Interpretation of the nine-step test for Eustachian tube function should consider mastoid cavity volume.

INTRODUCTION: The modified nine-step test is a classical method for evaluating Eustachian tube function. However, clinical interpretation of the increased maximal difference in middle ear pressure (mdMEP) in the modified nine-step test is unknown. We hypothesised that the different reservoir effects of the mastoid cavity can bias the results of the modified nine-step test. METHODS: A total of 108 consecutive participants (216 ears) were retrospectively screened. Of these, 55 participants (82 ears) who met the inclusion/exclusion criteria were enrolled. The volumetric results of the mastoid cavity, parameters of the modified nine-step test (mdMEP, middle ear pressure, tympanic membrane compliance), and demographic data were analysed. RESULTS: A significant negative correlation was found between mdMEP and mastoid cavity volume (R = .467, p < .001). Ears with mdMEP >70 daPa showed poor pneumatization in the mastoid cavity, with volumes less than 3000 mm3 (10th percentile of all ears analysed). Ears with mastoid cavity volumes lower than the 25th percentile showed a significantly higher mdMEP (p < .001). Patients with mastoid cavity volumes higher than the 75th percentile were significantly younger (p < .001). Multivariate regression analysis for mdMEP showed a good fit (R = .854) using factors including middle ear pressure, admittance and, most importantly, the reciprocal of mastoid volume (Beta = 0.752, p < .001). CONCLUSIONS: The mdMEP, the main parameter of the modified nine-step test, was negatively correlated with the mastoid cavity volume. Therefore, the results of the modified nine-step test should be interpreted with consideration of mastoid cavity volume.

Characterization of Vestibular Phenotypes in Patients with Genetic Hearing Loss.

Background: The vestibular phenotypes of patients with genetic hearing loss are poorly understood. Methods: we performed genetic testing including exome sequencing and vestibular function tests to investigate vestibular phenotypes and functions in patients with genetic hearing loss. Results: Among 627 patients, 143 (22.8%) had vestibular symptoms. Genetic variations were confirmed in 45 (31.5%) of the 143 patients. Nineteen deafness genes were linked with vestibular symptoms; the most frequent genes in autosomal dominant and recessive individuals were COCH and SLC26A4, respectively. Vestibular symptoms were mostly of the vertigo type, recurrent, and persisted for hours in the genetically confirmed and unconfirmed groups. Decreased vestibular function in the caloric test, video head impulse test, cervical vestibular-evoked myogenic potential, and ocular vestibular-evoked myogenic potential was observed in 42.0%, 16.3%, 57.8%, and 85.0% of the patients, respectively. The caloric test revealed a significantly higher incidence of abnormal results in autosomal recessive individuals than in autosomal dominant individuals (p = 0.011). The genes, including SLC26A4, COCH, KCNQ4, MYH9, NLRP3, EYA4, MYO7A, MYO15A, and MYH9, were heterogeneously associated with abnormalities in the vestibular function test. Conclusions: In conclusion, diverse vestibular symptoms are commonly concomitant with genetic hearing loss and are easily overlooked.

Vestibular dysfunction in lateral semicircular canal dysplasia.

Introduction: Lateral semicircular canal (LSCC) dysplasia is the most common inner ear malformation. The severity of dysplasia can appear in various spectrums, from a short and broad LSCC with normal or small-sized central bony island (CBI) to a single fluid-filled cavity confluent with the vestibule without CBI. However, reports on the association between LSCC dysplasia and the loss of vestibular function are still lacking. In this study, the results of vestibular function tests [caloric test and video-head impulse test (vHIT)] in patients with LSCC dysplasia were analyzed and compared between groups with and without CBI. Methods: This study retrospectively enrolled 17 patients (23 ears) who had LSCC dysplasia following computed tomography or magnetic resonance imaging and underwent vestibular function tests. Results: LSCC dysplasia was observed unilaterally in 11 patients and bilaterally in six patients. Nine of 23 ears had CBIs, and 14 ears had no CBI. Three of 17 patients experienced dizziness. Abnormal caloric tests were detected in 11 of the 16 patients who underwent the caloric tests (69%); in contrast, 11 of 12 patients who underwent the vHIT (92%) had normal LSCC vestibulo-ocular reflex (VOR) gain on vHIT. A significant correlation was found between the maximum slow-phase velocity of the caloric test and LSCC VOR gain of the vHIT (correlation coefficient 0.792, p = 0.004). The CBI-absent group showed significantly lower SPV and LSCC VOR gains than the CBI-present group (p = 0.001 and 0.004, respectively). Discussion: LSCC dysplasia impairs VOR function, especially in the absence of CBI.

