Ratio of Vestibular Endolymph in Patients with Isolated Lateral Semicircular Canal Dysplasia

Otic Capsule Dehiscences Simulating Other Inner Ear Diseases: Characterization, Clinical Profile, and Follow-Up-Is Ménière's Disease the Sole Cause of Vertigo and Fluctuating Hearing Loss?

INTRODUCTION

We present a series of six cases whose clinical presentations exhibited audiovestibular manifestations of a third mobile window mechanism, bearing a reasonable resemblance to Ménière's disease and otosclerosis. The occurrence of these cases in such a short period has prompted a review of the underlying causes of its development. Understanding the pathophysiology of third mobile window syndrome and considering these entities in the differential diagnosis of conditions presenting with vertigo and hearing loss with slight air-bone gaps is essential for comprehending this group of pathologies.

MATERIALS AND METHODS

A descriptive retrospective cohort study of six cases diagnosed at a tertiary center. All of them went through auditive and vestibular examinations before and after a therapeutic strategy was performed.

RESULTS

Out of 84 cases of dehiscences described in our center during the period from 2014 to 2024, 78 belonged to superior semicircular canal dehiscence, while 6 were other otic capsule dehiscences. Among these six patients with a mean age of 47.17 years (range: 18-73), all had some form of otic capsule dehiscence with auditory and/or vestibular repercussions, measured through hearing and vestibular tests, with abnormalities in the results in five out of six patients. Two of them were diagnosed with Ménière's disease (MD). Another two had cochleo-vestibular hydrops without meeting the diagnostic criteria for MD. In two cases, the otic capsule dehiscence diagnosis resulted from an intraoperative complication due to a gusher phenomenon, while in one case, it was an accidental radiological finding. All responded well to the proposed treatment, whether medical or surgical, if needed.

CONCLUSIONS

Otic capsule dehiscences are relatively new and unfamiliar entities that should be considered when faced with cases clinically suggestive of Ménière's disease, with discrepancies in complementary tests or a poor response to treatment. While high-sensitivity and specificity audiovestibular tests exist, completing the study with imaging, especially petrous bone CT scans, is necessary to locate and characterize the otic capsule defect responsible for the clinical presentation.

Vestibular dysfunction in lateral semicircular canal dysplasia

Introduction

Lateral semicircular canal (LSCC) dysplasia is the most common inner ear malformation. The severity of dysplasia can appear in various spectrums, from a short and broad LSCC with normal or small-sized central bony island (CBI) to a single fluid-filled cavity confluent with the vestibule without CBI. However, reports on the association between LSCC dysplasia and the loss of vestibular function are still lacking. In this study, the results of vestibular function tests [caloric test and video-head impulse test (vHIT)] in patients with LSCC dysplasia were analyzed and compared between groups with and without CBI.

Methods

This study retrospectively enrolled 17 patients (23 ears) who had LSCC dysplasia following computed tomography or magnetic resonance imaging and underwent vestibular function tests.

Results

LSCC dysplasia was observed unilaterally in 11 patients and bilaterally in six patients. Nine of 23 ears had CBIs, and 14 ears had no CBI. Three of 17 patients experienced dizziness. Abnormal caloric tests were detected in 11 of the 16 patients who underwent the caloric tests (69%); in contrast, 11 of 12 patients who underwent the vHIT (92%) had normal LSCC vestibulo-ocular reflex (VOR) gain on vHIT. A significant correlation was found between the maximum slow-phase velocity of the caloric test and LSCC VOR gain of the vHIT (correlation coefficient 0.792, p = 0.004). The CBI-absent group showed significantly lower SPV and LSCC VOR gains than the CBI-present group (p = 0.001 and 0.004, respectively).

Discussion

LSCC dysplasia impairs VOR function, especially in the absence of CBI.

Characteristics of vestibular-evoked myogenic potentials in children with vestibular malformation and severe sensorineural hearing loss

BACKGROUND

With the increasing clinical focus on the safety of bilateral cochlear implantation (CI) and the potential risk of bilateral vestibular dysfunction, evaluating vestibular end-organ function in patients with vestibular malformations with accompanying abnormalities has been strongly recommended.

