Endolymphatic hydrops, a pathological feature of Ménière\'s disease, has been experimentally and clinically confirmed to be influenced by the blood circulation of vasopressin (VP). VP is a well-known hormonal regulator of water homeostasis. In addition, VP is influenced by various environmental changes, dehydration, fluctuation of atmospheric pressure, pregnancy, and other factors. Furthermore, VP is a key regulator of the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis is a major neuroendocrine system that controls reactions to emotional and physical stresses, as well as the sleep/wake cycle (circadian rhythm). Therefore, VP is susceptible to change via the HPA axis. This review considers possible mechanisms of the formation of endolymphatic hydrops from the perspective of the vasopressin-aquaporin 2 system.

OBJECTIVE: To apply machine learning models based on air conduction thresholds of pure-tone audiometry for automatic diagnosis of Meniere\'s disease (MD) and prediction of endolymphatic hydrops (EH).
METHODS: Retrospective study.
METHODS: Tertiary medical center.
METHODS: Gadolinium-enhanced magnetic resonance imaging sequences and pure-tone audiometry data were collected. Subsequently, basic and multiple analytical features were engineered based on the air conduction thresholds of pure-tone audiometry. Later, 5 classical machine learning models were trained to diagnose MD using the engineered features. The models demonstrating excellent performance were also selected to predict EH. The model\'s effectiveness in MD diagnosis was compared with experienced otolaryngologists.
RESULTS: First, the winning light gradient boosting (LGB) machine learning model trained by multiple features demonstrates a remarkable performance on the diagnosis of MD, achieving an accuracy rate of 87%, sensitivity of 83%, specificity of 90%, and a robust area under the receiver operating characteristic curve of 0.95, which compares favorably with experienced clinicians. Second, the LGB model, with an accuracy of 78% on EH prediction, outperformed the other 3 machine learning models. Finally, a feature importance analysis reveals a pivotal role of the specific pure-tone audiometry features that are essential for both MD diagnosis and EH prediction. Highlighted features include standard deviation and mean of the whole-frequency hearing, the peak of the audiogram, and hearing at low frequencies, notably at 250 Hz.
CONCLUSIONS: An efficient machine learning model based on pure-tone audiometry features was produced to diagnose MD, which also showed the potential to predict the subtypes of EH. The innovative approach demonstrated a game-changing strategy for MD screening and promising cost-effective benefits for the health care enterprise.

