In Vivo Vibration Measurement of Middle Ear Structure Using Doppler Optical Coherence Tomography: Preliminary Study

Objectives

Doppler optical coherence tomography (DOCT) is useful for both, the spatially resolved measurement of the tympanic membrane (TM) oscillation and high-resolution imaging. We demonstrated a new technique capable of providing real-time two-dimensional Doppler OCT image of rapidly oscillatory latex mini-drum and in vivo rat TM and ossicles.

Methods

Using DOCT system, the oscillation of sample was measured at frequency range of 1–4 kHz at an output of 15 W. After the sensitivity of the DOCT system was verified using a latex mini-drum consisting of a 100 μm-thick latex membrane, changes in displacement of the umbo and contacted area between TM and malleus in normal and pathologic conditions.

Results

The oscillation cycles of the mini-drum for stimulus frequencies were 1.006 kHz for 1 kHz, 2.012 kHz for 2kHz, and 3.912 kHz for 4 kHz, which means that the oscillation cycle of the mini-drum become short in proportional to the frequency of stimuli. The oscillation cycles of umbo area and the junction area in normal TM for frequencies of the stimuli showed similar integer ratio with the data of latex mini-drum for stimuli less than 4 kHz. In the case of middle ear effusion condition, the Doppler signal showed a tendency of attenuation in all frequencies, which was prominent at 1 kHz and 2 kHz.

Conclusion

The TM vibration under sound stimulation with frequencies from 1 kHz to 4 kHz in normal and pathologic conditions was demonstrated using signal demodulation method in in vivo condition. The OCT technology could be helpful for functional and structural assessment as an optional modality.

Optical assessment of the in vivo tympanic membrane status using a handheld optical coherence tomography-based otoscope

OBJECTIVE

Conventional otoscopes and oto-endoscopes, which are used to examine the tympanic membrane (TM), do not provide tomographic information. Optical coherence tomography (OCT) non-invasively reveals the depth-resolved internal microstructure of the TM with very high spatial resolution. We designed this study to examine the TMs with middle ear diseases using a handheld otoscope employing 860 nm spectral domain (SD)-OCT, combined with video camera and to demonstrate the clinical applicability of this system.

DESIGN

A total of 120 patients with otologic symptoms were enrolled. TM images were obtained using the handheld OCT-based otoscope (860 nm central wave length, 15 μm axial resolution, 15 μm lateral resolution, and 7 mm scanning range using relay lens). Both OCT and oto-endoscope images were compared according to the clinical characteristics such as perforation, retraction, and postoperative healing process.

RESULTS

The objective grade about the thickness of perforation margins and the accurate information about the extent of TM retraction that was not distinguishable by oto-endoscopic exam could be identified using this system. The postoperative healing process of TMs could be also followed using the OCT device.

CONCLUSION

These analyses from the surgeon-oriented perspective suggest another useful application of the handheld OCT device.

Diagnostic role of cone beam computed tomography for the position of straight array

OBJECTIVE

To assess the usefulness of cone beam computed tomography (CBCT) for characterizing electrode insertion and evaluate the influence of electrode insertion status on post-cochlear implantation (CI) outcomes.

DESIGN

Twenty-six ears with post-CI CBCT scans were included. The devices were MED-EL Flex28 (n = 21) and Nucleus slim straight (n = 5). The parameters including cochlear duct length (CDL), insertion depth angle (IDA), insertion length of electrode (IL), and cochlear coverage (CC) were analyzed and compared with aided pure-tone threshold (PTA) with implant in free field, and open-set sentence score.

RESULTS

The mean CDL was 36.8 ± 1.4 mm. Electrode array was dislocated into scala tympani in two ears. The mean IL and IDA were 26.5 ± 1.9 mm and 541.4 ± 70.2°. The mean linear CC (IL/CDL, 0.73 ± 0.06) was larger than the mean angular CC (IDA/900, 0.60 ± 0.08). The CBCT parameters showed correlation one another. While the aided pure-tone threshold was correlated with IL and IDA, there were no significant correlations in the open-set sentence score. For the postlingually deaf patients with single electrode (Flex 28), the sentence score had no significant correlation and the aided PTA was positively correlated with IL (R = 0.517, p = .028).

CONCLUSIONS

This study validated the CBCT evaluating the electrode array position. The CBCT could be helpful for the preoperative selection of the optimal array and prediction of the CC.

