Sustained bias of spatial attention in a 3 T MRI scanner.

When lying inside a MRI scanner and even in the absence of any motion, the static magnetic field of MRI scanners induces a magneto-hydrodynamic stimulation of subjects' vestibular organ (MVS). MVS thereby not only causes a horizontal vestibular nystagmus but also induces a horizontal bias in spatial attention. In this study, we aimed to determine the time course of MVS-induced biases in both VOR and spatial attention inside a 3 T MRI-scanner as well as their respective aftereffects after participants left the scanner. Eye movements and overt spatial attention in a visual search task were assessed in healthy volunteers before, during, and after a one-hour MVS period. All participants exhibited a VOR inside the scanner, which declined over time but never vanished completely. Importantly, there was also an MVS-induced horizontal bias in spatial attention and exploration, which persisted throughout the entire hour within the scanner. Upon exiting the scanner, we observed aftereffects in the opposite direction manifested in both the VOR and in spatial attention, which were statistically no longer detectable after 7 min. Sustained MVS effects on spatial attention have important implications for the design and interpretation of fMRI-studies and for the development of therapeutic interventions counteracting spatial neglect.

Effect of Late-Stage Meniere's Disease and Vestibular Functional Impairment on Hippocampal Atrophy.

OBJECTIVE: We investigated correlations among clinical features, degree of inner ear endolymphatic hydrops (EH), and hippocampal volume (HV) in different stages of Meniere's disease (MD). METHODS: From February 2021 to April 2022, clinical data were collected from 99 patients (39 males, 60 females, mean age: 50.4 ± 10.0 [range: 26-69] years) with unilateral MD admitted to the Department of Vertigo Disease of Shandong ENT Hospital. The left and right ears were affected in 64 and 35 patients, respectively. There were 50 and 49 cases in early (Stages 1, 2) and late stages (Stages 3, 4), respectively. Fifty healthy participants were included as controls. Audiovestibular function test results, EH grading using gadolinium-enhanced magnetic resonance imaging (MRI), and HV determined on MRI were analyzed for patients at different stages of MD. RESULTS: Between-group comparisons of early and late MD revealed significant differences in the disease course, vestibular function (VF), degree of EH, and HV. There were no significant between-group differences based on age, sex, affected side, subjective degree of dizziness, hospital anxiety, or depression. Mean HV in patients with early-stage MD was correlated with the canal paresis value of the caloric test and pure tone hearing threshold, HV in late-stage patients was correlated with vestibular EH. CONCLUSION: Patients with late-stage MD exhibited severe auditory and VF impairments, increased EH, and atrophy of the HV. More advanced disease was associated with greater vestibular damage and degree of EH. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:410-418, 2024.

Blood-labyrinth barrier breakdown in Meniere's disease.

OBJECTIVE: We compared the signal intensity ratio (SIR) of the cochlear basal turn between Meniere's disease and healthy controls to investigate potential damage of the blood-labyrinth barrier in Meniere's disease. METHODS: Thirty patients diagnosed with unilateral definite Meniere's disease and 24 healthy controls were enrolled. 3D-FLAIR scan was conducted to assess the grades of endolymphatic hydrops in Meniere's patients while measuring the SIR of cochlear basal turns in both groups. The differences of bilateral SIR between Meniere's disease and healthy control were compared, and the correlation between the SIR on affected ear in Meniere's disease and the grades of cochlear and vestibular hydrops were analyzed. RESULTS: SIR of affected ear in Meniere's disease exhibited significant increase compared to that of unaffected ear. No significant difference was observed in SIR between the two ears in the healthy control. Furthermore, the SIR of unaffected side in Meniere's disease was higher than that of both ears in healthy controls. The SIR in affected ear of Meniere's disease exhibited positive correlation with hydrops in both cochlea and vestibula. CONCLUSION: The permeability of blood-labyrinth barrier is increased in Meniere's disease, in combination with the typical criteria of Meniere's disease it may be a good biological marker. Destruction of blood-labyrinth barrier may be one of the causes of endolymphatic hydrops in Meniere's disease.

Is vestibular function related to human hippocampal volume?