OBJECTIVE: Ménière\'s disease (MD) is an idiopathic inner ear disorder characterized by recurrent episodes of episodic rotational vertigo, fluctuating hearing loss, tinnitus, and a feeling of ear stuffiness. Endolymphatic sac (ES)-related surgery is used primarily in patients with MD who have failed to respond to pharmacologic therapy. Endolymphatic duct blockage (EDB) is a new procedure for the treatment of MD, and related clinical studies are still scarce. This study aims to investigate the dynamic changes in endolymphatic hydrops (EH) and the long-term surgical outcomes in MD patients undergoing EDB, and to evaluate the impact of different types of ES on the surgical efficacy.
METHODS: A retrospective analysis was conducted on 33 patients with refractory MD who underwent EDB. Based on the morphology of their endolymphatic sacs, patients were divided into a normal-type group (n=14) and an atrophic-type group (n=19). The frequency of vertigo symptoms, hearing, vestibular function, and the dynamic changes of gadolinium-enhanced MRI of the inner ear were compared were compared before and after surgery between the 2 groups.
RESULTS: Compared with the atrophic-type group, the patients in the normal-type group had a higher rate of complete vertigo control, better cochlear and vestibular function, and a lower endolymph to vestibule volume ratio (all P<0.05). In addition, 7 patients in the normal-type group were found to have reversal of EH, while no reversal of EH was detected in the atrophic-type group after surgery.
CONCLUSIONS: The response to EDB treatment varies between normal and atrophic MD patients, suggesting that the 2 pathological types of endolymphatic sacs may have different underlying mechanisms of disease.
目的: 梅尼埃病(Ménière’s disease，MD)是一种特发性的内耳疾病，临床表现为反复的发作性旋转性眩晕、波动性听力下降、耳鸣和耳闷胀感。内淋巴囊相关的手术主要用于药物治疗无效的MD患者。内淋巴管夹闭术(endolymphatic duct blockage，EDB)是一种治疗MD的新术式，相关临床研究较少。本研究旨在探讨MD患者行EDB后内淋巴积水(endolymphatic hydrops，EH)的改变及手术远期疗效，评估不同类型内淋巴囊的手术效果。方法: 回顾性分析33例接受EDB治疗的难治性MD患者，根据患者的内淋巴囊形态分为正常形态组(n=14)和萎缩形态组(n=19)。比较2组患者在术前和术后眩晕症状的发作频率、听力、前庭功能和内耳钆增强MRI的变化。结果: 与萎缩形态组比较，正常形态组患者具有更高的眩晕完全控制率、更好的耳蜗和前庭功能以及更低的前庭内淋巴间隙体积占前庭总淋巴体积的比值(均P<0.05)。此外，正常形态组共有7例患者出现EH的逆转，而萎缩形态组术后未检测到EH的逆转。结论: 正常形态和萎缩形态内淋巴囊的MD患者对EDB治疗的反应存在差异，提示2种不同病理类型的内淋巴囊可能存在不同的发病机制。.

Endolymphatic hydrops has been documented as a possible complication of cochlear implantation; however, few studies have addressed its treatment. We describe the first case ever reported of delayed endolymphatic hydrops after a cochlear implant successfully treated with intratympanic gentamicin injection. A detailed discussion of this case with a focus on its management and outcomes will be provided in comparison with literature data. The intratympanic gentamicin injection has been demonstrated to be an effective treatment for symptomatic endolymphatic hydrops after cochlear implantation. We advocate further studies to validate this strategy as a promising alternative to surgical labyrinthectomy.

OBJECTIVE: To compare the calibre of the cochlear (CN), superior vestibular (SVN) and inferior vestibular (IVN) nerves on magnetic resonance imaging (MRI), both between Ménière\'s Disease (MD) ears and clinical controls, and between inner ears with and without endolymphatic hydrops (EH) on MRI.
METHODS: A retrospective case-control study evaluated patients undergoing MRI for suspected hydropic ear disease from 9/2017 to 8/2022. The CN, SVN, IVN and facial nerve (FN) diameters and cross-sectional areas (CSA) were measured on T2-weighted sequences whilst EH was evaluated on delayed post-gadolinium MRI. Absolute nerve calibre (and that relative to the FN) in unilateral definite MD ears (2015 Barany criteria) was compared to that in both asymptomatic contralateral ears and clinical control ears. Nerve calibre in ears with severe cochlear and vestibular EH was compared to ears without EH. t tests or Wilcoxon signed-rank test/Mann-Whitney U test were applied (p < 0.001).
RESULTS: 173 patients (mean age 51.3 ± 15.1, 65 men) with 84 MD (62 unilateral) and 62 clinical control ears were studied. Absolute and relative CN dimensions were decreased in both MD ears (CSA and diameter) and the contralateral asymptomatic ears (CSA) when compared to clinical controls (p < 0.001). Absolute nerve dimensions were reduced in both severe vestibular EH (CN, IVN and SVN) and severe cochlear EH (CN) (p < 0.001), however this was not evident when adjusted according to facial nerve calibre.
CONCLUSIONS: There is decreased absolute CN calibre in both symptomatic and asymptomatic MD ears as well as ears with severe cochlear and vestibular EH on MRI.