OBJECTIVES

To identify the vestibular-evoked myogenic potential (VEMP) values among children with sensorineural hearing loss (SNHL) with vestibular malformation and assess the effectiveness of VEMP testing for inner ear malformations (IEM) diagnosis.

METHODS

This study included 96 children (192 ears), including those with vestibular malformations (48 ears), large vestibular aqueduct syndrome (LVAS) (50 ears), and SNHL without IEM (94 ears; control group). All groups underwent ocular and cervical VEMP (oVEMP and cVEMP, respectively) testing. The response rates, VEMP parameters, and wave characteristics were compared.

RESULTS

The cVEMP response rates were 37.5 %, 64 %, and 58.51 % and the oVEMP response rates were 42.86 %, 78.95 %, and 77.27 % in the vestibular malformation, LVAS, and control groups, respectively, and significantly differed between groups (cVEMP: X2 = 18.228, P<0.001) (oVEMP: X2 = 7.528, P = 0.023). Significant inter-group differences were observed for the cVEMP and oVEMP latency and amplitude (P < 0.05). The LVAS group's waveform exhibited a prolonged latency and increased amplitude compared with that of the other groups.

CONCLUSION

Patients with SNHL were highly susceptible to otolith dysfunction, regardless of comorbid vestibular malformation presence. Measuring VEMPs is an effective and rapid evaluation technique for vestibular function and could provide a basis for vestibular rehabilitation training.

Vestibular hydrops in patients with semicircular canal malformation

OBJECTIVE

To investigate the vestibular endolymphatic hydrops in patients with semicircular canal malformation.

METHODS

We searched 7864 patients who underwent MR Imaging after contrast injection and found 21 patients with semicircular canal malformations. Another 9 non-malformed patients with unilateral hearing loss were randomly included. We asked patients about their medical history and measured the volume of total vestibular fluid space and endolymphatic space. The vestibular volume ratio = endolymphatic space/total fluid space × 100.

RESULTS

Hearing loss was observed in 18 of 30 malformed ears and in 7 of 12 non-malformed ears. Statistical analysis showed no association between semicircular canal malformation and hearing loss. In the semicircular canal malformation group, the average vestibular volume ratio (22.6%) in the ears with hearing loss was higher than that in the ears without hearing loss (11.4%). There was no statistically significant difference in the average vestibular %EL in ears with hearing loss between the malformed inner ear group (22.6%) and non-malformed group (28.2%) (P>0.05).

CONCLUSION

There was no correlation between semicircular canal malformation and hearing loss. The mean vestibular hydrops volume ratio of the semicircular canal deformed ears with hearing loss was about 22.6%, which was not different from that of normal ears.

Research on congenital severe-to-profound sensorineural hearing loss associated with central lucency of the bony island of the lateral semicircular canal

BACKGROUND

Central lucency of the bony island of the lateral semicircular canal (LSCC) is commonly found in patients with congenital severe-to-profound sensorineural hearing loss (SNHL).

OBJECTIVE

Exploring the significance of bony island lucency of LSCC in congenital severe-to-profound SNHL patients.

MATERIAL AND METHODS

Retrospective measurements of the inner ear structures were made on axial temporal bone CT scans from 182 (364 ears) congenital severe-to-profound SNHL patients and 50 (100 ears) tympanic membrane perforation (TMP) patients.

RESULTS

The incidence of bony island lucency of LSCC was 46.7% in the congenital severe-to-profound SNHL group and 0% in the TMP group. There was a statistically significant difference in inner ear structures among congenital severe-to-profound SNHL patients with normal inner ear structure and bony island lucency of LSCC, congenital severe-to-profound SNHL patients with normal inner ear structure and no bony island lucency of LSCC, and TMP patients. The importance of the bony island lucency of LSCC was further confirmed through multiple linear regression analysis.

CONCLUSIONS AND SIGNIFICANCE

Bony island lucency may have significance in congenital severe-to-profound SNHL and may be a manifestation of largely overlooked SCC malformation or hypoplasia of the inner ear.

The clinical features and image characteristics of Meniere's disease patients with endolymphatic hydrops confirmed by enhanced magnetic resonance imaging

OBJECTIVES

To analyze and summarize the clinical features and image characteristics of Meniere's Disease (MD) patients with Endolymphatic Hydrops (EH) confirmed by enhanced Magnetic Resonance Imaging (MRI).

