 vaccination. We review the available literature pertinent to each case and summarise the key learning points, highlighting the variable presentation of vestibular impairment in AIED.

Audiological Patterns in Patients with Autoimmune Hearing Loss

INTRODUCTION

The aim of this study was to illustrate clinical and audiological patterns of hearing impairment in patients with autoimmune hearing loss (AIHL).

METHODS

Fifty-three patients with AIHL were retrospectively recruited, and a tapering schema of steroid treatment was administered in all these patients. The diagnosis of AIHL was essentially based on clinical symptoms, such as recurrent, sudden (sensorineural hearing loss [SSHL]), fluctuating, or quickly progressing (<12 months) SSHL (uni-/bilateral), in association with the coexistence of autoimmune diseases, high antinuclear antibodies (ANA) and the presence of human leukocyte antigen (HLA) B27, B35, B51, C04, and C07. Logistic regression analysis was applied to correlate the clinical data and laboratory features of AIHL with final outcomes.

RESULTS

The onset of AIHL was mainly progressive (49%), followed by SSHL (39.6%) or fluctuating (11.3%). The pure-tone audiogram showed more commonly a downsloping pattern (42.6% of ears), but also an upsloping, flat, cookie-bite, or inverse cookie-bite shape. Bilateral progressive AIHL was more frequently simultaneous (23 patients) than heterochronous (4 patients). Nineteen patients (35.8%) showed a favorable response to steroid therapy. The presence of recurrent, bilateral SSHL versus recurrent, unilateral SSHL had statistically negative effect on hearing recovery (OR = 0.042, p < 0.05). The heterochronous bilateral SSHL may have better prognosis than simultaneous bilateral SSHL (OR = 10.000, p = 0.099). The gender, age, concomitant autoimmune disease, high ANA, HLA alleles, tinnitus, and vestibular symptoms had no statistical effect on a favorable outcome of AIHL.

CONCLUSIONS

A bilateral, simultaneous, and progressive hearing loss combined with downsloping audiogram occurred more often in patients with AIHL. Bilateral simultaneous SSHL with recurrences represents the worse prognostic form of AIHL.

The Pathogenesis of secondary forms of Autoimmune Inner Ear Disease (AIED): advancing beyond the audiogram data

INTRODUCTION

Autoimmune Inner Ear Disease (AIED) can be of a primary or secondary type. To date, a clear pathogenesis of the disease is still not available. Focusing on the secondary forms of AIED, the aim of this review is to (i) assess and describe the hearing involvement in patients affected by autoimmune diseases, (ii) describe the possible association between clinical features (among serological/laboratory data and disease activity/duration) and hearing impairment, (iii) show evidence connecting the AIED types with various etiopathogenetic mechanisms.

AREAS COVERED

A PRISMA-compliant systematic review was performed. Medline, Cochrane, Embase, and Cinahl were searched from 1 January 2015 through to 5 August 2020. Overall, 16 studies (involving 1043 participants) were included in the review. The data in the literature suggested that bilateral mild-to-moderate sensorineural hearing loss is a commonly reported clinical symptom of AIED.

EXPERT OPINION

Patients with systemic autoimmune disorders present a cochlear injury which might be associated with the humoral and/or cellular immune response against the inner ear. To date, AIED pathogenesis remains an open issue, due to the rarity of these clinical entities and due to the difficulties in investigating the inner ear immunology, considering the inner ear inaccessibility for tissue sampling.

Psoriasis Increases the Risk of Sudden Sensorineural Hearing Loss: A Longitudinal Follow Up Study Using a National Sample Cohort

Psoriasis is a well-known immune-mediated disease. Its autoimmune pathophysiology is consistent with the immune-mediated systemic vascular hypothesis regarding the pathogenesis of sudden sensorineural hearing loss (SSNHL). The purpose of our study was to investigate whether psoriasis affects the prevalence of SSNHL in all age groups matched by age, sex, income, and region of residence. Korean Health Insurance Review and Assessment Service-National Patient Samples were collected from 2002 to 2013. A 1:4 matched psoriasis group (n = 12,864) and control group (n = 51,456) were selected. The crude (simple) and adjusted (Charlson comorbidity index) hazard ratios (HR) for psoriasis and SSNHL were analyzed using the stratified Cox proportional hazard model. The incidence of SSNHL was significantly higher in the psoriasis group than in the control group (0.5% vs. 0.4%, p = 0.004). Psoriasis increased the risk of SSNHL (adjusted HR = 1.44, 95% confidence interval (CI) = 1.09–1.90, p = 0.010). In the stratification analysis, the incidence of SSNHL was significantly higher in the 30–59-year-old group than other group SSNHL (adjusted HR = 1.50, 95% CI = 1.06–2.12, p = 0.023). In addition, SSNHL occurred significantly more frequently in men with psoriasis (adjusted HR = 1.70, 95% CI = 1.17–2.49, p = 0.006). Psoriasis increased the risk of SSNHL, and SSNHL was more prevalent in between the age of 30–59-year-olds and men with psoriasis.

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.

Audiological disturbances in patients with primary antiphospholipid syndrome

Background

Antiphospholipid syndrome (APS) is an autoimmune disease of hypercoagulability state in the presence of antibodies against phospholipids. Many neurological deficits related to APS have been described. Sensory neural hearing loss has been described only anecdotally, mostly in case reports. This study investigated a possible association between hearing disorders and APS.

