Ménière's disease: damaged hearing but reduced vertigo

Acute histological reactions in the otolith organs to inner ear drug delivery through a cochlear implant

Introduction

Cochlear implantation is currently regarded as a safe and minimally invasive procedure. However, cochlear implantation can have an impact on vestibular function, despite the lack of correlation between patient symptomatology and damage in vestibular tests. Thus, the present study aims to analyze the presence of hydrops and histological reactions at the level of the vestibule after cochlear implantation with dexamethasone pump delivery in Macaca fascicularis (Mf).

Materials and methods

A detailed histological study was conducted on a total of 11 Mf. All 11 Mf were divided into three groups: 5 Mf were implanted with an electrode array HL-14 connected to a pump delivering FITC-dextran for 24 h (Group A); 4 Mf were implanted with a CI electrode array attached to a pump for FITC-dextran delivery for 7 days (Group B); and 2 Mf were considered the control group, without any kind of cochlear device implantation (Group C). After drug deliver, the selected macaques were euthanized to collect tissue samples for histological analysis. An experienced observer, focusing on the utricle and saccule areas, conducted a blinded inner ear histology analysis.

Results

Surgical procedures were successfully performed in all cases. No signs of cochlear reaction to the device were observed, including neither collapse nor fibrosis. Endolymphatic sinus dilatation was observed in Mf4A and Mf3B, while cochlear hydrops was observed in Mf3A. The mean areas of the utricle and saccule exhibited some statistically significant differences, specifically, in the saccule between groups C and both groups A (p = 0.028) and B (p = 0.029); however, no significant differences were observed between groups A and B or among comparisons of the utricle.

Discussion

A significant concern relates to the safety of cochlear implantation with regard to vestibular preservation and hearing. New advancements in electrode arrays, such as CI devices coupled with delivery pumps, pose a challenge in maintaining minimally traumatic surgical concept-based procedures without affecting the inner ear homeostasis. The implantation of this device may cause vestibular hydrops in the saccule, indicating that the longer the time of substance release, the greater the grade of hydrops evidenced at the saccular level. Apart from this finding, the risk of histological damage to the vestibule is low.

Evidence of cochlear neural degeneration in normal-hearing subjects with tinnitus

Tinnitus, reduced sound-level tolerance, and difficulties hearing in noisy environments are the most common complaints associated with sensorineural hearing loss in adult populations. This study aims to clarify if cochlear neural degeneration estimated in a large pool of participants with normal audiograms is associated with self-report of tinnitus using a test battery probing the different stages of the auditory processing from hair cell responses to the auditory reflexes of the brainstem. Self-report of chronic tinnitus was significantly associated with (1) reduced cochlear nerve responses, (2) weaker middle-ear muscle reflexes, (3) stronger medial olivocochlear efferent reflexes and (4) hyperactivity in the central auditory pathways. These results support the model of tinnitus generation whereby decreased neural activity from a damaged cochlea can elicit hyperactivity from decreased inhibition in the central nervous system.

Predicting neural deficits in sensorineural hearing loss from word recognition scores

The current gold standard of clinical hearing assessment includes a pure-tone audiogram combined with a word recognition task. This retrospective study tests the hypothesis that deficits in word recognition that cannot be explained by loss in audibility or cognition may reflect underlying cochlear nerve degeneration (CND). We collected the audiological data of nearly 96,000 ears from patients with normal hearing, conductive hearing loss (CHL) and a variety of sensorineural etiologies including (1) age-related hearing loss (ARHL); (2) neuropathy related to vestibular schwannoma or neurofibromatosis of type 2; (3) Ménière’s disease; (4) sudden sensorineural hearing loss (SSNHL), (5) exposure to ototoxic drugs (carboplatin and/or cisplatin, vancomycin or gentamicin) or (6) noise damage including those with a 4-kHz “noise notch” or reporting occupational or recreational noise exposure. Word recognition was scored using CID W-22 monosyllabic word lists. The Articulation Index was used to predict the speech intelligibility curve using a transfer function for CID W-22. The level at which maximal intelligibility was predicted was used as presentation level (70 dB HL minimum). Word scores decreased dramatically with age and thresholds in all groups with SNHL etiologies, but relatively little in the conductive hearing loss group. Discrepancies between measured and predicted word scores were largest in patients with neuropathy, Ménière’s disease and SSNHL, intermediate in the noise-damage and ototoxic drug groups, and smallest in the ARHL group. In the CHL group, the measured and predicted word scores were very similar. Since word-score predictions assume that audiometric losses can be compensated by increasing stimulus level, their accuracy in predicting word score for CHL patients is unsurprising. The lack of a strong age effect on word scores in CHL shows that cognitive decline is not a major factor in this test. Amongst the possible contributions to word score discrepancies, CND is a prime candidate: it should worsen intelligibility without affecting thresholds and has been documented in human temporal bones with SNHL. Comparing the audiological trends observed here with the existing histopathological literature supports the notion that word score discrepancies may be a useful CND metric.