METHODS

252 MD patients with EH confirmed by MRI were enrolled. All patients met the diagnostic criteria for MD and underwent intravenous gadolinium injection. After 4 h, MR examinations were performed. The Nakashima grading standard was used to classify EH and evaluate its correlation with clinical features.

RESULTS

Different degrees of EH were shown in all MD patients, and 157 of the 252 (62.3%) patients showed significant EH, 95 of the 252 (37.7%) patients showed mild EH. Only 89 (35.3%) met the diagnostic criteria for definite MD, and the remaining 163 (64.7%) patients met the diagnostic criteria for probable MD. Compared with patients with unilateral EH, the symptoms of the first affected ear of patients with bilateral EH were more serious. The degree of EH was related to the degree of hearing loss (p < 0.05).

CONCLUSION

MRI with intravenous gadolinium injection can provide a better assessment of EH in MD patients. The clinical features of MD patients with EH confirmed by enhanced MRI did not fully meet the existing diagnostic criteria for definite MD. Including the diagnosis of EH in the diagnostic criteria of MD can increase the diagnosis rate of MD. The degree and distribution of EH may be related to the degree of hearing loss.

LEVEL OF EVIDENCE

4.

Case Report: Ménière's Disease-Like Symptoms in 22q11.2 Deletion Syndrome

The 22q11.2 deletion syndrome (22q11.2DS), caused by a microdeletion on the long arm of chromosome 22, is characterized by congenital heart disease, hypoparathyroidism, immunodeficiency, developmental delay, and velopharyngeal insufficiency. Anatomic malformations of the middle and inner ears are frequently present, leading to high prevalence of hearing impairment. We present a first case of 22q11.2DS showing fluctuating hearing loss with recurrent vertigo attacks, resembling Ménière's disease. A 38-year-old male known to have 22q11.2DS developed recurrent vertigo, tinnitus, and fluctuating hearing loss in the left ear during a 10-year follow-up period. During vertigo attack, he had spontaneous left-beating nystagmus with downbeat components, but bithermal caloric and video head impulse tests showed normal vestibulo-ocular reflex functions. Sequential pure tone audiograms demonstrated fluctuating sensorineural hearing loss (SNHL) in both ears, which finally progressed to permanent hearing loss in the left ear. Computed tomography imaging of the temporal bone exhibited bilaterally malformed lateral semicircular canals, and delayed 3D-FLAIR sequences revealed cochlear endolymphatic hydrops with dilation of the scala media in the left ear. This case shows that acute vertigo with SNHL can be one of the audiovestibular presentations in 22q11.2DS caused by disturbance of endolymphatic flow.

MRI Evaluation of Vestibular Endolymphatic Space in Patients with Isolated Cystic Lateral Semicircular Canal Malformation

Isolated lateral semicircular canal dysplasia (LSCCD) is one of the most frequent malformations of the bony labyrinth. The aim of this study is to depict morphology and size of the vestibular endolymphatic space in patients with isolated LSCCD using a dedicated 3D high resolution MR sequence called 3D inversion recovery with REAL reconstruction (3D-REAL-IR). From January 2018 to February 2020, we reviewed 281 CT and 241 MR temporal bone studies, and 103 MR studies performed for the evaluation of endolymphatic hydrops (EH). Five patients with LSCCD were found, one of them with bilateral malformation. Three patients (four affected ears) underwent specific MR examination for the evaluation of EH, consisting of a heavily T2-weighed cisternography sequence (T2 SPACE) and a 3D inversion-recovery with REAL reconstruction. The endolymphatic volumetric ratio (ELR) was calculated as the total endolymphatic volume divided by the total lymph (vestibular) volume multiplied by 100. Hydrops MR imaging was available in four of the affected ears. ELR ranged from 22% to 81%. Both extremes were present in the same patient, corresponding to a patient with right unilateral Ménière’s syndrome but with bilateral LSCCD. A patient affected with hearing loss had an ELR of 33% and the last patient with unilateral probable Ménière’s syndrome showed an ELR of 42%. Endolymphatic hydrops imaging is feasible and can be performed on patients with inner ear malformations like LSCCD. The endolymphatic volumetric ratio could be a useful and reproducible tool in daily clinical practice.