Methods

Seventeen patients (aged 20–80 years) diagnosed with primary APS were evaluated for evidence of hearing disorders. All had otoscopy, full audiometry test, brainstem evoked response audiometry and otoacoustic emissions testing, and completed a questionnaire. Hearing levels were compared to the standard hearing levels of the general population by age group.

Results

Of the 17 APS patients, 10 (age groups 20–29 and 50–59) had significantly reduced hearing levels in all or part of the tested frequencies compared to standard levels. Three patients (age group 60–69) had better hearing levels at low frequencies compared to standard hearing levels.

Conclusion

These findings support the existence of hearing disorders in primary APS.

Update on Vertigo in Autoimmune Disorders, from Diagnosis to Treatment

The prevalence of autoimmune diseases has been increasing over the last 20 years. The clinical presentation of this large and heterogeneous group of disorders depends on whether the involvement is organ-specific or non-organ-specific. Dizziness, vertigo, and disequilibrium are common symptoms reported by patients with vestibulocochlear involvement. The association of vertigo and autoimmune diseases has been largely documented, suggesting that autoimmune disorders could be overrepresented in patients with vertigo in comparison to the general population. The aim of this review is to present the recent literature findings in the field of autoimmune-mediated diseases with cochleovestibular involvement, focusing on the clinical presentation, diagnosis, and treatment of immune-mediated inner ear diseases including autoimmune inner ear disease (AIED), Meniere's disease, and bilateral vestibulopathy, as well as of systemic autoimmune diseases with audiovestibular disorders, namely, Behçet's disease, Cogan's syndrome, sarcoidosis, autoimmune thyroid disease, Vogt-Koyanagi-Harada syndrome, relapsing polychondritis, systemic lupus erythematosus, antiphospholipid syndrome, IgG4-related disease, and ANCA-associated vasculitides.

Audiovestibular Symptoms in Systemic Autoimmune Diseases

Immune-mediated inner ear disease can be primary, when the autoimmune response is against the inner ear, or secondary. The latter is characterized by the involvement of the ear in the presence of systemic autoimmune conditions. Sensorineural hearing loss is the most common audiovestibular symptom associated with systemic autoimmune diseases, although conductive hearing impairment may also be present. Hearing loss may present in a sudden, slowly, rapidly progressive or fluctuating form, and is mostly bilateral and asymmetric. Hearing loss shows a good response to corticosteroid therapy that may lead to near-complete hearing restoration. Vestibular symptoms, tinnitus, and aural fullness can be found in patients with systemic autoimmune diseases; they often mimic primary inner ear disorders such as Menière's disease and mainly affect both ears simultaneously. Awareness of inner ear involvement in systemic autoimmune diseases is essential for the good response shown to appropriate treatment. However, it is often misdiagnosed due to variable clinical presentation, limited knowledge, sparse evidence, and lack of specific diagnostic tests. The aim of this review is to analyse available evidence, often only reported in the form of case reports due to the rarity of some of these conditions, of the different clinical presentations of audiological and vestibular symptoms in systemic autoimmune diseases.

Hearing loss in autoimmune disorders: Prevalence and therapeutic options

The objective of this study was to review our current knowledge relative to the correlation between sensorineural hearing loss (SNHL) and autoimmune diseases, focusing on the prevalence of hearing loss in different pathologies and possible therapeutic approaches. A review of the literature on hearing loss in different forms of autoimmune disease has been carried out, with emphasis on incidence and prevalence of SNHL. Therapeutic protocols have been assessed including both conservative medical and rehabilitative methods. Cochlear implant outcomes have been investigated. The prevalence of hearing loss in autoimmune and immune-mediated inner ear diseases, as referred by case reports or single-center statistics, is widely variable. More difficult is the evaluation of severe/profound SNHL, usually reported in relation to cochlear implantation. Though these patients represent ideal candidates for cochlear implantation, as they become deaf after years of hearing; the associated systemic disease, the specific damage on inner ear structures and the medication taken may influence the result of cochlear implantation. The main problem is the cochlear fibrosis or ossification that has been found to affect 50% of implanted ears in patients suffering from autoimmune and immune-mediated SNHL. Hence, in the presence of severe/profound SNHL earlier implantation may be indicated before post-inflammatory obliterative changes to the cochlea.

Mobile tablet audiometry in fluctuating autoimmune ear disease

BACKGROUND

Autoimmune inner ear disease (AIED) is a rare condition characterized by bilateral fluctuating sensorineural hearing loss (SNHL). The labile nature of this hearing loss makes it difficult to accurately quantify with conventional methods, and therefore it is challenging to rehabilitate.

METHODS

Over a 9-month period one pediatric patient with severe AIED was monitored and conducted home audiograms using a previously validated testing system (Shoebox Audiometry). During this period he also underwent several clinical audiograms. The correlation between clinical and home audiograms was analyzed with a Pearson coefficient, and the range and frequency of fluctuations was recorded.

RESULTS

Sixty-four automated home audiograms and nine clinical audiograms were conducted. When tested at home using a calibrated system the pure tone average (PTA) fluctuated between 12 dB and 72 dB indicating large variability in hearing. Fluctuations were frequent: on 28 occasions the PTA varied by at least 5 dB when retested within 4 days. The mean PTA was 50 dB and 95% of the thresholds were within 36 dB of the mean. Clinical audiograms obtained on the same day or within 1 day of home testing were highly concordant (with a Pearson coefficient of 0.93).

