Vestibulospinal function in two syndromes with spontaneous attacks of vertigo: evaluation by posturography

Two vestibular syndromes comprising attacks of spontaneous vertigo were studied and disturbance of the vestibulospinal reflex was evaluated. Patients with Menière's disease were examined between attacks and patients with a sudden unilateral vestibular loss syndrome at least 3-4 weeks after the initial attack. Posturography, (recording and analysing the postural sway) was used to evaluate the influence of these disorders upon the vestibulospinal reflex. In 50% of the patients, the postural sway was disturbed compared with the performance of a normal control group. Menière's disease had a more pronounced effect on the posturographic results, whereas for the unilateral vestibular loss syndrome the rotation tests showed more asymmetry. It is obvious that the effect upon the vestibulospinal reflex cannot be deduced from the rotational test results. Indeed in a large number of patients discordance between rotational test results and posturography was seen. The presence or absence of attacks during the previous year in patients with Menière's disease had no influence on the presence of abnormal posturographic results. If other complaints of dizziness were mentioned by the patient, posturography was nearly always abnormal. It is evident that a complete evaluation of such patients must include information obtained by posturography.     

Vestibular evoked myogenic potentials show altered tuning in patients with Ménière's disease.

OBJECTIVE: Acoustic stimulation of the saccule gives rise to a vestibulocollic reflex, the output of which can be measured in the neck as inhibition of activity in the ipsilateral sternocleidomastoid muscle. This vestibular evoked myogenic potential has been promoted as a means of assessing integrity of saccular function. In this study, we test the hypothesis that the cochleosaccular hydrops of Ménière's syndrome leads to alterations in saccular motion that change the dynamics of the vestibular evoked myogenic potential. STUDY DESIGN: Prospective cohort study. SETTING: Large specialty hospital, department of otolaryngology. SUBJECTS: Fourteen normal adult volunteers and 34 consecutive consenting adult patients with unilateral Ménière's disease by American Academy of Otolaryngology-Head and Neck Surgery diagnostic criteria. INTERVENTIONS: All subjects underwent vestibular evoked myogenic potential testing using ipsilateral broadband click and short tone-burst stimuli at 250, 500, 1,000, 2,000, and 4,000 Hz. MAIN OUTCOME MEASURES: Threshold, amplitude, and latency of vestibular evoked myogenic potential responses in normal and Ménière's affected and unaffected ears. RESULTS: Vestibular evoked myogenic potential was present in all ears tested. Normal subjects show a frequency-dependent vestibular evoked myogenic potential threshold, with best response ("frequency tuning") at 500 Hz. Compared with normal subjects and unaffected ears of Ménière's subjects, affected Ménière's ears had significantly increased vestibular evoked myogenic potential thresholds. Affected Ménière's ears showed threshold shifts at all frequencies and there was less tuning apparent at 500 Hz. Unaffected ears of Ménière's subjects also showed significantly elevated vestibular evoked myogenic potential thresholds compared with normal subjects. Analyses of vestibular evoked myogenic potential thresholds for effects of age, hearing loss, and audiometric configuration showed no significant differences. CONCLUSIONS: Ménière's ears display alterations in vestibular evoked myogenic potential threshold and tuning, supporting our hypothesis of altered saccular motion mechanics arising from hydropic distention. Unaffected ears of unilateral Ménière's subjects show similar changes, though to a lesser degree. This finding may be because of occult saccular hydrops in the asymptomatic ear or binaural interactions in the vestibular evoked myogenic potential otolith-cervical reflex arc.     

