Over 5% of the world’s population – 360 million people – has disabling hearing loss (328 million adults and 32 million children). Early diagnosis of hearing loss in children and providing hearing devices, including cochlear implants helps to develop speech, language, and listening skills needed for oral communication. Because of this reason, identifying children early with accurate hearing assessment in children is crucial. The aim of this study was to determine advantage of auditory steady-state response testing in comparing ABR and ASSR thresholds in children with severe hearing loss. Totally 21 children, 8 female and 13 males, aged between 18 and 46 months were included to this study. Mean age was 26 months. All the children underwent otoscopy and ABR before the measurement of ASSR thresholds. ABR and ASSR threshold measurements were performed by different physicians. They were performed in a quiet room, where sound level is less than 50 dB. Each child was asleep by nature during the test. Pearson’s correlation test have been used to evaluate correlation of thehearing thresholds of ABR and ASSR. The hearing thresholds in ABR correlated well with the threshold obtained with ASSR (Pearson’s correlation coefficient (0.231) is significant at the 0.01 level). In addition; in patients, where the thresholds for ABR were not measurable, it could be found in ASSR tests. If there is not any residual hearing for subjects, both tests resulted with no response. Based on these findings, both ABR and ASSR techniques may be used to provide an estimate of hearing sensitivity in children, but ASSR is a more valuable test than ABR. Determining thresholds for 0.5, 1, 2, 4 kHz is very important. Identifying children early with accurate hearing assessment leads to earlier fitting of sensory devices, including cochlear implants, which minimizes delays in auditory, speech, and language development.

Over 5% of the world’s population – 360 million people – has disabling hearing loss (328 million adults and 32 million children). Early diagnosis of hearing loss in children and providing hearing devices, including cochlear implants helps to develop speech, language, and listening skills needed for oral communication. Because of this reason, identifying children early with accurate hearing assessment in children is crucial. The aim of this study was to determine advantage of auditory steady-state response testing in comparing ABR and ASSR thresholds in children with severe hearing loss.Totally 21 children, 8 female and 13 males, aged between 18 and 46 months were included to this study.Mean age was 26 months. All the children underwent otoscopy and ABR before the measurement ofASSR thresholds. ABR and ASSR threshold measurements were performed by different physicians.They were performed in a quiet room, where sound level is less than 50 dB. Each child was asleep by nature during the test. Pearson’s correlation test have been used to evaluate correlation of thehearing thresholds of ABR and ASSR.The hearing thresholds in ABR correlated well with the threshold obtained with ASSR (Pearson’scorrelation coefficient (0.231) is significant at the 0.01 level). In addition; in patients, where the thresholds for ABR were not measurable, it could be found in ASSR tests. If there is not any residual hearing for subjects, both tests resulted with no response.Based on these findings, both ABR and ASSR techniques may be used to provide an estimate of hearing sensitivity in children, but ASSR is a more valuable test than ABR. Determining thresholds for 0.5, 1, 2, 4 kHz is very important. Identifying children early with accurate hearing assessment leads to earlier fitting of sensory devices, including cochlear implants, which minimizes delays in auditory, speech, and language development.

