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The sensitivity of endolymphatic hydrops (EH) to the glycerol test varies in patients with Menière's disease (MD).To explore the features of EH and its glycerol-induced dynamics in MD.Case-control study.Twenty patients with MD (24 affected ears) were included.3.0T 3D-FLAIR (fluid-attenuated inversion recovery) MRI and late gadolinium enhancement.Intratympanic gadolinium-enhanced MRI was performed in the MD-affected ears before and after the glycerol test. The borders of the endolymphatic and total lymphatic space were contoured on the axial MRI slices to evaluate the volume of hydrops in both the cochlear and vestibular regions.Paired and unpaired t-tests, the Mann-Whitney U-test, linear discriminant analysis, Pearson's correlation, and linear regression.After glycerol ingestion, vestibular EH decreased in all patients, whereas cochlear EH significantly decreased only in patients with positive glycerol test results (all P 0.01). At baseline, cochlear EH in the positive result group was greater than in the negative result group (P = 0.007). Unexpectedly, in the positive result group a drastic glycerol-induced dehydrating effect was observed in patients whose pretest cochlear EH ratio was16% (P = 0.011). Moreover, the dehydrating role of glycerol was positively correlated with the baseline cochlear hydrops level (r = 0.7691, P 0.001).MRI provides evidence that glycerol administration improves the hearing threshold via dehydrating the EH. In the cochlear region, the baseline level of cochlear EH is a closely related factor for the validity of the glycerol test, whereas EH is consistently dehydrated in the vestibular component.2 TECHNICAL EFFICACY STAGE: 3 J. Magn. Reson. Imaging 2020;52:1066-1073.

Vestibular disorders can manifest several patterns of horizontal vestibulo-ocular reflex (VOR) impairment, which can be detected by caloric test and video head impulse test (vHIT). Several studies have examined the patterns of caloric-vHIT response in Ménière disease (MD). The purpose of this study was to investigate the diversity of caloric-vHIT response and its related factors in unilateral MD patients. We also explore the possibility of assessing the progression of unilateral MD by using the horizontal VOR tests. Ninety-eight patients with unilateral MD were enrolled and underwent a battery of audio-vestibular evaluations, including the pure tone audiogram, caloric test, and horizontal vHIT. Some patients received the electrocochleography and glycerol test. The combined results of caloric test and horizontal vHIT were categorized qualitatively into 4 patterns: Pattern I: normal caloric and vHIT responses; Pattern II: abnormal caloric and normal vHIT responses; Pattern III: normal caloric and abnormal vHIT response; and Pattern IV: abnormal caloric and vHIT responses. The abnormal caloric results were semi-quantitatively subdivided into sub-patterns as mild, moderate, and severe abnormality. The associations between these patterns/sub-patterns and related factors were analyzed. Pattern I was found in 35 cases (35.7%), Pattern II in 57 (58.2%), and Pattern IV in 6 (6.1%). No patient had Pattern III. No significant differences were found between the patterns/sub-pattern distribution and age, electrocochleography, and glycerol test results. Disease duration was not associated with the pattern distribution, while remained a relation with sub-pattern distribution. The pattern/sub-pattern distribution varied significantly across MD stages. The proportion of pattern II or pattern IV increased with the stage of unilateral MD. MD can manifest several patterns of horizontal VOR impairment, of which the impaired caloric response with normal vHIT is the most common pattern. With the progression of unilateral MD, the caloric-vHIT pattern tends to shift, which may reflect the deterioration of endolymphatic hydrops and vestibular hair cells impairments.

Present study aimed to find if multiple audio-vestibular tests can be used to improve in diagnosing Meniere’s disease. The study compares the results of four test procedures of glycerol test, Electrocochleography (ECochG), cervical Vestibular Evoked Myogenic Potential (c-VEMP) and ocular Vestibular Evoked Myogenic Potential (o-VEMP) individually and also together to see whether the diagnosis of Meniere’s disease can be improved. Experimental group consist of 16 participants (32 ears) diagnosed with Meniere’s disease as per American Academy of Otolaryngology (AAO) -Head and Neck Foundation (2020) guidelines. Control group consist of 16 participants with compliant of only vertigo participated in the study. Participants in both group underwent glycerol test, Electrocochleography (ECochG), cervical Vestibular Evoked Myogenic Potential (c-VEMP) and ocular Vestibular Evoked Myogenic Potential (o-VEMP). Glycerol test showed a 38% positive rate for the presence of Meniere’s disease. ECochG indicated the presence of endolymphatic hydrops in 62% of the participants. Abnormal finding in c-VEMP and o-VEMP was seen in 31% and 56% of the participants respectively. The combination of two tests such as ECochG and o-VEMP has increased the positive rate upto 87%. Adding one more test of c-VEMP or combining all four audiovestibular tests had a positive rate of 94% only. The present study indicated ECochG is a more sensitive tool in the diagnosis of Meniere disease followed by o-VEMP. Thus, the present study indicated that combination ECochG and o-VEMP could be used to find the presence of Meniere’s disease successfully.