CONCLUSION

AIED can result in significant fluctuations in hearing over short periods of time. Home testing enables a more granular look at variations over time and correlates well with clinical testing, and thus facilitates rapid action and informed rehabilitation.

AAO: Autoimmune and Autoinflammatory (Disease) in Otology: What is New in Immune-Mediated Hearing Loss

OBJECTIVES

Autoinflammatory diseases are a family of immune-mediated, rare diseases, some of which, exhibit sensorineural hearing loss (SNHL), suggesting potentially similar mechanisms of molecular pathogenesis between autoinflammatory-mediated hearing loss and autoimmune inner ear disease (AIED) may exist. The purpose of this review is to compare the clinical features of autoimmune and autoinflammatory diseases that affect hearing, discuss the limitations of our knowledge, and highlight potential new disease mechanisms and therapeutics.

DATA SOURCES

Pubmed Literature Review; Google Scholar Literature review.

REVIEW METHODS

A focused comparison of AIED with a number of autoinflammatory diseases that manifest with sensorineural hearing loss was performed. The pathogenesis of these diseases is reviewed in the context of the innate and adaptive immune system, cytokine expression and genetic polymorphisms.

RESULTS

AIED, since first described by Cogan and Lehnhardt and first clinically characterized by McCabe, has remained an enigmatic disease, with limited advances in both new diagnostics and new therapeutics. Since the discovery of autoinflammatory diseases, a number of systemic autoimmune diseases have either been re-classed as autoinflammatory diseases or identified to have features of autoinflammatory disease.

CONCLUSION

AIED has clinical features of both autoimmune and autoinflammatory disease. It is critical that autoinflammatory diseases be correctly identified, as failure to do so may result in systemic amyloidosis and kidney damage.

N-Acetylcysteine attenuates tumor necrosis factor alpha levels in autoimmune inner ear disease patients

Autoimmune inner ear disease (AIED) is a poorly understood disease marked by bilateral, rapidly progressive hearing loss triggered by unknown stimuli, which is corticosteroid responsive in 60 % of patients. Although the mechanism of the disease is not precisely understood, a complex interaction of cytokines is believed to contribute toward the inflammatory disease process and hearing loss. Previously, we showed the role of TNF-α in steroid-sensitive and IL-1β in steroid-resistant immune-mediated hearing loss. N-Acetylcysteine (NAC), a broad spectrum antioxidant, has been effective in other autoimmune disorders. Other studies have shown NAC to have a protective adjunct role in human idiopathic sudden hearing loss, where the addition of NAC resulted in better hearing recovery than with steroids alone, although the mechanism of this protection was not elucidated. In the present study, we observed PBMCs from AIED patients exhibited higher baseline TNF-α and MPO levels compared with normal healthy controls. NAC effectively abrogates LPS-mediated TNF-α release from PBMC of both AIED patients and controls. We demonstrated that in AIED patients, the TNF-α downstream signaling pathway appears aberrantly regulated, influencing both MPO and IL-8 expression. Given that NAC effectively abrogated LPS-mediated TNF-α release and exerted minimal effects on the downstream targets of this pathway, we feel NAC may be a rational adjunct therapy for this enigmatic disease, worthy of clinical exploration.

Sudden Sensorioneural Hearing Loss and Autoimmune Systemic Diseases

Introduction  Several authors have demonstrated the relationship between sudden sensorineural hearing loss (SNHL) and systemic autoimmune diseases (SAD). Immune-mediated SNHL can rarely present as unilateral sudden SNHL and manifests itself in the contralateral ear only after years. It presents clinical relevance for being one of the few SNHL that may be reversible given that early and appropriate treatment is applied. Objective  The objective of this study is to describe the clinical presentations and audiological findings from patients with idiopathic sudden SNHL and SAD associated with a probable diagnosis of immune-mediated SNHL. Furthermore, we strive to estimate the prevalence of SAD in patients with sudden SNHL. Methods  This is an observational retrospective cohort. We have selected and studied patients with SAD. Revision of available literature on scientific repositories. Results  We evaluated 339 patients with sudden SNHL. Among them, 13 (3.83%) patients suffered from SAD. Three patients had bilateral involvement, a total of 16 ears. We evaluate and describe various clinical, epidemiological, and audiological aspects of this sample. Conclusion  In our sample of patients with sudden SNHL, the prevalence of SAD was found relevant. The majority had tinnitus and dizziness concomitant hearing loss, unilateral involvement and had experienced profound hearing loss at the time of the installation. In spite of instituted treatment, most cases showed no improvement in audiometric thresholds. Apparently, patients with sudden SNHL and SAD have a more severe initial impairment, higher percentage of bilateral, lower response to treatment, and worse prognosis than patients with sudden SNHL of unknown etiology.

Current understanding of the pathogenesis of autoimmune inner ear disease: a review

BACKGROUND

Autoimmune inner ear disease (AIED) is a poorly understood form of sensorineural hearing loss that causes bilateral, asymmetric, progressive hearing loss, sometimes with vestibular symptoms, often associated with a systemic autoimmune disease, which is noteworthy as the only sensorineural loss responsive to medical therapy. Despite much research interest of the past 25 years, its aetiopathogenesis is still unproven.

