Results in caloric test, video head impulse test and inner ear MRI in patients with Ménière's disease.

Our aim was to elucidate relationships between results from the caloric test (c-test), video Head Impulse Test (vHIT) and inner ear gadolinium-enhanced MRI (ieMRI) in patients with endolymphatic hydrops (EH), especially patients with Ménière's disease (MD). We managed 1789 successive patients at the Vertigo/Dizziness Center in Nara Medical University from May 2014 to December 2018. After providing informed consent for vertigo/dizziness examinations, 281 patients were hospitalized to check their inner ear function for proper diagnosis and treatment. Then 76 participants underwent the c-test, vHIT and ieMRI. Among these 76 cases, 20 were diagnosed with MD (20/76; 26.3%) and 56 were non-MD (56/76; 73.7%) according to the 2015 diagnostic guideline of the International Classification of Vestibular Disorders. The MD group included 15 unilateral and 5 bilateral cases. The non-MD group included 22 benign paroxysmal positional vertigo, 10 vestibular neuritis, 8 sudden deafness with vertigo, 6 orthostatic dysregulation, 4 vestibular neuropathy and 6 others. Results in these examinations in the side of an active lesioned inner ear were representative in each peripheral case. Twenty-nine of the 76 patients (38.1%) showed discrepant results between the c-test (outside of normal range) and vHIT (within normal range). Twenty-two of 76 patients (28.9%) had a positive EH sign on ieMRI. The c-test/vHIT discrepancy percentage in MD (14/20; 70.0%) was significantly higher than that in non-MD (15/56; 26.8%) (p=0.00179). The positive EH sign in ieMRI percentage in MD (15/20; 75.0%) was significantly higher than that in non-MD (7/56; 12.5%) (p=0.0015). There was a significant positive relationship between the c-test/vHIT discrepancy and the positive EH sign (p=0.00058) in all 76 cases combined. However, there was no significant relationship between c-test/vHIT discrepancy and positive EH sign (p=0.13) in the 20 MD cases. Considering the 15 unilateral and 5 bilateral MD cases, the c-test/vHIT discrepancy was observed in 14 of the 25 affected ears. Positive signs of vestibular EH herniation into the cupula in the lateral semicircular canal was seen in 14 of the 25 MD ears. There was significant relationship between the c-test/vHIT discrepancy and EH herniation (p=0.0012) in MD ears. The present results suggest that patients with MD could have inner ear EH significantly more often than those with non-MD. In cases with MD, a positive EH sign on ieMRI did not always indicate a c-test/vHIT discrepancy; both findings may occur due to herniation of vestibular EH adjacent to the lateral semicircular canal.

Kitano K ，Kitahara T ，Ito T ，Shiozaki T ，Wada Y ，Yamanaka T ... -  《-》

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

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). 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%. 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). The volume of the ELS may affect the discrepancy of results between the C-test and vHIT.

Ueda K ，Ito T ，Inui H ，Fujita H ，Shiozaki T ，Miyasaka T ，Kichikawa K ，Kitahara T ... -  《-》

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

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. 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. 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%. 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.

Kirbac A ，Incesulu SA ，Toprak U ，Caklı H ，Ozen H ，Saylisoy S ... -  《-》

Impact of endolymphatic hydrops on the function of the horizontal canal during caloric stimulation in Ménière's disease.

When a dizzy patient with episodic vertigo has an abnormal caloric and a normal video head impulse test (vHIT), this caloric-vHIT dissociation provides vital information for a diagnosis of Ménière's disease (MD). Endolymphatic hydrops (EH), a histological marker of MD, is hypothesized to be involved in the caloric-vHIT dissociation in MD through hydropic duct distension of the horizontal semicircular canal (SC). This study was designed to determine the impact of EH on the function of horizontal SC during caloric stimulation. Caloric test and vHIT were used to evaluate the function of horizontal SC every six months, annual magnetic resonance imaging (MRI) was used to evaluate the degree of EH size in the vestibule, and monthly vertigo and hearing evaluation was done for 12 months. EH shrinkage was defined as the size change of vestibular EH from significant to none. Among 133 MD patients evaluated for eligibility, 67 patients with caloric-vHIT dissociation entered the study. Fifteen participants had EH shrinkage (G-I), while 52 participants had no remarkable EH change (G-II). Average values (IQR) of the maximum slow phase velocity in G-I and G-II were 29.6 (13.0-34.0) and 25.9 (17.3-31.3), respectively, at baseline, 26.1 (9.0-38.0) and 23.6 (18.0-28.3) at 12 months. Two-factor repeated-measures ANOVA showed no significant differences between the groups (P = 0.486). The values of vestibulo-ocular reflex gain of the horizontal SC in G-I and G-II remained above 0.8 during the study period. EH detected by MRI shows limited correlation with caloric stimulation results.

Fukushima M ，Kadowaki S ，Nakatani S ，Waki S ，Matsumoto K ，Okamoto H ... -  《-》

Endolymphatic hydrops severity in magnetic resonance imaging evidences disparate vestibular test results.

It has been suggested that in Ménière's disease (MD) a dissociated result in the caloric test (abnormal result) and video head-impulse test (normal result) probably indicates that hydrops affects the membranous labyrinth in the horizontal semicircular canal (HSC). The hypothesis in this study is that based on endolymphatic hydrops' cochleocentric progression, hydrops should also be more severe in the vestibule of these patients than in those for whom both tests are normal. 22 consecutive patients with unilateral definite MD were included and classified as NN if both tests were normal or AN if the caloric test was abnormal. MRI evaluation of endolymphatic hydrops was carried out with a T2-FLAIR sequence performed 4h after intravenous gadolinium administration. The laterality and degree of vestibular endolymphatic hydrops and the presence or absence of cochlear endolymphatic hydrops were recorded. Demographic data, audiometric and vestibular evoked myogenic potentials were collected, and video head-impulse and caloric tests were performed. Patients in both groups (NN and AN) were similar in terms of demographic data and hearing loss. The interaural asymmetry ratio was significantly higher for ocular and cervical VEMP in patients in the AN group. There was a significantly higher degree of hydrops in the vestibule of the affected ear of AN patients (χ2; p=0.028). Significant canal paresis in the caloric test is associated with more severe endolymphatic hydrops in the vestibule as detected with gadolinium-enhanced MRI and with a more severe vestibular deficit. 2a.

Pérez-Fernández N ，Dominguez P ，Manrique-Huarte R ，Calavia D ，Arbizu L ，Garcia-Eulate R ，Alvarez-Gomez L ，Guajardo C ，Zubieta JL ... -  《-》