Distinct changes in brain metabolism in patients with dementia and hearing loss.

INTRODUCTION: Previous studies have reported that hearing loss (HL) is associated with dementia, although the mechanistic underpinnings remain elusive. This study aimed to evaluate the changes in brain metabolism in patients with HL and different types of dementia. METHODS: Patients with cognitive impairment (CI) and HL treated at the university-based memory clinic from May 2016 to October 2021 were included. In total, 108 patients with CI and HL prospectively underwent audiometry, neuropsychological test, magnetic resonance imaging, and 18 F-fluorodeoxyglucose positron emission tomography. Twenty-seven individuals without cognitive impairment and hearing loss were enrolled as a control group. Multivariable regression was performed to evaluate brain regions correlated with each pathology type after adjusting for confounding factors. RESULTS: Multivariable regression analyses revealed that Alzheimer's disease-related CI (ADCI) was associated with hypometabolic changes in the right superior temporal gyrus (STG), right middle temporal gyrus (MTG), and bilateral medial temporal lobe. Lewy body disease-related CI (LBDCI) and vascular CI were associated with hypermetabolic and hypometabolic changes in the ascending auditory pathway, respectively. In the pure ADCI group, the degree of HL was positively associated with abnormal increase of brain metabolism in the right MTG, whereas it was negatively associated with decreased brain metabolism in the right STG in the pure LBDCI group. CONCLUSION: Each dementia type is associated with distinct changes in brain metabolism in patients with HL.

Results of Eustachian tube balloon dilation measured using the nine-step test.

Suggested several decades ago, the nine-step test is an intuitive test of Eustachian tube function. However, studies employing the nine-step test to assess the results of Eustachian tube balloon dilation (EBD) are limited. We aimed to objectively evaluate the efficacy of EBD in opening failure patients with decreased maximal peak pressure difference (MPD) using the nine-step test. Patients who had MPD values ≤ 13 daPa in the nine-step test were enrolled. The patients were categorized into two groups according to treatment decisions after discussion with a clinician: an EBD group (N = 26) and a medication group (N = 30). One month after treatment, the seven-item Eustachian Tube Dysfunction Questionnaire (ETDQ7) and the nine-step test were administered to all participants and subgroups of symptomatic participants (ETDQ7 > 15). MPD improved (increased) in both the EBD group and the medication group. ETDQ7 values improved (decreased) in the EBD group, but not in the medication group. In subgroup analysis, MPD and ETDQ7 values improved only in the symptomatic EBD group. According to the nine-step test, EBD can normalize 53.8% of decreased MPD. Posttreatment MPD and ETDQ7 scores were significantly better in the EBD group than in the medication group. However, EBD in patients with abnormal nine-step test results seemed less efficacious when the treatment results of the medication group were considered.

Incidence of Hearing Loss in Corpus Callosum Agenesis.

OBJECTIVES: Congenital corpus callosum agenesis (CCA) is one of the congenital anomalies in newborns, which usually presents with syndromic features. It can be asymptomatic or have variable neurological deficits. Some studies demonstrated that hearing loss can occur in patients with CCA; however, the exact prevalence remains unclear. Therefore, we aimed to investigate the prevalence of hearing loss in CCA using data from newborn hearing screening in a single tertiary referral center. METHODS: A total of 126 patients with CCA combined with hearing loss diagnosed at our hospital from November 2005 to November 2022 were retrospectively included in our study. All patients had at least one screening or diagnostic auditory brainstem response result. Brain ultrasonography and magnetic resonance imaging were used to diagnose CCA. RESULTS: Among 126 patients, 93 had automated auditory brainstem response within a month from birth. Of the 93 patients, 20 (21.5%) had a "refer" result in the screening tests in at least one ear. The final incidence of hearing loss in patients with CCA was 16.1%. We observed no hearing loss in 22 patients with isolated CCA. CONCLUSIONS: Patients with CCA have a higher incidence of hearing loss. However, this is likely related to the concurrent condition of patients. CCA seems not to be a risk factor for hearing loss.

Feasibility of Speech Testing Using Wireless Connection in Single-Sided Cochlear Implant Users.