Computed tomographic findings in Ménière's disease

Symptoms in Ménière's disease are explained by hydrops of the endolymphatic system with recurrent ruptures of the membranous labyrinth. The primary cause of the increased endolymphatic volume appears to be an imbalance between secretion and resorption of endolymph which may be due to an obstruction of the endolymphatic duct and sac, located in the vestibular aqueduct (VA). Non-visualization or narrowing of the latter have been demonstrated by conventional tomography. Also, sclerosis and hypoplasia of the retrolabyrinthine portions of the temporal bone have been documented. By high resolution computed tomography (CT) we prospectively tried to demonstrate morphological alterations in 10 patients with Ménière's disease. These were compared with a group of 14 non-Ménière patients. Visualization of the VA as well as perilabyrinthine pneumatization were assessed and the width of the retrolabyrinthine part of the temporal bone was measured. Whereas there was a slight difference in the average retrolabyrinthine width (3.8 mm in Ménière versus 5.8 in non-Ménière cases) and degree of pneumatization, there was a distinctly decreased visualization of the VA in the Ménière group. As findings were always bilateral and only 3 of 20 temporal bones showed peripheral hypopneumatization, possibly due to chronic otitis media, the theory of a predisposing constitutional abnormality must be taken into consideration. However, we were not able to confirm a statistically proven usefulness of the CT technique in identifying an anatomical abnormality which is directly in correlation with the side of the lesion in cases of unilateral Ménière's disease.     

Results of vestibular autorotation testing at the end of intratympanic gentamicin treatment for Ménière's disease

OBJECTIVE: The vestibular autorotation test (VAT) examines the ocular response to voluntary horizontal and vertical head movements at frequencies for which the vestibular system is the main source for eye stabilization. The purpose of this study was to analyse the VAT results in patients with disabling Ménière's disease and to evaluate the change in VAT values once treatment with intratympanic gentamicin had terminated and clinical signs of vestibular hypofunction could be observed. MATERIAL AND METHODS: The 30 study subjects were patients diagnosed with definitive unilateral Ménière's disease that could not be controlled with medication. The vestibulo-ocular reflexes of each patient were evaluated by means of the VAT before the first injection of gentamicin and after the last injection. RESULTS: The pattern of abnormalities found in this population conformed to the selection criteria and the findings reflected a severe disabling process, with major modifications in the vestibulo-ocular reflex. At the end of treatment there was a reduction in the peak frequency of head oscillation. Furthermore, we commonly found that, in the horizontal VAT, gain and phase were reduced while in the vertical VAT some subjects registered a normal response. The phase in the horizontal and vertical VATs was most significantly reduced for oscillation frequencies of 2-3.7 Hz. CONCLUSION: This study provides further evidence that effective control of vertigo in patients with Ménière's disease can be achieved by administering intratympanic gentamicin.     

Vestibular evoked myogenic potential (VEMP) in patients with Ménière's disease with drop attacks

OBJECTIVE: In this retrospective study, we tested the hypothesis that vestibular evoked myogenic potential (VEMP) thresholds are more often elevated or absent in patients with Ménière's disease experiencing Tumarkin drop attacks than in other patients with Ménière's disease. METHODS: Subjects included normal subjects (n = 14) and patients with unilateral Ménière's disease by AAO-HNS (1995) diagnostic criteria with (n = 12) and without (n = 82) Tumarkin drop attacks at a large specialty hospital otology service. VEMP threshold testing was conducted using 250, 500, and 1,000 Hz tone burst stimuli. RESULTS: VEMP responses were present in at all frequencies in both ears of all normal subjects. In unaffected ears of patients with unilateral Ménière's disease, VEMPs were undetectable in 13% of measurements attempted. This number rose to 18% in affected ears of patients with unilateral Ménière's disease and to 41% in Meniere ears with Tumarkin drop attacks. Frequency tuning of the VEMP response in normal subjects showed lowest thresholds at 500 Hz. In Meniere ears, the tuning was altered such that the 500-Hz thresholds were higher than the 1,000-Hz thresholds. There was a gradient of threshold elevation and altered tuning that corresponded to the gradient of worsening disease. CONCLUSION: Our findings support the hypothesis that Tumarkin drop attacks arise from advanced disease involving the saccule and that VEMP may be a clinically valuable metric of disease severity or progression in patients with Ménière's disease.     

Histopathologic changes of contralateral human temporal bone in unilateral Ménière's disease.

