Congenital hearing impairment

Establishing the etiology of congenital hearing impairment can significantly improve treatment for certain causes of hearing loss and facilitates genetic counseling. High-resolution CT and MRI have contributed to the evaluation and management of hearing impairment. In addition, with the identification of innumerable genetic loci and genetic defects involved in hearing loss, genetic testing has emerged as an invaluable tool in the assessment of hearing impairment. Some of the common forms of congenital hearing loss are reviewed and their imaging features illustrated.     

Genetic deafness in a preterm infant with a critical postnatal course.

OBJECTIVE: We present a case of deafness in a preterm infant with several predisposing factors of an acquired hearing impairment that, however, turned out to have a genetic cause. We describe the severe postnatal course and review the relevant literature. DESIGN: Case report. SETTING: University-based tertiary neonatal intensive care unit. PATIENT: Preterm infant (gestational age, 26/37; wks). MEASUREMENTS AND MAIN RESULTS: A preterm infant exhibited hearing impairment after a complicated clinical course with pneumothoraces, a hemodynamically relevant patent ductus arteriosus, treatment with potentially ototoxic drugs, intraventricular hemorrhage, and periventricular leukomalacia. Despite the absence of a family history for deafness, genetic testing was performed. Surprisingly, genetic analysis revealed the presence of two compound heterozygous mutations in the patient's GJB2 gene as the cause for his early-onset nonsyndromic deafness. CONCLUSION: To elucidate the nature of a hearing disorder, it is worthwhile to consider a genetic cause, despite the fact that it may seem unlikely in a severely sick preterm infant with numerous risk factors for a postnatally acquired hearing impairment and without a positive family history.     

The use of genetic testing in the evaluation of hearing impairment in a child

PURPOSE OF REVIEW: To review the role of genetic testing in the evaluation of hearing impairment in children. RECENT FINDINGS: The introduction of genetic testing has greatly enhanced the evaluation of deafness and hearing impairment in children. It can save time and money as well as providing patients, their families, and their physicians with important information; however, this testing is different from the medical testing that pediatricians typically order. SUMMARY: For patients and families to realize the benefits of genetic testing it must be done early in the evaluation process and must be accompanied by appropriate pretest and posttest counseling.     

The identification and management of deaf children

Deafness is defined as the inability to use hearing as a primary channel for receiving speech, even with amplification.¹ Hearing loss, on the other hand, is hearing impairment of various degrees that could be unilateral or bilateral. In the United States, approximately one out of every 1,000 children is born deaf with 3–5 being born with less severe degrees of hearing impairment2. Deafness present at birth could be due to genetic abnormalities or due to injury to the developing auditory system or due to developmental anomalies of this system. Deafness can also develop after birth and, in broad terms, the cause can be toxic, infectious, neoplastic, traumatic or degenerative. The purpose of this paper is to : (1) review the effects of deafness on the child, (2) discuss the causes of deafness, (3) describe the clinical characteristics which allow early diagnosis and the algorithm otolaryngologists use to investigate a child suspected to be deaf, (4) describe the management of the deaf child and finally, (5) review the results of rehabilitation.     

Audiologische Diagnostik bei Kindern

In Germany the early detection of hearing impairments in children is still an unresolved problem and therefore still relevant for the pediatrician. There are various practical and valid methods to detect hearing impairments in children of every age group. The most important assessment methods are described. On the basis of own data and literature sources the current situation in Germany is evaluated. It can be ascertained that the diagnosis of deafness at about 16 months still occurs at a very late timepoint and that parents are the first to suspect a hearing impairment. In each case of presumed hearing impairment a specialized pediatric-audiological institution should be involved and in particular attention should be paid to the parents' observations and comments. The introduction of a general newborn hearing-screening program would greatly improve the situation. For this reason the demand for an area-wide screening should be realized as soon as possible.     

Adverse perinatal conditions and the inner ear

Epidemiological studies in a number of Western countries have attributed 6–14% of sensorineural hearing impairment from birth or early childhood to problems relating to the birth process [1–4]. In spite of this association it is not always clear in individual instances whether adverse perinatal conditions identified subsequently have been causative of a hearing loss or not. It is possible that the hearing impairment was the consequence of an earlier intrauterine insult or is a coincidental finding. Infants carrying genetic mutations for hearing loss may coincidentally experience perinatal stress. It is therefore important to investigate the cause of a hearing loss discovered in infancy irrespective of the history of the infant having experienced adverse conditions surrounding the time of birth.     

