Soree Ear Clinic

Seoul, South Korea

Soree Ear Clinic

Seoul, South Korea
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Choi S.-Y.,Kyungpook National University | Lee K.Y.,Kyungpook National University | Kim H.-J.,Kyungpook National University | Kim H.-K.,Kyungpook National University | And 6 more authors.
Molecular Medicine | Year: 2011

Mutations in the gap junction β2 (GJB2) gene, encoding the connexin26 (CX26) protein, are the most common cause of non-syndromic hearing loss (HL) in many populations. In the East Asian population, two variants, p.V27I (c.79G>A) and p.E114G (c.341G>A), are considered benign polymorphisms since these variants have been identified in both HL patients and normal hearing controls. However, some studies have postulated that homozygotes carrying both p.V27Iand p.E114Gvariants could cause HL. To elucidate possible roles of these variants, we used in vitro approaches to directly assess the pathogenicity of four haplo-types generated by the two polymorphisms: VE (wild type), I*E (p.V27I variant only), VG* (p.E114G variant only), I*G* (both variants). In biochemical coupling assays, the gap junctions (GJs) composed of VG* and I*G* types displayed defective channel activities compared with those of VE wild types or I*E types, which showed normal channel activities. Interestingly, the defect in hemichannel activity was a bit less severe in I*G* type than VG* type, suggesting that I* variant (p.V27I) may compensate for the deleterious effect of G* variant (p.E114G) in hemichannel activities. Our population studies using 412 Korean individuals showed that I*G* type was detected at around 20% in both HL patients and normal controls, suggesting that I*G* type may not be a pathogenic polymorphism. In contrast, VG* type was very rare (3/824) and detected only in HL patients, suggesting that VG* ho-mozygotes (VG*/VG*) or compound heterozygotes carrying VG* type with other mutations may cause HL. © 2011 The Feinstein Institute for Medical Research.

Woo H.-M.,National Institute of Health | Park H.-J.,Soree Ear Clinic | Baek J.-I.,Kyungpook National University | Park M.-H.,National Institute of Health | And 3 more authors.
BMC Medical Genetics | Year: 2013

Background: The genetic heterogeneity of hearing loss makes genetic diagnosis expensive and time consuming using available methods. Whole-exome sequencing has recently been introduced as an alternative approach to identifying causative mutations in Mendelian disorders.Methods: To identify the hidden mutations that cause autosomal recessive nonsyndromic hearing loss (ARNSHL), we performed whole-exome sequencing of 13 unrelated Korean small families with ARNSHL who were negative for GJB2 or SLC26A4 mutations.Results: We found two novel compound heterozygous mutations, IVS11 + 1 and p.R2146Q, of MYO15A in one (SR903 family) of the 13 families with ARNSHL. In addition to these causative mutations, 13 nonsynonymous variants, including variants with uncertain pathogenicity (SR285 family), were identified in the coding exons of MYO15A from Korean exomes.Conclusion: This is the first report of MYO15A mutations in an East Asian population. We suggest that close attention should be paid to this gene when performing genetic testing of patients with hearing loss in East Asia. The present results also indicate that whole-exome sequencing is a valuable method for comprehensive medical diagnosis of a genetically heterogeneous recessive disease, especially in small-sized families. © 2013 Woo et al.; licensee BioMed Central Ltd.

Kim J.-H.,Anyang University, China | Kim J.-H.,Hallym University | Lee J.H.,Hallym University | Lee H.-K.,Soree Ear Clinic
Clinical and Experimental Otorhinolaryngology | Year: 2014