HYPOTHESIS: To disclose the histopathologic findings in the contralateral temporal bone in unilateral Ménière's disease. BACKGROUND: Several functional studies reported abnormal findings in the contralateral ears in patients with unilateral Ménière's disease. METHODS: This study involved quantitative analysis, including the number of spiral ganglion cells, the loss of cochlear hair cells, the area of stria vascularis, and the density of fibrocytes in the spiral ligament. It included 14 temporal bones from 7 subjects with bilateral Ménière's disease, 30 temporal bones from 15 subjects with unilateral Ménière's disease, and 17 age-matched normal control temporal bones from 12 subjects. RESULTS: The mean number of spiral ganglion cells in the contralateral temporal bones in patients with unilateral Ménière's disease was 17,376.0 and was significantly lower than that in normal controls. The mean loss of inner and outer hair cells in the contralateral temporal bones in patients with unilateral Ménière's disease was significantly greater than that in normal controls in all turns. The stria vascularis was severely atrophic and degenerated in patients with Ménière's disease. The mean area of stria vascularis in contralateral temporal bones in patients with unilateral Ménière's disease was significantly smaller than normal controls. There was no significant difference in the density of fibrocytes in the spiral ligament between the diseased side and the contralateral side in patients with unilateral Ménière's disease and between normal control and contralateral side. CONCLUSION: The contralateral inner ear in patients with unilateral Ménière's disease has significantly more damage compared with inner ears of normal controls.     

Inheritance of Meniere's disease in the Finnish population

OBJECTIVE: To study the inheritance of Ménière's disease in the Finnish population. DESIGN: A detailed questionnaire was sent to patients with symptoms resembling Ménière's disease previously examined at the Department of Otorhinolaryngology, Helsinki University Central Hospital, Finland. PATIENTS: The study population comprised 118 patients with symptoms resembling Ménière's disease. The patients were divided into groups based on the diagnostic criteria by the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery. MAIN OUTCOME MEASURES: Relatives with Ménière's disease, geographic distribution of birthplaces of grandparents, symptoms, vestibular findings, and audiologic and otoneurologic tests. RESULTS: Approximately 15% of the patients with definite Ménière's disease were found to represent familial disease. The majority of these patients were female, and they had more severe and intense attacks compared with patients with sporadic Ménière's disease. The mode of inheritance is autosomal dominant with incomplete penetrance. CONCLUSIONS: A significant part of Ménière's disease is inherited. The use of genetic isolates in which genetic homogeneity can be assumed might lead to the identification of gene defects leading to Ménière's disease.     

Measurement of the endolymphatic sac potential in human

In this study, we measured human endolymphatic sac potential (ESP) in 8 patients with vestibular schwannoma and in five patients with Ménière's disease during surgery. ESP was measured with a glass electrode filled with 154 mM NaCl and with an outside tip diameter ranging from 2 to 3 microm. The mean value of human ESP in patients with vestibular schwannoma was +13.3+/-1.9 mV. Since electron microscopy showed that the endolymphatic sacs of the eight patients with vestibular schwannoma were normal in the ultrastructures the value can be close to normal human ESP. While in Ménière's disease, three cases showed low potentials and two cases showed almost the same values observed as in the eight patients with vestibular schwannoma. In the two cases with Ménière's disease, the epithelial cells of the endolymphatic sac were preserved. Our study can be considered as the first successful measurement of human ESP and revealed the existence of Ménière's disease having normal endolymphatic sac in function as well as morphology.     

Secondary Menière's disease

Among 93 patients presenting the typical symptoms of a Ménière's disease associating an unilateral fluctuating hearing loss of sensorineural type, tinnitus and vertiginous attacks lasting minutes to hours, 40 patients (43%) presented in their personal history a particular otologic insult in the ear which later on developed into the full Ménière's symptomatology, or a particular systemic disease with otologic manifestations. The Ménière's triad appeared in these patients six months to twenty nine years after the initial otologic or systemic lesion. Among these initial lesions were 16 cases of sudden partial or complete deafness related to viral or bacterial infection, 3 cases of sudden cochleo-vestibular deficit and 1 case of vestibular neuritis, 5 cases of temporal bone fractures and 4 cases of significant acoustic trauma, 2 cases of otosclerosis, 1 case of chronicotitis media and 1 case of severe hearing loss after otologic surgery, 5 cases of meningo-encephalitis and 2 cases of acquired syphilis. These particular lesion could be, in our opinion, the releasing factor of the inner ear dysfonction leading eventually to a secondary Ménière's syndrome.     

Postural control and glycerol test in Ménière'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 Ménière's disease.     