This stud to explore the effect of glycerol on audiovestibular tests in patients with Meniere’s disease (MD) and to reflect different pathologic states of endolymphatic hydrops (EH) in the inner ear and compare the results of glycerol on these results. Subjects Thirty patients and 15 normal volunteers. Methods Each subject of this study underwent pure tone audiometry testing, evoked vestibular evoked myogenic potential (VEMP) and Vidionystagmography (VNG) before G1 and 2 h after glycerol G2 administration (1.3 g/kg). Results Affected ears were 32 and unaffected ears were 28. The affected ears had higher hearing and SRT thresholds when compared to the unaffected ears and control group. VEMPs of the affected ears were normal in six ears (18.75%), absent in four ears (12.5%) and augmented amplitude in 22 (68.75%), their VNG results showed peripheral vestibular disorder. After oral administration of glycerol, the previous test battery was repeated and it’s result on PTA showed that 53.13% (17/32) of affected ears had positive glycerol test mainly in stage II and III. Ten of the 32 affected ears (31.26%) showed improvement of VEMPs after glycerol administration. Also, two (7.8%) of the unaffected ears showed positive glycerol. Latency of the VEMP had no significant changes after glycerol administration and there was no statistical correlation between the results of G-PTA and G-VEMP. There was statistical significant improvement of the slow peak velocity of caloric test in patient’s affected ears and insignificant improvement in control group and in unaffected ears after glycerol administration.

Objective: To evaluate resonance frequency (RF) values via dehydration effects in the inner ear caused by the glycerol test, which is used as a diagnostic method for Ménière’s disease (MD). Methods: Twenty adult patients with unilateral MD were included in the study. Before, and then at 1, 2, and 3 h after administration of glycerol (1 g/kg), pure-tone hearing levels (125–8,000 kHz) and multifrequency tympanometry tests were performed. As a control, the RF values of the ears of 25 healthy subjects (i.e., 50 ears) were compared to the affected and unaffected ears in the 20 MD patients. Results: There was a significant difference between the RF values of affected and healthy ears before glycerol administration (p = 0.047). The RF values before and after glycerol administration into affected ears were compared. The average RF values decreased significantly from 748.0 ± 402.1 to 808.0 ± 410.1 Hz at 1 h after glycerol intake, and this value increased during the subsequent hours. There were no statistically significant differences between the pure-tone levels before and 1 h after glycerol administration, but a significant decrease was observed at 3 h. Conclusion: We suggest that MD has different inner-ear dynamics and normal RF values when compared to healthy ears. Furthermore, decreased inner ear pressure causes reduction of the mass effect and a stiffening of the annular ligament. We conclude that pre- and post-RF tests should be added to the test battery for diagnosis of MD.

Conclusion. 3 T MRI after intratympanic injection of gadolinium-based contrast agent (GBCA) is more useful for the diagnosis of endolymphatic hydrops compared with the glycerol test and electrocochleography (ECoG). Objective: To investigate the relationship between 3 T MRI after intratympanic injection of GBCA, the glycerol test, and ECoG in patients with Meniere's disease (MD). Methods: A total of 20 patients with MD were evaluated. Diluted gadodiamide (a gadolinium-based contrast agent) was administered to the bilateral tympanic cavity by injection through the tympanic membrane. After 24 h, the endolymphatic hydrops was evaluated by a 3.0 T MR scanner. To investigate cochlear hydrops, the glycerol test and ECoG were carried out in all patients. Results: A positive result was observed in 11 patients (55%) in the glycerol test and in 12 patients (60%) by ECoG. The incidence of positive findings when evaluating the same patients with both the glycerol test and ECoG increased to 75%. Nineteen of 20 (95%) patients showed positive results for 3 T MRI., Article, ACTA OTO-LARYNGOLOGICA. 132(2):141-145 (2012)