OBJECTIVE OF REVIEW

To succinctly consolidate research and opinion regarding the pathogenesis of autoimmune inner ear disease, in ongoing efforts to elucidate the molecular and intracellular pathways that lead to inner ear damage, which may identify new targets for pharmacotherapy.

TYPE OF REVIEW

Systematic review

SEARCH STRATEGY

PubMed/MEDLINE search using key terms to identify articles published between January 1980 and Apr 2014. Additionally, any landmark works discussed in this body of literature were obtained and relevant information extracted as necessary.

EVALUATION METHOD

Inclusion criterion was any information from animal or human studies with information relevant to possible aetiopathogenesis of AIED. Studies that focused on diagnosis, ameliorating symptoms or treatment, without specific information relevant to mechanisms of immune-mediated injury were excluded from this work. Articles meeting the inclusion criteria were digested and summarised.

RESULTS

A proposed pathogenic mechanism of AIED involves inflammation and immune-mediated attack of specific inner ear structures, leading to an excessive Th1 immune response with vascular changes and tissue damage in the cochlea. Studies have identified self-reactive T cells and immunoglobulins, and have variously implicated immune-complex deposition, microthrombosis and electrochemical disturbances causing impaired neurosignalling in the pathogenesis of AIED. Research has also demonstrated abnormalities in the cytokine milieu in subjects with AIED, which may prove a target for therapy in the future.

CONCLUSION

Ongoing research is needed to further elucidate the aetiopathogenesis of AIED and discern between various mechanisms of tissue injury. Large-cohort clinical studies employing IL-1 receptor blockade are warranted to determine its potential for future therapy.

Pathophysiology of the cochlear intrastrial fluid-blood barrier (review)

The blood-labyrinth barrier (BLB) in the stria vascularis is a highly specialized capillary network that controls exchanges between blood and the intrastitial space in the cochlea. The barrier shields the inner ear from blood-born toxic substances and selectively passes ions, fluids, and nutrients to the cochlea, playing an essential role in the maintenance of cochlear homeostasis. Anatomically, the BLB is comprised of endothelial cells (ECs) in the strial microvasculature, elaborated tight and adherens junctions, pericytes (PCs), basement membrane (BM), and perivascular resident macrophage-like melanocytes (PVM/Ms), which together form a complex "cochlear-vascular unit" in the stria vascularis. Physical interactions between the ECs, PCs, and PVM/Ms, as well as signaling between the cells, is critical for controlling vascular permeability and providing a proper environment for hearing function. Breakdown of normal interactions between components of the BLB is seen in a wide range of pathological conditions, including genetic defects and conditions engendered by inflammation, loud sound trauma, and ageing. In this review, we will discuss prevailing views of the structure and function of the strial cochlear-vascular unit (also referred to as the "intrastrial fluid-blood barrier"). We will also discuss the disrupted homeostasis seen in a variety of hearing disorders. Therapeutic targeting of the strial barrier may offer opportunities for improvement of hearing health and amelioration of auditory disorders. This article is part of a Special Issue entitled <Annual Reviews 2016>.

An open label study to evaluate the safety and efficacy of intratympanic golimumab therapy in patients with autoimmune inner ear disease

OBJECTIVE

To evaluate the safety and efficacy of intratympanically injected golimumab (GLM), a TNF-α inhibitor, as a steroid-sparing agent for patients with steroid-dependent autoimmune inner ear disease (AIED).

STUDY DESIGN

Open label.

SETTING

Tertiary referral center.

PATIENTS

Ten patients with steroid-dependent AIED were enrolled in Stage 2. The average patient age at enrollment was 59, with an average of 12.5 years from the start of bilateral hearing loss symptoms. The average dose of daily prednisone at the start of injections was 18 mg.

INTERVENTION

Intratympanic injection of GLM.

MAIN OUTCOME MEASURE

Hearing loss progression (treatment failure) was defined as either an increase in pure-tone thresholds by frequency or a decrease in word recognition score.

RESULTS

There were no serious adverse events. Five of seven per-protocol subjects experienced stable pure-tone thresholds in the injected ear, whereas 4 had stable word recognition scores. Two subjects experienced an improvement in word recognition scores. The results support the hypothesis that GLM may be a promising treatment.

CONCLUSIONS

The TNF-α inhibitor GLM stabilized hearing in 3 of 7 per-protocol subjects with AIED and allowed a complete tapering off of prednisone in those 7 subjects. Studies with larger samples sizes are warranted.

Vestibular disorders in euthyroid patients with Hashimoto's thyroiditis: role of thyroid autoimmunity

INTRODUCTION

A relationship between vestibular disorders and thyroid autoimmunity independently from thyroid function has been postulated.

AIM

To shed more light on the actual relationship between vestibular lesions and Hashimoto's thyroiditis (HT) regardless of thyroid function.

METHODS

Forty-seven patients with HT (89·4% F; aged 48·3 ± 12·7 years), 21 with multinodular goitre (MNG; 57·1% F; 54·1 ± 9·8 years) and 30 healthy volunteers (56·7% F; 50·7 ± 13·9 years) were enrolled. Inclusion criteria were the presence of normal thyroid function tests and no clinical history of vestibular dysfunction. Each subject was submitted to complete vestibular evaluation [Caloric Test, Vestibular evoked myogenic potentials (VEMPs), Head Shaking Test (HST)].

