Gravity perception disturbance in patients with unilateral Meniere disease.

Objective: To investigate gravity perception disturbance (GPD) in patients with Meniere disease (MD), we classified GPD type based on the results of the head-tilt perception gain (HTPG) and the head-upright subjective visual vertical (HU-SVV) evaluated by the head-tilt SVV (HT-SVV) test in patients with unilateral MD. Methods: We conducted the HT-SVV test on 115 patients with unilateral MD and 115 healthy controls. Among the 115 patients, the period from the first vertigo episode to the examination (PFVE) was known for 91 patients. Results: The HT-SVV test classified 60.9% and 39.1% of patients with unilateral MD as GPD and non-GPD, respectively. GPD was classified according to HTPG/HU-SVV combinations as follows: Type A GPD (21.7%, normal HTPG/abnormal HU-SVV), Type B GPD (23.5%, abnormal HTPG/normal HU-SVV), and Type C GPD (15.7%, abnormal HTPG/abnormal HU-SVV). As the PFVE became longer, patients with non-GPD and Type A GPD decreased; however, those with Types B and C GPD increased. Conclusion: This study provides novel information on unilateral MD from the perspective of gravity perception by classifying GPD based on the results of the HT-SVV test. This study's findings suggest that overcompensation for vestibular dysfunction in patients with unilateral MD exhibited by large HTPG abnormalities may be strongly associated with persistent postural-perceptual dizziness. Level of Evidence: 3b.

Late-onset and congenital hearing loss detected using AABR due to congenital cytomegalovirus infection that improved with valganciclovir.

Congenital cytomegalovirus (cCMV) infection is the most common congenital viral infection and is the leading non-genetic cause of sensorineural hearing loss and an important cause of neurodevelopmental disabilities. Auto auditory brainstem response (AABR) is a simple hearing test and used for the purpose of neonatal hearing screening, but can use it for early detection hard of hearing within the study age of the model. We experienced two case of asymptomatic CMV infection in which congenital and late-onset hearing loss were diagnosed early with AABR, and hearing loss improved with valganciclovir.

Association between home-based exercise using a pedometer and clinical prognosis after endovascular treatment in patients with peripheral artery disease.

BACKGROUND: Exercise therapy following endovascular treatment (EVT) is important for patients with peripheral artery disease (PAD); however, continuous exercise therapy is difficult to be performed in clinical practice. This study aimed to investigate the association between the implementation of home-based exercise using pedometers after EVT and 1-year clinical outcomes. METHODS: This multicenter observational prospective cohort registry included patients with PAD complaining of intermittent claudication who underwent EVT for aortoiliac and/or femoropopliteal artery lesions between January 2016 and March 2019. Patients were instructed to perform home-based exercises using a specific pedometer after EVT. The study population was divided into good and poor recording groups according to the frequency of the pedometer measurements. The good recording group was defined as those who completed ≥50 % of the prescribed daily pedometer recording during the follow-up period. The poor recording group was defined as those with an inability to use a pedometer and/or who completed <50 % of the prescribed daily pedometer recordings. The primary outcome was 1-year major adverse events (MAE), defined as a composite of all-cause death, non-fatal myocardial infarction, non-fatal stroke, target vessel revascularization, and major amputation of the target limb. RESULTS: The mean age was 74.4 years; 78 % were male. A total of 623 lesions were analyzed (58.7 % aortoiliac, 41.3 % femoropopliteal). At 1 year, a lower cumulative incidence of MAE was observed in the good recording group compared to that in the poor recording group [10/233 (4.3 %) vs. 35/267 (13.7 %) patients, respectively; p < 0.001]. Multivariate Cox regression analysis showed that patients in the good recording group had a lower hazard ratio for 1-year MAE (0.33; 95 % confidence interval, 0.16-0.68; p = 0.004) than that in the poor recording group. CONCLUSIONS: Good self-recording of pedometer measurements was associated with favorable prognosis in patients with PAD following EVT.

Orthostatic hemodynamics in the vertebral artery and blood pressure in patients with orthostatic dizziness/vertigo.