BACKGROUND AND OBJECTIVES: The speech tests used to evaluate language performance in patients with bilateral deafness (BiD) and cochlear implant (CI) are problematic if applied to patients with single-sided deafness (SSD) because normal ear hearing should be excluded. Thus, we investigated the feasibility of using wireless connection to evaluate speech intelligibility of the CI ear in patients with SSD. Subjects and. METHODS: Patients with BiD and SSD were administered the word recognition scores (WRS) and speech intelligibility tests using an iPadbased wireless connection and conventional methods. To exclude normal side hearing in patients with SSD, masking noise and "plugged and muffed" method were used in the WRS and speech intelligibility tests, respectively. RESULTS: In patients with BiD, the WRS and speech intelligibility tests results using wireless connection and conventional methods were similar. In patients with SSD, the WRS using masking noise in the normal hearing ear was similar to that of using wireless connection. However, 3 of 11 patients with SSD showed under-masked results if using the "plugged and muffed" method. CONCLUSIONS: Speech intelligibility testing using wireless connection is a convenient and reliable method for evaluating CI performance in patients with SSD. The "plugged and muffed" method is not recommended for evaluating CI performance in patients with SSD.

Clinical Factors Associated With Prognosis of Tinnitus and Aural Fullness After Sudden Sensorineural Hearing Loss.

OBJECTIVES: We evaluated the long-term prognosis and risk factors associated with tinnitus and aural fullness, which occurred with sudden sensorineural hearing loss. STUDY DESIGN: Retrospective cross-sectional review. SETTING: Tertiary referral center. PATIENTS: Those who visited our clinic for sudden hearing loss from January 2016 to May 2020, diagnosed with sudden sensorineural hearing loss based on pure-tone audiometry, and underwent magnetic resonance imaging to rule out other cause of hearing loss. In total, 106 patients were enrolled in this study. INTERVENTION: All patients were treated with oral glucocorticoids. Salvage intratympanic dexamethasone injection therapy was performed for the patients whose hearing was not fully recovered. MAIN OUTCOME AND MEASURES: We scored the loudness of tinnitus and the intensity of aural fullness using the numerical rating scale. We used a mixed-effects model for repeatedly measured tinnitus and aural fullness scores. RESULTS: The time after the onset of sudden sensorineural hearing loss (SSNHL; ß = -0.07; 95% confidence interval, -0.09 to -0.05; p < 0.001) and hearing outcome after treatment (overall p = 0.003) were significant factors associated with the prognosis of tinnitus. Concerning aural fullness, the time after the onset of SSNHL was a significant prognosis factor ( ß = -0.08; 95% confidence interval, -0.09 to -0.06; p < 0.001), unlike hearing outcome (overall p = 0.261). Pretreatment pure-tone audiometry average threshold and mainly affected frequencies were not significant factors for tinnitus and aural fullness recovery, respectively. CONCLUSION: The persistence of tinnitus with SSNHL was significantly affected by hearing recovery after treatment, whereas aural fullness was not associated with hearing recovery. However, both symptoms were improved over time after SSNHL.

Diagnostic Value of the Air-Bone Threshold Gap in Stapes Fixation.

INTRODUCTION: The Carhart notch is a well-known sign of stapes fixation. However, previous studies have reported that the Carhart notch is not specific to stapes fixation and is also present in other middle ear diseases. Therefore, this study investigated the diagnostic value of threshold gap between air conduction and bone conduction (ABG) for stapes fixation, instead of the bone conduction dip representing the Carhart notch. METHODS: A total of 199 ears that underwent exploratory tympanotomy were enrolled in this retrospective study. They were categorized into three groups according to surgical findings: stapes fixation (SF), other ossicle fixation (OF), and chain disconnection (CD). Preoperative pure-tone audiograms and impedance audiograms were compared between the groups. RESULTS: The incidence of the Carhart notch did not differ between the groups. The ABG at 2,000 Hz showed a good diagnostic performance for distinguishing between the SF and CD groups (area under the curve, AUC = 0.816, p < 0.001), but poor performance for distinguishing between the SF and OF groups (AUC = 0.662, p = 0.003). Bone conduction at 2,000 Hz showed a moderate performance for distinguishing between the SF and CD groups (AUC = 0.707, p < 0.001) and did not show statistically significant results for distinguishing between the SF and OF groups (AUC = 0.594, p = 0.080). The tympanic membrane compliance was significantly higher in the CD group than in the SF group (p = 0.001). CONCLUSIONS: The Carhart notch was not a specific finding of SF. The sensitivity and specificity of ABG ≤15 dB at 2,000 Hz for distinguishing between SF and CD were 60.4% and 89.2%, respectively. To prepare for surgical interventions in patients with conductive hearing loss but a normal tympanic membrane, clinicians should comprehensively consider these results.