Hearing Benefits of Clinical Management for Meniere's Disease

Meniere’s disease is a progressive hearing−disabling condition. Patients can benefit from strict clinical management, including lifestyle and dietary counseling, and medical treatment. A prospective cohort study was carried out with 154 patients with definite Meniere’s disease, with an average age of 43.53 ± 11.40, and a male to female ratio of 0.97:1. The pure-tone thresholds of all 165 affected ears, over a one-year clinical management period, were analyzed. After one year, 87.27% of patients had improved or preserved their hearing at a low frequency, and 71.51% at a high frequency. The hearing threshold at frequencies from 250 Hz to 2000 Hz had improved significantly (p < 0.001, p < 0.001, p < 0.001, p < 0.01), and deteriorated slightly at 8000 Hz (p < 0.05). Of all the patients, 40.00% had a hearing average threshold that reached ≤25 dB HL after the clinical management period, among whom 27.27% were patients in stage 3. The restoration time was 2.5 (1.0, 4.125) months, with a range of 0.5−11.0 months, and the restoration time was longer for stage 3 than for stages 1 and 2 (u = −2.542, p < 0.05). The rising curves improved the most (p < 0.05), with most becoming peaks, whereas most peaks and flats remained the same. Patients who were initially in the earlier stages (95% CI 1.710~4.717, OR 2.840, p < 0.001), have an increased odds ratio of hearing by an average of ≤25 dB HL. Age (95% CI 1.003~1.074, OR 1.038, p = 0.031), peak curve (95% CI 1.038~5.945, OR = 2.484, p = 0.041), and flat curve (95% CI 1.056~19.590, OR = 4.549, p = 0.042), compared with the rising curve, increase the odds ratio of hearing on average by >25 dB HL. Most patients can have their hearing preserved or improved through strict clinical management, and sufficient follow-up is also essential. Stage 3 patients also have the potential for hearing improvement, although the restoration time is longer than in the early stages. The initial hearing stage, age, and audiogram pattern are related to the hearing benefits.

Intratympanic gentamicin injection for refractory ménière's disease (MD) has potential effect in preventing contralateral MD occurrence

BACKGROUND

Ménière's disease (MD), characterized by episodic vertigo attacks and fluctuating progressive hearing loss, is treated by low-dose intratympanic gentamicin (ITG) injections. Whether ITG causes hearing loss is controversial, and knowledge about its effects on the contralateral hearing and vestibular function is lacking.

AIMS/OBJECTIVES

We aimed to evaluate the effect of ITG on bilateral auditory and otolith organ function in patients with unilateral refractory MD.

MATERIAL AND METHODS

The data of 30 patients was collected, including history, and pure tone audiometry and vestibular-evoked myogenic potentials (VEMPs) results before and one month after ITG treatment. Changes in vertigo were assessed at a two-year follow-up.

RESULTS

One month after ITG injection, auditory thresholds between 125 Hz and 8 kHz on the injection side remained unchanged but have improved on the contralateral side at 125 Hz, 250 Hz, 1 kHz. The cervical and ocular VEMP solicitation rates on the injection side were lower than before the injection. Two years after treatment, vertigo was improved in 88.5% and complete controlled in 76.7% patients respectively.

CONCLUSIONS AND SIGNIFICANCE

The intractable vertigo of MD can be effectively controlled by ITG injection. This can improve the low and medium frequency hearing level in the contralateral ear, suggesting that it might help prevent contralateral MD occurrence.

Transmastoid Labyrinthectomy for Menière's Disease: Experience and Outcomes

OBJECTIVE

To characterize presurgical symptoms and treatment history and postoperative course in patients with medically recalcitrant Menière's disease undergoing transmastoid labyrinthectomy in the post-intratympanic gentamicin era.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary academic medical center.

PATIENTS

All patients who underwent transmastoid labyrinthectomy for medically recalcitrant Menière's disease in 2003 to 2019 by the senior author.

INTERVENTIONS

Review of patients' medical records for: preoperative history of drop attacks, gentamicin injections, endolymphatic sac decompression or vestibular neurectomy, preoperative audiograms, length of hospital stay, postoperative complications, and persistent symptoms or challenging recovery.

MAIN OUTCOME MEASURES

Presurgical clinical history and proximal postoperative outcomes.