BACKGROUND: Recent studies implicate the effect of vestibular loss on cognitive decline, including hippocampal volume loss. As hippocampal atrophy is an important biomarker of Alzheimer's disease, exploring vestibular dysfunction as a risk factor for dementia and its role in hippocampal atrophy is of interest. OBJECTIVE: To replicate previous literature on whole-brain and hippocampal volume in semicircular canal dysfunction (bilateral vestibulopathy; BV) and explore the association between otolith function and hippocampal volume. METHODS: Hippocampal and whole-brain MRI volumes were compared in adults aged between 55 and 83 years. Participants with BV (n = 16) were compared to controls individually matched on age, sex, and hearing status (n = 16). Otolith influence on hippocampal volume in preserved semicircular canal function was evaluated (n = 34). RESULTS: Whole-brain and targeted hippocampal approaches using volumetric and surface-based measures yielded no significant differences when comparing BV to controls. Binary support vector machines were unable to classify inner ear health status above chance level. Otolith parameters were not associated with hippocampal volume in preserved semicircular canal function. CONCLUSIONS: No significant differences in whole-brain or hippocampal volume were found when comparing BV participants with healthy controls. Saccular parameters in subjects with preserved semicircular canal function were not associated with hippocampal volume changes.

Posterior Canal Fibrosis: A Case Series.

OBJECTIVE: To establish a case series where loss of magnetic resonance fluid signal intensity in the posterior semicircular canal (SCC) corresponded with a functional deficit on clinical and video head impulse testing, and most likely a result of canal fibrosis or obstruction. PATIENTS: Three patients with an magnetic resonance imaging (MRI) showing loss of T2-weighted signal intensity in their posterior SCC corresponding to a vestibular weakness in that canal. INTERVENTIONS: All patients underwent a comprehensive neuro-otologic examination. Vestibulo-ocular reflex was evaluated using clinical head impulse testing (cHIT) and quantified with video head impulse testing. MRI for all patients was obtained using clinical protocols for gadolinium-enhanced MRI of the internal auditory canal on 1.5 or 3 T scanners, which all included high-resolution, heavily T2-weighted imaging of the membranous labyrinth. MAIN OUTCOME MEASURE: Correlation of MRI findings with vestibular weakness in the corresponding posterior SCC. RESULTS: Subject 1 showed abnormal vHIT in the left lateral and left posterior SCCs. MRI showed loss of T2 signal intensity of the entire left posterior SCC as well as in the posterior limb of the superior SCC. Subject 2 showed isolated loss of function (cHIT) and low gain with catch-up saccade (vHIT) of the left posterior SCC. MRI showed loss of T2 signal intensity of the superior portion of the left posterior SCC, as well as in the posterior limb of the superior SCC. Subject 3 showed catch-up saccades of the left posterior SCC on cHIT and vHIT and loss of T2 signal intensity of the entire left posterior SCC and partial loss of bilateral lateral SCC on MRI. CONCLUSIONS: In this case series, loss of posterior SCC function correlated with vestibular function testing and high-resolution, T2-weighted MRI findings, perhaps related to fibrosis of the posterior SCC.

Transcranial Doppler Remote Positioning System with Virtual Reality Integration for Vestibular Studies.

Transcranial doppler (TCD) ultrasound probes are an invaluable tool in cerebral blood flow (CBF) studies. Their operation demands maintaining consistent pose on the subject throughout the experimental protocol. However, the displacement of the TCD probe during vestibular studies is common and substantially prolongs the experiment or even terminates it. This is a significant challenge for integrating motion-based vestibular studies with CBF investigations. In response, a mechatronics system is designed to allow remote repositioning of the TCD probe during data collection experiments while the subject is wearing a head mounted virtual reality (VR) display and seated in a vestibular disorientation device. This paper presents the design, prototype, and operation of this mechatronics apparatus.Clinical Relevance- The mechatronics apparatus of this paper can enable motion-based vestibular studies that entail the use of CBF velocity measurement and head-mounted virtual reality display.

Measuring the Influence of Magnetic Vestibular Stimulation on Nystagmus, Self-Motion Perception, and Cognitive Performance in a 7T MRT.