Effects of industrial noise have been recognized by humanity since mid 19th century and works to study and prevent industrial noises had begun globally. Strong industrial noises damage human internal ear and hair cell of cort-organ rapidly and gradually, which causes deafness; and thousands of people are suffering from health problems. Many noisy industries, where thousands of people work, were built in our country by 1960’s anddeafness has increased due to exposure of industrial noise. Scientific studies to measure the level of industrial noise, to determine the hearing level of people who are working in it, to study the relationship between noise and hearing loss still haven’t been conducted completely. Aim: To measure distribution zone of industrial noise generator which generates noise with more than 85, to study hearing threshold of the people who are constantly affected by it, to prevent noise hearing loss.The plants of “Erdenet Industry” JSC, TPP-4 SOC, “Darkhan TU” SOC, TPP-3 SOC have been chosenwithin scope of the research. Noise level of 42 instruments of these plants which produces noise over85 “Noise distribution zone” where noise level decreases to 85, Chose 480 employees who have beenaffected by it for more than 5 years.Using modern audiometer at 250, 500, 1000, 2000, 4000, 8000 Hz to measure for each bone and air conduction in noise-proof rooms Average hearing thresholds are calculated at dense, medium, pitched noise levelEarplug and headphone were used at shop and assembly line with noise over 85 дБ for more than 24 hours by employees, their satisfaction was studied and it was watched that if they were using the protective equipment regularly.Hearing threshold of employees who constantly work at noisy environment found to be 28.5±3.8 dB atdense noise 31.8±4.4±0.3 at medium noise, 38.2±5.7 dB at pitched noise level for “Erdenet Industry” JSC, 30.9±3.1±0.3 дБ at dense noise, 34.6±3.5 dB at medium noise, 39.5±4.3 dB at pitched noise level for TPP-4 SOC, 31.9±3.6 dB at dense noise, 34.9±3.8 dB at medium noise, 40.9±4.1 dB at pitched noise level for “Darkhan TU” SOC, 28.9±2.6 dB at dense noise, 32.4±2.8 dB at medium noise, 36.4±4.4 dB at pitched noise level for TPP-3 SOC. 95.6% of employees of “Erdenet Industry” JSC, 95.7% of employees of TPP-4 SOC, 96.5 % of employees of “Darkhan TU” SOC, 95.8 % of employees of TPP-3 SOC were satisfied when noise protection tools Ear classic and Bilsom were used at environment with noise level over 85 dB. Average hearing threshold of employees who have worked for more than 5 years in weak industrial noise level (85 – 92.5 dB) found to be 28.4±3.0 dB at dense noise, 32.3±3.2 dB at medium noise, 37.1±4.5 dB at pitched noise level, for medium noise level environment 30.2±3.4±0.3 dB at dense noise, 33.5±4.0 dB at medium noise, 39.2±4.4 dB at pitched noise level, for strong noise environment 34.1±3.6 dB at dense noise, 34.5±3.8±0.4 at medium noise, 34.8±4.5 dB at pitched noise level, or it was reduced from healthy hearing threshold with true possibility when p=0.05.95.6% of employees of “Erdenet Industry” JSC, 95.7% of employees of TPP-4 SOC, 96.5 % of employees of “Darkhan TU” SOC, 95.8 % of employees of TPP-3 SOC were satisfied when noise protection tools Ear classic and Bilsom were used at environment with noise level over 85 dB, which makes these tools reliable protectors from hearing loss due to noise.

BACKGROUND. Sensorineural hearing impairment (SNHI) is the most common inherited sensory defect, affecting about 3 per 1000 children. More than 50% of these patients have a genetic cause (i.e. hereditary hearing impairment; HHI). Mutations in certain genes were noted to be extraordinarily popular in the deaf patients across different populations, making molecular screening feasible for these common deafness genes. One of the most important characteristics that we have learned concerning hereditary hearing loss is that common deafness genes and their mutations are usually different according to the ethnic background. As demonstrated in our previous studies performed in Taiwanese patients, the mutation spectrums of common deafness genes, such as the GJB2 gene and the SLC26A4 gene, are different from those in the Caucasian or even other Asian populations. These findings further underscore the indispensability of the collection of local data in terms of genetic counseling. In the collaborative project, we have successfully established a cohort of >100 hearing-impaired families, and clarified the genetic epidemiology of deafness in the Mongolian population. We identified several special deafness mutations such as GJB2 c.23+1G>A, c.559_604dup, and SLC26A4 c.919-2A>G, and our results revealed that Mongolian patients demonstrate a unique genetic profile in deafness as compared to other East Asian populations (paper in preparation). Meanwhile, by organizing a seminar at National Taiwan University Hospital in March 2017, we have transferred crucial concepts and techniques regarding how to perform genetic testing for deafness to the Mongolian colleagues. In the future, we plan to strengthen the mutual collaboration by expanding the clinical cohort and upgrading the genetic examination platform using the NGS techniques.