听力障碍儿童17例听力检测结果分析

目的探讨完善的听力学评估在听力障碍(听障)儿童听力检测及康复中的重要性。方法对17例既往诊断为听障的儿童进行常规声导抗测试、行为测听、耳声发射等综合听力学评估。结果听障儿童17例中3例听力正常,14例感音神经性听力损失,其中仅1例配戴助听器。结论听障儿童的听力学诊断应建立在完善的听力学评估的基础上。对听障儿童应进行长期听力学随访,直到获得可靠的双耳行为听阈、作出明确的听力学诊断为止。     

Childhood hearing impairment

Hearing impairment is one of the most common disabilities in the UK and globally. Worldwide, 60% of cases are thought to be preventable and fewer than 10% globally have access to the hearing support they need. Childhood hearing impairment can impact on development, speech, language, auditory processing, listening skills, behaviour, self-esteem, quality of life and learning. Our responsibility as clinicians is to prevent developmental impairment in these areas and ensure children with a hearing impairment have the same life chances as children who hear well. There are 45,000 children in the UK diagnosed with a hearing impairment. Hearing impairment can be isolated or part of a more complex presentation. Visual, neurodevelopmental, balance and communication difficulties as well as safeguarding issues are more common in children with hearing impairment.     

Low prevalence of hearing impairment among very low birthweight infants as detected by universal neonatal hearing screening

OBJECTIVES: To (a) study the prevalence of hearing impairment in a cohort of very low birthweight (VLBW) infants and (b) evaluate the effectiveness of transient evoked otoacoustic emissions (TEOAE) as a first stage in-hospital hearing screening tool in this population. STUDY DESIGN: The study group was a cohort of 346 VLBW infants born in 1998-2000 at The Sheba Medical Center. The prevalence of hearing impairment in the study group was compared with that of all other newborn infants participating in a universal newborn hearing screening programme during the same period. To evaluate the effectiveness of TEOAE, a control group of 1205 healthy newborns who had no known risk factors for hearing impairment was selected. The results and follow up of hearing screening for these infants were examined retrospectively. RESULTS: Only one VLBW infant (0.3%) was diagnosed with bilateral sensory-neural hearing loss. In addition, nine infants (2.7%) were diagnosed with conductive hearing loss. Bronchopulmonary dysplasia and low Apgar score were the most significant factors for predicting the occurrence of conductive hearing loss. The percentage of VLBW infants who successfully passed the in-hospital TEOAE screening was 87.2, compared with 92.2% in the full term control group. No false negative cases were detected on follow up. CONCLUSIONS: The study shows a low incidence of sensory-neural hearing loss in a cohort of VLBW infants and a relatively high incidence of conductive hearing loss. TEOAE screening was found to be an effective first stage in-hospital hearing screening tool in this population.     

The mutation 35delG of the gene of the connexin 26 is a frequent cause of autosomal-recessive non-syndromic hearing loss in Morocco]

Mutations of the connexin 26 gene, GJB2, are the most common cause of non syndromic autosomal-recessive hearing loss. One of the GJB2 mutations, the 35delG, is recurrent in European and Mediterranean populations with allelic frequency of at least 70% in patients with hearing loss caused by GJB2 impairment. OBJECTIVES: To determine the prevalence of the 35delG mutation in non-syndromic autosomal-recessive deafness in Morocco. PATIENTS AND METHODS: We looked for the 35delG mutation among 25 non-related Moroccan children suffering from an autosomal recessive hearing loss. A screening for GJB2 mutations, and then a search for GJB6 deletions were carried out among patients who do not bear the 35delG. RESULTS: Twelve patients were homozygous for the 35delG mutation. This mutation was responsible for almost half of the hearing loss among our patients (48%). There was no other GJB2 or GJB6 mutation among 13 patients. CONCLUSION: This study underlines the advantages of a systematic search for this mutation among deaf children when environmental causes are considered irrelevant. The identification of this genetic anomaly signs the etiologic diagnosis of deafness, which allows a relevant genetic advice, and a better treatment of patients.     