RESULTS

52·2% of HT patients showed an alteration of VEMPs and 44·7% of caloric test (P < 0·0001 for both). None of the MNG patients showed any vestibular alteration, while one healthy control showed an altered caloric test. A correlation was found between vestibular alterations of HT patients and the degree of serum TPOAb level, not affected by age and serum TSH value. By logistic regression analysis, the absence of thyroid autoimmunity significantly reduced the risk of vestibular alterations: HR 0.19 (95%CI: 0·003-0.25, P = 0·0004) for caloric test; HR 0·07 (95%CI: 0·02-0·425, P < 0·0001) for VEMPs; and HR 0·22 (95%CI: 0·06-0·7, P = 0·01) for HST.

CONCLUSION

In euthyroid HT patients, a significant relationship between subclinical vestibular damage and the degree of TPOAb titre was documented. This finding suggests that circulating antithyroid autoantibodies may represent a risk factor for developing vestibular dysfunction. An accurate vestibular evaluation of HT patients with or without symptoms is therefore warranted.

Innate immune recognition of molds and homology to the inner ear protein, cochlin, in patients with autoimmune inner ear disease

Autoimmune Inner Ear Disease (AIED) is characterized by bilateral, fluctuating sensorineural hearing loss with periods of hearing decline triggered by unknown stimuli. Here we examined whether an environmental exposure to mold in these AIED patients is sufficient to generate a pro-inflammatory response that may, in part, explain periods of acute exacerbation of disease. We hypothesized that molds may stimulate an aberrant immune response in these patients as both several Aspergillus species and penecillium share homology with the LCCL domain of the inner ear protein, cochlin. We showed the presence of higher levels of anti-mold IgG in plasma of AIED patients at dilution of 1:256 (p = 0.032) and anti-cochlin IgG 1:256 (p = 0.0094 and at 1:512 p = 0.024) as compared with controls. Exposure of peripheral blood mononuclear cells (PBMC) of AIED patients to mold resulted in an up-regulation of IL-1β mRNA expression, enhanced IL-1β and IL-6 secretion, and generation of IL-17 expressing cells in mold-sensitive AIED patients, suggesting mold acts as a PAMP in a subset of these patients. Naïve B cells secreted IgM when stimulated with conditioned supernatant from AIED patients' monocytes treated with mold extract. In conclusion, the present studies indicate that fungal exposure can trigger autoimmunity in a subset of susceptible AIED patients.

Autoimmune inner ear disease: a retrospective review of forty-seven patients

The purpose of this retrospective study was to characterize and further define autoimmune inner ear disease (AIED) using the Harris AIED classification. A retrospective review was conducted at two tertiary medical centers for 47 patients who were diagnosed with AIED. The overall patient response rate to oral prednisone treatment was 69.7%. The sensitivity of the test for a serum antibody against heat-shock protein 70 (HSP70) was 54.5% and the specificity was 42.9%. Therefore, the clinical utility of the HSP70 antibody test appeared to be limited with respect to the diagnosis of AIED. Vertigo, tinnitus and aural fullness improved significantly with both of the newly developed adalimumab (Humira®) and rituximab (Rituxan®). However, hearing loss did not improve in the present study.

Vibration-induced nystagmus in patients with unilateral peripheral vestibular disorders

This study was done to clarify the clinical significance of vibration-induced nystagmus (VIN) and to calculate the sensitivity and the specificity of the vibration test. One hundred and twelve patients with unilateral peripheral vestibular disorders and thirty normal subjects were enrolled into this study. However, patients with spontaneous nystagmus were excluded. Vibration stimuli (approximately 100 Hz) were presented to the mastoids and the forehead. Patients and normal subjects also underwent head shaking nystagmus (HSN) test and caloric testing. Among the 112 patients, 91(81 %) showed VIN which were mainly horizontal. VIN was more frequently elicited on the mastoids than on the forehead. In the majority of patients (76 cases), the direction of VIN was toward the healthy side, whereas patients with Meniere's disease (15 cases), showed nystagmus toward the affected side. None of 30 normal subjects showed VIN. Whereas HSN was found in 70 (63 %) patients and 9 (30 %) in normal subjects. Among 112 patients, 10 showed a canal paresis (CP) value of caloric testing less than 25 %, while 32 with a CP value between 25 and 40 %, 48 with a CP value between 40 and 70 %, and 22 with a CP value no less than 70 %. It is notable that with increasing CP value on caloric testing, VIN was more likely to be elicited. So VIN test is a simple, non-invasive and well-tolerated clinical test that indicates unilateral peripheral vestibular dysfunction. VIN test had greater sensitivity and specificity than HSN test in the diagnosis of unilateral peripheral vestibular disorders.

Expression of Autoantibodies in Patients with Sudden Sensorineural Hearing Loss

Objectives:

The aim of this study was to establish the expression rate of autoimmunity in patients with sudden sensorineural hearing loss and to determine whether a positive marker is associated with a higher rate of hearing recovery after steroid treatment.

Methods:

A prospective study was performed on 137 patients who experienced sudden sensorineural hearing loss and underwent immunoserologic investigations. Autoantibodies evaluated on the day of admission included anti-double-stranded DNA, rheumatoid factor, antiphospholipid immunoglobulins G and M, antinuclear antibody, and complements C3 and C4.