Strong magnetic fields induce dizziness, vertigo, and nystagmus due to Lorentz forces acting on the cupula in the semi-circular canals, an effect called magnetic vestibular stimulation (MVS). In this article, we present an experimental setup in a 7T MRT scanner (MRI scanner) that allows the investigation of the influence of strong magnetic fields on nystagmus as well as perceptual and cognitive responses. The strength of MVS is manipulated by altering the head positions of the participants. The orientation of the participants' semicircular canals with respect to the static magnetic field is assessed by combining a 3D magnetometer and 3D constructive interference in steady-state (3D-CISS) images. This approach allows to account for intra- and inter-individual differences in participants' responses to MVS. In the future, MVS can be useful for clinical research, for example, in the investigation of compensatory processes in vestibular disorders. Furthermore, it could foster insights into the interplay between vestibular information and cognitive processes in terms of spatial cognition and the emergence of self-motion percepts under conflicting sensory information. In fMRI studies, MVS can elicit a possible confounding effect, especially in tasks influenced by vestibular information or in studies comparing vestibular patients with healthy controls.

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.

Radiological presence of vascular loops in the cerebellopontine angle region in patients with unilateral Ménière's disease.

OBJECTIVE: The relationship between vascular compression of the vestibulocochlear nerve and audio-vestibular symptoms remains controversial. We aimed to examine the radiological features of vascular loops signs in cerebellopontine angle (CPA) and internal auditory canal (IAC) in patients with unilateral Ménière's disease (MD). METHODS: One hundred and thirty-seven patients with unilateral definite MD and 69 control subjects (138 ears) were enrolled. All subjects received magnetic resonance imaging of CPA-IAC. The configuration of vascular loops in CPA-IAC, based on the Kazawa classification system, from MD-affected, non-affected and control ears were compared. The associations between imaging findings and Ménière's stage, electrocochleogram (EcochG) and caloric test were analyzed. RESULTS: (1) Among the MD-affected ears, 6 cases (4.4%) were classified as Kazawa type IA, 27 cases (19.7%) as IB, 60 cases (43.8%) as IIA, and 44 cases (32.1%) as IIB. No significant interaural difference in the distribution of Kazawa's types was found ([Formula: see text] = 4.737, p = 0.578) in unilateral MD patients. (2) The distribution of Kazawa's types were not significantly different between the MD-affected ears and the control subjects ([Formula: see text] = 2.876, p = 0.411). (3) No relationship was found between Kazawa staging of the MD-affected ear and Ménière's stage (H = 2.679, p = 0.444), EcochG ([Formula: see text] = 0.827, p = 0.867) and caloric test ([Formula: see text] = 4.116, p = 0.248). CONCLUSIONS: In patients with unilateral MD, the configuration of vascular loops in CPA-IAC region, measured by Kazawa criteria, did not correlate with the laterality, clinical stage, the results of EcochG and caloric test, suggesting that vascular loops may be natural anatomical variations for patients with MD.

Characteristics and diagnostic approach of vestibular migraine in children and adolescents: A systematic review.

OBJECTIVE: Vestibular migraine (VM) is the most common cause of episodic vertigo afflicts 1% of the general population. The complexity of VM is owing to the migrainous, and vestibular components and much knowledge have been gained in recent years on VM in the adult population. Akin to that, numerous studies focusing on VM in children and adolescent has emerged. We reviewed the literature to understand the characteristics and diagnostic approach of VM in children and adolescents. METHODS: A literature search was conducted over a period of one month (April 2022). RESULTS: 16 articles were selected based on our objective and selection criteria. A total of patients was included, with a median age of 10.9 years. 11 studies diagnosed VM based on diagnostic criteria. Caloric test and electro/videonystagmography are the most favoured investigation used (50%). Imaging was performed in 56.2% of included studies. CONCLUSION: Deciphering the ideal diagnostic approach for VM is prudent to ensure children and adolescents suffering from VM are treated earlier. VM can be diagnosed using the established diagnostic criteria, which requires thorough and meticulous history taking. The available oto-neurological examination aims to exclude other disorders as its significance in diagnosing VM is still debatable.

Effects of endolymphatic space volume on discrepancy of results between caloric test and video head impulse test.

