Oral steroid treatment for hearing improvement in Ménière's disease and endolymphatic hydrops

Meniere's disease: Pathogenesis, treatments, and emerging approaches for an idiopathic bioenvironmental disorder

Meniere's disease (MD) is a severe inner ear condition known by debilitating symptoms, including spontaneous vertigo, fluctuating and progressive hearing loss, tinnitus, and aural fullness or pressure within the affected ear. Prosper Meniere first described the origins of MD in the 1860s, but its underlying mechanisms remain largely elusive today. Nevertheless, researchers have identified a key histopathological feature called Endolymphatic Hydrops (ELH), which refers to the excessive buildup of endolymph fluid in the membranous labyrinth of the inner ear. The exact root of ELH is not fully understood. Still, it is believed to involve several biological and bioenvironmental etiological factors such as genetics, autoimmunity, infection, trauma, allergy, and new theories, such as saccular otoconia blocking the endolymphatic duct and sac. Regarding treatment, there are no reliable and definitive cures for MD. Most therapies focus on managing symptoms and improving the overall quality of patients' life. To make significant advancements in addressing MD, it is crucial to gain a fundamental understanding of the disease process, laying the groundwork for more effective therapeutic approaches. This paper provides a comprehensive review of the pathophysiology of MD with a focus on old and recent theories. Current treatment strategies and future translational approaches (with low-level evidence but promising results) related to MD are also discussed, including patents, drug delivery, and nanotechnology, that may provide future benefits to patients suffering from MD.

Systemic Steroids for Otolaryngology-Head and Neck Surgery Disorders: An Evidence-Based Primer for Clinicians

OBJECTIVE

To offer pragmatic, evidence-informed guidance on the use of systemic corticosteroids (SCS) for common otolaryngologic disorders.

DATA SOURCES

PubMed, Cochrane Library, and American Academy of Otolaryngology-Head and Neck Surgery Foundation clinical practice guidelines.

REVIEW METHODS

A comprehensive search of published literature through November 2021 was conducted on the efficacy of SCS, alone or in combination with other treatments, for managing disorders in otolaryngology and the subdisciplines. Clinical practice guidelines, systematic reviews, and randomized controlled trials, when available, were preferentially retrieved. Interventions and outcomes of SCS use were compiled to generate summary tables and narrative synthesis of findings.

CONCLUSIONS

Evidence on the effectiveness of SCS varies widely across otolaryngology disorders. High-level evidence supports SCS use for Bell's palsy, sinonasal polyposis, and lower airway disease. Conversely, evidence is weak or absent for upper respiratory tract infection, eustachian tube dysfunction, benign paroxysmal positional vertigo, adenotonsillar hypertrophy, or nonallergic rhinitis. Evidence is indeterminate for acute laryngitis, acute pharyngitis, acute sinusitis, angioedema, chronic rhinosinusitis without polyps, Ménière's disease, postviral olfactory loss, postoperative nerve paresis/paralysis, facial pain, and sudden sensorineural hearing loss.

IMPLICATIONS FOR PRACTICE

Clinicians should bring an evidence-informed lens to SCS prescribing to best counsel patients regarding the risks, anticipated benefits, and limited data on long-term effects. Alternate routes of corticosteroid administration-such as sprays, drops, inhalers, and intralesional injections-may be preferable for many disorders, particularly those that are self-limited or require a prolonged duration of therapy. Prudent use of SCS reduces the risk of medication-related adverse effects. Clinicians who are conversant with high-level evidence can achieve optimal outcomes and stewardship when prescribing SCS.

In Silico Localization of Perilymph Proteins Enriched in Meńier̀e Disease Using Mammalian Cochlear Single-cell Transcriptomics

Hypothesis

Proteins enriched in the perilymph proteome of Meńier̀e disease (MD) patients may identify affected cell types. Utilizing single-cell transcriptome datasets from the mammalian cochlea, we hypothesize that these enriched perilymph proteins can be localized to specific cochlear cell types.