Results:

Of 137 patients, 75 were male and 62 were female (mean age, 45.1 years). Hearing loss was found on the left side in 61 patients and on the right side in 76 patients. Elevation of at least 1 autoantibody or abnormal complement levels were found in 80 patients (58%), and abnormalities of 2 or more antibodies were found in 28 (20%). There were no statistically significant correlations between autoantibody abnormalities and age, initial hearing level, or positive treatment response.

Conclusions:

There is no clear evidence of a correlation between autoimmunity and hearing improvement in patients with autoantibody abnormalities. A high (but not significant) expression rate of autoantibody abnormality and complement level was seen in patients with sudden sensorineural hearing loss.

The role of allergy in the etiopathogenesis of idiopathic sudden sensorineural hearing loss

To evaluate the role of allergy in the etiopathogenesis of sudden hearing loss using cytokine profile, allergic parameters, and lymphocyte subgroups, a total of 31 patients aged between 30 and 62 years (mean age: 42.48 ± 15.86 years) with the diagnosis of sudden hearing loss were enrolled in the study between 2008 and 2011. The control group comprised 30 age-matched adult subjects accepted as clinically healthy individuals living in the same region with comparable socioeconomic parameters. The patient and the control group were questioned for history of allergy. Lymphocyte subgroups in the peripheral blood were evaluated using Becton-Dickinson monoclonal CD4, CD8, CD19, and CD23 antibodies. In the patient and control groups, the levels of IFN- γ, IL4, IL10, and total IgE were measured and compared between the groups. Skin test was used for detection of inhaler allergens in the patient and the control groups, and specific IgE tests were performed using the RAST method for food allergens. The Spearman's rho correlation, the unpaired t test, the Mann-Whitney U test, and the Shapiro-Wilk test were used to determine the differences between the groups. The limit for statistical significance was p < 0.05. When the patient and the control group were compared, the differences between CD4, CD23, IL4, IL10, and IgE were statistically significant. On analyses of the patients' serum samples, strongly positive correlations were determined between IgE and CD23, IL10, IL4; IL4 and IL10, CD23, CD4; IL10 and CD23, CD4 (Spearman rho, p = 0.000), while a weakly positive correlation was found between IgE and CD4 (Spearman rho, p = 0.020). A correlation between IFN-γ and CD4 was weakly negative (Spearman rho, p = 0.040). The total IgE levels were estimated to be above the normal reference ranges (0-100 IU/ml) in 25.8 % of the cases in the patient group. History of allergy was found in 61.9 % of the patients. The results of this study substantiate the role of allergy in the etiopathogenesis of sudden hearing loss. We think that during the diagnostic work-up of these patients allergy should be interrogated seriously, necessary tests should be performed, and allergy should be considered in the decision-making process of the treatment of sudden hearing loss.

Vascular Pathophysiology in Hearing Disorders

The inner ear vasculature is responsible for maintenance of the blood-labyrinth barrier, transport of systemic hormones for ion homeostasis, and supplying nutrients for metabolic functions. Unfortunately, these blood vessels also expose the ear to circulating inflammatory factors resulting from systemic diseases. Thus, while the inner ear blood vessels are critical for normal function, they also are facilitating pathologic mechanisms that result in hearing and vestibular dysfunction. In spite of these numerous critical roles of inner ear vasculature, little is known of its normal homeostatic functions and how these are compromised in disease. The objective of this review is to discuss the current concepts of vascular biology, how blood vessels naturally respond to circulating inflammatory factors, and how such mechanisms of vascular pathophysiology may cause hearing loss.

IL-1β is overexpressed and aberrantly regulated in corticosteroid nonresponders with autoimmune inner ear disease

Autoimmune inner ear disease is an enigmatic disorder characterized by recurring episodes of sudden or progressive sensorineural hearing loss. Hearing loss can be improved by timely corticosteroid administration, but only half of those treated respond, and for many responders, that response is lost over time. The mechanisms that control corticosteroid responsiveness in this disorder are largely uncharacterized. We have previously identified that the induction by dexamethasone of IL-1R type II (IL-1R2) expression in PBMC predicts corticosteroid responsiveness in this disorder. In this study, we asked whether IL-1β was overexpressed, and whether clinical corticosteroid responders differentially regulated IL-1β expression or release in response to dexamethasone, as compared with nonresponders. IL-1β has been reported to induce matrix metalloproteinase-9 (MMP-9) expression. Given that metalloproteinases can cleave IL-1R2, we also asked whether MMP-9 expression was altered in this disorder. In this study, we demonstrate that corticosteroid nonresponders have elevated plasma levels of IL-1β and MMP-9 as compared with clinically responsive patients (p = 0.0008 and p = 0.037, respectively). Increasing MMP-9 expression correlated with increasing IL-1β concentration, suggesting that IL-1β expression regulates MMP-9 expression. As expected, monocytes were the predominant producers of IL-1β. In vitro exposure of PBMC to dexamethasone from clinical corticosteroid responders suppressed IL-1β release. PBMC of corticosteroid nonresponders have substantially higher release of IL-1β into the conditioned media, and when exposed to dexamethasone, failed to repress IL-1β release (p = 0.05). Treatment of PBMC from clinical corticosteroid nonresponders with anakinra resulted in repression of IL-1β release, suggesting that IL-1β blockade may be a viable therapy for these patients.

