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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.

An analysis of the effects of electromagnetic pulses from a high-power microwave (HPM) radiation technique is conducted using a relativistic backward-wave oscillator (RBWO) which uses relativistic ...

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.

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.

Aim The aim of this study was to investigate the effect of yttrium-90 radioembolization on the outcome of Asian patients with early to advanced stage hepatocellular carcinoma (HCC). Methods Sixty-two patients were screened and 50 patients (80.6%) were eligible. Response was evaluated using the Response Evaluation Criteria in Solid Tumors (RECIST), and overall survival was estimated using the Kaplan–Meier method. Results The Barcelona Clinic Liver Cancer (BCLC) stage was A in 40% of patients, B in 24%, and C in 36%; 66% of patients had hepatitis B virus infections. According to RECIST criteria, partial responses occurred in 40% of patients, and stable disease was achieved in 46%. Tumor response was significantly associated with BCLC stage (P = 0.003). The median overall time to progression was 5.8 months (range, 0.9–46.1 months). Follow-up treatments after radioembolization were carried out in 31 patients due to remnant HCC (n = 18) or HCC progression (n = 13). The median overall survival was 40.9 months (95% confidence interval, 10.2–71.6 months). Treatment was tolerable except for one lung toxicity and two hepatic toxicities. Conclusion Yttrium-90 radioembolization appears to be well tolerated and effective in Asian patients with BCLC stage A–C HCC. Follow-up treatments after radioembolization can be safely provided.

BACKGROUND AND AIM We aimed to subclassify hepatocellular carcinoma (HCC) using Barcelona Clinic Liver Cancer intermediate and advanced stages, which include a highly heterogeneous population. METHODS From two registries ("random" and "voluntary" cohorts in the Korean Liver Cancer Study Group), patients who were newly diagnosed as HCC with intermediate or advanced stage between 2003 and 2005 were considered eligible. Overall survival (OS) was analyzed using Kaplan-Meier method with comparison by log-rank test. RESULTS Patients with intermediate-stage HCC (n = 994) were subclassified according to tumor size and Child-Pugh class. Patients with tumor size

Objective We analyzed audiologic and surgical findings in patients with conductive hearing loss (CHL) with an intact tympanic membrane (TM) that was of a non-inflammatory origin. Methods We reviewed data from patients who underwent exploratory tympanotomy for CHL with intact TM from January 1995 to November 2012. Patients with diseases of non-inflammatory origin were enrolled (69 patients; 79 ears). Patients were categorized into two groups: non-trauma (50 ears) and trauma (29 ears). Demographic data, intraoperative findings, and audiologic results were obtained and analyzed. Results Overall, the second decade was the most common age of diagnosis in both the non-trauma and trauma groups. Operative findings showed that ossicular dislocation was more prevalent than ossicular fixation; all trauma group subjects had ossicular dislocation. Short columellization or partial ossicular replacement was the most frequently adopted surgical procedures in both groups. Overall, audiologically, air-conduction thresholds (ACs) and air–bone gaps were significantly improved over the short- and long-term period in both groups. However, the non-trauma group had significantly higher preoperative ACs than the trauma group, especially at low frequencies. Conclusion This study provides clinicians with useful information regarding the clinical characteristics of CHL with intact TM of non-inflammatory origin.

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.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.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).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.

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.

Cardiomyopathy is becoming the leading cause of death in patients with Duchenne muscular dystrophy because mechanically assisted lung ventilation and assisted coughing have helped resolve respiratory complications. To clarify cardiopulmonary function, we compared cardiac function between the home ventilator-assisted and non-ventilator-assisted groups.We retrospectively reviewed patients with Duchenne muscular dystrophy from January 2010 to March 2016 at Gangnam Severance Hospital. Demographic characteristics, pulmonary function, and echocardiography data were investigated.Fifty-four patients with Duchenne muscular dystrophy were divided into 2 groups: home ventilator-assisted and non-ventilator-assisted. The patients in the home ventilator group were older (16.25±1.85 years) than those in the nonventilator group (14.73±1.36 years) (Noninvasive ventilator assistance can help preserve cardiac function. Therefore, early utilization of noninvasive ventilation or oxygen may positively influence cardiac function in patients with Duchenne muscular dystrophy.

