Hosuk Chu

A new measurement tool for speech development based on Ling's stages of speech acquisition in pediatric cochlear implant recipients.

OBJECTIVES With the rapid increase of pediatric cochlear implantation (CI), there exists a need for a standardized assessment tool regarding speech and communication skills in children with CI. However, the current testing tools are not appropriate for the longitudinal evaluation of young children after CI. The aims of this study were to describe a progressive testing tool developed for the evaluation of speech acquisition and production in young children who have undergone CI and to examine its validity. METHODS Sixty children younger than six years of age with CI participated in this study. A Korean version of Lings stages (K-Ling) was developed based on the Ling speech teaching model to longitudinally assess phonologic and phonetic developments in young children after CI. The K-Ling, the Categories of Auditory Performance (CAP), and the Sequenced Language Scale for Infants (SELSI) were performed in the children with CI preoperatively and three, six, and 12 months postoperatively. Correlations among these three testing tools were analyzed. RESULTS Auditory, language, and speech skills assessed using the CAP, SELSI, and K-Ling improved continuously for 12 months in young children following CI. Strong correlations were obtained among K-Lings level, CAP scores, and the equivalent age of SELSI; correlation indices ranged from 0.540 to 0.800. CONCLUSIONS The K-Ling was a valid evaluation tool regarding speech development in young children who are using CI and who are in the early stages of speech development. Longitudinal assessments of phonetic and phonologic developments may be attainable in young children using the K-Ling.

Auditory characteristics and therapeutic effects of enzyme replacement in mouse model of the mucopolysaccharidosis (MPS) II

Mucopolysaccharidosis (MPS) II is an X‐linked metabolic disorder caused by dysfunction of iduronate‐2‐sulfatase (I2S). This abnormality causes the progressive accumulation of incompletely degraded glycosaminoglycans (GAGs) in the lysosomes. The auditory characteristics of MPS II in mouse models have not been reported. In this study, we evaluated the auditory characteristics of the MPS II in IDS knock‐out (IDS‐KO) mice. In addition, the effect of enzyme replacement therapy (ERT) on hearing was studied. The IDS‐KO mice had normal histology of the cochlea and retained good hearing at 7 weeks of age. However, at 17 weeks of age, the hearing thresholds of the IDS‐KO mice were elevated and exudates were found in the middle ear. The hearing thresholds of the enzyme‐treated IDS‐KO (IDS‐ERT) mice were similar to the wild‐type (WT) mice at 17 weeks. Moreover, the microstructure of the inner ear was similar to the IDS‐KO by transmission electron microscopy. The histology findings indicated that the microstructure of the inner ear was similar in comparisons between IDS‐KO and IDS‐ERT mice, even after 10 weeks of treatment. However, the hearing deficits in the MPS II mouse model can be prevented if ERT is started before the onset of hearing impairment.

Open-type congenital cholesteatoma: Differential diagnosis for conductive hearing loss with a normal tympanic membrane

Abstract Conclusion: In patients with progressive conductive hearing loss and a normal tympanic membrane (TM), and with soft tissue density in the middle ear cavity (MEC) on temporal bone computed tomography (TBCT) scan, open-type congenital cholesteatoma (OCC) should be highly suspected and a proper surgical plan that includes mastoid exploration and second-stage operation is required. Objective: The clinical presentation of OCC is very similar to congenital ossicular anomaly (COA) presenting with a conductive hearing loss with intact TM. Therefore, it is challenging to make a correct preoperative diagnosis in patients with OCC. We evaluated the clinical characteristics of OCC compared with those of COA to find diagnostic clues useful in diagnosis of OCC. Methods: The medical records of 12 patients with surgically proven OCC and 14 patients with surgically proven COA were reviewed for demographic data, otologic history, preoperative TBCT findings, intraoperative findings, and pre- and postoperative audiologic data. Results: There was no difference between OCC and COA based on demographic data, preoperative hearing, and ossicular status on TBCT. However, the presence of progressive hearing loss, soft tissue density in the MEC on TBCT scan, and the need for mastoid surgery and second-stage operation were significantly more frequent in OCC patients.

Sequence Variations and Haplotypes of the GJB2 Gene Revealed by Resequencing of 192 Chromosomes from the General Population in Korea.