Objective: To investigate the relationship between the plasma antidiuretic hormone (p-ADH) level, electrocochleogram (ECoG), and the glycerol test in patients with endolymphatic hydrops (ELH). Patients and Methods: The subjects were 60 patients, including 51 with Ménière’s disease (except for cochlear Ménière’s disease), 7 with delayed ELH, and 2 with syphilitic ELH. The time period for measurements of the p-ADH level, ECoG and the glycerol test was within 4 weeks. Results: 13 patients showed positive results for all tests. 58 patients showed positive results for at least one of three tests. Only 2 patients showed negative results for all tests. Conclusion: The p-ADH level, ECoG and the glycerol test show different selectivity of ELH detection. It is useful to perform all three tests to diagnose ELH.

The glycerol test is currently widely used to evaluate Meniere's disease, particularly in regard to its suitability for decompressive surgical therapy. Our previous findings have shown that patients with Meniere's syndrome respond extremely well to placebo treatment. We have investigated the effect of psychological factors in the outcome of the glycerol test. It was administered twice to each of a group of patients with a typical Meniere's syndrome. On one occasion the patient was told the hearing would improve, and on the other that the hearing would worsen. The same dose of glycerol was provided for each test, but with a different flavor. The sequence of test was randomly applied. The audiologist was unaware of instructions given to the patient. The patients usually responded as instructed. These results are discussed with particular regard to the risk of patient selection for surgery.

Objectives: To present electrocochleographic findings in patients with autoimmune disease (AD) with sensorineural deafness (ADSD), and to discuss the etiologies of sensorineural hearing loss (SNHL) in cases of ADSD. Methods: Study design is a retrospective review of electrocochleographic results of 26 patients with ADSD. To evaluate the electrocochleographic results, average SP/AP ratios were compared between ADSD and normal subjects. In the ADSD group, audiologic pattern, fluctuations in hearing and results of the glycerol test were also reviewed. Electrocochleography (ECoG) was recorded using the extratympanic method, and the SP to AP ratio (SP/AP ratio) was analyzed. Results: The mean of average SP/AP ratios in the ADSD groups (0.46) was significantly higher than that in normal subjects (0.27). Further, 17 of 29 affected ears in patients with ADSD showed fluctuating hearing loss. Eighteen ears showed low tone loss (rising and peak audiologic patterns). Only 5 of 26 ears (19.2%) showed positive results on glycerol test. There was no correlation between glycerol test results and hearing fluctuation or between glycerol test results and the SP/AP ratio on χ2-test. There was no tendency between audiologic pattern and glycerol test results or between audiologic pattern and the SP/AP ratio. Conclusion: These results suggest the etiologies of SNHL in cases of ADSD remain unclear. However, some cases showed clinical findings similar to endolymphatic hydrops. We should bear in mind that clinical Meniere’s syndrome involves ADSD. Further investigation is needed to resolve the etiology of SNHL of ADSD.

A patient with Meniere's disease demonstrating alternating seesaw-like fluctuation of bilateral hearing loss was treated by intravenous drip injection of glycerol for about 3 years and glycerol test had been performed 59 times. The results showed that the response on the glycerol test was very good even at the advanced stage, but the hearing activity gradually worsened. When the response on the glycerol test was good, his hearing activity recovered quickly after the glycerol test regardless of the hearing level. These results suggest that glycerol is not effective for controlling the hearing loss in Meniere's disease but glycerol might be useful for predicting the recovery of hearing loss or checking the potential of hearing activity.

Between 1993 and 1995, 178 patients complaining of fullness of the ear visited our clinic. Of these, 24 were found to have low-tone sensorineural hearing loss. Glycerol test revealed positive/ pseudopositive results in 20 of these 24 cases. Of these, 15 cases were followed up more than 3 years. Average hearing level at low-tone (125 Hz, 250 Hz and 500 Hz) in the 24 hearing-impaired patients were 34.0 dB. Clinical symptoms and low-tone sensorineural hearing loss of all patients were improved by isosorbide or betamethasone. The subjects who had temporary hearing impairment at 4, 000 Hz or 8, 000 Hz had significantly higher risk of recurrence. One findings suggested that low-tone deafness with a chief complaint of ear fullness is caused by endolymphatic hydrops. Prognosis may be dependent on the extent rather than the degree of the impairment in the inner ear. Prompt treatment and follow-up is important for patients who complain ear fullness, because some of them may progress to Meniere disease in the future.