Background

The limited understanding of human inner ear pathologies and their associated biomolecular variations hinder efforts to develop disease-specific diagnostics and therapeutics. Perilymph sampling and analysis is now enabling further characterization of the cochlear microenvironment. Recently, enriched inner ear protein expression has been demonstrated in patients with MD compared to patients with other inner ear diseases. Localizing expression of these proteins to cochlear cell types can further our knowledge of potential disease pathways and subsequent development of targeted therapeutics.

Methods

We compiled previously published data regarding differential perilymph proteome profiles amongst patients with MD, otosclerosis, enlarged vestibular aqueduct, sudden hearing loss, and hearing loss of undefined etiology (controls). Enriched proteins in MD were cross-referenced against published single-cell/single-nucleus RNA-sequencing datasets to localize gene expression to specific cochlear cell types.

Results

In silico analysis of single-cell transcriptomic datasets demonstrates enrichment of a unique group of perilymph proteins associated with MD in a variety of intracochlear cells, and some exogeneous hematologic and immune effector cells. This suggests that these cell types may play an important role in the pathology associated with late MD, suggesting potential future areas of investigation for MD pathophysiology and treatment.

Conclusions

Perilymph proteins enriched in MD are expressed by specific cochlear cell types based on in silico localization, potentially facilitating development of disease-specific diagnostic markers and therapeutics.

The role of the stria vascularis in neglected otologic disease

The stria vascularis (SV) has been shown to play a critical role in the pathogenesis of many diseases associated with sensorineural hearing loss (SNHL), including age-related hearing loss (ARHL), noise-induced hearing loss (NIHL), hereditary hearing loss (HHL), and drug-induced hearing loss (DIHL), among others. There are a number of other disorders of hearing loss that may be relatively neglected due to being underrecognized, poorly understood, lacking robust diagnostic criteria or effective treatments. A few examples of these diseases include autoimmune inner ear disease (AIED) and/or autoinflammatory inner ear disease (AID), Meniere's disease (MD), sudden sensorineural hearing loss (SSNHL), and cytomegalovirus (CMV)-related hearing loss (CRHL). Although these diseases may often differ in etiology, there have been recent studies that support the involvement of the SV in the pathogenesis of many of these disorders. We strive to highlight a few prominent examples of these frequently neglected otologic diseases and illustrate the relevance of understanding SV composition, structure and function with regards to these disease processes. In this study, we review the physiology of the SV, lay out the importance of these neglected otologic diseases, highlight the current literature regarding the role of the SV in these disorders, and discuss the current strategies, both approved and investigational, for management of these disorders.

The Pharmacological Treatment of Pediatric Vertigo

Vertigo in children is a challenging topic. The lack of dedicated trials, guidelines and papers causes inhomogeneity in the treatment of vertigo in children. Meniere’s disease, migraine equivalents, vestibular neuritis, paroxysmal positional benign vertigo (BPPV), persistent postural-perceptual dizziness (PPPD) and motion sickness may affect children with various degrees of incidence and clinical severity compared to adults. Several drugs are proposed for the management of these conditions, even if their use is subordinated to the child’s age. In this review, we summarize the existing evidence related to the use of drugs for this clinical condition in children as a start point for new trials, stating the urgent need for international guidelines.

Pharmacotherapy of cerebellar and vestibular disorders

PURPOSE OF REVIEW

Major therapeutic advances have been made in patients with episodic and progressive cerebellar ataxias, downbeat nystagmus and some vestibular disorders. We provide an update review on this subject highlighting important research findings from the last two years.