Objectives Hearing impairment (HI) is the most common sensory deficit in human. The Gap Junction Protein, Beta-2 (GJB2) gene encodes the protein connexin 26, and this gene accounts for up to half of the cases of autosomal recessive nonsyndromic HI. This study was conducted to obtain a set of sequence variations (SVs) of the GJB2 gene among Koreans from the general population for making molecular genetic diagnoses and performing genetic counseling. Methods We resequenced the GJB2 gene in 192 chromosomes from 96 adult individuals of Korean descent and who were without a history of hearing difficulty. The data of the SVs was obtained and the haplotypes were reconstructed from the data. Results Five SVs were observed, including a novel one (c.558G>A; p.T186T), with the allele frequencies ranging from 0.5% (1/192) to 41% (79/192). The linkage disequilibrium study and haplotype construction showed that some of the SVs are in tight linkage, resulting in a limited number of haplotypes. Conclusion We observed SVs of the GJB2 gene with different allele frequencies, and a limited number of haplotypes were constructed. The data from this study can be used as reference data for GJB2-related hearing genetic studies, including studies on the founder effect and population genetics, and this data is particularly relevant to people of East Asian decent.

Response to Letter to the Editor: Prevalence of vestibular and balance disorders in children and adolescents according to age category: A multi-center study in Korea ☆

First, we thank you for your interesting comments on our study. This study was designed to identify the etiologies and prevalence of vestibular and balance disorders according to age categories, in children and adolescents, in a multi-center study. In our study, vestibular migraine (VM) was the most common cause of vertigo and balance disorders in children and adolescents (29.2%). The next most common cause was BPVC (22.9%); these results differed from those in your study. There was a difference in the patient age distribution between our and your study populations. In your study, 7-year-olds were the youngest, and only two (1.6%) were younger than 10 years. However, in our study, 31 (7.5%) patients were under 6 years of age and 96 (23.4%) patients were under 10 years old. As we reported that the prevalence of disease by age showed differing distributions in children and adolescents with vertigo, the difference in age distribution is considered to be an important factor in the difference between the causes of dizziness of your and our studies. As a cause of dizziness, you classified hyperventilation/anxiety and psychogenic dizziness separately, and we included hyperventilation/anxiety in the psychogenic vertigo category. Psychogenic vertigo is a vertigo-inducing disorder associated with different psychiatric comorbidities (anxiety disorders, depressive, dissociative, and somatoform disorders) [1]. Although your study had a higher percentage of the older age group, which is known to have a higher prevalence of psychogenic vertigo, the proportion of hyperventilation seems to be high in your study compared not only with our study but also with other previous reports [2e4]. Although in young adults, “phobic postural vertigo” is the most common diagnosis [5], there has been no systematic study on psychogenic vertigo in children and adolescents and further studies are needed. In our paper, we mentioned that ‘Others’ was used to indicate diseases that were seldom diagnosed and ‘Others’ accounted for 9.2% of all patients. Compared with adults, it is difficult to consider the medical history of children as definite. However, if pediatric patients with dizziness are 5 years old or older, we can get important information related to their symptoms, and necessary for a diagnosis, from them. To do so, we have spent more time taking a detailed history and reaching a definite diagnosis. Also, our studywas designed as amulti-center study to include a wide range of population groups at different locations and to increase the generalizability of the study. As mentioned in the Methods, we collected pediatric dizziness patients in 11 hospitals in Korea, including primary, secondary, and tertiary hospitals. Thus, we consider that the patient group in our study was

A Novel Frameshift Mutation of the USH2A Gene in a Korean Patient with Usher Syndrome Type II

Usher syndrome type II (USH2) is the most common form of Usher syndrome, characterized by moderate to severe hearing impairment and progressive visual loss due to retinitis pigmentosa. It has been shown that mutations in the USH2A gene are responsible for USH2. The authors herein describe a 34-year-old Korean woman with the typical clinical manifestation of USH2; she had bilateral hearing disturbance and progressive visual deterioration, without vestibular dysfunction. Molecular genetic study of the USH2A gene revealed a novel frameshift mutation (c.2310delA; Glu771LysfsX17). She was heterozygous for this mutation, and no other mutation was found in USH2A, suggesting the possibility of an intronic or large genomic rearrangement mutation. To the best of our knowledge, this is the first report of a genetically confirmed case of USH2 in Korea. More investigations are needed to delineate genotype-phenotype correlations and ethnicity-specific genetic background of Usher syndrome.

Perilymph Fistula Test

A 42-year-old man presented with severe nausea and vertigo, which were precipitated by the application of pressure just anterior to the left external auditory canal. Otoscopic examination revealed a cholesteatoma arising from the pars flaccida of the left tympanic membrane.