Surgical and nonsurgical treatment outcomes in traumatic facial nerve palsy.

PURPOSE: Facial nerve decompression surgery is performed on patients with immediate, complete traumatic facial palsy. However, the clinical advantage of the surgical treatment has weak evidence because of lack of control groups in previous studies. Therefore, this study compared facial function outcomes between the patients who underwent surgery and those who did not. Furthermore, in cases of bilateral traumatic facial palsy, the outcomes of the surgical and nonsurgical sides were also discussed. METHODS: A retrospective medical chart review of immediate and severe (House-Brackman [HB] grade V and VI) traumatic facial palsy was conducted. Twenty-five ears from the surgical group and eight ears from the conservative treatment group were enrolled. Among the patients, three with immediate and severe bilateral facial palsy underwent unilateral surgery. RESULTS: The average HB grade after 1-year follow-up was 1.7 in the surgical group and 1.5 in the nonsurgical group. Four patients who have definite facial canal disruption in the imaging study have recovered to HB grades I-III without surgical intervention. In patients with bilateral facial palsy, the nonsurgical side showed the same or better facial functions than the surgical side. CONCLUSIONS: Compared with nonsurgical conservative treatment, facial nerve decompression surgery did not show superior outcomes in immediate HB grade V-VI traumatic facial palsy. The clinical advantage of facial nerve decompression is questionable and should be re-evaluated in a prospectively designed study.

Is the cochleovestibular nerve function affected in patients with hemifacial spasm?

Hemifacial spasm (HFS) is a motor disorder caused by the vascular compression of the facial nerve in the posterior fossa. The cochleovestibular nerve is close to the facial nerve and shares the same entry to the periphery, also has disorders caused by vascular compression. We evaluated the cochleovestibular nerve function in patients with HFS based on the hypothesis that vascular compression, which causes HFS, can also affect the nearby cochleovestibular nerve function. The medical charts of 49 patients with surgically confirmed HFS were reviewed retrospectively. The results of the pure-tone threshold, auditory brainstem response (ABR), video head impulse test (vHIT), and magnetic resonance imaging were analyzed. In each patient, the HFS side and the unaffected side were compared in the paired manner. The anterior inferior cerebellar artery was the major offending vessel (69.4%). There were no significant differences in the pure-tone threshold, properties of ABR waves, and vHIT gain. There was no evidence of cochleovestibular nerve compression syndrome in all patients. The angulation of the nerve by the offending vessel was more frequently identified in the HFS side than in the unaffected side (p = 0.040). The effect of HFS on cochleovestibular nerve function is limited.

High incidence of cleft palate and vomer deformities in patients with Eustachian tube dysfunction.

Although the cleft palate is regarded as a contraindication for Eustachian tube ballooning, the presence of submucosal cleft palate may be overlooked while diagnosing Eustachian tube dysfunction. Therefore, we aimed to determine the incidence of the presence of a hard palate bony notch and vomer defect, which indicate the presence of submucosal cleft palate in patients with Eustachian tube dysfunction. In the Eustachian tube dysfunction group (n = 28), 4 patients (14.3%) exhibited a hard palate bony notch and a concurrent vomer defect. Three of them exhibited the presence of occult submucosal cleft palate, which had not been diagnosed previously. None of the control group (n = 39) showed any of these findings. The hard palate length of patients in the Eustachian tube dysfunction group was significantly lesser than that of those in the control group (34.2 ± 5.6 mm vs. 37.2 ± 2.1 mm, P = 0.016). Patients with Eustachian tube dysfunction have a high incidence of submucosal cleft palate and its occult variant, which are challenging to diagnose without any preexisting suspicion. Clinicians should evaluate the hard palate and vomer to exclude the presence of occult submucosal cleft palate while diagnosing Eustachian tube dysfunction.

The Time Course of Monocytes Infiltration After Acoustic Overstimulation.