Objectives. The goal of the present study was to examine whether Acceptable Noise Levels (ANLs) would be lower (greater acceptance of noise) in binaural listening than in monaural listening condition and also whether meaningfulness of background speech noise would affect ANLs for directional microphone hearing aid users. In addition, any relationships between the individual binaural benefits on ANLs and the individuals' demographic information were investigated. Methods. Fourteen hearing aid users (mean age, 64 years) participated for experimental testing. For the ANL calculation, listeners' most comfortable listening levels and background noise level were measured. Using Korean ANL material, ANLs of all participants were evaluated under monaural and binaural amplification with a counterbalanced order. The ANLs were also compared across five types of competing speech noises, consisting of 1- through 8-talker background speech maskers. Seven young normal-hearing listeners (mean age, 27 years) participated for the same measurements as a pilot testing. Results. The results demonstrated that directional hearing aid users accepted more noise (lower ANLs) with binaural amplification than with monaural amplification, regardless of the type of competing speech. When the background speech noise became more meaningful, hearing-impaired listeners accepted less amount of noise (higher ANLs), revealing that ANL is dependent on the intelligibility of the competing speech. The individuals' binaural advantages in ANLs were significantly greater for the listeners with longer experience of hearing aids, yet not related to their age or hearing thresholds. Conclusion. Binaural directional microphone processing allowed hearing aid users to accept a greater amount of background noise, which may in turn improve listeners' hearing aid success. Informational masking substantially influenced background noise acceptance. Given a significant association between ANLs and duration of hearing aid usage, ANL measurement can be useful for clinical counseling of binaural hearing aid candidates or unsuccessful users. © 2014 by Korean Society of Otorhinolaryngology-Head and Neck Surgery.

Lee H.K.,Kyungpook National University | Park H.-J.,Soree Ear Clinic | Lee K.-Y.,Wonkwang University | Park R.,Kyungpook National University | Kim U.-K.,Kyungpook National University
Biochemical and Biophysical Research Communications | Year: 2010

Autosomal dominant mutations in the transcription factor POU4F3 gene are associated with non-syndromic hearing loss in humans; however, there have been few reports of mutations in this gene worldwide. We performed a mutation analysis of the POU4F3 gene in 42 unrelated Koreans with autosomal dominant non-syndromic hearing loss, identifying a novel 14-bp deletion mutation in exon 2 (c.662del14) in one patient. Audiometric examination revealed severe bilateral sensorineural hearing loss in this patient. The novel mutation led to a truncated protein that lacked both functional POU domains. We further investigated the functional distinction between wild-type and mutant POU4F3 proteins using in vitro assays. The wild-type protein was completely localized in the nucleus, while the truncation of protein seriously affected its nuclear localization. In addition, the mutant failed to activate reporter gene expression. This is the first report of a POU4F3 mutation in Asia, and moreover our data suggest that further investigation will need to delineate ethnicity-specific genetic background for autosomal dominant non-syndromic hearing loss within Asian populations. © 2010 Elsevier Inc. All rights reserved.

Kim B.G.,Yonsei University | Shin J.-W.,Yonsei University | Park H.-J.,Soree Ear Clinic | Kim J.M.,Yonsei University | And 2 more authors.
International Journal of Pediatric Otorhinolaryngology | Year: 2013

Objectives: SLC26A4 (PDS) mutations are common cause of congenital hearing loss in East Asia. Hearing loss caused by PDS mutations tends to have delayed presentation; thus universal newborn hearing screening (UNHS) can be less effective in these patients. We examined the efficiency of newborn hearing screening test in patients with bi-allelic PDS mutations. Methods: Forty-three patients with sensorineural hearing loss were recruited. Patients had an enlarged vestibular aqueduct and biallelic PDS mutations. Among them, newborn hearing screening test had been performed on 14. The remaining 29 patients did not undergo newborn hearing screening test. Another 15 patients without a PDS mutation but who had sensorineural hearing loss were also recruited as a comparison group. We reviewed the hearing loss history of the children using medical records and parent interviews. Results: Among 14 patients with PDS mutation, four (28.6%) passed newborn hearing screening test in both ears and six (42.9%) passed in one ear. In contrast, only 2 of 15 (13.3%) children without a PDS mutation passed newborn hearing screening test bilaterally. The age at confirmation of bilateral hearing loss in bilateral "pass" patients with PDS mutation was 31.5 ± 17.9 months, which was significantly delayed compared to the age for bilateral "refer" children (1.75 ± 0.96 months) (p< 0.05). Conclusion: The UNHS is not an accurate tool for predicting long-term hearing loss in patients with PDS mutations. We recommend that genetic screening be combined with UNHS, particularly in communities with a high prevalence of PDS mutations, to better identify children in need of early habilitation. © 2013 Elsevier Ireland Ltd.