Background & Aims We examined the durability of the virological response after discontinuing lamivudine (LVD) in chronic hepatitis B (CHB) patients with LVD-resistant hepatitis B virus (HBV), who responded to LVD plus adefovir (ADV) combination therapy, and the outcome of switching to ADV monotherapy compared to maintaining combination therapy. Methods This study enrolled 72 patients with undetectable viral loads (≤12 IU/ml) and normal alanine aminotransferase levels after ADV add-on therapy for at least 6 months in LVD-resistant CHB patients. The enrolled patients were randomly assigned to continue with LVD–ADV combination therapy or switch to ADV monotherapy (n = 36 per group). Virological rebound was defined as HBV DNA detection at more than 12 IU/ml by quantitative polymerase chain reaction determined on two consecutive measurements. Results During 96 weeks of follow-up, 100% (36/36) of the patients in the LVD–ADV combination maintained group had persistently undetectable HBV DNA, compared with 94.4% (34/36) patients in the ADV monotherapy switched group. These two patients had undetectable HBV DNA after switching back to LVD–ADV combination therapy. There were no significant differences in the HBsAg levels between the two treatment groups during the 96-week follow-up period. Conclusions In our study, switching to ADV monotherapy resulted in sustained HBV DNA suppression in 94.4% of the patients for 96 weeks. Prior complete viral suppression with LVD–ADV combination therapy conferred a significant advantage in patients who switched to ADV monotherapy. LVD may be discontinued in patients who show a complete virological response to LVD–ADV combination therapy for at least 6 months.

Intestinal metaplasia (IM), a premalignant lesion, is associated with an increased risk of gastric cancer. Although estrogen exposure, including tamoxifen, has been studied in correlation with gastric cancer, little has been investigated about its effects on IM.Therefore, we investigated whether chronic tamoxifen use was associated with the risk of IM in human stomach.We evaluated 512 gastric biopsies from 433 female breast cancer patients that underwent endoscopic gastroduodenoscopy (EGD) ≥6 months after breast surgery. Histopathological findings were scored according to the updated Sydney classification. Demographic and clinical characteristics were also included to identify predictive factors for IM.In a multivariate logistic regression analysis, age at EGD (odds ratio [OR], 1.04; P = 0.002), biopsies from antrum (OR 2.08; P0.001), and Helicobacter pylori positivity (OR 1.68; P = 0.016) were significantly associated with an increased risk of IM, whereas chronic tamoxifen use (≥3 months) was associated with a decreased risk of IM (OR 0.59; P = 0.025). After stratifying by biopsy site, association between tamoxifen use and IM persisted for corpus (OR 0.42; P = 0.026) but not for antrum (OR 0.74; P = 0.327). In analysis limited to patients with follow-up EGD, chronic tamoxifen use also correlated with improved IM score compared to no tamoxifen use (improved, 77.8 vs. 22.2%; no change, 65.4 vs. 34.6%; worsened, 30.0 vs. 70.0%; P = 0.019).This study suggests that chronic tamoxifen use can decrease the risk of IM in human stomach. The effect of tamoxifen is predominantly observed in the corpus.

The TMPRSS3 gene (DFNB8/10), which encodes a transmembrane serine protease, is a common hearing loss gene in several populations. Accurate functions of TMPRSS3 in the hearing pathway are still unknown, but TMPRSS3 has been reported to play a crucial role in inner ear development or maintenance. To date, 16 pathogenic mutations have been identified in many countries, but no mutational studies of the TMPRSS3 gene have been conducted in the Korean hearing loss population. In this study, we performed genetic analysis of TMPRSS3 in 40 unrelated Korean patients with autosomal recessive hearing loss to identify the aspect and frequency of TMPRSS3 gene mutations in the Korean population. A total of 22 variations were detected, including a novel variant (p.V291L) and a previously reported pathogenic mutation (p.A306T). The p.A306T mutation which has been detected in only compound heterozygous state in previous studies was identified in homozygous state for the first time in this study. Moreover, the clinical evaluation identified bilateral dilated vestibules in the patient with p.A306T mutation, and it suggested that p.A306T mutation of the TMPRSS3 gene might be associated with vestibular anomalies. In conclusion, this study investigated that only 2.5% of patients with autosomal recessive hearing loss were related to TMPRSS3 mutations suggesting low prevalence of TMPRSS3 gene in Korean hearing loss population. Also, it will provide the information of genotype-phenotype correlation to understand definite role of TMPRSS3 in the auditory system.