UNASSIGNED: Three-tesla MRI with gadolinium-based contrast agents is important in diagnosing Ménière\'s disease. However, contrast agents cannot be used in some patients. By using the compositional difference between the inner ear endolymph and perilymph, we performed basic and clinical research focused on potassium ions and protein to find the optimal parameters for visualizing endolymphatic hydrops on MRI without contrast. We then examined the relationship between severity stage and visualization rate of endolymphatic hydrops.
UNASSIGNED: In phantom experiments simulating the endolymph and perilymph, we explored MRI parameters that could be used to separate endolymph from perilymph by gradually changing the inversion time. We then used these parameters to perform both new non-contrast MRI and contrast MRI on the same day in Ménière\'s disease patients, and we compared the visualization rates of endolymphatic hydrops under the two modalities. Fifty patients were selected from 478 patients with Ménière\'s disease of different severity stages; 12 patients had asthma and allergy to contrast agents.
UNASSIGNED: The higher the disease stage, the higher the endolymphatic hydrops visualization rate. The new non-contrast MRI gave significantly higher (p < .01) visualization rates of endolymphatic hydrops on the affected side in patients at Stage 3 or above than in Stages 1 and 2 combined.
UNASSIGNED: New non-contrast MRI with parameters focusing on the endolymph-perilymph difference in the density of protons surrounding the potassium ions and protein can produce images consistent with endolymphatic hydrops. We believe that this groundbreaking method will be useful for diagnosing Ménière\'s disease in patients.
UNASSIGNED: Clinical studies are at evidence level 3 in non-randomized controlled trials.

OBJECTIVE: To explore the efficacy of diagnostic tests in accurately reclassifying patients initially diagnosed with probable Meniere\'s disease (MD) into either definite or non-MD categories.
METHODS: A retrospective cohort study was conducted at a neurotology clinic between 1/2016 and 5/2022. Patients underwent a battery of tests, from which sensitivity, specificity, positive and negative predictive values, as well as positive and negative likelihood ratios, were calculated. Additionally, prediction nomograms were developed.
RESULTS: Of the 69 patients, 25 (36.2 %) were initially classified as definite MD, 21 (30.4 %), probable MD, and 23 (33.4 %) non-MD. The mean follow-up was 3.5 years. The sensitivity of electrocochleography (ECochG) was the highest (92 %), with a negative likelihood ratio of 15 %. Magnetic resonance imaging (MRI) with MD-protocol had the highest specificity (100 %), with a positive likelihood ratio of 100 %. Videonystagmography, video head impulse test, and cervical vestibular-evoked myogenic potentials, had lower sensitivity and specificity. We were able to reclassify 18 (86 %) patients with probable MD: 12 (57 %) were diagnosed with definite MD, and 6 (29 %) were diagnosed with non-MD, consistent with their clinical course.
CONCLUSIONS: The combination of ECochG and MRI with MD-protocol provides the most reliable approach to reclassify patients with Probable MD, ensuring a precise and accurate diagnosis. Vestibular tests express the functional status of the labyrinth and may not be reliable. Our findings provide valuable insights into clinical decision-making for patients with Probable MD and raise the consideration of additional diagnostic tests as supplementary to the existing clinical-only diagnosis criteria.