Quantum-mechanical analysis of effect of alloying elements on ε-martensite start temperature of steels

With regard to the transformation mechanism of austenitic high manganese steel, the prediction of the ε-martensite start temperature is a critical consideration in alloy design. Evaluation of the ε-martensite start temperature makes it possible to predict the microstructure and to understand the phase transformation occurring during deformation. Here we use the quantum mechanical calculation of random alloys to understand the physics for ε-martensitic transformation in steels. We could find the linear relationship between the measured ε-martensite start temperatures and the crystal structure stability for various compositions. We also could estimate the effect of several alloying elements. It is expected that the effect of decreasing the temperatures for the same amount of alloying elements addition will be larger moving farther from Group VIII. By creating a free-energy model that reflects the temperature effect, we were able to calculate the average driving force required for the ε-martensitic transformations.

Biomimetic Artificial Basilar Membranes for Next-Generation Cochlear Implants

Patients with sensorineural hearing loss can recover their hearing using a cochlear implant (CI). However, there is a need to develop next-generation CIs to overcome the limitations of conventional CIs caused by extracorporeal devices. Recently, artificial basilar membranes (ABMs) are actively studied for next-generation CIs. The ABM is an acoustic transducer that mimics the mechanical frequency selectivity of the BM and acoustic-to-electrical energy conversion of hair cells. This paper presents recent progress in biomimetic ABMs. First, the characteristics of frequency selectivity of the ABMs by the trapezoidal membrane and beam array are addressed. Second, to reflect the latest research of energy conversion technologies, ABMs using various piezoelectric materials and triboelectric-based ABMs are discussed. Third, in vivo evaluations of the ABMs in animal models are discussed according to the target position for implantation. Finally, future perspectives of ABM studies for the development of practical hearing devices are discussed.

Typewriter tinnitus revisited: The typical symptoms and the initial response to carbamazepine are the most reliable diagnostic clues

Although neurovascular compression of the cochlear nerve (NVC-C) presenting as typewriter tinnitus is a discrete disease category, verified diagnostic criteria are lacking. We sought to refine the diagnostic criteria for NVC-C by reference to a relatively large case series. The medical records of 22 NVC-C patients were retrospectively reviewed. Psychoacoustic characteristics, the results of diagnostic work-up (including audiovestibular neurophysiological tests and radiological evaluations), and the initial treatment response to carbamazepine were investigated. All subjects described their tinnitus as a typical “typewriter” or “staccato” sound. Of the 22 subjects, 11 (50%) had histories of vertiginous spells, but none had ipsilesional hearing loss. Vestibular function tests in 11 subjects tested revealed only 2 (18.2%) isolated cervical vestibular evoked myogenic potential abnormalities. Radiological comparisons of the symptomatic and asymptomatic sides, regarding the type of the vascular loop and neurovascular contact, revealed no significant differences. However, all 22 subjects exhibited immediate and marked responses to short-term carbamazepine treatment. Meticulous history-taking in terms of the psychoacoustic characteristics and the response to initial carbamazepine, are more reliable diagnostic clues than are radiological or neurophysiological data in NVC-C subjects. Therefore, the typical psychoacoustic characteristics and the response to initial carbamazepine should be included in the diagnostic criteria.

Smartphone-Based Endoscope System for Advanced Point-of-Care Diagnostics: Feasibility Study

Background

Endoscopic technique is often applied for the diagnosis of diseases affecting internal organs and image-guidance of surgical procedures. Although the endoscope has become an indispensable tool in the clinic, its utility has been limited to medical offices or operating rooms because of the large size of its ancillary devices. In addition, the basic design and imaging capability of the system have remained relatively unchanged for decades.

Objective

The objective of this study was to develop a smartphone-based endoscope system capable of advanced endoscopic functionalities in a compact size and at an affordable cost and to demonstrate its feasibility of point-of-care through human subject imaging.

Methods

We developed and designed to set up a smartphone-based endoscope system, incorporating a portable light source, relay-lens, custom adapter, and homebuilt Android app. We attached three different types of existing rigid or flexible endoscopic probes to our system and captured the endoscopic images using the homebuilt app. Both smartphone-based endoscope system and commercialized clinical endoscope system were utilized to compare the imaging quality and performance. Connecting the head-mounted display (HMD) wirelessly, the smartphone-based endoscope system could superimpose an endoscopic image to real-world view.