RECENT FINDINGS

Recently, the use of omaveloxolone for 2 years significantly improved upright stability in Friedreich's ataxia patients. In an open-label study, N-acetyl-l-leucine administered for 6-weeks significantly improved clinical impression of change, ataxia, and quality of life in patients with Niemann-Pick disease type C1. A 12-week treatment with dalfampridine was associated with improved standing balance in a subgroup of patients with multiple sclerosis. A gluten-free diet alone improved ataxia in half of patients with antiglutamic acid decarboxylase (GAD) ataxia, suggesting that gluten sensitivity might be part of the underlying pathogenesis in anti-GAD ataxia. In a head-to-head trial, both prolonged-release 4-aminopyridine (4-AP) and acetazolamide effectively reduced the attacks up to 60% in patients with episodic ataxia type 2 (EA2), albeit 4-AP had fewer adverse effects. Small observational studies have shown that patients with episodic vestibular syndrome who cannot be diagnosed as definite or probable vestibular migraine, might still improve vestibular symptoms following preventive treatment for migraine. The use of vitamin D supplementation in benign paroxysmal positional vertigo, steroids in acute unilateral vestibulopathy, and betahistine in Ménière's disease patients remains controversial.

SUMMARY

Although the use of several therapies is being established in the treatment of cerebellar and vestibular disorders, there is an urgent need for prospective controlled therapeutic trials.

Drug-Drug Interactions in Vestibular Diseases, Clinical Problems, and Medico-Legal Implications

Peripheral vestibular disease can be treated with several approaches (e.g., maneuvers, surgery, or medical approach). Comorbidity is common in elderly patients, so polytherapy is used, but it can generate the development of drug-drug interactions (DDIs) that play a role in both adverse drug reactions and reduced adherence. For this reason, they need a complex kind of approach, considering all their individual characteristics. Physicians must be able to prescribe and deprescribe drugs based on a solid knowledge of pharmacokinetics, pharmacodynamics, and clinical indications. Moreover, full information is required to reach a real therapeutic alliance, to improve the safety of care and reduce possible malpractice claims related to drug-drug interactions. In this review, using PubMed, Embase, and Cochrane library, we searched articles published until 30 August 2021, and described both pharmacokinetic and pharmacodynamic DDIs in patients with vestibular disorders, focusing the interest on their clinical implications and on risk management strategies.

Current Insights into Treating Vertigo in Older Adults

The number of older people has been increasing over recent decades in Western populations. Dizziness, imbalance, and vertigo constitute some of the most common complaints in older patients, and risk of falling is the most frequent and worrying consequence. It has been reported that 15–20% of the adult population experiences these debilitating symptoms. Among the diseases that may be associated with vertigo, the three classes of otological, central, and functional (psychological) dizziness may be distinguished. Overall, vestibular disorders account for 48% of vertiginous complaints in the older population. The main focus of this article is to review the forms of pharmacotherapy for vertigo, especially with regard to older patients, who may be treated simultaneously with other drugs for different comorbidities. Interactions with other drugs should be considered in the choice of a particular course of treatment. Moreover, overuse of pharmacotherapy for the management of vertigo in the elderly may prevent the development of the central compensatory mechanism that sustains both static and dynamic imbalance after a vertiginous crisis. In the majority of patients, vestibular and physical rehabilitation are strongly advised and rarely contraindicated.

On the Relationship Between Menière's Disease and Endolymphatic Hydrops

: The relationship between Menière's disease and endolymphatic hydrops is ambiguous. On the one hand, the existence of cases of endolymphatic hydrops lacking the classic symptoms of Menière's disease has prompted the assertion that endolymphatic hydrops alone is insufficient to cause symptoms and drives the hypothesis that endolymphatic hydrops is a mere epiphenomenon. Yet, on the other hand, there is considerable evidence suggesting a relationship between the mechanical pressure effects of endolymphatic hydrops and resultant disordered auditory physiology and symptomatology. A critical appraisal of this topic is undertaken, including a review of key histopathologic data chiefly responsible for the epiphenomenon hypothesis. Overall, a case is made that A) the preponderance of available evidence suggests endolymphatic hydrops is likely responsible for some of the auditory symptoms of Menière's disease, particularly those that can be modulated by mechanical manipulation of the basilar membrane and cochlear microphonic; B) Menière's disease can be reasonably considered part of a larger spectrum of hydropic inner ear disease that also includes some cases that lack vertigo. C) The relationship with endolymphatic hydrops sufficiently robust to consider its presence a hallmark defining feature of Menière's disease and a sensible target for diagnostic detection.