OBJECTIVES: Orthostatic dizziness/vertigo (ODV) is a common symptom and is believed to occur due to the cerebral hypoperfusion caused by orthostatic hypotension (OH). However, the detailed mechanism underlying ODV onset is poorly understood. The vertebral artery (VA) mainly supplies blood to the central vestibular system; therefore, the orthostatic decrease of VA blood flow could possibly lead to ODV. This study investigated the orthostatic blood pressure and VA hemodynamics in ODV patients to elucidate the hemodynamic mechanism underlying ODV onset. Furthermore, the influence of orthostatic hypotension (OH) on VA hemodynamics was examined because OH is probably the most common cause of ODV. METHODS: This study included 181 patients with ODV and 73 control patients without ODV. All subjects underwent an active standing test to measure the extracranial Doppler (ECD) sonography spectrum of the VA and blood pressure (BP). VA blood flow velocity and BP were simultaneously measured for each patient in the supine static position and then in the upright standing positions following 3 min of standing. We investigated the orthostatic change in the average of flow velocity in bilateral VAs (VAFV) and BP for ODV patients compared with the control patients. RESULT: VAFV in ODV patients was significantly reduced when standing up compared with the control patients. In the ODV patients, there was no difference in orthostatic decrease in VAFV between patients those with OH and without OH. However, the VAFV in the standing position was significantly lower in patients with OH than without OH. In cases with OH, the ODV patients exhibited a greater decrease in VAFV compared with the control patients, but this was not statistically significant. In the absence of OH, a significantly greater orthostatic decrease in VAFV was observed in ODV patients compared with the controls. CONCLUSION: Our findings suggest that the orthostatic decrease of VA blood flow is deeply involved in the hemodynamic mechanism underlying ODV onset and is possibly associated with OH and other etiologies.

Posturographic Findings in Patients With Psychological Dizziness.

BACKGROUND: The diagnosis and treatment of patients with psychogenic vertigo (PSY) is difficult because of the lack of reliable objective findings for this condition. We examined the characteristics of foam posturography in patients with peripheral vestibular disorders (PVD) and those with PSY. In particular, we focused on the objective findings of foam posturography in PSY. METHODS: Between January 2010 and December 2011, 2-legged stance tasks were conducted in patients with vertigo/dizziness under 4 conditions: eyes opened with/without foam rubber and eyes closed with/without foam rubber. In terms of the velocity of movement of the center of pressure, we examined Romberg ratios, that is, the ratios of changes in visual conditions under the fixed foam rubber conditions, and foam rubber ratios, that is, the ratios of changes in foam rubber conditions under fixed visual conditions. These ratios were compared among 3 groups: healthy controls (CONT) (n=195), PVD (n=178), and PSY (n=32). RESULTS: Romberg ratios using foam rubber in the PVD group were significantly higher than those in the CONT group. Those in the PSY group were significantly lower. Likewise, the foam rubber ratios in the PVD group were significantly higher than those in the CONT group when the eyes were closed. Those in the PSY group were significantly lower. CONCLUSION: Judging from scores in Romberg ratios using foam rubber and foam rubber ratios when eyes were closed, foam posturography might have the potential to differentiate PSY from PVD.

A study of 24 cases of salivary gland carcinoma with distant metastasis.

Salivary gland carcinoma is a relatively rare disease of the head and neck. Although it frequently presents with distant metastases, few reports have been published on this subject. The present study investigated the prognosis of patients with distant metastases from salivary gland cancer. A total of 24 cases of salivary gland carcinoma with distant metastasis who were initially treated at the Department of Otolaryngology-Head and Neck Surgery of Nara Medical University during a 16-year period from August 2004 to July 2020 were included. The histopathological types included salivary duct carcinoma (8 cases), adenoid cystic carcinoma (6 cases), myoepithelial carcinoma (3 cases), Squamous cell carcinoma (2 cases), adenocarcinoma (2 cases), acinic cell carcinoma (2 cases) and mucoepidermoid carcinoma (1 case). A total of 18 patients had stage IV carcinoma, which represented the majority. Of all patients, ~80% developed distant metastases within 2 years of initial diagnosis. Survival rates after the appearance of distant metastases were 43.5% at 5 years and 14.5% at 10 years. The results of the current study revealed that no factors significantly influenced long-term prognosis after the development of distant metastases. In future, it may be necessary to re-examine these results in a larger sample size and standardise treatment methods as a result.

Word Categorization of Vowel Durational Changes in Speech-Modulated Bone-Conducted Ultrasound.