Results

A total of 15 volunteers who were accepted into our study were captured using our smartphone-based endoscope system, as well as the commercialized clinical endoscope system. It was found that the imaging performance of our device had acceptable quality compared with that of the conventional endoscope system in the clinical setting. In addition, images captured from the HMD used in the smartphone-based endoscope system improved eye-hand coordination between the manipulating site and the smartphone screen, which in turn reduced spatial disorientation.

Conclusions

The performance of our endoscope system was evaluated against a commercial system in routine otolaryngology examinations. We also demonstrated and evaluated the feasibility of conducting endoscopic procedures through a custom HMD.

The clinical efficacy of early intervention for infected preauricular sinus

OBJECTIVE

The study was designed to evaluate the outcomes of early surgical intervention, and to suggest the accurate operation time and surgical strategies.

METHODS

A total of 190 cases (144 patients) of PAS excision were classified into 2 groups according to their time of surgery; early intervention group (n = 53), and non-early intervention group (n = 137). Early intervention was defined as excision performed within 3 weeks from their first hospital visit, and after acute infection control, surgical removal was followed regardless of their infection status. The mean age of patients was 18.3 ± 15.7 years old (62 male, 82 female). During surgery, a parallel incision was added when iatrogenic fistula due to incision and drainage (I &D) or additionally opened wounds caused by infection was present.

RESULTS

Cases of I & D history, revision cases, use of preoperative antibiotics were significantly higher in the early intervention group compared to the non-early intervention group, however, the time of surgery did not affect the complication rate (p = 0.533). Within the infected cases, only 1 patient from the non-early intervention group showed a minor complication of keloid scar. During our follow up period of minimum of 6 months, there was no recurrence in either groups.

CONCLUSION

The early intervention of PASs does not seem to increase postoperative complication or recurrence rates. A double parallel skin incision is a simple but adequate technique to treat infected PASs.

In vivo 3D imaging of the human tympanic membrane using a wide-field diagonal-scanning optical coherence tomography probe

A wide-field optical coherence tomography (OCT) probe was developed that adapts a diagonal-scanning scheme for three-dimensional (3D) in vivo imaging of the human tympanic membrane. The probe consists of a relay lens to enhance the lateral scanning range up to 7 mm. Motion artifacts that occur with the use of handheld probes were found to be decreased owing to the diagonal-scanning pattern, which crosses the center of the sample to facilitate entire 3D scans. 3D images could be constructed from a small number of two-dimensional OCT images acquired using the diagonal-scanning technique. To demonstrate the usefulness and performance of the developed system with the handheld probe, in vivo tympanic membranes of humans and animals were imaged in real time.

Steroid intracochlear distribution differs by administration method: Systemic versus intratympanic injection

OBJECTIVE

Steroids have been widely used to treat inner-ear diseases such as sudden sensorineural hearing loss, tinnitus, and Meniere's disease. They can be given via either systemic or intratympanic (IT) injection. The purpose of the present study was to explore differences in intracochlear steroid distribution by the administration method employed (systemic vs. IT injection).

STUDY DESIGN

Animal study.

METHODS

Twenty-three Sprague-Dawley rats were given fluorescein isothiocyanate-labeled dexamethasone (FITC-DEX) three times (on successive days) via intraperitoneal (IP) or IT injection. Cochlear uptake of FITC-DEX was evaluated via immunohistochemistry and flow cytometry at 6 hours, and 3 and 7 days after the final injection.

RESULTS

FITC-DEX uptake was evident in spiral ganglion cells (SGs), the organ of Corti (OC), and the lateral walls (LWs), the basal turns of which were stained relatively prominently in both groups. Animals receiving IP injections exhibited higher FITC-DEX uptakes by the SGs and OC, whereas IT injection triggered higher-level FITC-DEX accumulation by the OC and LWs. Flow cytometry revealed that intracochlear FITC-DEX uptake by IT-injected animals was higher and more prolonged than in animals subjected to IP injections.

CONCLUSION

We thus describe differences in cochlear steroid distributions after systemic and IT injections. This finding could help our understanding of the pharmacokinetics of steroids in the cochlea.

LEVEL OF EVIDENCE

NA. Laryngoscope, 128:189-194, 2018.

Analysis of various risk factors predisposing subjects to allergic rhinitis

BACKGROUND

In Korea, the prevalence of allergic rhinitis (AR) is increasing, as in other industrialized countries. However, no large population-based study defining risk factors for AR has yet been conducted.

OBJECTIVE

The purpose of this study was to evaluate the prevalence and risk factors of AR in large population-based study.

METHODS

A cross-sectional study was performed using data from the Korea National Health and Nutrition Examination Survey. We evaluated data from 31,217 subjects who were interviewed between 2008 and 2011.

