One of the important tasks of children’s audiology is the early identification of hearing impairment in children and the timely commencement of rehabilitation activities, such as a hearing aid, and in the presence of deep hearing loss difficult to treat with traditional methods of hearing rehabilitation, cochlear implantation should be used. Currently, due to the introduction of objective methods of hearing evaluation in clinical practice,there is a real opportunity to detect hearing disorders in children from the βirst days of life including premature newborns. In this study, we analyzed data of hearing acuity audiological screening among children at the age of 0–17 years for the period from 2015 to 2016. During this period, 4,588,365 children were examined in 2015, and 4,562,489 children were examined in 2016, within the Republic of Kazakhstan.
Keywords: Audiological screening, child audiology, hearing impairment
|How to cite this article:
Zhaisakova D E, Kudaibergenova S F, Mukanova Z T, Djarkinbekova G K, Kaltayeva MB, Kuzembayev Y A. The incidence and prevalence of hearing disorders in children according to the audiological screening. Ann Trop Med Public Health 2017;10:1345-9
|How to cite this URL:
Zhaisakova D E, Kudaibergenova S F, Mukanova Z T, Djarkinbekova G K, Kaltayeva MB, Kuzembayev Y A. The incidence and prevalence of hearing disorders in children according to the audiological screening. Ann Trop Med Public Health [serial online] 2017 [cited 2020 Dec 5];10:1345-9. Available from: https://www.atmph.org/text.asp?2017/10/5/1345/217507
Children’s hearing loss is of particular importance since the hearing pathology in children is the cause of impediment of speech and mental development of a child. In 85% of children, hearing impairment is congenital or occurs in the 1st year of life, i.e., before the development of speech. Psycho-emotional and intellectual development of such children and the effectiveness of therapeutic and rehabilitation measures depend on timely and correct diagnosis of hearing impairment. Currently, due to the introduction of objective methods of hearing evaluation in clinical practice, there is a real opportunity to detect hearing disorders in children from the first days of life including premature newborns. The development of the child’s ability to understand human speech and to speak as well as the development of thinking capability are based on his/her ability to hear the speech of other people. Even a slight hearing loss in a child leads to difficulties in speech perception, disturbance of the formation of brain’s auditory and speech centers. The processes of their formation are especially intense in the first 2 years of life which makes early detection of the auditory function pathology an important and necessary stage in the program for helping children with hearing impairment. It is proved that regarding children hearing impairment, the helping programs initiated no later than within first 6 months of life are the most effective. Therefore, the detection and subsequent diagnosis of auditory function disorders in a child should be carried out in the first 3 months of life. Diagnosis of hearing impairment in children at such an early age is possible only with the newborn infant audiological screening – a mass hearing test using fast and simple methods to identify children with suspected auditory disorders. According to statistics, 1–2 babies per 1000 newborns have profound hearing impairment., In 2011, Europe adopted the Consensus on audiological screening of school-age children., The first pilot studies were conducted in 2006, in Poland. In 2010, 95,411 first graders in 4041 schools were examined in Poland, during 4 months. Each seventh child (13.9% of the examined) had hearing impairment, 15.1% had tinnitus. In 58.8% of cases, parents did not pay attention to hearing loss in children. About 27% of children with hearing impairment were examined only at birth (audiological screening of newborns in Poland has been conducted since 1993)., According to the American Academy of Audiology, every year, more than 665,000 children are born around the world with hearing impairment >40 dB.,
Based on the positive experience in the sphere of audiological screening programs for the early detection of children with various hearing impairments, an order was issued by the acting Minister of Health of the Republic of Kazakhstan dated September 28, 2009, No. 478 “On the approval of the Rules for the organization of screening and diagnosis of hearing impairment in young children.” Since 2009, maternity hospitals and children’s polyclinics began to be equipped with devices for evoked otoacoustic emission (OAE) test for carrying out audiological screening of newborns with an objective method. Screening is a universal study designed to identify individuals among those examined who are highly likely to have a disorder that is the subject of screening. The audiological screening provides an opportunity for early detection and rehabilitation of children with hearing impairment. The modern newborn screening algorithm has two stage and consists of conducting objective audiological studies: OAE test at the first stage and the short-latency auditory evoked potentials (SLAEPs) test at the second stage. The OAE test is carried out in the first days of the child’s life. If a negative result is obtained (OAE test is registered), no further testing is required. The second stage of screening includes SLAEP test, the most informative test for determining the equivalents of the auditory thresholds. This study is carried out by audiology and otorhinolaryngology specialists.
|Materials and Methods|
Audiological screening of newborns and children of the 1st year of life is carried out by medical workers of maternity hospitals and children’s polyclinics that had shown thematic improvement. The medical worker of the maternity hospital and the department for the newborn, who performs audiological screening recorded the information on the procedure and results of audiological screening during childbirth, development of the newborn (medical history), and in discharge statement. Information on the procedure and results of audiological screening were transferred to the territorial hearing rehabilitation center where second stage of screening was performed. This study analyzed the data of audiological screening for the period from 2015 to 2016.
Sensorineural hearing loss is the most common congenital sensory disturbance with incidence rate of 1 per 1000 newborns for the bilateral hearing loss of more than 70 dB while taking into account, the unilateral hearing loss and mild hearing loss – 4 per 1000 newborns.