Obstructing lesions of the endolymphatic sac and duct mimicking Ménière's disease

In this retrospective case series and literature review, we demonstrate that temporal bone lesions that obstruct the endolymphatic sac or duct can cause symptoms of Ménière's disease. This finding is likely attributable to endolymphatic hydrops; initially, such cases typically masquerade as Ménière's disease. Between July 1995 and April 2002, a total of 379 patients were treated for an initial diagnosis of Ménière's disease at our institution. Among this group, 3 patients were found to have an obstructing lesion of the endolymphatic sac or duct that we felt was causally related to their Ménière's-like symptomatology. We reviewed these cases and noted the similarities in each patient's presentation, including a common pathophysiology. On imaging studies, each patient had a different pathologic lesion that involved the endolymphatic sac or duct: patient 1 had a jugular megabulb, and she was ultimately treated with vestibular nerve section; patient 2 had a cholesterol granuloma, which was treated with surgical excision; patient 3 had an endolymphatic sac tumor that was treated with surgical excision. As has been suggested in previous reports, not all cases of Ménière's disease are idiopathic. We conclude that obstruction of the endolymphatic sac or vestibular aqueduct by a mass lesion or vascular anomaly can lead to vestibulocochlear pathology that mimics Ménière's disease.     

Use of electrocochleography for assessing endolymphatic hydrops in patients with Lyme disease and Ménière's disease

From an otological standpoint, Lyme disease can manifest itself as Ménière's disease both clinically and electrophysiologically. The aim of this study was to describe the findings of routine clinical, auditory and vestibular tests in patients with Ménière's and Lyme disease and to use electrocochleography (ECoG) to assess the presence of endolymphatic hydrops (EH) in both diseases. Transtympanic ECoG was performed in 91 patients with Ménière's disease and in 11 patients with confirmed Lyme disease. In both diseases the majority of patients had more than one complaint. There was one case with isolated hearing loss in the Lyme disease group. Typical clinical manifestations of Ménière's disease (vertigo, sensorineural hearing loss and tinnitus) were found in 6/11 patients (54.5%) in the Lyme disease group. The ECoG results indicated that there were 65/91 patients (71.4%) with Ménière's disease and 5 patients (45.5%) with Lyme disease who presented with EH. No statistically significant difference was found between the incidence of different symptoms of Ménière's and Lyme disease. On the basis of these results, patients with Lyme disease should undergo careful examination and investigation, especially in endemic regions. The presence of EH does not exclude the presence of infection with borreliosis as a cause of Ménière's disease-like symptoms.     

Status of the microcirculatory bed of the bulbar conjunctiva in various forms of vestibular dysfunction

Using biomicroscopy of the eye conjunctiva, blood microcirculation was investigated in 200 patients with vestibular dysfunction (cervical osteochondrosis, Ménière's disease, neurocirculatory dystonia). All the patients showed microcirculation changes such as arteriolar spasms, reduced number of functioning capillaries, congestion and convolution of venules of medium and small caliber, and red blood cell aggregation. Capillary blood flow was intermittent: dash-dotted or bead-like. The arteriovenular coefficient decreased. Blood microcirculation changes were detected on the normal and affected sides of patients with cervical osteochondrosis, mostly on the affected side of patients with Ménière's disease, and on both sides of patients with neurocirculatory dystonia. Short-term changes in blood flow of vertebral arteries caused by head movements led to reflex responses of blood microcirculation of the conjunctiva. These reactions were most distinct in patients with cervical osteochondrosis and Mérière's disease. Eye conjunctiva biomicroscopy carried out during provocative tests with head movements may be used as a diagnostic test for identifying the type of vascular changes (vasoparetic or vasospastic) in vestibular dysfunction.     

Histopathology of the vestibular nerve in Menière's disease

Histological and morphometrical investigations of the vestibular nerve were performed on surgical specimens from 19 patients suffering from Ménière's disease and on 5 autopsy preparations from patients without inner ear disease. The number of lipofuscin granules and vacuoles in the ganglion cells of specimens from Ménière patients was not increased compared with control specimens of a similar age, nor did the amount of endoneuronal connective tissue in the vestibular nerve specimens differ between the two groups. The density of capillaries in Scarpa's ganglion and vestibular nerve was significantly increased in the Ménière patients compared with the control specimens. Furthermore, the ratio of nerve fibres with a larger diameter was higher in specimens from Ménière patients than in control preparations. There was no difference in the density of myelinated fibres between the two groups.     