Effects of Glucocorticoids on the Inner Ear

Hypothesis: Recently, several lines of evidence have suggested that the inner ear is under hormonal control. It is likely that steroids have some influence on the inner ear. Background: Many clinicians have been empirically using steroids for the treatment of diseases associated with endolymphatic hydrops. The theoretical grounds for this are not clear, and there have been a number of debates on the effectiveness of steroid treatment. Furthermore, there are few reports on histological observations of the influences of steroids on the cochlea. Method: Fifteen guinea pigs (30 ears) were divided into three groups. In the control group, physiological saline solution was administered intra-peritoneally for 3 days. In two steroid groups, 40 mg/kg/day of hydrocortisone or 4 mg/kg/day of dexamethasone was administered intra-peritoneally for 3 days. Extension of Reissner's membrane and volume change of the scala media were checked 6 h after the last administration. The degree of Reissner's membrane extension and volumetric change of the scala media were quantitatively measured with the use of a video-digitizer. Results: We did not identify any distinct changes in the cochlea of the control group. In contrast, the extension of Reissner's membrane and endolymphatic hydrops were observed in the animals in the steroid groups. Statistical analysis revealed that Reissner's membrane extended significantly in the steroid groups, and that the volume of the scala media also increased significantly. Conclusion: This is the first report to investigate the effects of systemic administration of glucocorticoids on guineapig cochlea. The extension of Reissner's membrane and dilated endolymphatic space were evident in the steroid groups. However, the underlying mechanism of histological changes was not clear, marked care needs to be taken when administering steroids to patients with Meniere's disease whose histological feature is endolymphatic hydrops.

Clinical Practice Guideline: Ménière's Disease

OBJECTIVE

Ménière's disease (MD) is a clinical condition defined by spontaneous vertigo attacks (each lasting 20 minutes to 12 hours) with documented low- to midfrequency sensorineural hearing loss in the affected ear before, during, or after one of the episodes of vertigo. It also presents with fluctuating aural symptoms (hearing loss, tinnitus, or ear fullness) in the affected ear. The underlying etiology of MD is not completely clear, yet it has been associated with inner ear fluid (endolymph) volume increases, culminating in episodic ear symptoms (vertigo, fluctuating hearing loss, tinnitus, and aural fullness). Physical examination findings are often unremarkable, and audiometric testing may or may not show low- to midfrequency sensorineural hearing loss. Conventional imaging, if performed, is also typically normal. The goals of MD treatment are to prevent or reduce vertigo severity and frequency; relieve or prevent hearing loss, tinnitus, and aural fullness; and improve quality of life. Treatment approaches to MD are many and typically include modifications of lifestyle factors (eg, diet) and medical, surgical, or a combination of therapies.

PURPOSE

The primary purpose of this clinical practice guideline is to improve the quality of the diagnostic workup and treatment outcomes of MD. To achieve this purpose, the goals of this guideline are to use the best available published scientific and/or clinical evidence to enhance diagnostic accuracy and appropriate therapeutic interventions (medical and surgical) while reducing unindicated diagnostic testing and/or imaging.

Fluctuating Sensorineural Hearing Loss

BACKGROUND

Several otologic conditions can present with fluctuating sensorineural hearing loss, including Ménière's disease, autoimmune inner ear disease, and enlarged vestibular aqueduct. Although these 3 etiologies vary greatly, distinguishing between these conditions at initial presentation can be challenging. Furthermore, initial treatment of these conditions is often similar. In this review, we discuss historical and current perspectives on diagnosis and treatment of these conditions.