Hyperbaric oxygen therapy as salvage treatment for sudden sensorineural hearing loss: review of rationale and preliminary report

Background:

The management of sudden sensorineural hearing loss has not yet been standardised. Hyperbaric oxygen therapy influences recovery from sudden sensorineural hearing loss, but the underlying mechanism is unknown and the appropriate indications and protocols undetermined.

Materials and methods:

Nineteen patients affected by sudden sensorineural hearing loss were treated after unsuccessful medical therapy, either in an acute or chronic setting. Pure oxygen inhalation at 2.5 atmospheres absolute pressure was administered for 90 minutes, for 30 sessions. Frequency-specific and average pure tone hearing thresholds were determined before and after hyperbaric oxygen therapy. The number of hyperbaric oxygen therapy sessions, the patient's age and any therapeutic delay were considered as quantitative variables possibly influencing outcome. Stepwise multivariate analysis was performed.

Results:

Salvage hyperbaric oxygen therapy appeared to improve patients' pure tone hearing thresholds, particularly at low frequencies. Positive results were more likely with increased patient age and reduced delay in receiving hyperbaric oxygen therapy.

Conclusion:

Hyperbaric oxygen therapy has a strong scientific rationale, and improves pure tone hearing thresholds in cases of sudden sensorineural hearing loss unresponsive to medical therapy. Further research may be able to identify those patients with sudden sensorineural hearing loss for whom hyperbaric oxygen therapy would be most cost-effective.

Alternate splicing of interleukin-1 receptor type II (IL1R2) in vitro correlates with clinical glucocorticoid responsiveness in patients with AIED

Autoimmune Inner Ear Disease (AIED) is poorly characterized clinically, with no definitive laboratory test. All patients suspected of having AIED are given glucocorticoids during periods of acute hearing loss, however, only half initially respond, and still fewer respond over time.

We hypothesized that AIED is a systemic autoimmune disease characterized by dysfunctional peripheral blood mononuclear cells (PBMC) responses to a unique cochlear antigen(s). To test this hypothesis, we examined end-stage AIED patients undergoing cochlear implant surgery and compared autologous perilymph stimulated PBMC from AIED patients to controls. We determined that autologous perilymph from AIED patients was unable to induce expression of a long membrane-bound Interleukin-1 Receptor Type II (mIL1R2) transcript in PBMC as compared with controls, despite similar expression of the short soluble IL1R2 (sIL1R2) transcript (p<0.05). IL1R2 is a molecular decoy that traps interleukin-1β (IL-1β) and does not initiate subsequent signaling events, thereby suppressing an inflammatory response. IL1R2 transcript length is regulated by alternate splicing, and the major inhibitory function is attributed to the full-length mIL1R2. In addition, IL1R2 expression is induced by dexamethasone.

Separately, we prospectively examined patients with newer onset glucocorticoid-responsive AIED. Immediately prior to clinical treatment for acute deterioration of hearing thresholds, their PBMC demonstrated a robust induction of mIL1R2 in PBMC in response to dexamethasone in vitro that correlated with a clinical response to prednisone in vivo (p<0.0001) as measured by hearing restoration. In contrast, clinically steroid unresponsive patients demonstrated high basal levels of mIL1R2 in their PBMC and only minimally augmented expression in response to dexamethasone. Thus, induced expression of mIL1R2 appears to be a protective mechanism in hearing homeostasis and warrants further investigation in a large prospective clinical trial to determine if IL1R2 can be used as a specific biomarker for AIED.

Acoustic trauma augments the cochlear immune response to antigen

OBJECTIVES/HYPOTHESIS

To test whether noise-exposure, which activates a cochlear immune response with cytokine expression and infiltration of circulating leukocytes could augment the response to antigen (Ag).

STUDY DESIGN

Randomized, prospective, mice.

METHODS

We sensitized mice to an Ag, injected it intrathecally, and subsequently exposed the mice to noise (8-16 kHz, 90, 100, or 118 dB for 2 hours). Control mice received either noise exposure alone (100 or 118 dB), Ag challenge alone, intrathecal surgery and phosphate-buffered saline injection or no treatment. Four hours or 7 days later the mice were killed and cochlear sections were evaluated immunohistochemically for CD45, ICAM-1, and phospho-nuclear transcription factor-kappaB expression.

RESULTS

Intrathecal Ag injection caused no hearing loss, but did result in a small immune response. Loud noise (118 dB) caused severe hearing loss and slight inflammation. The number of CD45-positive cells was significantly greater in the Ag plus-118 dB noise group relative to the Ag-alone group or 118 dB noise-exposure group. ICAM expression was seen in the lower part of the spiral ligament and small vessels within the normal cochlea. The amount of expression increased after Ag injection and acoustic trauma. Activated nuclear transcription factor-kappaB occurred in the nuclei of hair cells, supporting cells, spiral ligament fibrocytes, and neurons 4 hours after noise exposure.

CONCLUSIONS

It seems that noise exposure can activate a cochlear immune response, which in the presence of Ag, allows for greater recruitment of inflammatory cells than occurred in response to Ag alone.