Cochlea macrophages regulate cochlea inflammation and may harbors the potentials to protect hearing function from injury, including acoustic overstimulation. Cochlea macrophage numbers increase at 3-7 days after acoustic stimulation. However, the exact timing of macrophage infiltration and maturation from inflammatory monocytes is unclear. Furthermore, neutrophils may also be involved in this process. Therefore, in this study, we investigated time-dependent immune cell infiltration, macrophage transformation, and neutrophil involvement following acoustic stimulation. Flow cytometry and immunofluorescence were conducted in C-X3-C motif chemokine receptor 1 (CX3CR1)+/GFP mice after acoustic overstimulation (at baseline and at 1, 2, 3, and 5 days after exposure to 120 dB for 1 h) to identify inflammatory monocytes in the cochlea. RNA-sequencing and quantitative polymerase chain reaction were performed to identify differentially expressed genes. Inflammatory monocytes infiltrated into the lower portion of the lateral wall within 2 days after acoustic overstimulation (dpn), followed by transformation into macrophages at 3-5 dpn via CX3CR1 upregulation and Ly6C downregulation. In addition, inflammatory monocytes were aggregated inside the collecting venule only at 1 dpn. Neutrophils were not a major type of phagocyte during this response. The gene encoding C-C motif chemokine ligand 2 gene was significantly upregulated as early as 3 h after acoustic overstimulation. Given these results, treatment to control immune response after a noise-induced hearing loss should be applied as soon as possible.

Association Between Eustachian Tube Dysfunction Questionnaire-7 Scores and Eustachian Tube Function Test Results in Symptomatic Patients With a Normal Drum.

BACKGROUND AND OBJECTIVES: We investigated the clinical validity of and correlation between the Eustachian Tube Dysfunction Questionnaire-7 (ETDQ-7) scores and the eustachian tube function test (ETFT) results in patients with a normal drum. SUBJECTS AND METHODS: The study included 49 patients (93 ears) with unilateral or bilateral ear fullness over >3 months. All patients were administered the ETDQ-7 survey and underwent the ETFT on the same day. The receiver operating characteristic (ROC) curve and the association between the results were statistically analyzed. RESULTS: ETDQ-7 scores were not significantly correlated with the ETFT results or with middle ear pressure. ETDQ-7 scores in patients with eustachian tube dysfunction (ETD) were significantly higher than those in patients with normal ETFT results (p=0.039) when ETD was defined as a pressure change <10 daPa on the ETFT. The area under the ROC curve was 0.631, with a sensitivity of 37.0% and specificity of 89.4%. CONCLUSIONS: The ETDQ-7 has limited clinical significance in patients with ETD but a normal drum. Therefore, concomitant objective tests should be performed to diagnose patients with ETD.

Revisiting the Diagnostic Performance of the Modified Nine-Step Test for Obstructive and Patulous Eustachian Tube Dysfunction.

The nine-step test is a classical method for evaluating Eustachian tube function. It directly assesses the patient's capacity to equilibrate middle ear pressure by swallowing. However, there are insufficient studies to appraise its diagnostic performance. The purpose of this study is to evaluate the sensitivity, specificity, and cut-off value of the nine-step test in patients with obstructive Eustachian tube dysfunction (oETD) and patulous Eustachian tube (PET). Enrolled subjects were divided into three groups. Control (50 ears of healthy volunteers), oETD (19 ears with oETD), and PET (29 ears with PET). Receiver operating characteristics curve analysis was conducted to evaluate the diagnostic performance of maximal peak pressure difference (ETTmd) in the nine-step test. Both the oETD group and the PET group showed decreased ETTmd. The nine-step test showed moderate accuracy when used to diagnose oETD (area under the curve = 0.875) and PET (area under the curve = 0.769). The highest diagnostic performance was observed when the cut-off value was 13 daPa for both the oETD group (sensitivity = 73.7%, specificity = 90.0%) and the PET group (sensitivity = 58.6%, specificity = 90.0%). The nine-step test has moderate diagnostic performance for oETD and PET.

Inflammatory Monocytes Infiltrate the Spiral Ligament and Migrate to the Basilar Membrane After Noise Exposure.

OBJECTIVES: Noise exposure leads to an increase in the macrophage population. This increment is thought to be caused by the transformation of infiltrated monocytes into macrophages rather than by proliferation of the cochlear resident macrophages. However, studies on infiltrated monocytes in the cochlea are scarce. Thus, we aimed to investigate the infiltration of monocytes and their transformation into macrophages after noise exposure. METHODS: In wild-type and CX3CR1+/GFP C57/B6 mice, inflammatory monocytes were identified by immunofluorescence of mouse cochlear cells. The findings were confirmed and quantitated by flow cytometry. RESULTS: One day after noise exposure, monocytes were identified in the spiral ligament. Flow cytometric analysis confirmed that the monocyte population peaked on post-noise exposure day 1 and decreased thereafter. On day 3 after noise exposure, amoeboid-type macrophages increased in the crista basilaris, and on day 5, they spread to the basilar membrane. CONCLUSION: Infiltrated monocytes were successfully observed 1 day after noise exposure, preceding the increase in the macrophage population. This finding supports the proposal that infiltrated monocytes transform into macrophages.