elucidate whether endolymphatic sac decompression surgery (ESDS) has the potential to prevent unilateral Meniere’s disease (MD) from becoming bilateral. Methods: Between 1996 and 2008, we performed a glycerol test (G-test) and electrocochleography (ECoG) on 237 patients with intractable unilateral MD. We performed ESDS on 179 patients (144 with no endolymphatic hydrops and 35 with silent endolymphatic hydrops in the contralateral ear). The other 58 patients (40 without endolymphatic hydrops and 18 with silent endolymphatic hydrops in the contralateral ear) were given available medical treatments. All underwent regular follow-up for at least 5 years. Results: Altogether,22.4% (53/237) of patients with clinically diagnosed unilateral intractable MD had silent endolymphatic hydrops in the contralateral ear using G-test and ECoG. In the nonsurgical group, 6 of 40 patients with unilateral MD with no endolymphatic hydrops in the contralateral ear developed bilateral disease, whereas in the surgical group 12 of 144 patients did so (p=0.231, Fisher’s test). In the nonsurgical group, 9 of 18 patients with unilateral MD and silent endolymphatic hydrops developed the disease in the contralateral ear, whereas in the surgical group 6 of 35 patients developed bilateral disease (p=0.022, Fisher’s test). Conclusions: The present findings suggest that ESDS may decrease the incidence of developing MD in silent endolymphatic hydronic contralateral ears diagnosed with G-test and ECoG within the first five postoperative years. Does Endolymphatic Sac Decompression Surgery With Local Steroids Prevent Bilateral Development of Meniere's Disease? Tadashi Kitahara, MD, PhD1,2; Hidenori Inohara, MD, PhD1 ; Takahiro Ichihara, MD3; Shin-Ichi Haginomori, MD3 1. Department of Otolaryngology & Head and Neck Surgery, Osaka University, Graduate School of Medicine, Suita, Japan 2. Department of Otolaryngology & Head and Neck Surgery, Nara Medical University, Kashihara, Japan 3. Department of Otolaryngology & Head and Neck Surgery, Osaka Medical College, Takatsuki, Japan

Monitoring of cochlear function is one proposed clinical application of otoacoustic emission (OAE). To determine the clinical utility of OAE in monitoring, we studied changes in OAE during the glycerol test used to diagnose endolymphatic hydrops. Transiently evoked OAE (TEOAE) and distortion product OAE (DPOAE) were measured before and 3 hours after oral administration of glycerol in 22 ears of patients with Meniere's disease. The positive result in the glycerol test was observed in 11 of 22 ears. TEOAE was recorded using a nonlinear click stimulus, and total echo power (TEP) of the whole response and filtered echo power (FEP) of its mid-frequency (1000-2000 Hz) component were used as TEOAE parameters. The growth functions of DPOAE were recorded at 3 F2 frequencies--1000, 1500, and 2000 Hz. Changes in the growth function were determined based on changes in 2 parameters--maximum level and detection threshold of DPOAE. When changes in these 4 parameters exceeded 2 standard deviations above mean test-retest variability determined from OAE data for 17 normal ears, they were considered significant. Significant changes indicating improved cochlear function in 4 OAE parameters or the appearance of OAE during the glycerol test were judged positive for OAE. Regardless of glycerol test results, positive findings were observed in both OAEs whenever a pure-tone threshold at 1000 or 2000 Hz improved. However, even in ears for which pure-tone thresholds at these frequencies did not improve, both OAEs frequently exhibited positive findings. In all ears with a positive result in the glycerol test, positive findings were observed in DPOAE, but not in TEOAE. Of the 2 parameters of TEOAE, FEP always exhibited a positive finding in ears with a positive TEP finding and FEP positivity was higher than that of TEP. In DPOAE, no cases showed a positive finding only at F2 = 2000 Hz, and DPOAE at F2 = 1000 Hz could not be detected in 4 ears due to high noise floor. Overall, positive findings were obtained in 14 ears (63.9%) for TEOAE and 20 ears (90.9%) for DPOAE. In only 1 ear were no positive findings observed in either OAE. The sensitivity of OAE measurement as a diagnostic test for endolymphatic hydrops was higher than that of pure-tone audiometry. Of the 2 OAEs, test sensitivity was much higher for DPOAE than for TEOAE. These results show that OAE measurement detects changes in cochlear function during the glycerol test more sensitively than pure-tone audiometry. They also suggest that FEP is a better indicator than TEP as a parameter of TEOAE, and that DPOAE measurement at F2 = 1000 and 1500 Hz is sufficient for practical clinical use. However, of the 2 OAEs, DPOAE was considered more appropriate than TEOAE for monitoring during the glycerol test because of its high sensitivity in detection of changes in cochlear function. In conclusion, clinical use of OAE, especially DPOAE, as a test complementary to pure-tone audiometry during the glycerol test is very useful and will improve the diagnosis of endolymphatic hydrops.

