Endolymphatic hydrops evaluation on MRI: Practical considerations

Four-hour delayed three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) sequence after intravenous gadolinium-based contrast agent administration is an optimal magnetic resonance imaging technique to evaluate endolymphatic hydrops in patients with known or suspected Ménière's disease. Nonenhanced endolymphatic space surrounded by enhanced perilymphatic space is evaluated in the cochlea and vestibule separately. In cochlear hydrops, the scala media is enlarged, potentially obliterating the scala vestibuli. In vestibular hydrops, the size of the saccule becomes equal to or larger than that of the utricle; as hydrops progresses, the saccule and utricle become larger and confluent until complete obliteration of the vestibule's perilymphatic space.In patients with a unilateral clinical presentation of Ménière's disease, it is possible to depict the asymmetries of perilymph enhancement, which may be increased on the affected side and reflect a permeability alteration of the blood-perilymph barrier. In addition, endolymphatic hydrops can be observed in the asymptomatic ear of these patients with a unilateral clinical presentation, showing that Ménière's disease tends to undergo bilateral evolution over time.     

Superior vestibular and "singular nerve" section--animal and clinical studies

Three patients are presented who experienced improved hearing for one month following a middle cranial fossa superior vestibular and “singular nerves” section. Depriving the vestibular labyrinth of its blood supply results in severe degeneration of the ampulla of the three semicircular canals and macula of the utricle, complete reversal of the sodium-potassium ratio of the vestibular endolymph and elevation of vestibular endolymph and perilymph protein concentrations. If the blood supply is preserved denervation of either the cochlea or vestibular labyrinth does not result in degeneration of the sense organs or alterations in the biochemistry of the inner ear fluids. The cochlea appears normal histologically and cochlear endolymph has normal sodium-potassium ion concentration after cutting the superior and “singular nerves” with accompanying vessels. This may be the first evidence that vestibular endolymph is secreted in the vestibular system and is independent of cochlear endolymph. The marked biochemical and histological changes observed in the vestibular labyrinth after cutting the superior vestibular and “singular nerves” with their blood supply in the internal auditory canal may have an effect on the clinical course of Ménière's disease.     

Postural Control and Glycerol Test in Me´nie`re's Disease

Ménière's disease is a clinical disorder, characterized by fluctuating hearing loss, recurrent spontaneous episodic vertigo, tinnitus and aural fullness, which may be defined as the idiopathic syndrome of endolymphatic hydrops. The most important test for diagnosis of Ménière's disease is the glycerol test. This is a simple and rapid method and several authors have confirmed its efficiency for identifying endolymphatic hydrops. This test provides information on the cochlear response to the osmotic changes produced by glycerol in the inner ear, whereas modifications in the vestibular labyrinth are usually not evaluated. The aim of this study was to evaluate the effects of glycerol on postural control during attacks of Ménière's disease, and to correlate this data with data on cochlear function. After the glycerol test, an improvement in postural control was recorded in 70% of patients, with all patients reporting a recovery of vertigo. The impairment of postural control during endolymphatic hydrops could be related to a pressure increase in the labyrinth, which interferes with the normal dynamics of the endolymph, and a rapid functional recovery could occur during an osmotic depletion. Dynamic posturography improves the sensitivity of the glycerol test and may therefore be useful in the diagnosis and staging of Me´nie &#164 re's disease.     

The etiology of Menière's attacks and their consequent physiologic aspects

On the basis of theoretical considerations and experimental studies, it can be shown that Menière's attacks result from rupture of the membranous labyrinth with diffusion of potassium into the perilymph and sodium into the endolymph.     

The surgical treatment of Ménière's disease.