Methionine sulfoxide reductase B3 (MsrB3) is a protein repair enzyme that specifically reduces methionine-R-sulfoxide to methionine. A recent genetic study showed that the MSRB3 gene is associated with autosomal recessive hearing loss in human deafness DFNB74. However, the precise role of MSRB3 in the auditory system and the pathogenesis of hearing loss have not yet been determined. This work is the first to generate MsrB3 knockout mice to elucidate the possible pathological mechanisms of hearing loss observed in DFNB74 patients. We found that homozygous MsrB3(-/-) mice were profoundly deaf and had largely unaffected vestibular function, whereas heterozygous MsrB3(+/-) mice exhibited normal hearing similar to that of wild-type mice. The MsrB3 protein is expressed in the sensory epithelia of the cochlear and vestibular tissues, beginning at E15.5 and E13.5, respectively. Interestingly, MsrB3 is densely localized at the base of stereocilia on the apical surface of auditory hair cells. MsrB3 deficiency led to progressive degeneration of stereociliary bundles starting at P8, followed by a loss of hair cells, resulting in profound deafness in MsrB3(-/-) mice. The hair cell loss appeared to be mediated by apoptotic cell death, which was measured using TUNEL and caspase 3 immunocytochemistry. Taken together, our data suggest that MsrB3 plays an essential role in maintaining the integrity of hair cells, possibly explaining the pathogenesis of DFNB74 deafness in humans caused by MSRB3 deficiency.

In this paper, a mesoband pulse radiator fed by a spark gap switch is designed, and its radiation characteristics are analyzed. Initially, a modified equivalent circuit model of spark gap switch is proposed to enable detailed explanation and fast design. Then, dual resonant characteristic due to the higher order mode of a mesoband pulse radiator is newly analyzed by changing the dipole length and radius. According to the analyzed results, the variation of the dipole length affects not only the radiating power, but also the operating frequency and bandwidth. The measured 3-dB bandwidth of the designed pulse radiator is about 57% (λ = 1.15 m), meeting the need for a mesoband condition. The radiated electric field at 4 m from the radiator has a peak of 7.19 kV/m.

Effects of voltage driving frequency on the gas composition, electrical and optical emission properties of aqua-plasmas generated in electrolyte solution, are investigated and the experiment was carried out in the range of 10 Hz–50 kHz. In the range of 10–300 Hz, H2 dominated bubbles are generated and it is attributed to electrolysis. With increasing frequency, the gas composition inside the bubble changes to the H2O which can be determined from the observation of atomic H to OH(A-X) transition from the optical measurements of aqua-plasma. In higher frequency than 2 kHz, the boiling on the electrode dominates to the formation of the bubble. Consequently, the radicals and plasma properties are varied with the driving frequency.

We report a case study on possible alterations in resting-state functional connectivity between the auditory network and non-auditory brain regions in tinnitus patients.Independent component analyses were performed to evaluate coherent spontaneous activity in distributed brain networks. The resting-state functional connectivity scores between the right and left auditory networks were measured. Direct comparison of resting-state connectivity between tinnitus patients and controls was made using a two-sample t-test.Four patients (three male, one female; mean age 45 ± 3.92 years) with chronic tinnitus lateralized to the left ear, and six age-matched controls (four male, two female; mean age 45 ± 2.76 years) participated in this case study.The average resting-state functional connectivity (FC) score between the left and right auditory cortical regions was significantly lower in tinnitus patients than in controls (P0.05). Direct comparison between patients and controls showed that increased functional connectivity caused by tinnitus occurred predominantly in the left amygdala and in the dorsomedial prefrontal cortex.Our pilot study suggested that resting state functional magnetic resonance imaging (fMRI) could be useful to investigate possible alterations in resting-state neuronal activity between the auditory and non-auditory networks in tinnitus patients.

In this study, we developed an optical coherence tomography(OCT) using a sweep-source laser whose center wavelength is 1310 nm and a probe of hand-held type. The developed hand-held probe targets to diagnose the middle ear, so it is miniaturized for ease and convenience of control. For the first time, we performed in-vivo clinical experiments on tympanic membrane(TM) perforation patients not reported from previous studies about OCT. The high-resolution sectional images of tympanic membrane perforation can be obtained. There aren`t many studies about diagnostic instrument of the middle ear and diagnosis with sectional image of the middle ear, so the developed OCT system and hand-held probe are applicable to tympanic membrane perforation and other pathologic diagnosis in the middle ear.