Ziel der vorliegenden Arbeit ist es, mit Hilfe von TEOAE-Messungen (TEOAE = transiently evoked otoacoustic emissions) bei ausgewählten otologischen Erkrankungen (Hörsturz und M. Ménière) Schlussfolgerungen zum Verlauf und gegebenenfalls zur Prognose dieser Erkrankungen unter besonderer Berücksichtigung der methodischen Auswertungsverfahren ziehen zu können. Es wurden bei 46 Patienten vor Therapiebeginn, nach 3 und 9 Tagen sowie nach 1 und 2 Monaten ein Reintonaudiogramm angefertigt und TEOAE-Messungen durchgeführt. Die wichtigsten TEOAE-Befunde waren die frühzeitige Zunahme der Amplitude vor einem Hörschwellenanstieg beim klassischen Morbus Ménière (Stadium I) sowie die frühzeitige Zunahme der Amplitude und der Reproduzierbarkeit beim kochleären M. Ménière (Stadium II). TEOAE-Parameter könnten somit Indikatorfunktion für die Erholung des Gehörs haben. Beim Hörsturz trifft dieses nicht zu, was eine wesentliche Ursache in der ungeklärten Ätiopathogenese der Erkrankung haben könnte. Die statistische Auswertung eines Patientenkollektives ermöglicht eine prognostische Aussage zur Hörschwellenentwicklung. Dabei wird deutlich, dass TEOAE-Resultate besonders bei der Verlaufsbeurteilung des M. Ménière gut dazu geeignet sein können, das Therapieregime zu überwachen (Monitoring) bzw. zu einer Modifikation der Behandlungsstrategie beizutragen.

The oral glycerol test is useful to diagnose endolymphatic hydrops. The test is known to indicate positive results in almost 50% of the patients with Meniere's disease. However, it prohibits food intake before the test, requires a long examination time, and is associated with side effects such as headache, nausea and vomiting. The intravenous glycerol test is known to have no such disadvantages. We examined here, the usefulness of the intravenous test.The intravenous glycerol test was performed in 30 ears of 30 cases of Meniere's disease. Audiometry was carried out before the administration. A total amount of 100 ml Glyceol (10% glycerol) was intravenously injected over 30 min. Audiometry was also performed immediately after, and then 1 hour and 3 hours after the injection. Before the examination, food intake was not prohibited. A positive result was defined as a threshold improvement of the audiogram of 10 dB or more in at least 2 frequencies.Positive results were observed in 11 of 30 ears (36.7%) immediately after the injection, in 15 of 30 ears (50.0%) 1 hour later, and in 10 of 20 ears (50%) 3 hours later. The positive ratio 1 hour later was almost the same as that of the oral glycerol test, which was previously described. Thus, the injection test can evaluate the disease 1 hour after the administration without prohibition of food intake before the test. No side effects such as headache, nausea or vomiting were observed in any case.The intravenous glycerol test has the following advantages compared to the oral test: it does not prohibit food intake before the test, the examination time is shortened, and it is not associated with side effects.

Volumetric changes of the scala media were histologically investigated in normal guinea pigs to see whether glycerol-induced volumetric change of the scala media followed a biphasic course similar to the auditory threshold in the glycerol test. Glycerol was administered orally in a 12 ml/kg dose. The volume of the scala media was assessed by examining the cross-sectional area of the scala media in the mid-modiolar sections of the cochlea. Histological study revealed that the time-course of the change in the volume of the scala media after glycerol intake showed biphasic changes. Specifically, the early phase of the glycerol effect is a decrease in endolymph volume. The volume of the scala media significantly decreased by 11.4+/-2.9% 2 h after glycerol intake. Thereafter, the volume began to increase, and reached its peak 6-12 h after intake. In addition, the volume of the scala media significantly increased by 17.6+/-1.1% after 6 h. The present study indicated that the secondary increase in the volume of the scala media following glycerol intake played an important role in the rebound phenomenon in the glycerol test, although the mechanism underlying the hearing loss with the endolymphatic hydrops remains to be elucidated.