Prevalence and clinical significance of anticardiolipin, anti-beta2-glycoprotein-1, and anti-heat shock protein-70 autoantibodies in sudden sensorineural hearing loss

Sudden sensorineural hearing loss (SSNHL) is frequently classified as 'idiopathic' since the causative factor responsible for its onset is not identified in most cases. In the present study, we determined whether SSNHL is clinically associated with serum anti-heat shock protein-70 (anti-HSP70) and antiphospholipids (anti-PLs) autoantibodies and whether these autoantibodies have an impact on the prognosis of SSNHL. Sera from 63 patients with SSNHL were screened prospectively for the presence of anti-HSP70 and anti-PLs autoantibodies by an enzyme-linked immunosorbent assay test. Anti-PLs antibodies in this study consisted of anticardiolipin, and anti-beta(2)-glycoprotein-1 antibodies. Serum was assayed for anti-HSP70 IgG antibodies using recombinant human HSP70. Demographic, clinical, and audiometric variables were analyzed to find the possible role of serum autoantibodies in SSNHL patients. Sixteen patients (25.4%) had demonstrable anti-HSP70 antibodies in serum. Twenty-one patients (33.3%) showed a positive result for at least one isotype (IgM or IgG) of anti-PLs. In 19% of the patients, anti-HSP70 and anti-PLs antibodies were positive in two combinations. A statistically significant association was found between anti-HSP70 antibodies and the Siegel recovery grade subgroup. SSNHL patients who were positive for anti-HSP70 antibodies showed a significantly higher rate of complete recovery and incomplete but partial recovery than SSNHL patients without anti-HSP70 antibodies (p = 0.0496). Statistically significant association was found between total anticardiolipin, total anti-beta(2)-glycoprotein-1, total anti-PLs, and anti-PLs in combination with anti-HSP70 antibodies and age (p = 0.0229). The detection of autoantibodies to HSP70 and PLs offers a pliable explanation for the immune-mediated mechanism of SSNHL. The present study confirms and supports previous studies regarding the association between anti-HSP70 and anti-PLs antibodies with SSNHL, and is the first to identify a positive association between anti-HSP70 antibodies and a positive outcome of SSNHL. Further studies are necessary in order to identify and further clarify the immunologic role of the presence of autoantibodies and their impact on the prognosis of SSNHL.

Diagnostic tests for immunomediated hearing loss: a systematic review

OBJECTIVE

To quantitatively evaluate the diagnostic accuracy of diagnostic tests for immunomediated hearing loss.

DATA SOURCES

We searched Medline and the Cochrane Database of Systematic Reviews for potentially relevant studies.

STUDY SELECTION

Twenty-five studies met the inclusion criteria of this systematic review. The diagnosis of immunomediated hearing loss was based on the clinical presentation and the response to corticosteroid administration.

DATA EXTRACTION

The following data were extracted from the selected studies and entered into a standardised database: population demographics; exclusion and inclusion criteria; diagnostic tests; sensitivity; specificity; the number of true positive, true negative, false positive and false negative values; therapy used, including dose and duration; and delay between symptom onset and therapy commencement.

DATA SYNTHESIS

This systematic review combined data from 679 patients with immunomediated hearing loss, reported by 22 research teams. Substantial heterogeneity was found among the included studies; for this reason, summary sensitivity and specificity values were not computed.

CONCLUSIONS

The results of diagnostic tests for immunomediated hearing loss depend on many factors, and there is a risk of potential bias. This is the first time that such a systematic review has been presented; such a review is a more rigorous method of demonstrating the utility of the available diagnostic tests.

Coeliac disease and hearing loss: preliminary data on a new possible association

OBJECTIVE

Coeliac disease (CD), an autoimmune gluten-dependent enteropathy, can be associated with several extra-intestinal manifestations, including neurological disorders. At present, no data are available on the presence of hearing loss disorder in coeliac patients. The aim of the present study was to investigate the prevalence of hearing loss in coeliac patients compared with that in healthy controls.

MATERIAL AND METHODS

Twenty-four adult coeliac patients and 24 healthy subjects matched for gender, age, smoking and drinking habits were enrolled in the study. Among the coeliac patients, 6 were newly diagnosed and 18 patients were on a gluten-free diet for at least one year.

RESULTS

A hearing loss was found in 10 (47.1%) coeliac patients and 2 (9.1%) healthy controls. All CD patients with hearing loss presented a sensorineural hearing loss. The prevalence of hearing loss was significantly higher in coeliac patients than in healthy controls (p = 0.01) but it was not significantly different between untreated (33.3%) and treated (44.4%) coeliac patients (p: NS).

CONCLUSIONS

Despite the low number of subjects evaluated, the present study showed a higher prevalence of hearing loss in coeliac patients than in healthy controls, suggesting an association between CD and hearing loss. Immunological processes such as ear-specific and non-specific autoantibodies and vasculitis could be the basis of this association. Further longitudinal investigations on a larger sample size will be necessary to confirm the present data.

The inner ear and the neurologist

Inner ear disorders are common and patients with vestibular failure often present to a neurology clinic because of their dizziness, gait unsteadiness and oscillopsia. Vestibular disorders can be divided into peripheral and central vestibular disorders. Most of the peripheral vestibular disorders have a clinical diagnosis, and a thorough history and examination will often provide a clear direction as to the diagnosis. Correct diagnosis allows treatment for many of the peripheral and central vestibular disorders. As inner ear damage is generally irreversible, early diagnosis allowing prompt treatment is important. The aim of this review is to discuss some audiovestibular conditions that may well appear in a neurology clinic, and to discuss some recent advances within the audiovestibular field that may be of interest to neurologists. Some of the most common audiovestibular conditions will be discussed along side more uncommon conditions.