Hypertrophic pachymeningitis is a progressive disease resulting in a diffuse thickening of dura mater due to inflammation, tumor or autoimmune diseases, but most cases are idiopathic. It is seldom reported to be related to sensorineural hearing loss, but it can cause sensorineural hearing loss which can be potentially reversed through treatment. Here, we report the case of a 54-year-old woman who had progressive, bilateral, worse in the left, sensorineural hearing loss and visual disturbance with an accompanying headache over several months. Brain MRI showed diffusely thickened dura mater, highly enhanced after gadolinium administration, which was consistent with pachymeningitis. It was assumed to be related to autoimmune pathogenesis on the basis of elevated serum myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) titers. After empirical steroid and cyclophosphamide therapy, auditory impairment improved, especially in the high frequency region of the pure tone audiogram, and significant improvement in the word recognition test. Moreover, a follow-up MRI revealed much decreased enhancement of the dura mater, and the MPO-ANCA titer decreased to within the normal range. In the case of rapidly progressive sensorineural hearing loss or hearing impairment accompanying other cranial neuropathy, pachymeningitis should be taken into consideration, and brain MRI with gadolinium enhancement is the best method of detecting it. Also, to ensure proper treatment, a cautious evaluation including an ANCA work-up should be performed.

In this article, a new antenna is introduced for ingestible capsule endoscope systems. As capsule endoscope systems are supposed to operate in the human body and they transmit internal image data with high resolution to external receivers, a wideband small antenna is required. To obtain these properties, the proposed antenna is designed in the form of thick-arm spiral structure. The total height of the antenna is 5 mm and the diameter is 10 mm. The fractional bandwidth of the proposed antenna is 21% with VSWR < 2, which is wide enough for WBAN in body communication and it has the isotropic radiation pattern. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:529–532, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25808

A small antenna with coupling feed and parasitic elements for multiband application is proposed. The proposed antenna is small, low-profile, and suitable for multiband mobile applications. The coupling feed structure provides wideband characteristic to a planar inverted-F antenna (PIFA). There are two resonance modes at 0.8 GHz, and their current distributions are observed. Four resonance modes from high-order resonance modes and parasitic elements are designed to be at 1.7 GHz. The proposed antenna is able to support the GSM850/GSM900/DCS/PCS frequency band in 3:1 VSWR standard. The radiation efficiency and radiation patterns are presented to verify compatibility in mobile handset applications.

In this paper, the small loop antenna with a parasitic loop structure for penta-band mobile phone application is proposed. This antenna is composed of a feed monopole, a radiating loop antenna with a parasitic loop structure and an additional radiating element. The antenna is printed on the very thin flexible substrate to mount on the dielectric carrier with a volume of 40 mm11 mm3 mm. The bandwidth of the proposed antenna is 402 MHz(773~1,175 MHz) for low band and 583 MHz(1,622~2,205 MHz) for high band. As a result, the proposed antenna covers the five bands of GSM850, GSM900, DCS1800, PCS1,900 and WCDMA for a 3:1 VSWR. Moreover, the radiation pattern, gain and efficiency are appropriate for mobile handset. Therefore, this antenna is suitable for small sized multi-band mobile handset applications.

Mode conversion of high-power electromagnetic microwave (HPEM) was successfully accomplished using a coaxial-beam rotating antenna (COBRA) in an X-band relativistic backward-wave oscillator (RBWO). The mode conversion from the TM01 mode to the circularly polarized TE11-likeness mode was identified by both cold test and hot test. To observe whether mode conversion is effective or not, the radiation pattern of TE11-likeness mode by COBRA lens was compared with the case of the radiation pattern of TM01 mode using simple horn antenna. Their radiation patterns could be described by fluorescent lamps. The experimental results of radiation pattern measurements are shown to be in a reasonable agreement with the simulated one. The maximum value of RF output power appeared at the center of COBRA lens from the experimental results.