Objectives/Hypothesis The aim of the study was to elucidate whether endolymphatic sac decompression surgery (ESDS) has the potential to prevent unilateral Meniere disease (MD) from becoming bilateral. Study Design Prospective case–control study at tertiary referral center. Methods Between 1996 and 2008, we performed a glycerol test (G-test) and electrocochleography (ECoG) on 237 patients with intractable unilateral MD. We performed ESDS on 179 patients (144 with no endolymphatic hydrops and 35 with silent endolymphatic hydrops in the contralateral ear). The other 58 patients (40 without endolymphatic hydrops and 18 with silent endolymphatic hydrops in the contralateral ear) were given available medical treatments. All underwent regular follow-up for at least 5 years. Results Altogether, 22.4% (53 of 237) of patients with clinically diagnosed unilateral intractable MD had silent endolymphatic hydrops in the contralateral ear using G-test and ECoG. In the nonsurgical group, six of 40 patients with unilateral MD with no endolymphatic hydrops in the contralateral ear developed bilateral disease, whereas in the surgical group 12 of 144 patients did so (P = .231, Fisher test). In the nonsurgical group, nine of 18 patients with unilateral MD and silent endolymphatic hydrops developed the disease in the contralateral ear, whereas in the surgical group six of 35 patients developed bilateral disease (P = .022, Fisher test). Conclusions The present findings suggest that ESDS may decrease the incidence of developing MD in silent endolymphatic hydronic contralateral ears diagnosed with G-test and ECoG within the first 5 postoperative years. Level of Evidence 3b Laryngoscope, 124:1932–1936, 2014

BACKGROUND The cochlear aqueduct is a route for direct pressure transfer between intracranial and intracochlear fluids. In patients with Meniere's disease, intracochlear pressure is presumably disturbed. The "Tympanic Membrane Displacement Analyser (TDA)" is a new system which provides a useful noninvasive method of detecting intracranial and intracochlear pressure changes. PATIENTS In this study TDA measurements in combination with a glycerol test were performed in nine patients with Meniere's disease and in seven normal persons. RESULTS Before ingestion of glycerol, no significant difference in pressure was found between the two groups. After ingestion of glycerol a temporary decrease in intracochlear pressure was detected in both groups without any significant difference between the two groups. CONCLUSION These results show that the combination of glycerol testing and TDA measurements does not seem to be helpful for the differential diagnosis of Meniere's disease.

In bilateral inner ear lesions, it is not always easy to estimate which ear is responsible for vertigo. We herein show the effectiveness of electrocochleography (ECoG) in determining which ear is causing vertigo in a patient with bilateral Meniere's disease and a patient with delayed endolymphatic hydrops (DEH).Case 1 was a 44-year-old male with bilateral Meniere's disease since 1985. He complained of progressive hearing loss and his hearing had decreased to a level of approximately 55 dB in the bilateral ears. The glycerol test was positive and the caloric response remained normal in both ears. ECoG revealed an increase of negative summating potential (SP)/action potential (AP) ratio in both ears, however the AP value in the right ear (140 uv) was much higher than that in the left ear (24.2 uv). Endolymphatic shunt surgery was performed on the right ear and vertigo attacks disappeared thereafter.Case 2 was a 37-year-old male with profound hearing loss in his right ear first noticed at the age of 7 years. He did not complain of tinnitus in the right ear and had normal hearing in his left ear. Vertigo attacks without cochlear symptoms had occurred every two months since 1993. Caloric response was normal and the furosemide test was negative in both ears. The ECoG revealed an increase in negative SP/AP ratio (49%) in the left ear, indicating that the left ear was responsible for vertigo attacks.