The most important condition for successful correction of hearing loss is timely initiation of rehabilitation-hearing aids, and in the presence of profound hearing loss, hard-to-treat with the traditional methods of hearing rehabilitation-cochlear implantation. This condition is especially true for children with congenital hearing loss because the longer a child suffer from sound deprivation, the worse are the rehabilitation results. Therefore, it is so important to maximize the early diagnosis of these children, which contributes significantly to the introduction of universal hearing screening in newborns, based on otoacoustic emission test. It should be noted that this process is very time consuming requiring great understanding and there is a need for proper selection of children for cochlear implantation, consultations of neurophysiologists, audiovisualists, psychologists, and other specialists with the aim of a successful cochlear implantation and child’s postoperative rehabilitation and adaptation to the new life conditions.
Hearing loss can be diagnosed in the first months of life only as a result of auditory evoked potentials testing. Over the past decade, SLAEP test has become a routine method of objective investigation of hearing in children during the first 4–5 years of life. During the 1st year of life, the SLAEP undergo some changes due to the mutational processes in auditory system of healthy infant ear, not to speak of the children with congenial nervous system disturbance that need to be considered when examining children.
According to the results of screening examinations in 2016, 4372 of 4,562,489 children of the Republic of Kazakhstan have been diagnosed with hearing impairment. It is found that 4262 of 4,588,365 children examined in 2015, have been diagnosed with hearing impairment as shown in [Table 1]. It was also found that there are more children in city (2435 children) than in village (1937 children) with hearing impairment.
|Table 1: The results of screening examinations among children for identification of hearing impairment for 2016, 2015
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According to the presented data, the largest number of children with hearing impairment was in the South Kazakhstan region (935 children) and Astana city (416 children). Compared with the same period in 2015, the number of children with hearing impairment significantly increased in Astana city, Karaganda, Kyzylorda regions. The number of children diagnosed with hearing impairment significantly decreased in South Kazakhstan, Zhambyl region [Figure 1] and [Table 1]. Analysis of the results showed that the identified issues require clarification. Thus, processes relating to urbanization, migration, population movements across Kazakhstan created certain conditions for the formation of large urban centers. According to the agency of the Republic of Kazakhstan on Statistics, in the first half of 2014, more than 25,000 Kazakhstan people left the rural areas. This outflow is most felt in the SKR – 6.4 thousand people, in Zhambyl, East Kazakhstan, Mangistau, Kostanay, and North Kazakhstan regions where the outflow of rural population led to decrease from 2.8 to 2.2 thousand people. During the same 6 months, the migration inflow to cities reached 22.9 thousand people with the largest number migrating to Astana (10.9 thousand) and Almaty (6.9 thousand). Such a statistical development explains the reasons for the migration process, which certainly affected the detection of hearing impairment in the children of the Republic of Kazakhstan.
|Figure 1: The number of children diagnosed with hearing impairment, 2016, 2015
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The 2435 of 2,467,752 examined children have hearing impairment among city’s residents. While in 2015, during the same period of time, 2479 children were diagnosed with hearing impairment from 2,490,380 examined children [Table 2].
|Table 2: The total amount of hearing impairment among residents of the city
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Analyzing the data presented in the comparative dynamics for 2015–2016 in 16 regions of the Republic of Kazakhstan, the following features was noted: the largest number of children with hearing impairment among city residents city was identified in Karaganda involving 299 children, South Kazakhstan region involving 346 children and in Astana city involving 416 children [Figure 2]. This fact testifies that the implementation of the audiological screening program is successful in these regions.
|Figure 2: The number of diagnosed cases of hearing impairment among children who live in city area
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It is worth noting that out of the examined 2,101,225 residents of the village, 1937 children were diagnosed with hearing impairment. While in 2015, for the same reporting period, out of 2,095,238 children examined, 1783 children were diagnosed with hearing impairment [Table 3] and [Table 4].
|Table 3: The number of children examined and identified cases of hearing loss in the period 2015–2016 among village residents
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|Table 4: The results of hearing impairment screening examinations for 2015–2016 in the context of the age groups among children from 0 to 17 years old
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The largest number of children residents of the village with hearing impairment revealed in Almaty (234 children), Kyzylorda (219 children), Zhambyl (216 children), and South Kazakhstan (589 children) regions [Figure 3].
|Figure 3: The number of diagnosed cases of hearing impairment among children living in the village area
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Analysis of the age structure of children identified through the screening examinations showed that the largest number of children with hearing impairment is revealed at the age of 617 years, which coincides with the data of 2015 [Figure 4].
|Figure 4: Results of screening examinations in the context of the age groups
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Audiological screening is a recognized method in the timely detection of children with hearing impairment around the world. In this regard, we believe that the Republic of Kazakhstan adaptation of modern early diagnosis of hearing impairment in children was timely, i.e., the neonatal screening program for identification of hearing impairment and deafness in the early stages.
During the implementation of the newborns audiological screening program in Kazakhstan, a large number of maternity homes and children’s polyclinics were equipped with diagnostic equipment, and trainings for screening specialists were also conducted. Further improvement of the material base, informing the society and parents about the importance of timely hearing diagnostics, coordinating of the work of maternity homes, children’s polyclinics and deaf-mute centers, improving the methodology for data collection and analysis will contribute to the improvement of program effectiveness.
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Conflicts of interest
There are no conflicts of interest.
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Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]