Ménière's disease is more common than was generally believed in the past. Stahle has calculated the incidence of Ménière's disease in Sweden. Using the same incidence for the United States, there ought to be 97,000 hospitalized inpatients with Ménière's disease of all ages in the whole population. The increased understanding of inner ear physiology and pathology during the past decade has changed the indication for operation towards an early intervention for preserving the hearing function. For the purposes of analyzing results, patients with Ménière's disease were divided into the following classes according to the hearing loss only: 1. Near normal hearing (no more than 10 db loss at 500, 1,000, 2,000). 2. Ascending audiogram, fluctuating (500 more than 10 db more than 2,000). 3. Flat audiogram, fluctuating (500 not 10 db different than 2,000). 4. Flat audiogram, non-fluctuating (500 not 10 db different than 2,000). 5. Other, more extreme hearing loss, non-fluctuating (2,000 10 db more than 500). In this study, 33 patients with early Ménière's disease had a subarachnoid endolymphatic shunt operation. Two patients belonged to Class 1 and 31 patients to Class 2. All had well-visualized vestibular aqueducts on polytomography and most had a positive glycerin test done in conjunction with transtympanic electrocochleography. During the first postoperative year, two patients in Class 2 improved to Class 1 (normal hearing). The other 29 in Class 2 remained in Class 2. None was worse as regards hearing. Most were completely relieved or improved as regards vertigo. Early surgical drainage in Ménière's disease is effective and safe and should be performed prior to irreversible dilatation of the membranous labyrinth. Patients in Classes 3, 4, and 5, with excessive and widespread hydrops of the membranous labyrinth, should have a vestibular nerve section.     

Masking Level Difference in Normal and Pathological Ears

The masking level difference (MLD) was studied in 9 normal subjects, in 15 patients with conductive hearing losses, in 9 subjects suffering from Menière's disease, and in 8 subjects with sensorineural hearing losses

Results showed that MLD's size not depend on the conductive impairement but it may be affected by the degree of the deafness both in Menière's disease and in sensorineural lesions     

Intratympanic gentamicin for unilateral Menière's disease: results of therapy

Intratympanic gentamicin for unilateral Menière's disease: results of therapy Patients with Menière's disease that remains refractory to conservative treatment have traditionally been subjected to ablative surgery. The purpose of this prospective study was to evaluate the use of intratympanic gentamicin in eliminating incapacitating vertigo, while preserving hearing. Over the past 8 years, 83 patients have received between 1 and 6 intratympanic injections of gentamicin in an out‐patient setting, with duration of therapy titrated to individual symptom response and effect on hearing. Using established AAO‐HNS guidelines, we present data on 50 patients who have a minimum of 2 years follow‐up. Control or significant improvement of definitive Menière's attacks was achieved in 92% of patients and hearing preserved or improved in 76%. Only one patient experienced profound sensorineural hearing loss. We feel this treatment option should be considered and offered to patients in whom medical treatment has failed.     

Long-term results after interval therapy with intratympanic gentamicin for Menière's disease

Objectives The new single‐shot and interval treatment for Menière's disease with gentamicin was designed to avoid cochlear damage during treatment with gentamicin. Methods To date, 90 patients were treated with the single‐shot or interval gentamicin therapy. Fifty‐seven cases of Menière's disease were followed up prospectively between 2 and 4 years. During one treatment series, a maximum of three intratympanic gentamicin injections within 15 days were applied, each consisting of 0.3 mL (12 mg) of gentamicin (days 1, 8, and 15). Thirty of these 57 patients (53%) needed only one injection to be controlled (single‐shot treatment). Results Vertigo attacks were completely controlled in 95% and partially controlled in 5%, whereas hearing remained unchanged or even improved. Tinnitus as well as aural fullness were controlled in approximately 50% of the cases. Conclusion Our results with this group of patients after interval‐treatment or single‐shot application of intratympanic gentamicin demonstrate the effectiveness of this treatment modality with very low side effects, and, although our experience is still limited, it allows for expanding the indication on early cases of Menière's disease before permanent hearing loss occurs. Even cases of bilateral Menière's disease can be treated successfully using this method. Cochleotoxic side effects can be prevented by treatment intervals of 7 days.     

Non-invasive perilymphatic pressure measurement in patients with Menière's disease

The MMS-10 Tympanic Displacement Analyser is a new device to measure the perilymphatic pressure in humans. This instrument was used in 25 patients with Menière's disease (28 affected ears) and a group of 50 young normal hearing subjects. No significant differences were found in perilymphatic pressure measurements between the groups. Although measurement parameters showed large inter-individual variation, the intra-individual correlation was good. In patients with Menière's disease, no relationship was found between perilymphatic pressure, hearing thresholds, blood pressure, gender or age.     