Objectives: Nearly half a century ago, administration of glycerol was shown to temporarily improve the threshold of hearing in patients with suspected Meniere’s disease (glycerol test). Although a positive test result provides strong evidence of Meniere’s disease, the test has not gained widespread acceptance. A probable reason is that there is no consensus as to the definition of positive. Moreover, a negative test result is of little diagnostic value because Meniere’s disease cannot be excluded. By reanalyzing archived data, the authors sought to understand the test in light of signal detection theory. Moreover, they explored the possibility of estimating the probability of a positive test result from the pretest audiogram. Design: The study is based on audiograms from 347 patients (356 ears) who underwent a glycerol test to corroborate a suspected diagnosis of Meniere’s disease. Subsequent to an initial pure-tone audiogram, glycerol (1.2 mL/kg body weight) was orally administered; follow-up audiograms were obtained after 1, 2, 3, and 4 hr. Transcription of the audiograms into a computer-readable form made them available for automated reanalysis. Results: Averaged difference audiograms provided detailed insight into the frequency dependence and the temporal dynamics of the glycerol-induced threshold reduction. The strongest threshold reduction was observed 4 hr after glycerol intake, although nearly the same effect was already found after 3 hr. Strong overall threshold reductions were associated with a pronounced maximum at approximately 1000 Hz; weaker effects were associated with a plateau between 125 and 1000 Hz and a rapid decrease toward higher frequencies. To date, criteria suggested for a positive test result vastly differ in both sensitivity (with regard to the detection of a threshold reduction) and specificity (1 minus false-positive rate). Here, a criterion based on the aggregate threshold reduction in adjacent audiometric frequencies is suggested. This approach does not only seem to be more robust but also permits to freely adjust the false-positive rate. A positive test result is particularly likely when the mean low-frequency hearing loss is approximately 60 dB and the mean high-frequency hearing loss does not exceed 50 dB. Conclusion: If the pretest audiogram does not render a positive test result unlikely, a state-of-the-art implementation of the glycerol test is a competitive method for corroborating a suspected diagnosis of Meniere’s disease.

Our study was designed to establish a diagnostic significance in Meniére's disease by means of evoked otoacoustic emissions (EOAEs). EOAEs were recorded from patients with Meniére, and the "main frequency" of the emissions, which shows the maximum peak in the frequency spectrum, was examined as a variable. The main frequencies in ears with Meniére ranged mainly from 0.8 kHz to 1.1 kHz and were to be found at lower frequencies than in ears with normal hearing whose range was mainly from 1.0 kHz to 1.6 kHz. Furthermore, in some ears with Meniére, the main frequencies changed from lower to higher after administration of osmotic diuretics such as glycerol or isosorbide. On the basis of these results it was speculated that in ears with Meniére, lower frequency dominant emissions might be elicited by modification of the basilar membrane in endolymphatic hydrops and that the main frequencies might change from lower to higher with reduction of endolymphatic hydrops induced by osmotic diuretics. It was considered that the EOAE testing might be useful for a diagnosis of endolymphatic hydrops in Meniére.

Changes in hearing were studied in 145 ears (103 patients) with endolymphatic hydrops before and after an 8-week administration of isosorbide. Hearing improvement was observed in 57 (39.3%) of the 145 ears. These improvements showed a significant correlation with positive results in the glycerol test (p 0.01). Of the 46 ears with a positive result, hearing was improved in 32 (69.6%). Therefore, results of the glycerol test predict a response to isosorbide therapy for the hearing loss of endolymphatic hydrops.

Objective evaluation of vestibular Meniére's disease has been difficult due to the lack of audiometric findings. Thus inevitably, the existence of vestibular Meniére's disease is constantly being challenged. In recent years, electrocochleography (ECochG) has proved to be a useful tool to verify the presence of endolymphatic hydrops electrophysiologically. To further clarify the nature of this disease, we collected 40 patients prospectively who met the following conditions as diagnostic criteria for clinical vestibular Meniére's disease: i) episodic vertigo, ii) aural fullness, and iii) normal hearing. We implemented the glycerol test and extratympanic ECochG in addition to routine survey in these cases. The diagnosis was confirmed if either test result was positive. A retrospective collection of 24 cases who underwent endolymphatic sac surgery was made to evaluate in retrospect the existence of endolymphatic hydrops indirectly proved by successful surgery. Results showed a positive SP/AP ratio in 25 cases (62.5%) of which 7 had bilateral positive responses. The glycerol test was positive in 5 cases including 3 who also had positive ECochG responses. In the retrospective group, 4 cases exhibited an abnormally large SP/AP amplitude ratio at preoperative baseline conditions after general anesthesia. Twenty cases showed an SP/AP ratio within normal limits. Only 7 cases (29%) showed a decrease in the SP/AP ratio at different surgical steps. Short-term surgical results showed a 96% success rate of relief of vertiginous symptoms. Symptoms of fullness were completely controlled in 22 patients (92%). Hearing was preserved in 18 patients (75%). We conclude that i) the above-listed clinical criteria combined with these objective tests may prove to be very useful in the diagnosis of vestibular Meniére's disease, and ii) a successful control of vertigo and aural fullness after endolymphatic sac surgery indirectly indicates that endolymphatic hydrops is involved in vestibular Meniére's disease, sharing as it does, a pathophysiology that is similar to that of classic Meniére's disease.