Ultrasound can deliver speech information when it is amplitude-modulated with speech and presented via bone conduction. This speech-modulated bone-conducted ultrasound (SM-BCU) can also transmit prosodic information. However, there is insufficient research on the recognition of vowel duration in SM-BCU. The aim of this study was to investigate the categorization of vowel durational changes in SM-BCU using a behavioral test. Eight Japanese-speaking participants with normal hearing participated in a forced-choice behavioral task to discriminate between "hato" (pigeon) and "haato" (heart). Speech signal stimuli were presented in seven duration grades from 220 ms to 340 ms. The threshold at which 50% of responses were "haato" was calculated and compared for air-conducted audible sound (ACAS) and SM-BCU. The boundary width was also evaluated. Although the SM-BCU threshold (mean: 274.6 ms) was significantly longer than the ACAS threshold (mean: 269.6 ms), there were no differences in boundary width. These results suggest that SM-BCU can deliver prosodic information about vowel duration with a similar difference limen to that of ACAS in normal hearing.

Anaplastic thyroid cancer with long-term survival with lenvatinib therapy and preservation of laryngeal function after one-stage reconstruction: A case report.

Laryngotracheal reconstruction is performed to treat locally advanced thyroid carcinoma invading the larynx and/or trachea. The reconstructive technique varies. The present report describes the case of a 71-year-old female patient who underwent surgery for thyroid carcinoma involving the larynx. Reconstructive surgical techniques were employed to maintain laryngeal structure and function. An anterolateral thigh flap with free rib cartilage grafts was used to compensate for laryngeal defects. Although a temporary tracheal stoma was constructed, it closed spontaneously after decannulation. Therefore, one-stage laryngeal reconstruction was accomplished. Post-operative histopathological examination revealed focal anaplastic changes in the lesion, which mainly consisted of papillary components. Post-operative positron emission tomography/computed tomography indicated early recurrence in the left side of the neck. Therefore, lenvatinib was started as adjuvant therapy. Complete response was observed with lenvatinib therapy. The patient was alive and had good laryngeal function 26 months after the operation. One-stage laryngeal reconstruction can reduce burden and improve quality of life in patients with thyroid carcinoma involving the larynx. Lenvatinib may be useful for treating early recurrence of anaplastic thyroid carcinoma after reconstructive surgery with a free flap.

Novel Magnetic Resonance Imaging-Based Method for Accurate Diagnosis of Meniere's Disease.

Background: Pathologically, Meniere's disease symptoms are considered to be associated with endolymphatic hydrops. Examinations revealing endolymphatic hydrops can be useful for accurate Meniere's disease diagnosis. We previously reported a quantitative method for evaluating endolymphatic hydrops, i.e., by measuring the volume of the endolymphatic space using three-dimensional magnetic resonance imaging (MRI) of the inner ear. This study aimed to confirm the usefulness of our methods for diagnosing Meniere's disease. Here, we extracted new explanatory factors for diagnosing Meniere's disease by comparing the volume of the endolymphatic space between healthy volunteers and patients with Meniere's disease. Additionally, we validated our method by comparing its diagnostic accuracy with that of the conventional method. Methods and Findings: This is a prospective diagnostic accuracy study performed at vertigo/dizziness centre of our university hospital, a tertiary hospital. Eighty-six patients with definite unilateral Meniere's disease and 47 healthy volunteers (25 and 33 males, and 22 and 53 females in the control and patient groups, respectively) were enrolled. All participants underwent 3-Tesla MRI 4 h after intravenous injection of gadolinium to reveal the endolymphatic space. The volume of the endolymphatic space was measured and a model for Meniere's disease diagnosis was constructed and compared with models using conventional criteria to confirm the effectiveness of the methods used. The area under the receiver operating characteristic curve of the method proposed in this study was excellent (0.924), and significantly higher than that derived using the conventional criteria (0.877). The four indices, sensitivity, specificity, positive predictive value, and negative predictive value, were given at the threshold; all of these indices achieved higher scores for the 3D model compared to the 2D model. Cross-validation of the models revealed that the improvement was due to the incorporation of the semi-circular canals. Conclusions: Our method showed high diagnostic accuracy for Meniere's disease. Additionally, we revealed the importance of observing the semi-circular canals for Meniere's disease diagnosis. The proposed method can contribute toward providing effective symptomatic relief in Meniere's disease.

Effects of Vestibular Rehabilitation on Physical Activity and Subjective Dizziness in Patients With Chronic Peripheral Vestibular Disorders: A Six-Month Randomized Trial.