RESULTS

The prevalence of AR decreased with age (adjusted odds ratio [AOR] = 0.985; 95% CI = 0.984-0.987). Higher-level stress (AOR for severe stress = 1.470; 95% CI = 1.209-1.788); asthma (AOR = 1.868; 95% CI = 1.582-2.205); atopic dermatitis (AOR = 1.552; 95% CI = 1.309-1.841); pulmonary tuberculosis (AOR = 1.320; 95% CI = 1.119-1.555); depression (AOR = 1.250; 95% CI = 1.117-1.400); and thyroid disease (AOR = 1.328; 95% CI = 1.104-1.597) increased the risk of AR. Participants whose parents had a history of AR also had higher AORs (father, AOR = 1.566; 95% CI = 1.130-2.172; mother, AOR = 1.546; 95% CI = 1.190-2.008). Marriage (AOR = 0.846; 95% CI = 0.741-0.966) decreased the risk of AR. Farmers, fishers, laborers, and soldiers were at lower risk of AR. Although high BMI, a high educational level, living in a large household, specific types of daily living, and a history of diabetes mellitus have been reported as risk factors for AR; none of these factors attained statistical significance in the present study.

CONCLUSION

Our study revealed that age, stress level, marriage, occupation, asthma, atopic dermatitis, pulmonary tuberculosis, depression, thyroid disease, and parental AR history, all affected the prevalence of AR. We believe that defining the influence of various factors on AR will help to prevent development of the condition in the future.

Anterolateral femoral bowing and loss of thigh muscle are associated with occurrence of atypical femoral fracture: Effect of failed tension band mechanism in mid-thigh

BACKGROUND

The purpose of this study was to characterize anterolateral bowing of the femur using X-rays and muscular atrophy in the mid-thigh using computed tomography (CT) in patients with atypical femoral fractures (AFFs). We then compared the results with those of an intertrochanteric fracture to understand whether these measures act as causative factors of AFFs.

METHODS

From January 2009 to December 2015, 37 patients with complete AFF and 12 patients with incomplete AFF were enrolled in this study. Lateral femoral bowing, anterior femoral bowing, cross-sectional area (CSA), and attenuation coefficient of thigh muscles in the AFF group are measured and compare with those in the intertrochanteric fracture group.

RESULTS

Lateral and anterior femoral bowing in the AFF group were significantly higher than those in the intertrochanteric fracture group. The level of fracture was found to be significantly associated with lateral and anterior femoral bowing (r = 0.569, r² = 0.324, p < 0.001; r = -0.530, r² = 0.281, p < 0.001, respectively). Total CSA and CSA of anterior and medial compartments were significantly lower in the AFF group (p < 0.05). The attenuation coefficient of the total thigh muscle and all three compartments in the AFF group were significantly lower than those in the intertrochanteric fracture group (p < 0.05).

CONCLUSIONS

This study demonstrated that anterolateral femoral bowing and loss of thigh muscle were highly associated with the occurrence of AFFs.

Clinical Aspects and Surgical Outcomes of Congenital Cholesteatoma in 93 Children: Increasing Trends of Congenital Cholesteatoma from 1997 through 2012

BACKGROUND AND OBJECTIVES

The recent increase in the reported incidence of congenital cholesteatoma (CC) may be secondary to the widespread use of otoendoscopy as well as an increased awareness of these lesions among primary care physicians. However, little research about CC has been conducted in a large group of patients. This study aimed to analyze the clinical characteristics of CC including the annual number of patients, symptoms, age at diagnosis, stage and type of disease, surgical techniques, recurrence, and postoperative complications.

SUBJECTS AND METHODS

Retrospective chart review was performed for patients who met the inclusion criteria between January 1997 and June 2012.

RESULTS

Ninety-three patients underwent surgery for CC. The age at operation ranged from 12 months to 17 years (mean age, 6.1 years). The number of patients was less than 4 per year until 2005, but increased to more than 10 per year since 2008. CC was most commonly reported as an incidental finding (58.1%). The operative procedures included the transcanal myringotomy approach (46.2%), canal wall up mastoidectomy (37.6%), tympanoplasty (8.6%), and canal wall down mastoidectomy (7.5%). The recurrence rate was 20.4% and the complication rate was 12.9%. No patients with stage I CC had complications.