OBJECTIVE: The caloric test (C-test) and video head impulse test (vHIT) are known to occasionally show contradictory results in patients with Meniere's disease (MD). The reasons underlying this discrepancy between the two tests are currently unclear. We aimed to reveal the mechanisms responsible for this discrepancy by performing volumetric evaluation of the endolymphatic space (ELS) by using endoluminal contrast-enhanced inner ear MRI (ieMRI). METHODS: We enrolled 136 patients (174 ears) who visited the vertigo/dizziness center of our university and underwent the C-test and vHIT between February 2018 and February 2020. Inner ear MRI was also performed to determine the presence of endolymphatic hydrops (EH). The percentage of patients diagnosed with each vestibular disease was as follows: MD, 23.0%; benign paroxysmal positional vertigo (BPPV), 17.8%; bilateral vestibular disorder (BVD), 9.2%; sudden deafness with vertigo (SD), 8.0%; peripheral dizziness (PD), 7.5%; unilateral vestibular disorder (UVD), 6.9%; vestibular neuritis (VN), 6.3%; delayed endolymphatic hydrops (DEH), 3.4%; central dizziness (CD), 2.9%; Hunt syndrome (Hunt), 1.2%; and other disorders (OD), 13.8%. RESULTS: Among the ears in the present study, 46.0% (80/174) showed a discrepancy in the results of the C-test and vHIT, and the disease-related distribution of patients showing this discrepancy was as follows; MD, 38.8% (27/80; p = 0.0019); BVD, 13.8% (11/80); UVD, 12.5% (10/80); SD, 7.5% (6/80); BPPV, 6.3% (5/80); PD, 6.3% (5/80); VN, 3.8% (3/80); DEH, 3.8% (3/80); CD, 2.5% (2/80); Hunt, 0.0% (0/80); and OD, 10.0% (8/80). In all cases, the discrepancy presented as a positive C-test result and negative vHIT result. The ELS ratio was measured for the whole inner ear, cochlea, vestibule, and semicircular canal, and the relationships between the rates and the presence of discrepancy was examined. Inner ear ELS ratio was 17.9% ± 10.8% in patients with the discrepancy and 15.2% ± 8.8% in those without the discrepancy (p = 0.036). Cochlear ELS ratio was 14.9% ± 11.3% in patients with the discrepancy and 11.9% ± 10.3% in those without the discrepancy (p = 0.0012). Vestibular ELS ratio was 22.3% ± 16.2% in patients with the discrepancy and 17.2% ± 12.7% in those without the discrepancy (p = 0.032). Semicircular canal ELS ratio was 18.0% ± 11.0% in patients with the discrepancy and 16.5% ± 9.6% in those without the discrepancy (p = 0.442). CONCLUSION: The volume of the ELS may affect the discrepancy of results between the C-test and vHIT.

Correlation between Histopathology and Signal Loss on Spin-Echo T2-Weighted MR Images of the Inner Ear: Distinguishing Artifacts from Anatomy.

BACKGROUND AND PURPOSE: MR imaging of the inner ear on heavily T2-weighted sequences frequently has areas of signal loss in the vestibule. The aim of the present study was to correlate the anatomic structures of the vestibule with areas of low signal intensity. MATERIALS AND METHODS: We reviewed T2-weighted spin-echo MR imaging studies of the internal auditory canal from 27 cases and cataloged signal intensity variations in the vestibulum of inner ears. Using a histologic preparation of a fully mounted human ear, we prepared 3D reconstructions showing the regions of sensory epithelia (semicircular canal cristae, utricular, and saccular maculae). Regions of low signal intensity were reconstructed in 3D, categorized by appearance, and compared with the 3D histologic preparation. RESULTS: The region corresponding to the lateral semicircular canal crista showed signal loss in most studies (94%). In the utricle, a focus of signal loss occurred in the anterior-cranial portion of the utricle and corresponded to the location of the utricular macula and associated nerve on histopathologic specimens (63% of studies). Additional areas of low signal were observed in the vestibule, corresponding to the fluid-filled endolymphatic space and not to a solid anatomic structure. CONCLUSIONS: Small foci of signal loss within the inner ear vestibule on T2-weighted spin-echo images correlate with anatomic structures, including the lateral semicircular canal crista and the utricular macula. More posterior intensity variations in the endolymphatic space are likely artifacts, potentially representing fluid flow within the endolymph caused by magneto-hydrodynamic Lorentz forces.

Audio-vestibular and radiological analysis in Meniere's disease.