NICU高危新生儿早期的听力研究

目的　探讨新生儿重症监护室 (NICU)中重症患儿及高危儿与听力障碍或丧失相关的危险因素及其发病率。方法　对 1999年 12月～ 2 0 0 1年 8月 ,入住我院NICU的 2 4 8例听力障碍高危儿 ,在病情稳定后或出院前用听性脑干反应进行听力评价。结果　全部受检患儿中有 72例呈阳性结果 ,该组新生儿初次检查听力异常的发生率为 2 9 0 3% ,其中 3例系重度以上听力障碍。听力障碍的发生率在窒息组为 4 0 0 0 % ;高胆红素血症组为 2 6 37% ;早产儿组为 34 0 9% ,出生体重 <15 0 0g者阳性率尤高 ;接受机械通气组为 4 0 0 0 % ;应用耳毒性药物组为 4 1 30 %。结论　在NICU住院的新生儿中 ,存在较多与听力障碍有关的高危因素 ,该组新生儿听力障碍的发生率较正常活产新生儿明显增高。所以 ,高危新生儿从NICU出院前应常规进行听力检查。     

Hearing loss at the age of 5 years of children born preterm–a matter of definition

The effect of three common hearing impairment criteria on the prevalence of hearing loss was evaluated in 58 prospectively followed-up 5-year-old children born preterm at 32 weeks of gestation. Audiological assessment was done as part of an extensive neurodevelopmental evaluation at the age of 5 years. With the criterion based on the classification of the World Health Organization (average threshold hearing level >25dB at frequencies of 0.5, 1 and 2 kHz, classified according to the less impaired side) there were two preterm children with mild hearing impairment. With Clark's criterion (unilateral average threshold hearing level > 15dB at frequencies of 0.5, 1 and 2 kHz) eight children had slight hearing impairment; seven of these had conductive hearing problems. With the criterion of a single frequency-specific deficit > 15 dB for 0.25-4 kHz the number of hearing-impaired children was 28 out of 54 (51.9%), most of whom had conductive or unspecified hearing deficits. Moreover, of the four multiply handicapped, retarded children whose pure tone thresholds were not assessed mon-aurally, three would belong to the hearing-impaired group according to Clark's criterion and four according to the frequency-specific criterion, Hearing impairment, hearing impairment classification, low birthweight, preterm     

Education of children with hearing impairment

Children with hearing impairments are educated in a variety of educational placements. To support their educational progress and ensure that appropriate provision is in place there are a number of key professional roles including special educational needs coordinators, teachers for children with hearing impairment and educational audiologists. There is also a variety of technology available to facilitate learning for children with hearing impairments.     

Newborn auditory follow-up

Because hearing is a key component in the infant's development of speech, language, and cognition, early detection of infant hearing loss is critically important. The routine evaluation of hearing should include the identification of parental concerns regarding infant hearing as well as the assessment and diagnosis of infants with potential hearing impairment. Identification of hearing loss should be followed by early interventions to prevent developmental delays. This article promotes universal screening of newborn hearing. The article also provides a review of the embryogenesis of hearing and includes a breakdown of risks for hearing loss, recommendations for auditory testing, and suggestions for follow-up, early intervention, and support for families of infants with hearing impairment.     

新生儿重度高胆红素血症伴听力损伤预后相关因素研究

目的探讨影响重度高胆红素血症新生儿听力损伤预后情况的相关因素。方法选择2008年11月至2009年10月本院新生儿科收治的重度高胆红素血症患儿,进行脑干听觉诱发电位（BAEP）的检测,对异常者分别于生后1个月、3个月、6个月、1岁时复查BAEP,直至BAEP恢复正常或年龄至1岁。按照随访时BAEP能否恢复正常分为随访正常组和随访异常组。对随访异常的影响因素进行单因素分析,并对单因素分析有统计学意义的因素纳入Logistic回归模型进行多因素分析。结果 967例重度高胆红素血症患儿中BAEP异常168例,其中150例按时进行随访的患儿纳入本研究。至随访结束,94.2%的轻度听力损伤者、85.5%的中度听力损伤者和19.2%的重度听力损伤者恢复正常。单因素分析结果显示,酸中毒、B/A比值、黄疸持续时间、BAEP异常程度、胆红素脑病临床表现是随访异常的影响因素。多因素Logistic回归分析结果显示,BAEP重度异常（OR=9.291）和胆红素脑病临床表现（OR=9.176）是听力损伤的重度高胆红素血症患儿随访异常的危险因素。结论新生儿重度高胆红素血症伴轻中度BAEP异常者1年内大多可恢复正常,但当存在BAEP重度异常和胆红素脑病临床表现时,1年内听力持续异常的可能性大,需要给予更加积极的神经康复治疗。     