Objectives The purpose of this study was to obtain sex- and age-specific reference level for hearing threshold of normal aging in Korean and to determine if the rate of change in pure-tone hearing thresholds differed by sex. Methods Subjects were clients who visited the Health Promotion Center, Daegu Fatima Hospital, Daegu, Korea, from January 2004 to September 2005. Pure-tone audiometric measures were obtained from 3,470 subjects who also completed a hearing questionnaire. The slope of a linear regression was used to estimate the rate of change in pure-tone thresholds at 0.25 to 8 kHz for each ear in 214 men and 902 women without past history of otorrhea, usage of ototoxic drugs, head injury, job in noisy environment, and military service. Results Hearing thresholds were elevated with age in all test frequencies. Significant sex differences were found in pure-tone thresholds at 4 and 8 kHz after adjusting for age using analysis of covariance. In those high frequencies, hearing was worse in men than in women. The average rate of change in threshold was 0.28 and 0.24 dB per year at 0.25 kHz, increasing gradually to 1.27 and 1.05 dB per year at 8 kHz for men and women, respectively. Men had significantly faster rates of threshold increase at 4 and 8 kHz than women. Conclusion These cross-sectional measures of hearing levels and rate of threshold increases at 4 and 8 kHz showed significant sex differences in Korean men and women with little evidence of noise-induced hearing loss.

In this letter, a multiband handset antenna using folded slots is proposed to support the five wireless communication bands of GSM850 (824-894 MHz), GSM900 (880-960 MHz), DCS1800 (1710-1880 MHz), PCS1900 (1850-1990 MHz), and UMTS (1920-2170 MHz). Since the proposed antenna has balanced resonating characteristics, resonant frequency shifting due to the hand effect is reduced while allowing a small size of 40 × 18 × 7 mm3 (W × L × H). As a result, the improved matching characteristic at the operating frequency band reduces the degeneration of the radiation efficiency due to the hand effect.

Microsatellites, short tandem repeats, are useful markers for genetic analysis because of their high frequency of occurrence over the genome, high information content due to variable repeat lengths, and ease of typing. To establish a panel of microsatellite markers useful for genetic studies for hereditary hearing loss in the Korean population, the allele frequencies and heterozygosities of 32 microsatellite markers in 172 unrelated Korean individuals were examined. The heterozygosity values for these markers ranged from 48 to 87%. All the markers except D6S1038 and D14S1034 marker showed PIC values over 0.5. This indicates these markers have a high degree of polymorphism and are randomly distributed in the Korean population. Therefore, the combinations of these STR loci provide a powerful tool to find the candidate loci of a causative gens for non-syndromic hearing loss in the Korean population.

The implantable middle ear hearing devices(IMEHDs) have been developed to overcome the conventional hearing aid`s problem(ringing effect caused by the acoustic feedback, cosmetic problem, etc.). In the IMEHDs, the vibrating transducer is a key component because its vibration enables to hear for hearing impaired people. The vibrating transducer is implanted on ossicular chain by surgical operation. The coupling status between implanted transducer and ossicular chain has an effect on delivering vibrating force from transducer to stapes. Noninvasive method is required to investigate the output characteristics of IMEHDs after implementation. Recently, emitted sound pressure measuring method of tympanic membrane is proposed to investigate the output characteristics of IMEHDs. However, the relationship between displacement of stapes and sound pressure by tympanic membrane was not cleared. In this paper, displacement of stapes and sound pressure by tympanic membrane were measured using the differential floating mass transducer(DFMT) that implanted on the ossicular chain of the human temporal bone and physical ear model. Through the experiments results, the relationship between displacement of stapes and sound pressure by tympanic membrane was investigated.

In this paper, a wideband LC oscillator which is composed of a high voltage switch and a fat dipole antenna was designed and radiation characteristics are analyzed. A Marx generator was used as a high voltage pulse generator of the proposed wideband LC oscillator and corner reflector was used to obtain high directivity. According to simulated and measured results, 3 dB bandwidth of high voltage switch without fat dipole based on the received power is about 9%(${\lambda}_1

In this paper, miniaturized conically stepped COBRA is proposed. In order to prevent electrical breakdown, COBRA, which consists of hem and lens, has to get bigger if it is designed with conventional method. Because of the phase error increase, shortening the length of the antenna without changing the aperture size leads to the reduction of the antenna gain. To avoid this, the phase error at the aperture is compensated by transforming the COBRA lens into conically stepped form. The simulations result shows that the proposed antenna has higher gain than the conventional COBRA in spite of the size reduction from 1,300 mm to 600 mm. The fabricated and measured COBRA has the gain of 26.2 dBi.