Nystagmus in patients with lateral semicircular canal dysplasia

BACKGROUND

Dizziness is not a common symptom in the lateral semicircular canal (LSCC) dysplasia, and nystagmus findings has been rarely described in LSCC dysplasia.

OBJECTIVE

To investigate the characteristics of spontaneous and positional nystagmus in patients with LSCC dysplasia.

METHODS

Patterns of spontaneous and positional nystagmus of twelve patients with LSCC dysplasia, who visited our clinic with a chief complaint of dizziness, were investigated.

RESULTS

LSCC dysplasia was observed unilaterally in 4, and bilaterally in 8 patients. Non-rotatory dizziness with various onset times was the most common description of dizziness, and unilateral caloric weakness was observed in 82% of patients. Direction-fixed nystagmus, in which the direction of spontaneous nystagmus was same with that of positional nystagmus, was observed in 9 patients, and direction-changing positional nystagmus, in which the direction of nystagmus was changed from that of spontaneous nystagmus by positioning maneuvers, was observed in 3 patients, of whom down-beating or direction-changing spontaneous nystagmus was observed in one patient each.

CONCLUSION

While direction-fixed horizontal nystagmus is the most commonly observed type of nystagmus in LSCC dysplasia, atypical spontaneous nystagmus, such as down-beating nystagmus or direction-changing spontaneous nystagmus, may be observed in patients with bilateral LSCC dysplasia.

The round window sign: a sensitive sign to detect perilymphatic fistulae on delayed postcontrast 3D-FLAIR sequence

OBJECTIVES

The aim of this study is to assess the diagnostic performance of a new MR sign, named the round window sign (RWS), to diagnose perilymphatic fistula (PLF) in a population of patients with chronic cochleo-vestibular symptoms, classified as definite or probable Menière's disease (MD).

METHODS

A total of 164 patients (mean age 52 ± 35 years) with chronic cochleo-vestibular symptoms underwent MRI, between 4 and 5 h after intravenous gadoteric acid injection (Dotarem®, 0.1 mmol/kg). MRI exploration was carried out on a 3-T Achieva® TX scanner. We analyzed the presence of the RWS, defined as a nodular FLAIR high signal in the round window (RW) and the presence of associated saccular hydrops. When this RWS was present, a temporal bone CT scan was performed and the RW was analyzed.

RESULTS

Of the 164 patients with definite MD (85 patients) or probable MD (79 patients), we found the RWS in 18 (11%), and 17/18 were classified into the group of probable MD. All these 18 patients showed other MR sequences considered as normal, including heavily weighted T2 imaging. Among these 18 patients, the temporal bone CT examination presented a filling of the RW in 13 patients (72%) and no filling of the RW in 5 patients (28%). Seven patients were surgically managed confirming in vivo the PLF diagnosis. The RWS was associated with the presence of a saccular hydrops in 4 cases.

CONCLUSION

Delayed postcontrast 3D-FLAIR may reveal perilymphatic fistulae in patients with probable Menière's disease using the round window sign.

KEY POINTS

• MRI with delayed acquisition can detect perilymphatic fistulae with perfect sensitivity, based on the presence of the round window sign. • This visual sign is only visible on a 3D-FLAIR sequence. • 3D-FLAIR sequence with delayed acquisition is more sensitive than temporal bone CT scan examination in detecting PLF.

The Correlation Between Endolymphatic Hydrops and Clinical Features of Meniere Disease

OBJECTIVES

The purpose of this study was to investigate the grades of endolymphatic hydrops determined by gadolinium-contrast magnetic resonance (MR) and correlation to the clinical features in patients with Meniere disease.

STUDY DESIGN

Prospective study.

METHODS

A total of 24 patients suffering from unilateral Meniere disease with either definite or probable clinical diagnosis were included. The duration of vertigo, duration of tinnitus, duration of vertigo attacks, hearing thresholds, and canal paresis (CP) value of caloric tests were assessed. Three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging (MRI) was performed 4 hours after intravenous injection of double dose of gadobutrol (Gd) to show endolymph and perilymph, and the grades of endolymphatic hydrops were measured. Additionally, the correlation between clinical features and the grades of endolymphatic hydrops of cochlea and vestibular were evaluated.