Endolymphatic hydrops in asymptomatic ears in unilateral Ménière's disease

OBJECTIVES/HYPOTHESIS: The aim of our study was the objective assessment of endolymphatic hydrops in asymptomatic ears in unilateral Ménière's disease with a noninvasive electrophysiological test and investigation of significant clinical signs. The null hypothesis was that there would be no signs of endolymphatic hydrops in the asymptomatic ear. STUDY DESIGN: Prospective study using the traveling wave velocity test for endolymphatic hydrops. METHODS: The traveling wave velocity test was used in conjunction with standard audiological tests to investigate both ears of 181 Ménière's patients attending the Medical Research Council Institute of Hearing Research in Southampton, United Kingdom. The test uses derived auditory brainstem responses to estimate the velocity of the cochlear traveling wave that is altered in endolymphatic hydrops. Ménière's disease was assessed using Arenberg's five staging criteria. Significant correlations were evaluated using standard statistical methods. RESULTS: Of 100 patients with clinically unilateral Ménière's disease, 27% showed evidence of endolymphatic hydrops in their asymptomatic ear. There was a significant correlation between signs of hydrops and the mean air-conduction threshold at 500 Hz. CONCLUSIONS: We recommend that a full assessment of incipient disease in the asymptomatic ear in unilateral Ménière's disease should be undertaken before offering any treatment options to patients. Any suspicion of early disease in the asymptomatic ear in unilateral Ménière's disease should lead to full electrophysiological assessment to assess the evidence of endolymphatic hydrops in that ear.     

Electrocochleography and gentamicin therapy for Ménière's disease: a preliminary report

OBJECTIVE: It is widely held that an enlarged summating potential (SP) relative to the eighth nerve action potential (AP) is a reflection of endolymphatic hydrops. Aminoglycosides are an accepted treatment for incapacitating Ménière's disease and are known to affect both sensory and secretory cells of the inner ear. The intent of this study was to determine whether this effect on secretory cells could be objectively confirmed by virtue of changes in the electrocochleogram (ECoG) of patients receiving gentamicin therapy for Ménière's disease. STUDY DESIGN: This was a prospective longitudinal study of repeated ECoG measures in three groups of subjects. Ménière's patients undergoing gentamicin treatment were compared with two control groups: individuals with stable Ménière's disease and normal-hearing control subjects. SETTING: The study was conducted at a tertiary referral center. PATIENTS: The sample included 21 normal-hearing subjects, 15 patients with stable unilateral Ménière's disease, and 12 with disabling unilateral Ménière's disease. INTERVENTIONS: For patients with disabling Ménière's disease, gentamicin was administered transtympanically. Audiograms, impedance tests, and ECoG were performed twice for all subjects. MAIN OUTCOME MEASURES: The SP and AP amplitudes, AP latency, and SP/AP ratio of the EcoG were measured. RESULTS: A statistically significant reduction in the SP/AP ratio was observed after gentamicin administration (analysis of variance interaction effect: F2 = 5.64; p = 0.0065). CONCLUSIONS: The significant reduction in the SP/AP ratio in the gentamicin-treated Ménière's group supports the hypothesis that gentamicin improves the electrophysiologic function of the cochlea, possibly by reducing the severity of the associated endolymphatic hydrops.     

Menière's disease in children

Fourteen children (aged 14 years or younger) with typical Ménière's triad with cochlear sensorineural hearing loss, tinnitus, and intermittent vertigo attacks lasting from minutes to hours were investigated in four different neuro-otologic centers. Nine children, labeled as having "idiopathic Ménière's disease," developed the auditory and vestibular symptoms without any detectable causative factor. Five children, labeled as suffering from "secondary Ménière's syndrome," had histories of an initial hearing loss following mumps, hemophilus influenza meningitis, temporal bone fracture, or congenital or embryopathic complications in the ear that developed into the full Ménière's triad 5 to 11 years later. The 14 children represent 1% of all cases affected with idiopathic or secondary Ménière's disease (or syndrome) that have been detected during the past five years in the four collaborating centers.     