CONCLUSIONS

This study showed that the incidence of CC has recently increased notably. Most patients with stage I and II CC were completely cured by transtympanic surgery, and complication and recurrence rates increased according to the extent of disease. Early detection of CC is important to facilitate minimally invasive surgery and to reduce complication and recurrence rates.

Chronological changes in microbial profiles in external and middle ear diseases: a 20-year study in Korea

Microbial infection is one of the most significant causes of ear diseases, but microbial profiles are very diverse according to the diseases and change over time. The purpose of the study was to clarify differences and chronological changes in causative pathogens among infectious ear diseases over the last 20 years, and to identify antibiotic resistance. In total, 1191 isolates were included from patients diagnosed with chronic otitis media without cholesteatoma (COM), cholesteatomatous otitis media (Chole), middle ear effusion (MEE), including acute otitis media and otitis media with effusion, and external otitis (EO). Data were collected periodically for the years 1995, 2000, 2004, 2009, and 2013. Culture results and antibiotic resistance were assessed. The most common microorganism identified was S. aureus. The microbial profiles differed significant among the COM, Chole, and MEE groups (p < 0.001). In contrast, there was no distinct difference between COM and EO (p = 0.332). COM, Chole, and MEE also showed significant chronological changes in microbial profiles over time. The frequency of CNS increased markedly in COM and Chole (p = 0.029 and 0.028, respectively); however, S. pneumoniae infection decreased significantly in MEE (p = 0.016). Methicillin-resistant S. aureus (MRSA) demonstrated a constant trend (p = 0.564), whereas ciprofloxacin-resistant P. aeruginosa increased over time (p < 0.001). Microbial profiles have changed over a 20-year period. Increases in the frequency of coagulase-negative Staphylococcus (CNS) and bacterial resistance to ciprofloxacin, used widely in treating ear infections, are noteworthy.

Predictors of general discomfort, limitations in activities of daily living and intention of a second donation in unrelated hematopoietic stem cell donation

We performed a retrospective study of 1868 consecutive unrelated donors to predict the risk factors related to general discomfort, limitations in activities of daily living (ADLs) and intention of a second donation in hematopoietic stem cell (HSC) donation. General discomfort and limitations in ADLs were assessed by numerical measurement (scores of 0-10) and donor's intention of a second donation by yes or no reply. The post-donation questionnaires were completed within 48 h after HSC collection and at 1 week, 4 weeks, and 4 months thereafter. Predictors of general discomfort included female sex (P<0.0001), bone marrow (BM) collection (P<0.0001) or PBSC collection through a central line (CL; P=0.0349), 2-day collection (P=0.0150) and negative or undetermined intention of a second donation on day 1 (P<0.0001). Predictors of limitations in ADLs included age group of 30-39 years (P=0.0046), female sex (P<0.0001), BM collection (P<0.0001) or PBSC collection through a CL (P<0.0001) and negative or undetermined intention of a second donation on day 1 (P<0.0001). The only predictor of positive intention of a second donation was male sex (P=0.0007). Age, sex and collection method and period should be considered risk factors when unrelated HSC donation is performed.

A Triboelectric-Based Artificial Basilar Membrane to Mimic Cochlear Tonotopy

A triboelectric-based artificial basilar membrane (TEABM) can mimic cochlear tonotopy by triboelectrification between Kapton film and aluminum foil. The two films are stacked and clamped to form a beam structure. The TEABM tonotopy is tested using an animal model to verify the feasibility of a self-powered acoustic sensor for a prototype cochlear implant.

Decalcification using ethylenediaminetetraacetic acid for clear microstructure imaging of cochlea through optical coherence tomography

The aim of this study was to analyze the effectiveness of decalcification using ethylenediaminetetraacetic acid (EDTA) as an optical clearing method to enhance the depth visibility of internal soft tissues of cochlea. Ex vivo mouse and guinea pig cochlea samples were soaked in EDTA solutions for decalcification, and swept source optical coherence tomography (OCT) was used as imaging modality to monitor the decalcified samples consecutively. The monitored noninvasive cross-sectional images showed that the mouse and guinea pig cochlea samples had to be decalcified for subsequent 7 and 14 days, respectively, to obtain the optimal optical clearing results. Using this method, difficulties in imaging of internal cochlea microstructures of mice could be evaded. The obtained results verified that the depth visibility of the decalcified ex vivo samples was enhanced.

