PEDIATRICS Vol. 121 No. 6 June 2008, pp. 1119-1126 (doi:10.1542/peds.2007-1479)
ARTICLE |
Etiologic and Audiologic Evaluations After Universal Neonatal Hearing Screening: Analysis of 170 Referred Neonates
Departments of a Otorhinolaryngology, Head and Neck Surgery, and Communication Disorders
b Medical Genetics, University of Antwerp, Anwerp, Belgium
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ABSTRACT |
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 TOP ABSTRACT METHODSRESULTSDISCUSSIONCONCLUSIONSREFERENCES |
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OBJECTIVE. The goal was to clarify the audiologic aspects and causes of congenital hearing loss in children who failed universal neonatal hearing screening.
METHODS. A prospective analysis of 170 consecutive records of neonates referred to a tertiary center after universal neonatal hearing screening failure, between 1998 and 2006, was performed. The data presented here represent the equivalent of 
87000 screened newborns. The screening results were validated with a clinical ear, nose, and throat examination and electrophysiological testing, including diagnostic auditory brainstem response, automated steady state response, and/or behavioral testing. A diagnostic evaluation protocol for identification of the cause of the hearing loss was also implemented, in collaboration with the departments of genetics and pediatrics.
RESULTS. Permanent hearing loss was confirmed in 116 children (68.2%). Bilateral hearing loss was diagnosed in 68 infants (58.6%) and unilateral hearing loss in 48 infants (41.4%). Median thresholds for the neonates with confirmed hearing loss were severe in both unilateral and bilateral cases, at 70 dB nHL and 80 dB nHL, respectively. In 55.8% of those cases, no risk factors for hearing loss were found. In 60.4%, the initial automated auditory brainstem response diagnosis was totally in agreement with the audiologic evaluation results. In 8.3% of the cases, however, a unilateral refer result was finally classified as bilateral hearing loss. An etiologic factor could be identified in 55.2% of the cases. Of the causes identified, a genetic mechanism was present in 60.4% of the cases, peripartal problems in 20.8%, and congenital cytomegalovirus infection in 18.8%.
CONCLUSIONS. An etiologic factor could be identified for nearly one half of the children with confirmed congenital hearing loss referred through a universal hearing screening program.
Key Words: congenital sensorineural hearing loss • cytomegalovirus • genetics • hearing screening • newborn
Abbreviations: UNHS—universal neonatal hearing screening • ABR—auditory brainstem response • AABR—automated auditory brainstem response • PCR—polymerase chain reaction • CMV—cytomegalovirus • WS—Waardenburg syndrome
Hearing loss is one of the most common congenital anomalies, occurring in 1 to 2 infants per 1000.1 The prevalence of hearing loss has been shown to be greater than that of most other diseases and syndromes screened for at birth (eg, phenylketonuria and sickle cell disease). The incidence of hearing loss is considerably higher in infants in the NICU (1–2 cases per 200 infants; 1.9% bilateral and 0.6% unilateral.2 Left undetected, hearing impairment in infants can negatively affect speech and language acquisition, academic achievement, and social and emotional development. These negative effects can be diminished and even eliminated through early intervention at or before 6 months of age.3 Reliable screening tests that minimize referral rates and maximize sensitivity and specificity are available. The goal of universal neonatal hearing screening (UNHS) is to maximize linguistic and communicative competence and literacy development for children who are hard of hearing or deaf.
In Flanders, a community-based screening program was successfully implemented by the federal health care agency in 1998. The hearing screening program is performed with automated auditory brainstem response (AABR) testing and aims to identify all children with a permanent unilateral or bilateral hearing impairment of 
35 dB nHL. The AABR testing is performed at the age of 4 weeks. If the infant fails the initial test, then it is repeated within 48 hours. Children who twice the test fail or for whom unreliable test results are obtained are referred for retesting and diagnostic evaluation. The coverage of the screening with AABR testing in Flanders has been 96% since its introduction, with a false-positive rate of only 0.06% (specificity: 99.94%).4 In many UNHS programs, the screening/therapy coordination is the weakest point of the pathway, with lost to follow-up monitoring (and treatment) rates as high as 2% to 52%.5
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METHODS |
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TOPABSTRACTMETHODSRESULTSDISCUSSIONCONCLUSIONSREFERENCES |
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In Flanders, a community-based screening program was successfully implemented by the federal health care agency (Kind & Gezin). The agency coordinates the preventive care and wellness of children in Flanders and is well organized, with 620 nurses working at 330 consultation bureaus in 62 Flemish regions.6 All neonates (NICU and non-NICU) referred after UNHS between March 1998 and April 2006 were included in the present study. Referral was initiated after 2 consecutive failures of the AABR testing. The pattern of referral to the tertiary centers by the federal health care agency was based on the geographical areas in which the children resided. Most children came from a suburban area around Antwerp, Belgium.