Woo H.-M.,National Institute of Health | Park H.-J.,Soree Ear Clinic | Park M.-H.,National Institute of Health | Kim B.-Y.,National Institute of Health | And 3 more authors.
BMC Medical Genetics | Year: 2014

Background: Patient genetic heterogeneity renders it difficult to discover disease-cause genes. Whole-exome sequencing is a powerful new strategy that can be used to this end. The purpose of the present study was to identify a hitherto unknown mutation causing autosomal recessive nonsyndromic hearing loss (ARNSHL) in Korean families.Methods: We performed whole-exome sequencing in 16 individuals from 13 unrelated small families with ARNSHL. After filtering out population-specific polymorphisms, we focused on known deafness genes. Pathogenic effects of the detected mutations on protein structure or function were predicted via in silico analysis.Results: We identified compound heterozygous CDH23 mutations in hearing-loss genes of two families. These include two previously reported pathological mutations, p.Pro240Leu and p.Glu1595Lys, as well as one novel mutation, p.Asn342Ser. The p.Pro240Leu mutation was found in both families. We also identified 26 non-synonymous variants in CDH23 coding exons from 16 hearing-loss patients and 30 Korean exomes.Conclusion: The present study is the first to show that CDH23 mutations cause hearing loss in Koreans. Although the precise contribution made by such mutations needs to be determined using a larger patient cohort, our data indicate that mutations in the CDH23 gene are one of the most important causes of non-syndromic hearing loss in East Asians. Further exome sequencing will identify common mutations or polymorphisms and contribute to the molecular diagnosis of, and development of new therapies for, hereditary hearing loss. © 2014 Woo et al.; licensee BioMed Central Ltd.

Yoon Y.-S.,Texas Tech University Health Sciences Center | Shin Y.-R.,Soree Ear Clinic | Gho J.-S.,Liberty University | Fu Q.-J.,University of California at Los Angeles
Cochlear Implants International | Year: 2015

Objectives: The present study characterizes the relationship between bimodal benefit and hearing aid (HA) performance, cochlear implant (CI) performance, and the difference in the performances of the two devices. Methods: Fourteen adult bimodal listeners participated in the study. Consonant, vowel, and sentence recognition were measured in quiet and noise (at a +5 and +10 dB signal-to-noise ratio (SNR)) with an HA alone, a CI alone, and with the combined use of an HA and CI in each listener. Speech and noise were presented directly in front of the listener. Results: The correlation analyses showed that bimodal benefit was significantly associated with the difference in performances of a CI and an HA in all testing materials, with HA-alone performance in vowel recognition, and with CI-alone performance in sentence recognition. However, regression analyses showed that the independent contribution of the difference in performance across ears to bimodal benefit was significant, irrespective of the testing material or the SNR: the smaller the difference, the greater the benefit. Further, the independent contributions of HA-only performance and CI-alone performance were not significant factors in predicting the existence of bimodal benefit across testing materials and SNRs when the effect of the difference between CI and HA performance was removed from the model. Conclusion: The results suggest that bimodal benefit is limited by how effectively the modalities integrate, rather than HA-only or CI-alone performance, and that this integration is facilitated when the performances of the modalities are similar. © 2015, W. S. Maney & Son Ltd.

Shin S.-H.,Yonsei University | Shim J.H.,Yonsei University | Lee H.-K.,Soree Ear Clinic
Clinical and Experimental Otorhinolaryngology | Year: 2010

Objectives: We propose here a classification system for external auditory canal cholesteatoma (EACC). We classified the EACC by the computed tomography findings and clinical findings of the patients, and we evaluated the EACC characteristics by the proposed staging system. Methods: Stage classification was done according to the results of temporal bone computed tomography and the clinical findings of the patients. Stage I indicates that the EACC lesion is limited to the external auditory canal. Stage II indicates that the EACC lesion invades the tympanic membrane and middle ear. Stage III indicates that the EACC lesion creates a defect of the external auditory canal and it involves the air cells in the mastoid bone. Stage IV indicates that the EACC lesion is beyond the temporal bone. Between 1996 and 2006, 29 patients with EACC and who underwent surgery were prospectively collected. This study was comprised of 16 males and 13 females with a mean age of 22.8±15.0 yr. We reviewed the characteristics and results of surgery by our proposed staging system. Results: A total of 29 patients who underwent operation due to EACC were classified by this system, and the number of stage I, II, III, and IV cases was 14, 3, 10, and 2, respectively. Symptoms such as otorrhea, hearing impairment and otalgia occurred in 12, 17, and 17 cases, respectively. The most common wall invaded by EACC was the inferior wall. The number of cases that had a spontaneous, congenital, post-traumatic, post-inflammatory or tumorous origin was 14, 9, 2, 2, and 1, respectively. Cholesteatoma recurred in 2 patients after surgery. Both cases were stage 1 and both were caused by congenital disease. There were 3 cases with meatal stenosis after surgery, and their primary disease was congenital. Conclusion: This proposed staging is simple and easily applicable for use when deciding the treatment plan for patients with EACC. © 2010 by Korean Society of Otorhinolaryngology-Head and Neck Surgery.