OBJECTIVE To determine normal values for the amplitude ratio of sensory nerve action potential (SNAP) from an ulnar sensory segmental nerve conduction study, and to the evaluate usefulness in the diagnosis of mild-degree ulnar neuropathy at the elbow (UNE). DESIGN Segmental sensory conduction study of the ulnar nerve was performed in 71 healthy subjects. Peak latency and baseline to peak amplitudes were measured. The amplitude ratio of below-elbow to wrist (BE/W) stimulations and above-elbow (AE) to below-elbow stimulations (BE) were calculated. Normal cutoff values were obtained by subtracting 2 SD from the mean value, and these values were applied to 22 symptomatic UNE cases. The amplitude ratio was also obtained in six subjects with C8 radiculopathy. RESULTS The amplitude ratios of BE/W and AE/BE were 0.61 +/- 0.08 and 0.82 +/- 0.08, respectively. The cutoff value of BE/W was 0.45, and that of AE/BE was 0.65. The amplitude ratio of BE/W showed a weak correlation to the length of the forearm segment (r = -0.25, P < 0.05). Five of the 22 UNE patients revealed only reduced amplitude ratios of SNAP across the lesion, whereas all the patients with C8 radiculopathy showed normal amplitude ratios of ulnar SNAP. CONCLUSIONS The amplitude ratio of ulnar SNAPs may be useful in the diagnosis of mild ulnar neuropathy with only sensory symptoms and normal segmental motor conduction.

Purpose To evaluate the effect of incidental magnetization transfer (iMT) in multislice brain imaging at 3.0T. Materials and Methods The contribution of iMT to multislice brain MRI was evaluated at 3.0T. In 10 normal subjects we obtained multislice fast spin-echo (FSE) MR images using a 16-echo pulse train without an off-resonance MT pulse at 3.0T and 1.5T. We quantified the extent of iMT by calculating the iMT ratio (iMTR). Results We found that the iMT contrast (iMTC) has a greater effect at 3.0T. As the number of slices increased in multislice FSE imaging, the difference between two field strengths became larger. Compared to WM structures, however, the difference in iMT effect between 1.5T and 3.0T was smaller in the case of GM structures. Conclusion The iMTC has a greater effect at 3.0T. The strength of the iMT is different for different tissue types and also varies according to the number of slices used. J. Magn. Reson. Imaging 2007. © 2007 Wiley-Liss, Inc.

Branchio-oto-renal (BOR) syndrome is an autosomal dominant disorder that is characterized by branchial cysts or fistulae, external ear malformations and/or preauricular pits, hearing loss and renal anomalies. Recent advances in molecular genetics have shown a human homologue of the Drosophila 'eyes absent' gene (EYA1) on chromosome band 8q13.3 to be the most common cause of BOR syndrome. Several mutations have been identified in the EYA1 gene in patients with BOR syndrome worldwide. Here, we report a second Korean family with BOR syndrome with a novel nonsense EYA1 mutation.

Local application of recombinant human insulin-like growth factor 1 (rhIGF-1) via a biodegradable hydrogel after onset of noise-induced hearing loss (NIHL) can attenuate functional and histologic damage.The biodegradable gelatin hydrogel makes a complex with drugs by static electric charges and releases drugs by degradation of gelatin polymers. We previously demonstrated the efficacy of local rhIGF-1 application via hydrogels before noise exposure for prevention of NIHL.First, we used an enzyme-linked immunosorbent assay to measure human IGF-1 concentrations in the cochlear fluid after placing a hydrogel containing rhIGF-1 onto the round window membrane of guinea pigs. Second, the functionality and the histology of guinea pig cochleae treated with local rhIGF-1 application at different concentrations after noise exposure were examined. Control animals were treated with a hydrogel immersed in physiologic saline alone.The results revealed sustained delivery of rhIGF-1 into the cochlear fluid via the hydrogel. The measurement of auditory brainstem responses demonstrated that local rhIGF-1 treatment significantly reduced the threshold elevation from noise. Histologic analysis exhibited increased survival of outer hair cells by local rhIGF-1 application through the hydrogel.These findings indicate that local rhIGF-1 treatment via gelatin hydrogels is effective for treatment of NIHL.

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.