SUMMARY

A literature search was performed regarding fluctuating hearing loss, and current treatment of these etiologies of fluctuating hearing loss was summarized. Immediate measures at the onset of acute hearing loss include corticosteroid therapy, while preventative and chronic therapies, which can limit disease severity and frequency, vary based on the specific condition treated. Key Messages: Fluctuating hearing loss can represent a range of pathologies, but the precise etiology may not be clear at initial presentation. Timely treatment and long-term follow-up, along with appropriate diagnostics, are necessary to optimize long-term hearing.

Novel Use of Portable Audiometry to Track Hearing Fluctuations in Menière's Disease: A Pilot Study

INTRODUCTION

Menière's Disease (MD) is a disorder of the inner ear consisting of episodic attacks of vertigo associated with aural fullness, tinnitus, and fluctuating hearing loss. Hearing levels in MD can often fluctuate over time, and may eventually decline permanently in a step-wise fashion. There are no current studies examining daily hearing fluctuations for prolonged periods in patients with MD. Portable audiometry has the potential to allow the patient to monitor their hearing on a daily basis without attending a center for formal audiology. The objective of this pilot study was to assess feasibility of using iPad-based audiometry on a daily basis to capture hearing fluctuations in a small sample of adult patients with active MD.

METHODS

We recruited five patients with active MD as defined by current diagnostic criteria (International Classification of Vestibular Disease 2015). "Active" MD was defined as the patient having had at least one typical Menière's episode within the last 4 weeks. Patients were trained on how to use the portable audiometer and asked to perform at least daily audiograms for 3 months. Patients were asked to manually track vertigo attacks in a diary. Qualitative feedback was obtained from each patient at each monthly visit. For each patient, individual pure tone thresholds at each frequency and pure-tone averages (PTA) were analyzed for maximum and minimum values and interquartile ranges.

RESULTS

There were four women and one man, with an average age of 49.8 years. Duration of MD ranged from 4 months to 5 years. None of the patients experienced any technical difficulties performing the testing at home. The average duration of each test was 4.2 minutes, with the longest test taking 19.2 minutes. Patients completed between 45 and 102 tests, with an average of 72. The interquartile range for the PTA ranged from 2.5 to 25 dB for affected ears, and 0 to 6.25 dB for unaffected ears with maximums ranging from 5 to 35 dB in affected ears, and 0 to 10 dB in unaffected ears.

CONCLUSIONS

Daily portable audiometry is feasible in patients with MD. Future studies are planned to further analyze hearing fluctuations in MD with respect to frequencies affected, relationship to vertigo attacks, and response to treatments. Understanding hearing fluctuations in MD may aid refinement of diagnostic criteria and improve prognostication for long-term hearing loss, with a goal of informing treatments that might improve final hearing outcome.

Menière's disease: combined pharmacotherapy with betahistine and the MAO-B inhibitor selegiline-an observational study

OBJECTIVES

Since oral betahistine has a very high first-pass effect (ca. 99%), metabolized by monoamine oxidases (MAO), the benefits of a high-dosage betahistine monotherapy were compared with those of a lower dosage of betahistine in combination with the MAO-B inhibitor (MAO-B) selegiline on the frequency of acute attacks of vertigo in patients with Menière's disease (MD).

METHODS

Thirteen adults aged 40-75 years (mean 58.9 years; six females) had initially been treated with a high dosage of betahistine dihydrochloride for at least 1 year. Under this therapy, all of them had ≤ 1 attack for ≥ 3 months prior to the combination pharmacotherapy. Subsequently, they received 5 mg/day selegiline and the dosage of betahistine was reduced to about one tenth and then individually adjusted to the dosage needed to achieve the same treatment response (≤ 1 per 3 months, observational period of at least 6 months).

RESULTS

The initial dosage for the long-term "titration" of the attacks of vertigo was 9-80 24-mg tablets/day (mean 37.3), i.e. 216-1920 mg/day (mean 895.4 mg/day). After the combination with selegiline, the dosage needed to achieve the same benefit for ≥ 3 months was 3-36 24-mg tablets (mean 8.5), i.e., 72-864 mg/day [mean 204.9 mg/day, p < 0.001 (paired t test)]. One patient transiently stopped the treatment with selegiline, another one reduced the dosage to 2.5 mg/day and the attacks re-occurred after 2-4 weeks. Six out of 13 patients reported transient fullness of the head during the combined treatment; in 2 of them this went away when they switched to 2.5 mg bid. In the longer term (> 9 months), one patient had to increase the selegiline dosage to 5 mg bd, one patient stopped the treatment with selegiline.