Introduction: The present study aimed to determine whether supervised vestibular rehabilitation therapy (VRT) by physical therapists (PTs) affects subjective dizziness in patients with chronic vestibular disorders, and whether supervised VRT-induced changes in subjective dizziness are related to the changes in physical activity levels in daily life. Methods: Patients (n = 47) with chronic peripheral vestibular disorders were randomly divided into the VRT group (n = 25) and control group (n = 22). Patients in the VRT group received weekly supervised visits from PTs for a period of 6 months. Every other month, both groups were advised by neuro-otologists to increase the amount of activity in their daily life. All patients wore an accelerometer device, which recorded their physical activity for seven successive days before the end of the intervention. Patients also completed the dizziness and unsteadiness questionnaires before and after the intervention. Results: Subjective dizziness decreased significantly regardless of whether supervised VRT was administered; however, dizziness evoked by social activity and head and body movements improved more significantly in the VRT group than in the control group. In the VRT group, there was a significant negative correlation between the increase in sedentary behavior and improvement in subjective dizziness, and a significant positive correlation between the increase in light physical activity and improvement in subjective dizziness at the second month of intervention. The VRT group showed a significantly higher rate of increase in light physical activity than the control group, after 6 months of intervention. Conclusion: Supervised VRT could be highly effective in treating subjective dizziness in patients with chronic peripheral vestibular disorders. We believe frequent (weekly) and medium-term (6 months) PT-guided interventions may be highly effective in enhancing physical activity in daily life, and may subsequently improve subjective dizziness in these patients. Trial registration: This clinical study was registered with University hospital Medical Information Network (identification number: 000028832). https://www.umin.ac.jp/.

Changes in the Results of the Subjective Visual Vertical Test After Endolymphatic Sac Drainage for Intractable Meniere's Disease.

OBJECTIVE: To investigate otolithic function before and after endolymphatic sac drainage (ELSD) for Meniere's disease (MD) by using the subjective visual vertical test (SVV) in the upright and tilted positions. METHODS: Eighteen patients with definite unilateral MD diagnosed in accordance with the American Academy of Otolaryngology Head and Neck Surgery criteria in 1995 and Barany Society criteria in 2015 were included. SVV in the upright position and the head-tilt position was performed preoperatively and on postoperative days 1, 5, 8, 28, and 112. Changes in the results of SVV in the upright position (UP-SVV) and head-tilt perception gain (HTPG) after surgery were measured. RESULTS: The average UP-SVV values significantly changed from 0.05° by the affected side before surgery to 2.5° by the unaffected side on the fifth postoperative day, followed by recovery to the normal range by the eighth postoperative day. The HTPG values for the unaffected side showed the maximum increase on postoperative day 5 during the present study period, although the values in the affected side did not alter significantly. CONCLUSION: ELSD for MD is a surgical treatment that involves less risk of otolith function damage and abnormalities in gravitational cognition. SVV in the head-tilt position could be one of the neuro-otologic examinations used to easily understand the vestibular compensatory process.

The Impact of the COVID-19 Pandemic on Follow-Ups for Vertigo/Dizziness Outpatients.

OBJECTIVES: In the present report, we aimed to investigate the impact of the coronavirus disease (COVID-19) pandemic on vertigo/dizziness outpatient cancellations in Japan. METHODS: We examined 265 vertigo/dizziness outpatients at the ear, nose, and throat department of the Nara Medical University between March 01, 2020, and May 31, 2020, during the COVID-19 pandemic in Japan. We also focused on 478 vertigo/dizziness outpatients between March 01, 2019, and May 31, 2019, before the COVID-19 pandemic, to compare the number of cancellations between these 2 periods. The reasons for cancellation and noncancellation were investigated using telephone multiple-choice questionnaires (telMCQs), particularly for patients with benign paroxysmal positional vertigo (BPPV) and Meniere's disease (MD). RESULTS: There were many cancellations for medical examinations during the 2020 study period. The total number of vertigo/dizziness outpatients decreased by 44.6% in the 2020 period compared to the same period in 2019. The percent reduction in clinic attendance from 2019 to 2020 (ie, [2019-2020]/2019) for patients with BPPV was higher than that for patients with MD. Compared to the other vertigo-associated conditions, patients with MD exhibited a lower percent reduction in clinic attendance. According to the results of the telMCQs, 75.0% of BPPV cases and 88.2% of MD cases cancelled their appointment and gave up visiting hospitals due to fear of COVID-19 infection, even if they had moderate to severe symptoms. On the contrary, 25.0% and 80.0% patients with BPPV and MD, respectively, did not cancel their appointment; they should not have visited the hospital but stayed at home because they had slight symptoms. CONCLUSIONS: These findings suggest that advanced forms should be prepared for medical care, such as remote medicine. These forms should not only be for the disease itself but also for the mental distress caused by persistent symptoms.