Neurofilament heavy chain expression and neuroplasticity in rat auditory cortex after unilateral and bilateral deafness

Deafness induces many plastic changes in the auditory neural system. For instance, dendritic changes cause synaptic changes in neural cells. SMI-32, a monoclonal antibody reveals auditory areas and recognizes non-phosphorylated epitopes on medium- and high-molecular-weight subunits of neurofilament proteins in cortical pyramidal neuron dendrites. We investigated SMI-32-immunoreactive (-ir) protein levels in the auditory cortices of rats with induced unilateral and bilateral deafness. Adult male Sprague-Dawley rats were divided into unilateral deafness (UD), bilateral deafness (BD), and control groups. Deafness was induced by cochlear ablation. All rats were sacrificed, and the auditory cortices were harvested for real-time quantitative polymerase chain reaction (RT-qPCR) and western blot analyses at 2, 4, 6, and 12 weeks after deafness was induced. Immunohistochemical staining was performed to evaluate the location of SMI-32-ir neurons. Neurofilament heavy chain (NEFH) mRNA expression and SMI-32-ir protein levels were increased in the BD group. In particular, SMI-32-ir protein levels increased significantly 6 and 12 weeks after deafness was induced. In contrast, no significant changes in protein level were detected in the right or left auditory cortices at any time point in the UD group. NEFH mRNA level decreased at 4 weeks after deafness was induced in the UD group, but recovered thereafter. Taken together, BD induced plastic changes in the auditory cortex, whereas UD did not affect the auditory neural system sufficiently to show plastic changes, as measured by neurofilament protein level.

Prediction of Cochlear Implant Outcomes in Patients With Prelingual Deafness

Objectives.

To evaluate the factors that limit post-cochlear implantation (CI) speech perception in prelingually deaf children.

Methods.

Patients with CI were divided into two groups according to Category of Auditory Performance (CAP) scores 3 years post-CI: the poor performance group (poor performance group, CAP scores≤4, n=41) and the good performance group (good performance group, CAP scores≥5, n=85). The distribution and contribution of the potential limiting factors related to post-CI speech perception was compared.

Results.

Perinatal problems, inner ear anomalies, narrow bony cochlear nerve canal (BCNC), and intraoperative problems was significantly higher in the poor performance group than the good performance group (P=0.010, P=0.003, P=0.001, and P=0.045, respectively). The mean number of limiting factors was significantly higher in the poor performance group (1.98±1.04) than the good performance group (1.25±1.11, P=0.001). The odds ratios for perinatal problems and narrow bony cochlear nerve canal in the poor performance group in comparison with the good performance group were 4.878 (95% confidence interval, 0.067 to 0.625; P=0.005) and 4.785 (95% confidence interval, 0.045 to 0.972; P=0.046).

Conclusion.

This study highlights the comprehensive prediction of speech perception after CI and provides otologic surgeons with useful information for individualized preoperative counseling of CI candidates.

Dexamethasone Is One of the Factors Minimizing the Inner Ear Damage from Electrode Insertion in Cochlear Implantation

The aim of this study was to investigate the efficacy of preoperative and intraoperative steroid administration for inner ear protection in cochlear implantation (CI). Nineteen subjects who underwent CI were included in the study, and 10 subjects were enrolled as controls (steroid-administered group, n = 19; control group, n = 10). Dexamethasone (dexamethasone sodium phosphate, 5 mg/ml) was systemically administered preoperatively (1 ml) and topically applied during CI (0.5 ml). The extent of hearing preservation (HP) after CI and the change in the bithermal caloric response were evaluated. Hearing level was calculated using mean thresholds [(250 Hz + 500 Hz + 1,000 Hz + 2,000 Hz)/4]. Preoperative hearing thresholds were similar in the steroid-administered and control groups (100.92 ± 12.60 vs. 103.29 ± 14.39 dB, p = 0.650). The mean thresholds significantly increased in both groups after surgery (108.46 ± 14.08 dB, p = 0.006, for the steroid-administered group; 117.50 ± 6.34 dB, p = 0.027, for the control group), and the difference between the groups was also significant (p = 0.027). The postoperative shift in the hearing thresholds at frequencies of 500 and 1,000 Hz was significant in the steroid-administered group and that at the frequencies of 500, 1,000 and 2,000 Hz was significant in the control group. However, the extent of the shift in hearing threshold levels at each frequency was not significantly different between the groups. Preservation of hearing thresholds was compared between the groups, and there were significantly more subjects with complete and partial HP in the steroid-administered group than in the control group (p = 0.008). The preoperative caloric response was maintained after CI in the steroid-administered group. This study suggests that the perioperative use of a steroid could minimize the inner ear damage after CI.