The standard method for validation of UNHS results is a combination of ear, nose, and throat and audiologic evaluations performed with electrophysiological testing, such as diagnostic auditory brainstem response (ABR), automated steady state response, and/or behavioral testing. The medical evaluation was performed by an otorhinolaryngologist, in close collaboration with a medical geneticist and a pediatrician. The purpose of this evaluation was not only to determine the pathogenesis of hearing loss but also to identify related medical conditions and to provide recommendations for medical treatment, as well as referral to other services.6
The evaluation included a detailed pedigree analysis for congenital hearing loss, medical history, and risk factors, as identified by the Joint Committee on Infant Hearing 2000 position statement.7 The clinical examination included tympanoscopy and an examination of the head and face to search for outer ear anomalies, preauricular pits or tags, and syndromic features.
The audiologic assessment in this study was performed according to guidelines published by the Royal Ear Nose Throat Society.6 The examinations included click-evoked ABR testing, measurement of auditory steady state responses, and acoustic immittance audiometry with high-frequency tones (678 Hz) and transient evoked otoacoustic emissions. This testing was performed by audiologists with technical expertise and training for testing in infants, and results were obtained for an ear-specific estimate of the type, degree, and configuration of the hearing loss.
The infant then was examined at the department of pediatrics and ophthalmology, where additional standard examinations were conducted (Table 1). Mutation analysis of connexin 26 (GJB2) was performed for every child. For GJB2, denaturing high performance liquid chromatography analysis was performed for the complete coding region (exon 1 and 2). If a mutation in GJB2 was found, then polymerase chain reaction (PCR) was performed to detect the most frequent deletion in connexin 30 (GJB6-D13S1830). Also, a toxoplasmosis, rubella, cytomegalovirus (CMV), herpes, and syphilis serologic screen was performed for every child (toxoplasmosis, IgM and IgG; rubella, IgM; CMV, IgG and IgM; herpes simplex, IgM and IgG; Treponema pallidum, rapid plasma reagin and T pallidum hemagglutination tests). These results were discussed by the multidisciplinary team and, depending on the type of hearing loss, familial history, risk factors, and associated features, complementary examinations were performed (Table 1).6
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The imaging modalities used consisted of computed tomography and MRI, and imaging was requested for all children with confirmed unilateral and/or bilateral hearing loss of
60 dB nHL or craniofacial malformations. The cutoff value was set according to the report by Bamiou et al.8 They found that profound or progressive hearing loss and craniofacial abnormalities were significant predictors of abnormal computed tomographic findings. The radiologic imaging was usually performed at 6 months of age. After the initial diagnostic evaluation and confirmation of the hearing loss, children were scheduled for early intervention programs (including hearing aids and rehabilitation) and auditory follow-up evaluation was performed with visual reinforcement audiometry or conditioned play audiometry according to the child's age and cooperation.
All data obtained were stored in a database system (Excel; Microsoft, Redmond, WA); for each child, a complete report was sent to the federal health care agency. Statistical analysis was performed with SPSS 13.0 (SPSS, Chicago, IL). The results were summarized as means, medians, and percentages. Subgroups within the study population were compared with Mann-Whitney and Kruskal-Wallis tests. A P value of 
.05 was accepted as indicating statistically significant results.
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RESULTS |
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TOPABSTRACTMETHODSRESULTSDISCUSSIONCONCLUSIONSREFERENCES |
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Audiologic Assessment
In Flanders,
120 infants each year are referred to a tertiary center after failed newborn hearing screening (mean birth rate: 61673 births per year during the years 1998–20059). The data presented here represent the equivalent of 87000 screened newborns. The referral population after failed screening (n = 170) consisted of 91 boys and 79 girls (gender ratio: 1.15), with a median age at first presentation in the referral center of 50 days (range: 36-86 days). A total of 157 infants (92.4%) were referred as non–NICU infants; 148 infants were referred directly from the UNHS program, and 9 were sent by referral hospitals for a second opinion. In addition, 13 infants (7.6%) came from a NICU. Indications for further audiologic evaluation after AABR screening (n = 148) were unilateral refer results (n = 87), bilateral refer results (n = 57), and failed tests (n = 4). The median period between referral by the federal health care agency and the first visit at the audiologic center was 8 days. A total of 96.5% (n = 164) of the referral population was of white origin and 3.5% (n = 6) black.
Audiologic evaluation after screening confirmed the presence of hearing loss in 121 children. Five children (2.9%) initially had secretory otitis media, which resolved during the testing period. Consequently, 116 (68.2%) of the referred children had permanent hearing loss of 35 dB nHL; 31.8% of the children from the screening population were found to have normal hearing. The male/female ratio remained almost constant at 1.11.