CONCLUSIONS

The achievement of the same clinical effect with a significantly lower (about 1/5) dosage of betahistine can be explained by the inhibition of the MAO-B by selegiline leading to higher serum concentrations of betahistine. This approach is in line with recent developments to bypass the first-pass effect of betahistine by transbuccal or intranasal application. Despite the substantial methodological limitations of such an observational study, this combined pharmacotherapy could be an alternative to a high-dosage monotherapy with betahistine of MD.

Hearing function after betahistine therapy in patients with Ménière's disease

Introduction

Objective

Methods

Results

Conclusion

Efficacy and safety of betahistine treatment in patients with Meniere's disease: primary results of a long term, multicentre, double blind, randomised, placebo controlled, dose defining trial (BEMED trial)

STUDY QUESTION

What is the long term efficacy of betahistine dihydrochloride on the incidence of vertigo attacks in patients with Meniere's disease, compared with placebo?

METHODS

The BEMED trial is a multicentre, double blind, randomised, placebo controlled, three arm, parallel group, phase III, dose defining superiority trial conducted in 14 German tertiary referral centres (for neurology or ear, nose, and throat). Adults aged 21-80 years (mean age 56 years) with definite unilateral or bilateral Meniere's disease were recruited from March 2008 to November 2012. Participants received placebo (n=74), low dose betahistine (2 × 24 mg daily, (n=73)), or high dose betahistine (3 × 48 mg daily, (n=74)) over nine months. The primary outcome was the number of attacks per 30 days, based on patients' diaries during a three month assessment period at months seven to nine. An internet based randomisation schedule performed a concealed 1:1:1 allocation, stratified by study site. Secondary outcomes included the duration and severity of attacks, change in quality of life scores, and several observer-reported parameters to assess changes in audiological and vestibular function.

STUDY ANSWER AND LIMITATIONS

Incidence of attacks related to Meniere's disease did not differ between the three treatment groups (P=0.759). Compared with placebo, attack rate ratios were 1.036 (95% confidence interval 0.942 to 1.140) and 1.012 (0.919 to 1.114) for low dose and high dose betahistine, respectively. The overall monthly attack rate fell significantly by the factor 0.758 (0.705 to 0.816; P<0.001). The population based, mean monthly incidence averaged over the assessment period was 2.722 (1.304 to 6.309), 3.204 (1.345 to 7.929), and 3.258 (1.685 to 7.266) for the placebo, low dose betahistine, and high dose betahistine groups, respectively. Results were consistent for all secondary outcomes. Treatment was well tolerated with no unexpected safety findings. Without a control group of patients who did not receive any intervention to follow the natural course of the disease, the placebo effect could not be accurately assessed and differentiated from spontaneous remission and fluctuation of symptoms.

WHAT THIS STUDY ADDS

Current evidence is limited as to whether betahistine prevents vertigo attacks caused by Meniere's disease, compared with placebo. The trial provides information on symptom relief on placebo intervention which is relevant for the design of future studies on potential disease modifying treatments in patients with Meniere's disease.

FUNDING, COMPETING INTERESTS, DATA SHARING

Support from the German Federal Ministry of Education and Research (BMBF support code 01KG0708). Potential competing interests have been reported in full at the end of the paper on thebmj.com. Data are available from the corresponding author (Michael.Strupp@med.uni-muenchen.de) or biostatistician (mansmann@ibe.med.uni-muenchen.de). Study registration EudraCT no 2005-000752-32; ISRCTN no ISRCTN44359668.