Blood glucose and insulin levels, thyroid function, and serology in Ménière's disease, recurrent vestibulopathy, and psychogenic vertigo.

Nineteen patients with unilateral Ménière's disease, 20 with psychogenic dizziness, and 20 with recurrent vestibulopathy (diagnostic criteria in text of paper) were found to have normal five hour glucose tolerance tests, serum thyroxine and effective thyroid indices, and serologic tests for syphilis. Hypothyroidism and hypoglycemia were absent in all groups. An unexplained finding of each diagnostic group was significant increase of fasting blood glucose and insulin levels, and elevated insulin:glucose ratios, compared to a control group. There appears to be no diagnostic indication for performing these chemical and serologic studies in patients with unilateral Ménière's disease, psychogenic vertigo, or recurrent vestibulopathy. Reasons are given to support the view that recurrent vestibulopathy may be a specific vestibular disturbance.     

Relationship of vestibular aqueduct and inner ear pressure in Ménière's disease and the normal population

OBJECTIVE: Etiopathogenesis of Ménière's disease has not been resolved. The principal histopathologic finding in this disease is endolymphatic hydrops. The majority of radiologic and histopathologic studies demonstrated a narrow vestibular aqueduct in Ménière's disease. There is no study in the literature investigating the relationship between inner ear pressure and vestibular aqueduct dimensions. Static acoustic compliance is a noninvasive procedure that is thought to measure perilymphatic pressure at the footplate. An increase in mechanical fluid pressure in the inner ear is transmitted to the footplate of the stapes. This causes a reduction in the compliance at the drum. The aim of this study is to investigate the relationship between vestibular aqueduct dimensions and static acoustic compliance in Ménière's disease and the normal population. STUDY DESIGN: Prospective study. METHODS: Forty patients with Ménière's disease and 40 healthy individuals with no otolaryngologic disorders were the subjects of this study. Each group was further divided into two according to static compliance value (normal and low static compliance). In these four groups dimensions of vestibular aqueduct were determined radiologically by high-resolution computerized tomography and correlated with normal and low static acoustic compliance values (normal and high perilymphatic pressure). RESULTS: The results demonstrated that vestibular aqueduct is narrower in patients with Ménière's disease than the normal population. However, there is no relationship between vestibular aqueduct dimensions and inner ear pressure obtained by static acoustic compliance measurements.     

Distortion product otoacoustic emissions after intratympanic gentamicin therapy for unilateral Ménière's disease

The treatment of patients with Ménière's disease that do not respond to conventional therapy becomes complicated, particularly when taking into account the issue of hearing damage as well as the control of vertigo. Treatment often involves the intratympanic administration of gentamicin, for which different protocols are used. Hence, it is important that we better understand how this treatment influences hearing, beyond mere audiometric assessments. The aim of this prospective study was to evaluate the effect of intratympanic gentamicin treatment for Ménière's disease on cochlear function, as assessed by otoacoustic emissions. The 41 patients included in the study had been diagnosed with unilateral Ménière's disease as defined by the American Academy of Otolaryngology-Head and Neck Surgery guidelines (1995), and had been refractory to medical treatment for at least 1 year. Intratympanic injections of gentamicin at a concentration of 27 mg/ml were performed at weekly intervals until indications of vestibular hypofunction appeared in the treated ear. Before beginning the treatment and 3 months after ending it, pure tone and speech audiometry tests were performed and the results are expressed in terms of the pure tone average (0.5, 1, 2, and 3 kHz) and the speech discrimination score, respectively. At the same time, a distortion product otoacoustic emission (DPOAE) study was performed and the results are expressed in terms of its presence or absence, and as the amplitude and threshold of the emission. When analyzed 3 months after the treatment had terminated, hearing loss was seen in 13 patients (31.7%). However, no significant change in the threshold and/or amplitude of otoacoustic emissions was observed in any of the patients. Neither were changes in the audiometric stage, number of injections required or the existence of DPOAE before treatment detected. Hence, the treatment method used here for patients with intractable unilateral Ménière's disease can be considered as having a low risk on auditory function, as assessed both audiometrically and with otoacoustic emissions, and can be considered as subablative for hearing function.