RESULTS

Seventy-two patients with a mean age of 56.7 (standard deviation [SD] 10.7) were included. All cases were unilateral. Forty-three patients (59.7%) suffered from drop attacks. Sixty-two (86.1%) had failed sufficient symptom control with gentamicin injections. The mean preoperative word recognition score was 36.4% (SD 23.7) versus 95.1% (SD 8.5) in the contralateral ear. The mean pure-tone average (PTA) of the ipsilateral ear before surgery was 65.5 dB (SD 18.0) versus 16.2 (SD 13.5) for the contralateral ear. Mean hospital stay was 2.0 days (SD 0.87 days, range of 1-5 d). Three patients (4.2%) had prolonged postoperative vertigo.

CONCLUSIONS

Transmastoid labyrinthectomy at our center is performed for unilateral Menière's disease, generally when intratympanic gentamicin has failed. A majority of surgical patients suffer from drop attacks preoperatively. Hospital stay is typically brief.

Benign paroxysmal positional vertigo associated with Meniere's disease

OBJECTIVE

We studied the clinical features of benign paroxysmal positional vertigo (BPPV) associated with Meniere's disease.

METHODS

The medical records of 120 patients with BPPV was retrospectively analyzed. Complete otolaryngological, audiological, and neurotological evaluation results were available for all patients, including nystagmography. All patients were diagnosed using the Dix-Hallpike test or roll test and treated with the canalith repositioning procedure. The outcomes were compared among the three groups.

RESULTS

A series of 120 BPPV cases. Results showed that Group A and Group B based on the following features: unilateral semicircular canal BPPV occurred more often than bilateral BPPV and the posterior semicircular canal was the most common canal involved. Additionally, Meniere's disease patients with multiple semicircular canal BPPV required repeated canalith repositioning procedures and had a higher recurrence rate.

CONCLUSION

A lower treatment success rate and a higher recurrence rate were found in the BPPV patients with Meniere's disease compared with the patients without Meniere's disease. The recurrence rate was highest in the patients with multiple semicircular canal BPPV with Meniere's disease.

Gadolinium-enhanced MRI reveals dynamic development of endolymphatic hydrops in Ménière's disease

INTRODUCTION

Meniere's disease is associated with impaired hearing, tinnitus, vertigo, and aural fullness. Many anatomical studies have suggested idiopathic endolymphatic hydrops as the pathological basis of Meniere's disease, which now can be visualized by using gadolinium -enhanced magnetic resonance imaging of the inner ear.

OBJECTIVE

To investigate the development of endolymphatic hydrops in Meniere's disease by monitoring the vestibules and cochleae of affected patients.

METHODS

Inner ears of 178 patients with definite unilateral Meniere's disease diagnosis were visualized by 3-dimensional fluid-attenuated inversion recovery and three-dimensional real inversion recovery magnetic resonance imaging following bilateral gadolinium intratympanic injection. The scans were used to evaluate the presence and degree of endolymphatic hydrops in the vestibules and cochlear structures, including the cochlear apical turn, the cochlear middle turn, and the cochlear basal turn. The correlation of endolymphatic hydrops occurrence between the various parts of the inner ear was determined.

RESULTS

Symptomatic endolymphatic hydrops was detected on the affected side in all patients, whereas asymptomatic endolymphatic hydrops was detected on the unaffected contra-lateral side in 32 patients (18.0%). On the affected side, the cochlear apical turn and the cochlear middle turn demonstrated significantly higher rates of endolymphatic hydrops than the cochlear basal turn and the vestibule. The severity of endolymphatic hydrops gradually decreased from the cochlear apical turn to the cochlear basal turn. On the contra lateral side, the incidence and degree of the detected asymptomatic endolymphatic hydrops were significantly greater in the cochleae than in the vestibules (p<0.05), with no significant difference detected between the cochlear turns.

CONCLUSION

Progression of endolymphatic hydrops appears to be directional, initiated in the cochlea. The order of endolymphatic hydrops severity gradually decreases from the cochlear apical turn to the cochlear basal turn and then to the vestibule. Endolymphatic hydrops in the vestibule is associated with symptomatic Meniere's disease.

Intratympanic corticosteroids in Ménière's disease: A mini-review

This article reviews the effectiveness of intratympanic corticosteroids for vertigo control in Ménière's disease at 2-years follow-up according to the guidelines expressed by the American Academy of Otolaryngology-Head & Neck Surgery. Despite the increased use of intratympanic corticosteroids for vertigo control in Ménière's disease there is debate as to their effectiveness, particularly compared to gentamicin. Even so, after just a single course of injections, corticosteroids can reliably provide complete vertigo control (Class A) at 2-years in about 50% of cases as indicated in a recent double-blind randomized controlled clinical trial (Patel et al., 2016). But the effectiveness of intratympanic corticosteroids truly increases when treatment is provided 'as-needed', whereby complete vertigo control is established in up to 91% of cases. On the basis of available literature, there is good evidence to recommend the use of intratympanic steroid treatment for vertigo control in Ménière's disease, but patients must be monitored for non-response. The rationale for treating patients as-needed and the possible reasons for corticosteroid non-response are discussed.