RESULTS

Different grades of the endolymphatic hydrops in the impaired ear were revealed by MRI. The Spearman correlation showed a strong correlation between the hearing thresholds of low, middle, and high tone and the grades of cochlea and vestibular hydrops (P < .05); However, no significant correlation between the duration of vertigo, duration of tinnitus, duration of vertigo attacks, CP value, and endolymphatic hydrops was determined (P > .05).

CONCLUSION

By visualizing the endolymph and perilymph of inner ear in patients with Meniere disease assisted with intravenous injection of double doses of Gd, the grades of endolymphatic hydrops could be assessed. As a result, the grades of endolymphatic hydrops in patients with Meniere disease can be used to predict the level of hearing impairment.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E144-E150, 2021.

Electrophysiological and inner ear MRI findings in patients with bilateral vestibulopathy

PURPOSE

Bilateral vestibulopathy (BV) is an uncommon disorder and the etiology remained idiopathic in most cases. Delayed 3D-FLAIR sequences have provided new insights into various inner ear diseases, allowing the evaluation of the endolymphatic space and the permeability of the blood-labyrinthine barrier (BLB). The aim of this study was to assess both the morphology of the endolymphatic space and the permeability of the BLB in patients with BV as evaluated by delayed 3D-FLAIR sequences.

METHODS

In this retrospective study, we performed 3D-FLAIR sequences 4 h after administering contrast media to 42 patients with BV. Two radiologists independently evaluated the morphology of the endolymphatic space (either vestibular atelectasis or endolymphatic hydrops) and the permeability of the BLB.

RESULTS

Morphologic anomalies of the endolymphatic space and vestibular blood-labyrinthine barrier impairment were observed in 59.6% of patients with BV. Bilateral vestibular atelectasis (VA) was found in 21 patients (50%), involving only the utricle and all three ampullas while the saccule was always observed with no sign of collapse: idiopathic BV (n = 19), aminoglycoside administration (n = 1) and few days following abdominal surgery (n = 1). One patient had bilateral vestibular malformation. BLB impairment was observed in five patients (11.9%): paraneoplastic (n = 1), lymphoma (n = 1), autoimmune (n = 1), and vestibular "neuritis" (n = 2). Seventeen patients (40.4%) had normal MRI with no endolymphatic space anomaly or BLB impairment.

CONCLUSION

Patients with BV presented with morphologic anomalies of the endolymphatic space or BLB impairment in 59.6% of patients.

Clinical Features and Endolymphatic Hydrops in Patients With MRI Evidence of Hydrops

OBJECTIVES:

The purpose of this study was to investigate the correlation between grades of endolymphatic hydrops (ELH) and clinical characteristics and determine the detailed clinical characteristics of Ménière's disease (MD) patients with evidence of hydrops based on magnetic resonance imaging (MRI).

METHODS:

One hundred ninety-eight MD patients (396 ears) with MRI evidence of hydrops were included. ELH grades were evaluated using the Nakashima grading standard. Correlations between the extent of ELH and clinical features were evaluated. Detailed clinical characteristics were analyzed to assess the clinical diagnostic criteria.

RESULTS:

Of 198 patients, ELH was observed in 100% of cases on the clinically affected side and 8.6% of cases on the asymptomatic side. In addition, 98.5% of ELH was classified as moderate or significant grade. Low-frequency hearing loss was significantly correlated with the extent of both vestibular and cochlear hydrops, whereas the vertigo attack frequency showed no significant correlation with ELH grades. The disease duration of MD with bilateral ELH was longer than that with unilateral ELH. The clinical characteristics were variant and did not completely fit the proposed diagnostic criteria.

CONCLUSIONS:

MRI findings have relevance to the clinical severity, to a certain extent, but not vestibular symptoms. The proposed diagnostic criteria based on clinical characteristics may be partially effective; analysis of the detailed clinical characteristics of MD was meaningful. Diagnosis of MD based on both MRI and clinical symptoms could facilitate an early diagnosis.

Menière and Friends: Imaging and Classification of Hydropic Ear Disease

BACKGROUND

Over 75 years ago, endolymphatic hydrops was discovered as the pathologic correlate of Menière's disease. However, this pathologic finding could be ascertained only in postmortem histologic studies. Due to this diagnostic dilemma and the variable manifestation of the various audiovestibular symptoms, diagnostic classification systems based on clinical findings have been used hitherto.