OBJECTIVE: Intravenous gadolinium-enhanced inner ear magnetic resonance imaging (IV Gd-enhanced inner ear MRI) is a new technique for diagnosing Meniere's disease (MD). Vestibular tests have also long been used for MD, but which tests should be included in the oto-neurological test battery remains controversial. The evaluation method to be used to confirm the clinical diagnosis in MD is not clear. This study aimed to examine the results of vestibular tests and IV Gd-enhanced inner ear MRI in individuals diagnosed with unilateral definite Meniere's disease. METHODS: IV Gd-enhanced inner ear MRI (Endolymphatic Hydrops [EH] and Perilymphatic Enhancement [PE]), conventional audiometry (0.25-8 kHz), video Head Impulse Test (vHIT), cervical Vestibular Evoked Myogenic Potential (cVEMP), air caloric test, and dizziness handicap inventory were applied to 16 adult patients diagnosed with unilateral definite MD. RESULTS: Among the patients with definite MD, EH (cochlear and/or vestibular) was identified in 93.7% and 68.7% of the symptomatic and the asymptomatic ears, respectively. There was a positive correlation between the hearing thresholds at 2, 4, 6 and 8 kHz and the degree of cochlear EH (p < 0.05). PE (cochlear and/or vestibular) was observed in 37.5% of the asymptomatic and symptomatic ears. The sensitivity of the vestibular test battery (vHIT, cVEMP, and caloric test) was 100% and its specificity was 50%, while the sensitivity of the IV Gd-enhanced inner ear MRI (EH and PE together) was 93.8% and the specificity was 81.3%. CONCLUSION: MRI had higher sensitivity and specificity than the vestibular test battery. PE or vHIT alone was not considered to be reliable in the diagnosis of MD. In suspected MD, the clinical history, hearing tests, and IV Gd-enhanced inner ear MRI are sufficient for diagnosis. If MRI technique is not possible, vestibular tests (caloric test and cVEMP, not vHIT) can provide reliable results when evaluated together.

Cochlear and Vestibular Volumes in Inner Ear Malformations.

A "gold standard" for quantitatively diagnosing inner ear malformations (IEMs) and a consensus on normative measurements are lacking. Reference ranges and cutoff values of inner ear dimensions may add in distinguishing IEM types. This study evaluates the volumes of the cochlea and vestibular system in different types of IEM. STUDY DESIGN: Retrospective cohort. SETTING: Tertiary academic center. PATIENTS: High-resolution CT scans of 115 temporal bones (70 with IEM; cochlear hypoplasia [CH]; n = 19), incomplete partition (IP) Types I and III (n = 16), IP Type II with an enlarged vestibular aqueduct (Mondini malformation; n = 16), enlarged vestibular aqueduct syndrome (n = 19), and 45 controls. INTERVENTIONS: Volumetry by software-based, semiautomatic segmentation, and 3D reconstruction. MAIN OUTCOME MEASURES: Differences in volumes among IEM and between IEM types and controls; interrater reliability. RESULTS: Compared with controls (mean volume, 78.0 mm3), only CH showed a significantly different cochlear volume (mean volume, 30.2 mm3; p < 0.0001) among all types of IEM. A cutoff value of 60 mm3 separated 100% of CH cases from controls. Compared with controls, significantly larger vestibular system volumes were found in Mondini malformation (mean difference, 22.9 mm3; p = 0.009) and IP (mean difference, 24.1 mm3; p = 0.005). In contrast, CH showed a significantly smaller vestibular system volume (mean difference, 41.1 mm3; p < 0.0001). A good interrater reliability was found for all three-dimensional measurements (ICC = 0.86-0.91). CONCLUSION: Quantitative reference values for IEM obtained in this study were in line with existing qualitative diagnostic characteristics. A cutoff value less than 60 mm3 may indicate an abnormally small cochlea. Normal reference values for volumes of the cochlea and vestibular system may aid in diagnosing IEM.

Insights into Inner Ear Function and Disease Through Novel Visualization of the Ductus Reuniens, a Seminal Communication Between Hearing and Balance Mechanisms.