OBJECTIVE: The aim was to evaluate endolymphatic hydrops in patients with severe Ménière\'s disease (MD) before and after vestibular neurectomy to verify if vestibular denervation results in hydrops regression.
METHODS: Magnetic resonance imaging was performed after intravenous gadolinium injection in twenty patients with unilateral definite MD before and after the vestibular neurectomy. Clinical symptoms and audiovestibular tests were evaluated. Follow-up intervals ranged from 18 to 35 months after the surgery.
RESULTS: Endolymphatic hydrops were visualized in all patients in the preoperative scans. After the vestibular neurectomy, all patients presented a complete resolution of vertigo episodes. Regression of the endolymphatic hydrops was observed in 35% and 15% of cases analyzing cochlea and vestibule, respectively. In 71.43% of patients with utricular herniation into the lateral semicircular canal, withdrawal of the hernia was visualized. Asymmetrical contrast enhancement in the cochlea regressed in 17.64% of cases. Analyzing all the parameters collectively, in 60% of patients, partial regression of at least one of the radiological signs was confirmed in the follow-up examination. No progression of the endolymphatic hydrops was visualized after the surgery in either the cochlea or the vestibule.
CONCLUSIONS: Vestibular neurectomy is an effective treatment, eliminating vertigo attacks and improving the quality of life in patients with MD. Magnetic resonance imaging of the inner ear allows visualization of changes in endolymphatic hydrops degree after treatment. Regression of the endolymphatic hydrops after vestibular neurectomy suggests that vestibular denervation may effectively halt the progression of the endolymphatic space dilatation and result in hydrops regression.

OBJECTIVE: To evaluate a three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) sequence using a long repetition time (TR) and constant flip angle (CFA) in differentiating between perilymph and endolymph in a phantom study, and unenhanced endolymphatic hydrops (EH) imaging in a patient study.
METHODS: Three solutions in similar ion and protein concentrations with endolymph, perilymph, and cerebrospinal fluid were prepared for variable flip angle (VFA) 3D-FLAIR (TR 10,000 ms) and CFA (120°) 3D-FLAIR using different TR (10,000, 16,000, and 20,000 ms). Fifty-two patients with probable or definite Meniere\'s disease received unenhanced CFA (120°) 3D-FLAIR using a long TR (20,000 ms) and 4-h-delay enhanced CFA (120°) 3D-FLAIR (TR 16,000 ms). Image quality, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of them were compared. Agreement in the evaluation of the EH degree between them was analyzed.
RESULTS: In the phantom study, CNRs between perilymphatic and endolymphatic samples of VFA 3D-FLAIR (TR 10,000 ms) and CFA 3D-FLAIR (TR 10,000, 16,000, and 20,000 ms) were 6.66 ± 1.30, 17.90 ± 2.76, 23.87 ± 3.09, and 28.22 ± 3.15 (p < 0.001). In patient study, average score (3.65 ± 0.48 vs. 4.19 ± 0.40), SNR (34.56 ± 9.80 vs. 51.40 ± 11.27), and CNR (30.66 ± 10.55 vs. 45.08 ± 12.27) of unenhanced 3D-FLAIR were lower than enhanced 3D-FLAIR (p < 0.001). Evaluations of the two sequences showed excellent agreement in the cochlear and vestibule (Kappa value: 0.898 and 0.909).
CONCLUSIONS: The CFA 3D-FLAIR sequence using a long TR could be used in unenhanced EH imaging with high accuracy.
CONCLUSIONS: Unenhanced imaging of endolymphatic hydrops is valuable in the diagnosis and follow-up of patients, especially those who cannot receive contrast-enhanced MRI.
CONCLUSIONS: Ion and protein concentration differences can be utilized in differentiating endolymph and perilymph on MRI. Endolymphatic and perilymphatic samples could be differentiated in vitro on this 3D-FLAIR sequence. This unenhanced 3D-FLAIR sequence is in excellent agreement with the enhanced constant flip angle 3D-FLAIR sequence.

Cogan\'s syndrome is a rare disorder first clinically defined in 1945, characterized by nonsyphilitic interstitial keratitis and progressive audiovestibular symptoms. Later, patients with audiovestibular dysfunction and various types of inflammatory eye disease were classified as having atypical Cogan\'s syndrome. The etiology and pathogenesis of Cogan\'s syndrome remain largely unknown. Here, we report a case of atypical Cogan\'s syndrome with a histological assessment of the temporal bone during the acute disease period. Temporal bone histology was compared to age- and gender-matched normal control, and our findings revealed endolymphatic hydrops and degenerative changes in various parts of the inner ear. Laryngoscope, 2024.