A stepwise approach to the diagnosis and treatment of hereditary hearing loss

What To Do Do suspect a genetic cause in all cases of hearing loss. Do develop a working knowledge of common types of HHI that you may draw on to aid in diagnosis. Do think of HHI when the audiogram reveals a hearing loss with a "cookie bite" configuration. Do refer the infant to a geneticist in cases where you suspect a syndromic HHI, a nonsyndromic HHI, and in cases of "cryptogenic" hearing loss where an underlying HHI may be present. Often, the associated symptoms are subtle and best detected by a professional who deals with these issues on a daily basis. Do get the infant or family plugged into an audiologist or otolaryngologist and speech pathologist who will preferably work as a team to maximize aural rehabilitation and ensure serial follow-up. It is never too early to fit a child with hearing aids. Do refer to the HHIRR center at Boys Town. Do refer to the correct "deaf" organization or "blind-deaf" organization. Do think about working up other siblings or family members. Do keep in mind that some members of the "deaf society" may regard deafness as an alternative lifestyle and may not be amenable to their child's referral for additional workup and aural rehabilitation. What Not To Do Do not assume the child is deaf and nothing can be done. Do not wait until the child is older to refer to an otolaryngologist, speech therapist, and audiologist. Do not order a sonogram. Do not order a temporal bone CT scan on newborns. Do not forget about other siblings who may have a similar pathology. Do not forget that some forms of HHI can present beyond infancy. The pediatrician is the front line and can play a major role in the diagnosis, workup, and treatment of HHI. Armed with the proper degree of suspicion, careful elicitation of family history, meticulous physical examination, evaluation of the audiogram, and adequate fund of knowledge of common types of genetic deafness, the pediatrician can make a timely diagnosis and appropriate referrals. This avoids delay in detection of significant hearing impairment and the associated lack of essential skills in speech, language, and social interaction. No child is too young to have some type of hearing assessment. Early detection and intervention are best done with a multidisciplinary team approach with a neonatologist or pediatrician, audiologist, speech therapist, and otolaryngologist. In the future, blood tests using genetic probes may be available to screen for many types of HHI.     

United Kingdom school-entry hearing screening: current practice.

OBJECTIVE: To determine if the school-entry hearing screening (SEHS) programme continues to make a useful contribution to the identification of childhood hearing impairment in the light of the recent implementation of universal newborn hearing screening, and thereby to inform future policy development. DESIGN: Postal questionnaire survey to determine current implementation and effectiveness of SEHS SETTING: 244 school health services managed within primary care and acute trusts throughout the UK. PARTICIPANTS: 229 SEHS service leads approached; 195 responded. MAIN OUTCOME MEASURE: Details of implementation; positive predictive value of the screening test and its referral criteria. RESULTS: Implementation of the SEHS is variable, and there is no national approach to data collection, audit and quality assurance. Less than 10% of services had available robust data. The yield from screening ranges from 0.05% to 0.59% for permanent sensorineural hearing impairment and from 0.07% to 0.44% for permanent conductive hearing impairment. The positive predictive values from screen referral vary from 0.62% to 12.16% for permanent sensorineural hearing impairment and 1.24% to 17.56% for permanent conductive hearing impairment. CONCLUSION: This comprehensive survey provides a previously unavailable national examination of the SEHS. The few available data on yield indicate that the SEHS may have a small but important role to play in identification of childhood hearing impairment, but the overwhelming conclusion is the urgent need for national guidelines on implementation of this screening programme to determine its value since the implementation nationally of universal newborn hearing screening.     

非综合征型遗传性耳聋常见基因突变及检测方法的研究进展

耳聋是严重影响人类生存质量的致残性疾病,遗传性因素在新生儿耳聋发病因素中占很大比例。随着基因组学技术的发展,耳聋分子遗传学研究逐渐成为研究的前沿领域。分子诊断技术作为查找致病原因、协助临床诊断以及开展产前诊断的主要手段发挥着重要的作用。该文就非综合征型遗传性耳聋常见的基因突变及检测方法的研究进展作一综述。     

Mondini dysplasia and recurrent bacterial meningitis in a girl with relapsing Langerhans cell histiocytosis

We report a case of a girl with Langerhans cell histiocytosis (LCH) of multifocal bone disease, who developed recurrent bacterial meningitis and unilateral sensorineural hearing loss during the relapsing course of the disease. Mondini dysplasia, a congenital inner ear anomaly, was suspected by high resolution computed tomographic scan and the dysplasia with cerebrospinal fluid leakage was confirmed by surgery in the ipsilateral ear showing hearing loss. Although rare, congenital inner ear anomalies such as Mondini dysplasia should be kept in mind in pediatric patients with hearing impairment and/or recurrent bacterial meningitis during chemotherapy for various types of neoplasms including LCH.