The sensory end-organs responsible for hearing and balance in the mammalian inner ear are connected via a small membranous duct known as the ductus reuniens (also known as the reuniting duct (DR)). The DR serves as a vital nexus linking the hearing and balance systems by providing the only endolymphatic connection between the cochlea and vestibular labyrinth. Recent studies have hypothesized new roles of the DR in inner ear function and disease, but a lack of knowledge regarding its 3D morphology and spatial configuration precludes testing of such hypotheses. We reconstructed the 3D morphology of the DR and surrounding anatomy using osmium tetroxide micro-computed tomography and digital visualizations of three human inner ear specimens. This provides a detailed, quantitative description of the DR's morphology, spatial relationships to surrounding structures, and an estimation of its orientation relative to head position. Univariate measurements of the DR, inner ear, and cranial planes were taken using the software packages 3D Slicer and Zbrush. The DR forms a narrow, curved, flattened tube varying in lumen size, shape, and wall thickness, with its middle third being the narrowest. The DR runs in a shallow bony sulcus superior to the osseus spiral lamina and adjacent to a ridge of bone that we term the "crista reuniens" oriented posteromedially within the cranium. The DR's morphology and structural configuration relative to surrounding anatomy has important implications for understanding aspects of inner ear function and disease, particularly after surgical alteration of the labyrinth and potential causative factors for Ménière's disease.

Using magnetic resonance imaging to improve diagnosis of peripheral vestibular disorders.

Peripheral vestibular disorders are caused by pathology of the inner ear. The majority of these disorders are diagnosed with a detailed history and vestibular physical exam. Imaging is rarely a part of diagnostic work up as the pathologies of these disorders are "invisible," or undetectable on imaging. However, these "invisible" diagnoses are becoming increasingly visible with advancements in imaging technology. Developments in magnetic resonance imaging are allowing for increased spatial resolution and better image contrast, improving our ability to see soft tissue structures including the membranous labyrinth, sensory epithelia and nerves. With these improvements in imaging, clinicians will be able to understand better atypical presentations of peripheral vestibular disorders, disease intractable to traditional therapy, disorders with unclear pathoetiology and disease only seen on histopathological studies. This review assesses the current state of imaging in the neurotology clinic with a special focus on magnetic resonance imaging and then gathers diseases identified by vestibular testing and histopathological studies that could be better understood with developments in imaging. In doing so, we hope to guide advancement in neurotologic imaging and apprise clinicians of the utility of imaging in peripheral vestibular disease diagnosis.

Injected 3T-3D-FLAIR-MRI labyrinthine patterns match with the severity and tonotopic alteration in sudden sensorineural hearing loss.

PURPOSE: The aim of the study was to assess a correlation between MRI labyrinthine changes detected with IV-gadolinium optimized high-resolution 3D-FLAIR sequences 4 h after injection (OPT4-3DFLAIR) and the type of SSNHL, in terms of frequency alteration and severity. METHODS: This was a prospective monocentric study achieved from July 2019 to December 2020. The inclusion criterion was acute hearing loss of at least 30 dB over three contiguous frequencies occurring within a 72-h period, documented by a pure-tone audiometry (PTA). The primary endpoint was the visual assessment of hyperintensity in labyrinthine structures on OPT4-3DFLAIR performed on 3T MRI. RESULTS: Thirty-six affected ears were included (20 men, 15 women; mean age: 54.5 ± 16.3 years) with 69.4% full-spectrum hearing loss. The median hearing loss, expressed as median and interquartile range [IQR] was 91 dB [74-120], with 47.2% of concomitant acute vestibular syndrome. Pathological signal was found in 26 out of 36 ears (72.2%). Basal turn enhancement was found in all abnormal MRIs, with 73.1% of apical turn enhancement and 50% of vestibular enhancement. Seventeen on 19 cases (89.5%) with apical involvement on MRI had low-frequency hearing loss. Vestibular involvement on MRI was significantly associated with a wider frequency range of hearing loss (p = 0.0002) and the severity of SSNHL (84.5 [71.7-92.5] dB versus 120 [85.8-120] dB, p = 0.0158). CONCLUSION: This report shows that in pathological MRI in SSNHL, a pathologic cochlear base signal is always detected, a cochlear apical turn enhancement matches with low-tone impairment, and a pathological signal within the posterior labyrinth is associated with an impairment of all frequencies and the severity of SSNHL.

Endolymphatic Hydrops Magnetic Resonance Imaging in Menire's Disease Patients on a Vertigo Attack.