The AAO–HNS Committee on Hearing and Equilibrium Guidelines for the diagnosis and evaluation of therapy in Menière's disease: have they been applied in the published literature of the last decade?

The AAO–HNS Committee on Hearing and Equilibrium Guidelines for the diagnosis and evaluation of therapy in Menière's disease: have they been applied in the published literature of the last decade? To assess how effectively the American Academy of Otolaryngology–Head and Neck Surgery Committee on Hearing and Equilibrium (AAO–HNS CHE) guidelines for the diagnosis and evaluation of therapy in Menière's disease have been applied in the last 11 years of published literature. This was a MedLine‐based review. Some 79.7% of papers attempted to use the AAO–HNS CHE guidelines. However, only 50% of these publications managed to use the AAO–HNS CHE criteria in the diagnosis and evaluation of therapy correctly. In order to advance our understanding of this condition, improved application of the AAO–HNS CHE guidelines by authors and editors alike is required in the reporting of results of the therapy of Menière's disease.     

The pharmacological treatment of Menière's disease

The management of Menière's disease often provides a formidable clinical challenge largely because its precise aetiology is unknown. There is no known ‘cure’ once the condition is established, but drugs may be helpful in treating both the acute attacks of vertigo, and in more long-term management, particularly in the earlier fluctuant stage. These remedies are largely symptomatic and there are few if any properly controlled studies of their efficacy. Suppressant drugs may act centraly at neurotransmitter sites, or peripherally on the labyrinth. Conventional diuretics and osmotically acting agents have been given to reduce the endolymph fluid volume Histamine anlogues directly reduce inner ear fluid pressure mainly by increasing the cochlear blood flow. and are probably the treatment of choice. Otovestibulotoxic drugs given systemically to cause chemical labyrinthine ablation are frequently effective in abolishing attacks of vertigo but often resulted in disabling oscillopsia and ataxia. There is now evidence that local administration by intratympanic injection may well be more efficacious resulting in selective partial end organ ablation. To date innovative immune modigying regimes have not proved helpful.     

Balance Rehabilitation Unit (BRUTM) posturography in Menière's disease

Posturography has been used in the evaluation of patients with vestibular disorders.AimTo evaluate balance control with the Balance Rehabilitation Unit (BRU^TM) posturography in patients with Menière's disease.Study designProspective case-control.Material and Method30 patients diagnosed with Menière's disease and a control group consisting of 40 healthy matching individuals in relation to age and gender, were submitted to a balance function evaluation by means of a Balance Rehabilitation Unit (BRU^TM) posturography.ResultsComparing patients with Menière's disease and the control group, we found significant differences between the values of the sway speed in the static force plate, down optokinetic stimulation (p=0.038) and horizontal visual vestibular interaction (p=0.049); and of the ellipse area in the static force plate, eyes closed (p=0.001); left optokinetic stimulation (p=0.007); down optokinetic stimulation (p=0.003); horizontal visual vestibular interaction (p=0.003); and vertical visual vestibular interaction (p=0.028).ConclusionThe postural control assessment with the Balance Rehabilitation Unit (BRU^TM) posturography enables the identification of sway speed and ellipse area abnormalities in patients with Menière's disease.     