A study of 17 cases for the identification of prognostic factors for anaplastic thyroid carcinoma.

Anaplastic thyroid cancer (ATC) has a poor prognosis. ATC accounts for only 1-2% of all thyroid carcinomas, yet it is one of the most lethal neoplasms in humans. Notably, there are no established treatment protocols for ATC. The present study investigated the prognostic and predictive factors of ATC. A retrospective analysis was conducted on 17 patients with histologically confirmed ATC. The median overall survival of all patients was 3.8 months. In patients under the age of 70 years, the statistically significant prognostic factors indicating longer survival were the absence of distant metastasis and treatment by radical resection. Furthermore, in contrast to previous findings, tumor size and white blood cell count were not associated with ATC prognosis in the present cohort. Importantly, tracheostomy did not contribute to improvement of prognosis and should perhaps not be considered, when unnecessary, to preserve the patient's quality of life. Prognostic factors for ATC are critical to clinicians to enable them to determine which patients will benefit from aggressive treatment strategies, as opposed to supportive care.

Effect of head roll-tilt on the subjective visual vertical in healthy participants: Towards better clinical measurement of gravity perception.

OBJECTIVE: Gravity perception is an essential function for spatial orientation and postural stability; however, its assessment is not easy. We evaluated the head-tilt perception gain (HTPG, that is, mean perceptual gain [perceived/actual tilt angle] during left or right head roll-tilt conditions) and head-upright subjective visual vertical (SVV) using a simple method developed by us to investigate the characteristics of gravity perception in healthy participants. METHODS: We measured the SVV and head roll-tilt angle during head roll-tilt within ±30° of vertical in the sitting and standing positions while the participant maintained an upright trunk (sitting, 434 participants; standing, 263 participants). We evaluated the head-upright SVV, HTPG, and laterality of the HTPG. RESULTS: We determined the reference ranges of the absolute head-upright SVV (<2.5°), HTPG (0.80-1.25), and HTPG laterality (<10%) for the sitting position. The head-upright SVV and HTPG laterality were not influenced by sex or age. However, the HTPG was significantly greater in women than in men and in middle-aged (30-64 years) and elderly (65-88 years) participants than in young participants (18-29 years). The HTPG, but not the head-upright SVV or HTPG laterality, was significantly higher in the standing vs sitting position. CONCLUSION: The HTPG is a novel parameter of gravity perception involving functions of the peripheral otolith and neck somatosensory systems to the central nervous system. The HTPG in healthy participants is influenced by age and sex in the sitting position and immediately increases after standing to reinforce the righting reflex for unstable posture, which was not seen in the head-upright SVV, previously considered the only parameter. LEVEL OF EVIDENCE: 4.

Effect of fixation place on airborne sound in cartilage conduction.

When a transducer is placed on aural cartilage, relatively loud sound becomes audible in a conduction form termed cartilage conduction (CC). Previous studies have revealed the acoustical differences between CC and conventional air or bone conduction. This study elucidates the working principle of CC through measurements of threshold shifts by water injection into the ear canal under various fixation place conditions. Seven volunteers with normal hearing participated. A lightweight transducer was fixed for three CC conductions (on the tragus, antitragus, and intertragal incisure), and two non-CC conditions (on the pre-tragus and mastoid). Thresholds were measured at 500, 1000, and 2000 Hz in the 0%-, 40%-, and 80%-water injection conditions. Results for the three CC conditions revealed unique features different from those for the non-CC conditions. For the CC conditions, the thresholds increased by the 40%-water injection at all frequencies. However, with additional water injection (80%-water injection), the thresholds decreased at 500 and 1000 Hz; in particular, dramatically at 500 Hz. The results suggest that a direct vibration of the aural cartilage is important to obtaining the significant contribution of airborne sound to hearing above 1000 Hz. Fixation place results in no significant difference in acoustic features among CC conditions.

Sound localisation ability using cartilage conduction hearing aids in bilateral aural atresia.

OBJECTIVE: Patients with bilateral aural atresia often exhibit poor sound localisation due to bone conduction (BC) features. However, most patients using cartilage conduction (CC) hearing aids reported improvement of sound localisation. DESIGN: CC hearing aids were fitted binaurally. Subsequently, sound localisation was evaluated in three conditions: unaided, aided with previously used hearing aids (air conduction or BC hearing aids), and aided with CC hearing aids. Ears were evaluated with eight loudspeakers positioned in a full-circle at 45-degree interval. Loudspeakers were classified into left and right by midline and front and back by horizontal line. The abilities to distinguish left from right and front from back were compared among three conditions. STUDY SAMPLE: Thirteen patients with bilateral aural atresia participated. RESULTS: The ability to distinguish sounds originating from left or right for participants aided with CC hearing aids was significantly better than that for other conditions (p < 0.05). For distinguishing sounds originating from front or back, unaided ears were significantly better than ears aided with CC hearing aids (p < 0.05). CONCLUSIONS: CC hearing aids provide the ability to distinguish left from right in patients with bilateral aural atresia.