Menière's disease

Menière's disease (MD) is a chronic multifactorial disorder of the inner ear characterized by episodic vestibular symptoms associated with sensorineural hearing loss, tinnitus, and aural pressure. Epidemiologic and genomic evidence supports a genetic susceptibility with multiple biochemical pathways involved, including the endocrine system, innate immune response, and autonomic nervous system. Allergens, infectious agents, vascular events, or genetic factors could modify inner-ear homeostasis and trigger MD. The diagnosis of MD is based on clinical criteria and requires the observation of an episodic vertigo syndrome associated with low- to medium-frequency sensorineural hearing loss and fluctuating aural symptoms (hearing loss, tinnitus, and/or fullness) in the affected ear. Headache is also found during the attacks and bilateral involvement is found in 25-40% of cases. Audiologic and vestibular assessment is recommended to monitor the clinical course. The treatment of MD is symptomatic to obtain relief of vestibular episodes and preventive to limit hearing loss progression. Treatment options include sodium restriction, betahistine, intratympanic gentamicin, or steroids and eventually surgery, such as cochlear implantation.

Prognostic implications of and audiometric evidence for hearing fluctuation in Meniere's disease

OBJECTIVES/HYPOTHESIS

1) To establish criteria for significant hearing fluctuation by assessing the range and occurrence of hearing fluctuations over the course of Meniere's disease; 2) to determine if audiometric evidence exists to support the notion that Meniere's disease is a pathophysiologic process involving the whole cochlea; and 3) to suggest prognostic implications for initial hearing fluctuation in patients with Meniere's disease.

STUDY DESIGN

Retrospective case series review.

METHODS

A total of 488 patients diagnosed by 1995 American Academy of Otolaryngology-Head and Neck Surgery Meniere's disease criteria for whom audiometric data were prospectively collected (2 cohorts: 341 and 146 patients initially seen between April 2002 to July 2003 and between January to December 2010, respectively). Based on several definitions for significant hearing fluctuation, change in hearing was categorized as "same," "worse," or "better" between any two consecutive evaluations. The relationship of initial hearing fluctuation to future hearing fluctuation and future hearing loss was evaluated.

RESULTS

Hearing fluctuation was evident in Meniere's disease patients with heterogeneous audiometric follow-up; and the characteristics of these hearing fluctuations, including the mean incidence, is described. Audiometric data suggests that there is a high congruence in Meniere's disease between changes in low- and high-frequency thresholds. Initial hearing fluctuation is associated with the occurrence of future and more frequent hearing fluctuations.

CONCLUSION

Understanding the range of hearing fluctuations establishes a basis for determining audiometric thresholds used in evaluating future therapeutic trials aimed at the prevention of hearing loss in Meniere's disease. This knowledge will also inform the counseling directed toward patients diagnosed with Meniere's disease.

The role of intracochlear drug delivery devices in the management of inner ear disease

INTRODUCTION

Diseases of the inner ear include those of the auditory and vestibular systems, and frequently result in disabling hearing loss or vertigo. Despite a rapidly expanding pipeline of potential cochlear therapeutics, the inner ear remains a challenging organ for targeted drug delivery, and new technologies are required to deliver these therapies in a safe and efficacious manner. In addition to traditional approaches for direct inner ear drug delivery, novel microfluidics-based systems are under development, promising improved control over pharmacokinetics over longer periods of delivery, ultimately with application towards hair cell regeneration in humans.

AREAS COVERED

Advances in the development of intracochlear drug delivery systems are reviewed, including passive systems, active microfluidic technologies and cochlear prosthesis-mediated delivery. This article provides a description of novel delivery systems and their potential future clinical applications in treating inner ear disease.

EXPERT OPINION

Recent progresses in microfluidics and miniaturization technologies are enabling the development of wearable and ultimately implantable drug delivery microsystems. Progress in this field is being spurred by the convergence of advances in molecular biology, microfluidic flow control systems and models for drug transport in the inner ear. These advances will herald a new generation of devices, with near-term applications in preclinical models, and ultimately with human clinical use for a range of diseases of the inner ear.