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.

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 is likely to be the most common congenital abnormality in newborns, with a reported prevalence of 1 to 2 per 1000 live births. It is vitally important to diagnose infant hearing loss or deafness at its early stages. Early detection and intervention is critical to prevent the adverse consequences of a delayed diagnosis on speech, language and cognitive development. Universal screening of hearing loss has been introduced in practice with distortion product of otoacoustic emission (DPOAE). The automated auditory brainstem response (AABR) screener is a dedicated hearing screening device which provides information not only about the outer and middle ear and cochlea but also about the auditory pathway up to the brainstem. METHODS. The study was descriptive and based on a retrospective analysis of the two year period databases (2014-2016) from the newborn hearing screening program. We have started the hearing screening from December 2012. Between 2014 to 2017 we have been screened total of 11218 newborns. We tested automated audiotory brainstem response of the newborns in their 1- 3 days of birth, using Maico MB11 Beraphone machine (German) according to the Joint Committee on Hearing Screening guidence. We assessed the test result of “pass” as “normal hearing, “refer” as to rescreen and tested again after 1 month. Infants referred again were gone to a specialist for further audio logic analysis (behavioral tests, auditory brainstem response, otoacoustic emissions and auditory steady state response). RESULTS. Our study was the first in Mongolia. Total of 10290 newborns passed bilaterally out of 11218 and 1323 referred in the first screening. For the rescreen test, 1088 out of 1134 infants resulted with “pass” and 46 infants with “refer”. For those infants, we did ABR test in their 3 and 6 months, and result of 9 children (18 ears) have bilateral profound hearing loss, 2 children (2 ears) have bilateral mixed profound hearing loss and 13 (26 ears) have bilateral profound conductive hearing loss. Coverage rate was 34,7%. First refer rate was 11,7%. Follow rate was 39,7%. We conducted the cochlear implantation surgery for 2 children out of 11. Currently, we are preparing other infants with bilateral profound hearing loss of 0-3 years old for the follow up CI surgery. CONCLUSION. In Mongolia, the data of infant hearing difficulties and prevalence of deafness is lacking. Although newborn hearing screening program has been approved in 2014 and brought opportunities to conduct universal neonatal hearing screening program. But at the moment, its only available at NCMCH which located in Ulaanbaatar city. 11 cases have a bilateral profound hearing loss out of 11218 newborns. Our study result shows similiar pattern (1.1 - 1.3 ear deafness in every 1000 birth. Lenarz et all.2008). Automated audiotory brainstem response was efficient in early identification of newborn hearing loss with high sensitivity and specification rates. Small population in the remote locations, high birth percentage, short period in the hospital after birth, lack of technology and human resources, and other factors result in higher level of referral rate newborn hearing screening and lower level of follow up and confirmation rate referals in Mongolia.

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.

There are a lot of influencing factors of facial nerve palsy; experts believe that is most likely caused by a Virus (54%) and Bacterial infections. Noninfectious causes of facial nerve palsy induce tumors (28%) and less commonly influences head trauma (18%). The retrospective analysis of WHO, in 2012. There are some cases of postoperative complication in middle ear surgery is facial nerve palsy and the total recovery outcome of function was not good. From 2013 to 2016 in EMJJ hospital, Mongolia, we enrolled 16 cases with facial nerve damaged in intratympanic canal but we could not recruit some patients with facial palsy over 6 months. Each subject was tested with pure tone test, ABR, Tympanometry. These were performed for the detection of hearing loss after Temporal bone injury. Then we also investigated location of facial nerve damages of patients by MRI and CT before reconstructive surgery. After that surgery, all patients were given corticosteroid treatment (20mg/day) and physical therapy performed such as acupuncture for a week. Study results revealed that 6 cases after 18 days, 2 cases after 30 days, 1 patient after 45 days of reconstructive surgery regained good symmetry. Therefore, we considered that, postoperative treatments like physical therapy with B12, steroid had good benefits for operation result and to shorten the recovery time. There was a patient who had damaged facial nerve in the tympanic segment during Mastoidectomy. In that case, we performed cable nerve grafting using the r.auricularismagnium but we could not recover facial nerve function. Traumatic facial nerve paralysis is the second most common type. We discussed that performing reconstruction surgery within first 3 months after intratemporal facial nerve injury is extremely desirable and more effective. In our opinion, nerve recovery might be not successfully cause of injured myelin sheet of facial nerve during middle ear surgery.

Hearing loss is likely to be the most common congenital abnormality in newborns, with a reported prevalence of 3 per 1000 live births. It is vitally important to diagnose infant hearing loss or deafness at its early stages. The automated auditory brainstem response (AABR) screener is a dedicated hearing screening device which provides information not only about the outer and middle ear and cochlea but also about the auditory pathway up to the brainstem. The data presented were collected in the well-baby nursery. Overall, data from 5857 neonates screened from December 2012 to July 2015 were analyzed in this study. During 1-3 days after birth, they were analyzed with automated auditory brainstem response (AABR). Neonates referred the screening were scheduled for repeated diagnostic evaluation within a month. And newborns referred again were sent to a specialist for further audiology analysis. Out of the 5857 babies screened, 5050 passed bilaterally and 807 referred. The number of infants referred for 2nd stage, post-discharge re-screening was 319. Of this group, 287 passed bilaterally and 32 failed the re-screening in one or both ears. Diagnostic testing was performed on all of the 32 infants who were referred. The resulting referral rate was 13.7% for first stage and 1,4% for second stage. The follow-up rate was 37%. The confirm rate was 0,13%. Profound bilateral sensor neural hearing loss was identified in 3 infants. Profound bilateral mixed hearing loss was identified in 1 infant. Automated auditory brainstem response (AABR) was efficient in the early identification of newborn and infant hearing loss with high sensitivity and specificity rates. Due to the results of the study, 3 out of 5857 infants were diagnosed with a profound hearing loss and it’s approximately close to the results of other studies and statistics.