METHODS

A review of the literature of magnetic resonance (MR) imaging of hydropic ear disease.

RESULTS

Recent developments of high resolution MR imaging of the inner ear have now enabled us to visualize in vivo endolymphatic hydrops in patients with suspected Menière's disease. The existing knowledge from temporal bone histologic studies and from the emerging evidence on imaging based evaluation of patients with suspected Menière's disease indicate that endolymphatic hydrops not only is responsible for the full-blown clinical triad of simultaneous attacks of auditory and vestibular dysfunction, but also for other clinical presentations such as "vestibular" and "cochlear Menière's disease."

CONCLUSION

As a consequence, we propose the term "Hydropic Ear Disease" as a new terminology which is based on symptomatic and imaging characteristics of these clinical entities to clarify and simplify their diagnostic classification.

Endolymphatic hydrops imaging: Differential diagnosis in patients with Meniere disease symptoms

PURPOSE

The goal of this retrospective study was to investigate the differential diagnosis of endolymphatic hydrops in patients with Meniere's disease (MD) symptoms by using magnetic resonance imaging (MRI) with intravenous injection of gadolinium chelate and delayed acquisition.

MATERIAL AND METHOD

Two hundred patients (133 women, 67 men; mean age=67.2±11 ([SD] years) with unilateral MD underwent MRI at 3-T, between 4.5 and 5.5hours after intravenous administration of gadoterate meglumine at a dose of 0.1mmol/kg. MR images were analyzed for the presence of saccular hydrops, perilymphatic fistulae, inner ear malformations, semicircular canal (SCC) abnormal enhancement and brain lesions. We also tested the potential relationship between past history of gentamicin intratympanic administration and perilymphatic fistula presence and SCC aspect.

RESULTS

Saccular hydrops were found in 96/200 patients with MD (48%). Three patients (1.5%) had perilymphatic fistulas associated with saccular hydrops, as confirmed by surgery. There was a correlation between the presence of perilymphatic fistula and past history of intratympanic gentamicin administration (P=0.02). We detected inner ear malformations in 5 patients (2.5%), SCC local enhancement in 15 patients (7.5%) always on the same side than the clinical symptoms of MD. There was a correlation between the presence of SCC abnormal enhancement and past intratympanic gentamicin administration (P=0.001). Five patients (2.5%) had brain lesions along central cochleovestibular pathways.

CONCLUSION

MRI may reveal brain lesions, SCC abnormalities and perilymphatic fistulae in patients with clinical MD.

What is Menière's disease? A contemporary re-evaluation of endolymphatic hydrops

Menière's disease is a chronic condition with a prevalence of 200-500 per 100,000 and characterized by episodic attacks of vertigo, fluctuating hearing loss, tinnitus, aural pressure and a progressive loss of audiovestibular functions. Over 150 years ago, Prosper Menière was the first to recognize the inner ear as the site of lesion for this clinical syndrome. Over 75 years ago, endolymphatic hydrops was discovered as the pathologic correlate of Menière's disease. However, this pathologic finding could be ascertained only in post-mortem histologic studies. Due to this diagnostic dilemma and the variable manifestation of the various audiovestibular symptoms, diagnostic classification systems based on clinical findings have been repeatedly modified and have not been uniformly used in scientific publications on Menière's disease. Furthermore, the higher level measures of impact on quality of life such as vitality and social participation have been neglected hitherto. Recent developments of high-resolution MR imaging of the inner ear have now enabled us to visualize in vivo endolymphatic hydrops in patients with suspected Menière's disease. In this review, we summarize the existing knowledge from temporal bone histologic studies and from the emerging evidence on imaging-based evaluation of patients with suspected Menière's disease. These indicate that endolymphatic hydrops is responsible not only for the full-blown clinical triad of simultaneous attacks of auditory and vestibular dysfunction, but also for other clinical presentations such as "vestibular" and "cochlear Menière's disease". As a consequence, we propose a new terminology which is based on symptomatic and imaging characteristics of these clinical entities to clarify and simplify their diagnostic classification.