Pure‐tone and speech audiometry in patients with Menière's disease

The aim of this study was to reinvestigate many of the claims in the literature about hearing loss in patients with Menière's disease. We carried this out on a well‐defined group of patients under well‐controlled circumstances. Thus, we were able to find support for some claims and none for many others. As part of a diagnostic protocol, pure‐tone and speech audiometry was performed on 111 patients with Menière's disease according to the ‘Definition Menière Groningen’. This was a prospective clinical cohort study. Affected ears of patients suffering from Menière's disease show reduced hearing, both in pure‐tone and in speech audiometry. A classification method was devised to determine audiogram shape in an objective manner. The results of this method indicate that affected ears more frequently show ‘low’ or ‘low + high’ hearing losses (P = 0.006). The shape of the hearing loss does not depend on the duration of the affection of the disease. In combination with the fact that the average hearing loss does not correlate with the duration of the disease, this leads to the conclusion that, if a classification of the hearing loss in Menière's disease is possible, such a classification cannot be connected to the duration. This conclusion is further supported by the fact that no relationship is found between the duration of the disease and the classification of the hearing loss over the 3 months before hospital admission, as given by the patients in a questionnaire. A relationship between the (objective) audiometric data and the (subjective) classification of the hearing loss by the patient seems to be present, but is not very strong. Correlations between pure‐tone and speech audiometry are present as in non‐Menière ears (r = 0.899, P < 0.001), and no indications are found of reduced speech discrimination relative to the expectation based on pure‐tone loss. The audiogram shape does not appear to play any additional role in speech discrimination (in addition to the influence of the average pure‐tone loss).     

Factors associated with quality of life in Menière's disease

The aim of this study was to identify the factors associated with better or worse quality of life in a sample of people with Menière's disease drawn from a UK self‐help group (the Menière's Society) and to assess the forms of support on which the respondents could draw. A postal survey was sent to 1000 randomly selected group members, containing validated questionnaires assessing: (1) quality of life (the Short Form 36 (SF‐36)); (2) factors that might predict quality of life; and (3) usage of resources provided to members by the Menière's Society. A total of 509 members completed the main survey, and 370 the second part of the survey. Factors associated with a less good quality of life included more severe vertigo, pressure in the ear, hearing loss and tinnitus, being younger, being female, living alone, having a lower occupational status and believing that the attitude of the consultant is unhelpful. Levels of vertigo severity in this sample were similar to those found in hospital samples, but it is possible that these respondents may differ in other respects from patients who do not join a self‐help group.     

Pathophysiology of endolymphatic hydrops.

Endolymphatic hydrops of the nonprogressive type occurs in response to a single traumatic or toxic insult of limited duration and although it may result in permanent deficits in sensorineural function, there is total subsidence of vestibular symptoms. Endolymphatic hydrops of the progressive type, on the other hand, appears to be the result of permanent impairment of endolymph resorption and is caused principally by disorders of the endolymphatic sac. It occurs in Menière's disease, syphilitic labyrinthitis and the delayed hydrops syndrome. In addition to deafness of varying extent, it is characterized by episodic vertigo and sometimes by Hennebert's sign. Histological studies suggest that the acute vertiginous episodes are caused by potassium intoxication following ruptures of the membranous labyrinth and that Hennerbert's sign is caused by vestibular fibrosis.     

Pathology as it relates to ear surgery. IV. Surgery of Menière's disease

Conservative shunting procedures, i.e. ESS, ultrasonic irradiation and cryosurgery, are based on the assumption that there is increased volume and/or pressure of endolymph in Menière's disease. Since there is no reliable clinical test to detect endolymphatic hydrops, shunting procedures on cases without hydrops are doomed to failure. Surgery on the endolymphatic sac was not associated with fibrosis or obliteration of its lumen. Silastic shunt tubes were well tolerated by the body, and the shunt between the sac and the subarachnoid space seemed to remain open. The results of experimental surgery on the endolymphatic sac and its applicability to humans should be revised. Temporary improvement of Menière's symptom-complex may be expected from any surgical procedure on the membranous labyrinth, even in cases without endolymphatic hydrops. Post-operative serous labyrinthitis with associated biochemical changes is the cause of this improvement. The success of shunting procedures cannot be judged histologically by the position of Reissner's membrane. This membrane acts like varicose veins: once dilated, always dilated. Ultrasonic irradiation and cryosurgery of the labyrinth result in limited degenerative changes close to the site of probe application. Degenerated intact membranous walls may act as an internal otic-perotic shunt and may result in symptomatic improvement in Menière's disease. The idea of selective vestibular neurectomy and internal shunting procedures, i.e. without drainage of endolymph to the outside (mastoid) or to the inside (CSF), should be developed further. Recurrence of symptoms following shunting procedures may be due to failure of the shunt, or to the presence of endolymphatic hydrops in the non-operated ear. MF vestibular neurectomy results in complete denervation of the vestibular end-organs, without effect on the cochlea or facial nerve. Excision of Scarpa's ganglion causes retrograde degeneration in the proximal stump of the vestibular nerve, most probably to the level of the brain-stem. Recurrence of dizziness following TC labyrinthectomy is most commonly due to inadequate removal of the vestibular end-organs. The high regenerative capacity of the vestibular nerve is evidenced by the formation of traumatic neuromas in the vestibule following TC labyrinthectomy. Whether these neuromas produce symptoms is unknown. Persistent cochlear hydrops occurs following TC labyrinthectomy and TL vestibular neurectomy owing to obstruction in the hook region of the cochlea and in the ductus reuniens. This may result in persistent tinnitus and feeling of pressure in the ear.     