Yoon Y.-S.,House Research Institute | Shin Y.-R.,Soree Ear Clinic | Fu Q.-J.,House Research Institute
Ear and Hearing | Year: 2013

OBJECTIVES: This study investigated whether a spectral mismatch across ears influences the benefit of redundancy, squelch, and head shadow differently in speech perception using acoustic simulation of bilateral cochlear implant (CI) processing. DESIGN:: Ten normal-hearing subjects participated in the study, and acoustic simulations of CIs were used to test these subjects. Sentence recognition, presented unilaterally and bilaterally, was measured at +5 dB and +10 dB signal-to-noise ratios (SNRs) with bilaterally matched and mismatched conditions. Unilateral and bilateral CIs were simulated using 8-channel sine wave vocoders. Binaural spectral mismatch was introduced by changing the relative simulated insertion depths across ears. Subjects were tested while listening with headphones; head-related transfer functions were applied before the vocoder processing to preserve natural interaural level and time differences. RESULTS:: For both SNRs, greater and more consistent binaural benefit of squelch and redundancy occurred for the matched condition whereas binaural interference of squelch and redundancy occurred for the mismatched condition. However, significant binaural benefit of head shadow existed irrespective of spectral mismatches and SNRs. CONCLUSIONS:: The results suggest that bilateral spectral mismatch may have a negative impact on the binaural benefit of squelch and redundancy for bilateral CI users. The results also suggest that clinical mapping should be carefully administrated for bilateral CI users to minimize the difference in spectral patterns between the two CIs. © 2013 by Lippincott Williams & Wilkins.

Shin J.-W.,Soree Ear Clinic | Lee S.-C.,Soree Ear Clinic | Lee H.-K.,Soree Ear Clinic | Park H.-J.,Soree Ear Clinic
Clinical and Experimental Otorhinolaryngology | Year: 2012

Objectives: Genetic hearing loss is highly heterogeneous and more than 100 genes are predicted to cause this disorder in humans. In spite of this large genetic heterogeneity, mutations in SLC26A4 and GJB2 genes are primarily responsible for the major etiologies of genetic hearing loss among Koreans. The purpose of this study is to investigate the genetic cause of deafness in Korean cochlear implantees by performing a genetic screening of the SLC26A4 and GJB2 genes. Methods: The study cohort included 421 unrelated Korean patients with sensorineural hearing loss (SNHL) and who had received cochlear implants (CI) at Soree Ear Clinic from July 2002 to December 2010. Among 421 CI patients, we studied 230 cases who had received the genetic screening for SLC26A4 or GJB2 genes. Written informed consent was obtained from all participants. All patients had severe to profound, bilateral hearing loss. For 56 patients who showed enlarged vestibular aqueduct on their computed tomography (CI) scan, we analyzed SLC26A4. For 174 CT negative patients, GJB2 gene was sequenced. Results: For the 56 SLC26A4 patients, 32 (57.1%) had two pathogenic recessive mutations in SLC26A4.A single recessive SLC26A4 mutation was identified in 14 patients (25%). H723R and IVS7-2A>G were the most commonly found mutations, accounting for 60.3% (47/78) and 30.8% (24/78) of the mutated alleles, respectively. For the 174 GJB2 patients, 20 patients (11.5%) had two pathogenic recessive mutations in GJB2.235delC was the most common mutation, accounting for 43.0% (31/72) of mutant alleles. Conclusion: Ihe two major genes, SLC26A4 and G/B2, contribute major causes of deafness in CI patients. Continuous studies are needed to identify new genes that can cause hearing loss to Korean CI patients. Copyright © 2012 by Korean Society of Otorhinolaryngology-Head and Neck Surgery.

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