The tympanic membrane displacement technique (TMD) is aimed at evaluating intracochlear and intracranial pressure changes non-invasively. Therefore, the present paper describes the findings in patients with Meniere's disease where an increase in volume of the endolymphatic spaces is discussed. It should be investigated to which extent a change in the intracochlear pressure corresponds to different stages of the disease. It could be described that the intracochlear pressure does change over a certain period of persisting Meniere's, but that there is no extensive increase in intracochlear pressure between the attacks. The glycerol test as well as the acute attack (case report on one patient) are, however, characterised by distinct patterns. The same holds true for the late-stage Meniere's. It could be demonstrated that the functional patency of the cochlear aquaeduct in patients with long-term Meniere's history is reduced. This finding is surprising and should be investigated further. In essence, the TMD technique enables to better characterise Meniere patients, but it should not be a tool of routine diagnosis of the disease. In some audiological patients, it can also be beneficially applied (10).

The purpose of this study is to follow up the dynamics of pure tone threshold and DPOAE amplitude changes induced by glycerol with reference to its activity in the inner ear. Selection was made among 38 patients with Meniere’s disease for those having positive glycerol test. Pure-tone audiometry and DP-gram were performed in four series: as an initial examination before glycerol intake, 1, 2 and 3 h after. Audiometric changes formed distinct biphasal pattern at all frequencies between 250 and 4,000 Hz. The most dynamic pure tone threshold decrease occurred during the first hour. Between the first and second hour after glycerol ingestion there was a phase of no significant hearing changes. Further pure tone threshold decrease went on within the third hour reaching its top. Observing DPOAE changes, the highest DP amplitude growth occurred after the second and the third hour at DP-gram frequencies 2, 3 and 4 kHz. The fastest DP-amplitude increase was registered as well during the first hour after glycerol ingestion. In 11 persons with both audiometry and DPOAE positive glycerol test, parallel dynamics in the course of the glycerol test was observed. Biphasal glycerol test dynamics suggests the possibility of two mechanisms of glycerol activity in the inner ear.

Correlations were investigated between plasma levels of antidiuretic hormone (ADH) and the frequency of vertigo attacks, and between hearing and serum Na levels in patients with Meniere's disease. Plasma ADH levels were measured every 3 months for 1 year in 48 patients. Those with persistently high plasma ADH levels tended to have frequent vertigo attacks (Fischer's exact probability test; P

Glycerol test results and electrocochleographic (EcochG) findings were correlated with the plasma antidiuretic hormone (ADH) level in patients with Meniere's disease. There was no statisticaly significant correlation between the glycerol test and plasma ADH. However, the plasma ADH level tended to decrease in patients with a positive reaction to the glycerol test and tended to increase in patients with a negative reaction. There was a statisticaly significant correlation between the dominant negative SP (-SP) of EcochG and the plasma AD H level. Plasma ADH tended to increase in patients with dominant -SP. It has been reported that the plasma ADH level in patients with Meniere's disease is higher than normal. Both the positive reaction to the glycerol test and the dominant -SP of the EcochG indicate the presence of endolymphatic hydrops. In this study, however, there seems to be a discrepancy between the correlations of glycerol test result and EcochG with the plasma ADH level. These results may mean that the positive reaction to the glycerol test and the dominant -SP of EcochG may represent different conditions of endolymphatic hydrops in Meniere's disease.

Over a 10-year period, two patients with a diagnosis of sudden deafness without vertigo and 15 patients with a diagnosis of sudden deafness with vertigo at their first episode of hearing loss later developed definite Meniere's disease. These early Meniere's disease patients were compared with 133 patients with sudden deafness without vertigo, 71 patients with sudden deafness with vertigo, and 90 patients with definite Meniere's disease. Differences in the results of audiography, glycerol test, caloric test, and electrocochleography were assessed.There was a significant difference in an upsloping audiogram between patients who had sudden deafness with vertigo and those with definite Meniere's disease (chi-square test: p