Cochlear Implants for Patients With Common Cavity Deformities and the Impact of Electrode Positioning.

OBJECTIVES: Common cavity deformity is a rare congenital bony labyrinth malformation associated with profound hearing loss. Cochlear implants are widely used for hearing rehabilitation for common cavity deformities; however, the reported prognosis is poor. Due to the deformed anatomical structure, it is important to consider the position of the electrodes to maximize the performance of the cochlear implant. The present study discusses the impact of electrode placement on hearing outcomes. METHODS: A retrospective medical chart review of eight common cavity deformity patients (10 cochlear implants) who received cochlear implants was performed at a single university hospital. In all eight patients, implant surgery was performed using single-slit labyrinthotomy. Electrodes wer e manually bent before insertion to prevent misplacement and to reduce physical damage to the neuroepithelium. RESULTS: Four of the 10 electrodes were misplaced, with their tips placed in the anterior semicircular canal or internal auditory canal. However, after implant surgery, all patients-including those with misplaced electrodes-gained auditory perception and improved hearing function. One patient who had electrodes that did not contact the inner wall of the cavity showed limited activity of the electrodes (27%) compared to others (64%-100%). CONCLUSION: Proper contact of the electrode with the inner wall was more likely to be important for cochlear implant success in cases of common cavity deformity than appropriate placement of the electrode tip.

Patients Requiring Gastrostomy Tube Insertion After Total Laryngectomy Have a Higher Incidence of Otitis Media.

BACKGROUND AND OBJECTIVES: Some reports propose an increased risk of otitis media and hearing impairment after total laryngectomy. However, the incidence of otitis media following laryngectomy and the mechanism remain unclear. This study aimed to identify the incidence and risk factors of otitis media after total laryngectomy. SUBJECTS AND METHODS: This retrospective cohort study assessed 77 patients who underwent total laryngectomy from 2010 to 2020 in a tertiary referral center. Serial imaging studies (computed tomography [CT], magnetic resonance imaging, and positron emission tomography-CT) were used to assess otitis media. RESULTS: The study enrolled 58 patients (mean age, 67.0±7.7 years; male, 56 [96.6%]); nine (15.5%) underwent a gastrostomy tube (four preoperatively and five postoperatively). Otitis media was confirmed in seven (12.1%) patients. Gastrostomy tube insertion was the only significant risk factor for otitis media (p=0.012). Of the nine patients who underwent gastrostomy tube insertion, four developed otitis media; all four had the procedure after laryngectomy. CONCLUSIONS: This study found an increased incidence of otitis media after total laryngectomy. Swallowing difficulties likely contribute to otitis media as it occurred more frequently in patients requiring postoperative gastrostomy tube insertion.

Effect of Dexamethasone Combination with Gentamicin in Chemical Labyrinthectomy on Hearing Preservation and Vertigo Control in Patients with Unilateral Meniere's Disease: A Randomized Controlled Clinical Trial.

Chemical labyrinthectomy using gentamicin is a popular method for treating intractable vertigo attacks in Meniere's disease. However, the risk of hearing loss remains a major concern for clinicians. We investigated the effect of simultaneous dexamethasone and gentamicin application on hearing preservation and vertigo control in patients with intractable unilateral Meniere's disease. A single-institutional, prospective, single-blinded, randomized clinical trial was conducted. Gentamicin-soaked Gelfoam® was directly applied on the oval window following middle ear exploration. On the round window, dexamethasone-soaked Gelfoam® was applied in the gentamicin with dexamethasone group (GD group, n = 18), and saline-soaked Gelfoam® was applied in the gentamicin with sham reagent group (GO group, n = 19). The hearing change 8 weeks after the procedure and vertigo control 2-12 months after the procedure were investigated. The high-frequency hearing threshold was significantly increased in the GO group (p = 0.005 and 0.012 for 4 and 8 kHz, respectively), but not in the GD group. The short-term (2-6 months) vertigo control was more successful in the GD group (57.89% vs. 94.44%, p = 0.019), but long-term control (6-12 months) was insignificant. In conclusion, the combined application of gentamicin and dexamethasone in chemical labyrinthectomy is an effective method for protecting high-frequency hearing and vertigo control.