Comparison of the video head impulse test results with caloric test in patients with Meniere's disease and other vestibular disorders.

Background: The caloric test has been used to evaluate the semi-circular canal function for decades. In 2009, the video head impulse test (vHIT) was introduced, which can be used to evaluate the semi-circular canal function within a short time. Although both tests examine the semi-circular canal, the stimulation methods differ and it is unclear whether the vHIT is equivocal to the caloric test.Aims/objectives: This study aimed to discern the differences between the vHIT and caloric test.Material and methods: This study comprised 112 patients with vertigo who visited the vertigo/dizziness centre at our university hospital. Each of these patients underwent a caloric test and vHIT within the same day, and their results were compared. Additionally, an electrocochleography (EcoG) examination, glycerol test (G test), and MRI (performed 4 h after an intravenous gadolinium injection) were conducted to evaluate the influence of endolymphatic hydrops (EH) on the caloric test and vHIT results.Results: Differences in the caloric test and vHIT results, among those with and without EH, were observed in 66.7 and 35.3% of patients, respectively.Conclusions and significance: EH resulted in a difference in results between the caloric test and vHIT. Activated hair cell type may also be implicated.

Combination of head-up sleep and vertical recognition training may cure intractable motion-evoked dizziness with unknown origin.

Background: It has been reported that head-up sleep (HUS) prevents free-floating otoliths from entering canals and that vertical recognition training (VRT) promotes vestibular compensation.Aims/objectives: We would like to assess HUS and VRT for intractable motion-evoked dizziness, including possible benign paroxysmal positional vertigo (BPPV).Materials and methods: 162 patients diagnosed with intractable motion-evoked dizziness of unknown origin were enrolled and randomly divided into the following four groups: HUS-/VRT-, HUS+/VRT-, HUS-/VRT+, and HUS+/VRT+. The at-home interventions comprised HUS with an upper head position of 45° when lying down and VRT with a right down-left down 30° head inclination while watching the vertical index.Results: At the post-treatment 6th month, visual analogue scale (VAS) scores for vertiginous sensation were significantly lower in the HUS+/VRT + group than in the HUS+/VRT - and HUS-/VRT + groups, which were in turn significantly lower than those in the HUS-/VRT - group. VAS scores in the HUS-/VRT + group of patients with abnormal subjective visual vertical (SVV) were significantly lower than those in the HUS+/VRT - group, while those in the HUS+/VRT - group of patients with normal SVV were significantly lower than those in the HUS-/VRT + group.Conclusions: HUS and/or VRT is a good initial treatment for patients with intractable undiagnosed motion-evoked dizziness, including possible BPPV.

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

OBJECTIVE: 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). METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Vestibular Compensation after Vestibular Dysfunction Induced by Arsanilic Acid in Mice.

When vestibular function is lost, vestibular compensation works for the reacquisition of body balance. For the study of vestibular dysfunction and vestibular compensation, surgical or chemical labyrinthectomy has been performed in various animal species. In the present study, we performed chemical labyrinthectomy using arsanilic acid in mice and investigated the time course of vestibular compensation through behavioral observations and histological studies. The surgical procedures required only paracentesis and storage of 50 µL of p-arsanilic acid sodium salt solution in the tympanic cavity for 5 min. From behavioral observations, vestibular functions were worst at 2 days and recovered by 7 days after surgery. Spontaneous nystagmus appeared at 1 day after surgery with arsanilic acid and disappeared by 2 days. Histological studies revealed specific damage to the vestibular endorgans. In the ipsilateral spinal vestibular nucleus, the medial vestibular nucleus, and the contralateral prepositus hypoglossal nucleus, a substantial number of c-Fos-immunoreactive cells appeared by 1 day after surgery with arsanilic acid, with a maximum increase in number by 2 days and complete disappearance by 7 days. Taken together, these findings indicate that chemical labyrinthectomy with arsanilic acid and the subsequent observation of vestibular compensation is a useful strategy for elucidation of the molecular mechanisms underlying vestibular pathophysiologies.