OBJECTIVE: To investigate the characteristics of endolymphatic hydrops (EH) in Menire's disease (MD) patient on a vertigo attack. STUDY DESIGN: Prospective study. SETTING: Tertiary referral center. PATIENTS: Thirty-six MD patients underwent the enhanced magnetic resonance imaging (MRI) examinations of the inner ear on a vertigo attack were enrolled. MAIN OUTCOME MEASURES: All patients met the diagnostic criteria for MD and underwent intravenous gadolinium injection 4 hours before the MRI examinations. The MRI examinations were performed in MD patients on a vertigo attack. RESULTS: Various degrees of vestibular EH appeared in almost all affected ears (2 ears had no EH, 11 ears had mild EH, 26 ears had significant EH). The positive rate of vestibular EH was 37/39 (94.9%). Cochlear EH occurred in 29 ears among 39 affected ears (17 ears had mild EH, 12 ears had significant EH). CONCLUSION: MRI with intravenous gadolinium injection can provide a better assessment of EH in MD patient on a vertigo attack. Vestibular EH seems to be closely related with the vertigo attacks in MD patients, which needs further study.

Correlation between magnetic resonance imaging classification of endolymphatic hydrops and clinical manifestations and audiovestibular test results in patients with definite Ménière's disease.

OBJECTIVES: The purpose was to evaluate magnetic resonance imaging (MRI) classification of endolymphatic hydrops with clinical features, audiological and vestibular tests in patients with definite unilateral Ménière's disease (MD). METHODS: Thirty-eight patients were enrolled in this study. The severity of the main clinical symptoms, audiovestibular tests, and MRI, performed 4 hours after intravenous injection of gadobutrol to visualize inner ear compartments, were evaluated. Endolymphatic space dilatation was assessed using Barath and Bernaerts grading systems, and the correlation between the grade of the hydrops and clinical features was evaluated. RESULTS: Using the Barath system, cochlear hydrops was visualized in 81.6% of affected ears, while vestibular was 63.2%. Sensitivity increased to 94.7% using Bernaerts' modification. Vestibular hydrops involving the utricle was present only among patients with cochlear and saccular endolymphatic space dilatation. There was a significant relationship between the hearing level and the vestibular hydrops degree in the Bernaerts scale. The grade of the hydrops correlated neither with the duration of MD nor with the severity of main clinical symptoms. Our study proved MRI to be a sensitive diagnostic tool in MD. The endolymphatic hydrops' grade correlates with the hearing level, which confirms endolymphatic space dilatation's role in hearing loss. CONCLUSIONS: In our study, two similar MRI grading systems were used; however, several differences were found compared to one another. The Bernaerts scale was more sensitive than the Barath scale, and several relationships between the radiological and clinical data were found. Therefore, several MRI evaluating scales and correlating them with the clinical features are needed. The increased perilymphatic enhancement of the cochlea and an extra low-grade vestibular hydrops distinguished in the Bernaerts scale may increase MD diagnosis sensitivity. Magnetic resonance findings in MD support the clinical diagnosis and may help to understand MD pathophysiology better. This study adds to the knowledge and diagnostics in MD for healthcare to improve patients' treatment.

The "vestibular neuromatrix": A proposed, expanded vestibular network from graph theory in post-concussive vestibular dysfunction.

Convergent clinical and neuroimaging evidence suggests that higher vestibular function is subserved by a distributed network including visuospatial, cognitive-affective, proprioceptive, and integrative brain regions. Clinical vestibular syndromes may perturb this network, resulting in deficits across a variety of functional domains. Here, we leverage structural and functional neuroimaging to characterize this extended network in healthy control participants and patients with post-concussive vestibular dysfunction (PCVD). Then, 27 healthy control subjects (15 females) and 18 patients with subacute PCVD (12 female) were selected for participation. Eighty-two regions of interest (network nodes) were identified based on previous publications, group-wise differences in BOLD signal amplitude and connectivity, and multivariate pattern analysis on affective tests. Group-specific "core" networks, as well as a "consensus" network comprised of connections common to all participants, were then generated based on probabilistic tractography and functional connectivity between the 82 nodes and subjected to analyses of node centrality and community structure. Whereas the consensus network was comprised of affective, integrative, and vestibular nodes, PCVD participants exhibited diminished integration and centrality among vestibular and affective nodes and increased centrality of visual, supplementary motor, and frontal and cingulate eye field nodes. Clinical outcomes, derived from dynamic posturography, were associated with approximately 62% of all connections but best predicted by amygdalar, prefrontal, and cingulate connectivity. No group-wise differences in diffusion metrics or tractography were noted. These findings indicate that cognitive, affective, and proprioceptive substrates contribute to vestibular processing and performance and highlight the need to consider these domains during clinical diagnosis and treatment planning.