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.

Among world population, 23.4% have different kinds of hearing disorders and 56% are middle ear disorders, 30% are inner ear disorder, 10% are congenital deaf and 4% are congenital mixed outer and middle ear disorder (WHO info, 2006).In 1995, by the German research, 2% of newborn babies were deaf therefore, among children from 1-18, 16% had middle ear disorder and 0.8% had inner ear disorder. In most cases (54%) cause of hear loss and deaf as sound transmitting apparatus. Later in 2010, sound transmitting apparatus related disorder was decreased by 22.4% J.Helms1995 , K.Schwager 2010 . Doctors proved that 62% of sound transmitting apparatus related disorders are middle ear diseases, 16,2% out of the diseases have the defect of malleus, 44,1 % have the defect of incus and discontinuity of incus and stapedius, and 39,7% is totally absent of ossicular chain 120 tympanoplasty III type surgeries were operated in 2011-2013 in Mongolia. Clinical and operative features of the tympanoplasty III type surgeries were prospectively recorded. Aim: To recover sound transmitting related hear loss with titan prosthesis implant. 120 tympanoplasty III type surgeries were operated in 2011-2013 in Mongolia. Clinical and operative features of the tympanoplasty III type surgeries were prospectively recorded. Out of the surgeries, 51 cases (42.5%) were cholesteatoma, 53 cases (44.2%) were granuloma middle ear and 16 cases (13.3%) were adhesive otitis media. The air and bone gap of all patients were above 15-35 dB. HEINZKURZ firm’s TTP-Variac system’s titan prosthesis was used. Titan prosthesis PORP was carried out in 86 cases (71.6%). For 40 (45.5%) out of the 86 cases, size of titan prosthesis PORP 2.25 mm was chosen. Hearing level increased for 72% out of patients by 10-25 dB after the operation. However, for 46 (54.5%) out of the 86 cases, size of titan prosthesis PORP 2.5 mm was chosen. Hearing level increased for 82% out of patients by 10-30 dB after the operation. Titan prosthesis TORP size 4-4.25 mm waschosen for 34 (28.4%) out of 120 cases. Hearing level increased by 10-30 dB for 80% out of patients involved after the operation Out of the surgeries, 51 cases (42.5%) were cholesteatoma, 53 cases (44.2%) were granuloma middleear and 16 cases (13.3%) were adhesive otitis media.Titan prosthesis PORP was carried out in 86 cases (71.6%). For 40 (45.5%) out of the 86 cases, size oftitan prosthesis PORP 2.25 mm was chosen. Hearing level increased for 72% out of patients by 10-25 dB after the operation. However, for 46 (54.5%) out of the 86 cases, size of titan prosthesis PORP 2.5 mm was chosen. Hearing level increased for 82% out of patients by 10-30 dB after the operation. Titan prosthesis TORP size 4-4.25 mm was chosen for 34 (28.4%) out of 120 cases. Hearing level increased by 10-30 dB for 80% out of patients involved after the operation. Implantation of Titanium prosthesis increased hearing capability by 80% dB. We drum cover the cartilage and cartilage film is used to by Canal wall down, Canal wall updone. Hearing level decrease d by patients involved after the operation. Implantation of Titanium prosthesis increased hearing capability by 80% dB. The air transfer of more than35 dB air-bonegapofmorethan15dB we observed defect of hearing bone

Hearing loss is likely to be the most common congenital abnormality in newborns, with a reported prevalence of 3 per 1000 live births. It is vitally important to diagnose infant hearing loss or deafness at its early stages. The automated auditory brainstem response (AABR) screener is a dedicated hearing screening device which provides information not only about the outer and middle ear and cochlea but also about the auditory pathway up to the brainstem.The data presented were collected in the well-baby nursery. Overall, data from 5857 neonates screened from December 2012 to July 2015 were analyzed in this study. During 1-3 days after birth, they were analyzed with automated auditory brainstem response (AABR). Neonates referred the screening were scheduled for repeated diagnostic evaluation within a month. And newborns referredagain were sent to a specialist for further audiology analysis.Out of the 5857 babies screened, 5050 passed bilaterally and 807 referred. The number of infantsreferred for 2nd stage, post-discharge re-screening was 319. Of this group, 287 passed bilaterally and 32 failed the re-screening in one or both ears. Diagnostic testing was performed on all of the 32 infants who were referred. The resulting referral rate was 13.7% for first stage and 1,4% for second stage. The follow-up rate was 37%. The confirm rate was 0,13%. Profound bilateral sensor neural hearing loss was identified in 3 infants. Profound bilateral mixed hearing loss was identified in 1 infant.Automated auditory brainstem response (AABR) was efficient in the early identification of newborn and infant hearing loss with high sensitivity and specificity rates. Due to the results of the study, 3 out of 5857 infants were diagnosed with a profound hearing loss and it’s approximately close to the results of other studies and statistics.

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.