BACKGROUND. Sensorineural hearing impairment (SNHI) is the most common inherited sensory defect, affecting about 3 per 1000 children. More than 50% of these patients have a genetic cause (i.e. hereditary hearing impairment; HHI). Mutations in certain genes were noted to be extraordinarily popular in the deaf patients across different populations, making molecular screening feasible for these common deafness genes. One of the most important characteristics that we have learned concerning hereditary hearing loss is that common deafness genes and their mutations are usually different according to the ethnic background. As demonstrated in our previous studies performed in Taiwanese patients, the mutation spectrums of common deafness genes, such as the GJB2 gene and the SLC26A4 gene, are different from those in the Caucasian or even other Asian populations. These findings further underscore the indispensability of the collection of local data in terms of genetic counseling. In the collaborative project, we have successfully established a cohort of >100 hearingimpaired families, and clarified the genetic epidemiology of deafness in the Mongolian population. We identified several special deafness mutations such as GJB2 c.23+1G>A, c.559_604dup, and SLC26A4 c.919-2A>G, and our results revealed that Mongolian patients demonstrate a unique genetic profile in deafness as compared to other East Asian populations (paper in preparation). Meanwhile, by organizing a seminar at National Taiwan University Hospital in March 2017, we have transferred crucial concepts and techniques regarding how to perform genetic testing for deafness to the Mongolian colleagues. In the future, we plan to strengthen the mutual collaboration by expanding the clinical cohort and upgrading the genetic examination platform using the NGS techniques.

Background: Hearing loss (HL) is one of the most common sensory disorders, affecting over 5-8% of the world's population. Approximately half of HL cases are attributed to genetic factors. In hereditary deafness, about 75-80% is inherited through autosomal recessive inheritance, and common pathogenic genes include GJB2 and SLC26A4. Pathogenic variants in the SLC26A4gene are the leading cause of hereditary hearing loss in humans, second only to the GJB2 gene. Variants in the SLC26A4gene cause hearing loss, which can be non-syndromic autosomal recessive deafness (DFNB4, OMIM #600791) associated with enlarged vestibular aqueduct (EVA) or Pendred syndrome (Pendred, OMIM #605646). DFNB4 is characterized by sensorineural hearing loss combined with EVA or less common cochlear malformation defect. Pendred syndrome is characterized by bilateral sensorineural hearing loss with EVA and an iodine defect that can lead to thyroid goiter. Currently, it is known that EVA is associated with variants in the SLC26A4 gene and is a penetrant feature of SLC26A4-related HL. Predominant mutations in these genes differ significantly across populations. For instance, predominant SLC26A4 mutations differ among populations, including p.T416P and c.1001G>A in Caucasians, p.H723R in Japanese and Koreans, and c.919-2A>G in Han Taiwanese and Han Chinese. On the other hand, there has been no study of hearing loss related to SLC26A4 gene variants among Mongolians, which is the basis of our research. Aim: We aimed to identify the characteristics of the SLC26A4 gene variants in Mongolian people with Enlarged vestibular aqueduct and Mondini malformation. Materials and Methods: In 2022-2024, We included 13 people with hearing loss and enlarged vestibular aqueduct, incomplete cochlea (1.5 turns of the cochlea with cystic apex- incomplete partition type II- Mondini malformation) were examined by CT scan of the temporal bone in our study. WES (Whole exome sequencing) analysis was performed in the Genetics genetic-laboratory of the National Taiwan University Hospital. Results: Genetic analysis revealed 26 confirmed pathogenic variants of bi-allelic SLC26A4 gene of 8 different types in 13 cases, and c.919-2A>G variant was dominant with 46% (12/26) in allele frequency, and c.2027T>A (p.L676Q) variant 19% (5/26), c.1318A>T(p.K440X) variant 11% (3/26), c.1229C>T (p.T410M) variant 8% (2/26) ) , c.716T>A (p.V239D), c.281C>T (p.T94I), c.1546dupC, and c.1975G>C (p.V659L) variants were each 4% (1/26)- revealed. Two male children, 11 years old (SLC26A4: c.919-2A>G) and 7 years old (SLC26A4: c.919-2A>G:, SLC26A4: c.2027T>A (p.L676Q))had history of born normal hearing and progressive hearing loss. Conclusions 1. 26 variants of bi-allelic SLC26A4 gene mutation were detected in Mongolian people with EVA and Mondini malformation, and c.919-2A>G was the most dominant allele variant, and rare variants such as c.1546dupC, c.716T>A (p.V239D) were detected. 2. Our study shows that whole-exome sequencing (WES) can identify gene mutations that are not detected by polymerase chain reaction (PCR) or NGS analysis.