Clinical Electrocochleography in the Diagnosis and Management of Menière's Disorders

Patients with a fluctuating hearing loss, episodic vertigo and tinnitus with no known aetiological cause were investigated as cases of Menière's disorder. Transtympanic electrocochleography was found to be helpful in reaching the diagnosis of an inner ear disorder. In 65% of the patients, a large DC potential was recorded which caused an apparent widening of the summating potential/action potential (SP/AP) waveform. This potential was thought to be an SP which was enhanced relative to the AP component, and believed to be related directly to the presence of endolymphatic hydrops. A method is described which 'scores' the clinical history with respect to the certainty of the diagnosis of Menière's disorder. It was found that the more certain cases, with high scores, were statistically more likely to show an abnormal SP/AP waveform. The results of endolymphatic sac surgery were also assessed over 1 year in 28 cases, and it was found that those patients whose ECochG had revealed an abnormal SP/AP waveform prior to surgery benefitted in a statistically significant manner more from the operation.     

Graphic angle measure as an electrocochleography evaluation parameter

To improve electrocochleography's diagnostic sensitivity in Meniére's disease - new assessment methods are being studied.AimTo determine whether or not graphic angle measurement is sensitive and specific to Menière's disease laboratorial diagnosis and if there is an increase in the electrocochleography's sensitivity and specificity when graphic angle measurements are associated with Summating Potential-Action Potential ratio (SP/AP ratio).MethodsElectrocochleography's was used to analyze 71 ears from 55 subjects: 41 patients with clinical diagnosis of Menière's disease (MD group), and 14 healthy individuals as control (Group C). Graphic results were analyzed initially to obtain the SP/AP ratio; afterwards, through another program graphic angle measurements were calculated.ResultsSensitivity and specificity values of angle measures, SP/AP ratio, and the association between them varied according to the cutoff point, the highest equilibrium between sensitivity and specificity was observed with the values of 166.25 for angle measurement and 27% for SP/AP relation; 62.79% / 60.71% and 74.42% / 67.86%, respectively. The association between measurements showed a sensitivity increase due to the specificity decrease; 88.37% and 50%, respectively.ConclusionAngle graphic measurement is not sensitive and specific enough for the laboratorial diagnosis of MD. Angle graphic measurement and SP/AP ratio association proved to be higher in sensitivity, in detriment of exam specificity.     

Vestibular rehabilitation with virtual reality in Ménière's disease

Virtual reality technology can provide a wide range of sensory stimuli to generate conflicts of varying degrees of complexity in a safe environment.ObjectiveTo verify the effect of a virtual reality-based balance rehabilitation program for patients with Menière's disease.MethodThis observational clinical study included 44 patients aged between 18 and 60 years diagnosed with Menière's disease submitted to a controlled randomized therapeutic intervention. The case and control groups took betahistine and followed a diet. Case group subjects underwent 12 rehabilitation sessions with virtual reality stimuli in a Balance Rehabilitation Unit (BRU?). Patients were assessed based on DHI scores, the dizziness visual analogue scale, and underwent posturography with virtual reality before and after the intervention.ResultsAfter the intervention, the case group showed significantly lower scores in DHI (p < 0.001) and in the dizziness visual analog scale (p = 0.012), and had significantly greater limit of stability areas (p = 0.016) than controls.ConclusionVirtual reality-based balance rehabilitation effectively improved dizziness, quality of life, and limit of stability of patients with Menière's disease.