Bilateral hearing loss was diagnosed in 68 infants (58.6%) and unilateral hearing loss in 48 infants (41.4%). Bilateral involvement was more frequently seen in boys. The bilateral/unilateral ratio was 1.54 for boys and 1.29 for girls. Considering only the infants (n = 116) with confirmed hearing loss (>35 dB nHL), the median thresholds were 70 dB nHL in unilateral cases and 80 dB nHL in bilateral cases. The distribution of hearing loss in the 184 ears (116 infants) involved is presented in Fig 1. There was no statistical difference between the hearing loss levels in the unilateral and bilateral hearing impairment populations (Mann-Whitney test, P = .098). However, patients with bilateral hearing loss were more apt to have profound hearing loss than were those with unilateral hearing loss (41.0% vs 20.8%) (Table 2).
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The relationship between the initial AABR screening results from the federal health care agency (n = 144) and the final audiologic diagnoses is shown in Table 3. In 60.4%, the initial AABR screening diagnosis was totally in agreement with the audiologic evaluation. However, 11.6% of neonates with a unilateral refer result revealed a permanent bilateral hearing loss. Children with a unilateral refer result were more likely to have normal hearing than were those with a bilateral refer result (41.9% vs 14.0%). For children with bilateral refer results at screening, this diagnosis was confirmed in 80.7% of cases.
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At first presentation at the referral center, risk factors for hearing loss were identified by using the guidelines of the Joint Committee on Infant Hearing 2000 position statement.7 Ninety-six children (57.8%) had no risk factors, there were 4 children for whom risk factors were unknown because of unavailable questionnaires, and 70 children (42.2%) had 1 (n = 58) or more (n = 12) risk factors. The relationship between the presence or absence of risk factors and the hearing status after audiometric evaluation is presented in Table 4. A total of 65.6% of children without risk factors were found to have a hearing loss, whereas 28.6% of the children with risk factors had normal hearing. The distribution of the different risk factors is presented in Fig 2.
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Familial history of deafness was the most frequently encountered risk factor for congenital hearing loss in our population. Risk factors were not statistically different between the normal hearing and hearing loss groups (Kruskal-Wallis test, P = .44).
The screening population of NICU infants demonstrated a permanent hearing loss in 61.5% of cases. The male/female ratio was 3.0. The median hearing loss of the hearing-impaired children was 60 dB nHL. The most-prevalent risk factors were mechanical ventilation, low birth weight, and hyperbilirubinemia.
Etiologic Evaluation
Additional diagnostic testing for the permanently hearing-impaired infants (n = 116) could be performed in 87 cases. Dropout of 29 (25.0%) of 116 children was observed, in which case the complete diagnostic protocol could not be conducted. A specific etiologic diagnosis was established for 48 (55.2%) of the 87 children for whom a permanent hearing loss was confirmed. For the remaining 39 children (44.8%), the cause underlying the congenital hearing loss remained unknown. The distribution of the etiologic diagnoses is presented in Fig 3. Of the causes identified, a genetic cause was present in 60.4% of cases, peripartal problems in 20.8%, and congenital CMV infection in 18.8%. With respect to the genetic causes of hearing loss in our population, mutations in the GJB2 gene accounted for 37.9% of the cases, chromosomal aberrations were found in 13.8% (n = 4), specific syndromic deafness for which the underlying molecular basis was known was proven in 6.9% (n = 2), and a yet unknown genetic factor was involved in 41.4% (n = 12). The last category was based on pedigree characteristics demonstrating a mendelian type of inheritance or specific phenotypes for which the gene or the sequence is not yet known.
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For 11 children, hearing loss was attributed to mutations in the GJB2 gene. A detailed description of the different GBJ2 mutations and the resulting hearing loss is shown in Table 5. All of these children were either homozygous or compound heterozygous. Homozygotic carriage of the 35delG mutation was the most common pattern but demonstrated variable clinical expression.
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Apart from GBJ2 mutations, the following specific genetic phenotypes were found: trisomy 21 (n = 2), partial trisomy 19p (n = 1), trisomy 18 (n = 1), Jervell and Lange-Nielsen syndrome (n = 1), Waardenburg syndrome (WS) (n = 1), and craniofacial malformations (n = 6). The last category included 4 cases of aural atresia.
For 9 children, a diagnosis of congenital CMV infection was made. CMV was detected through PCR assays with the blood spots on Guthrie cards, viral cultures, or blood serologic tests. A detailed description of these children and their hearing thresholds at birth and at follow-up evaluations is presented in Table 6.
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Perinatal causes of hearing loss were cerebral bleeding (n = 3), asphyxia (n = 3), kernicterus attributable to ABO incompatibility (n = 2), bacterial meningitis (n = 1), and fetal alcohol syndrome (n = 1). The other laboratory tests demonstrated various findings in a number of cases, without any contribution to the final etiologic diagnosis. Ophthalmologic examination revealed 5 infants with eye abnormalities, including astigmatism (n = 2), eye ptosis, pseudofakia, and strabismus. In the present population, ophthalmologic evaluations were of only limited importance for the diagnosis of deafness.
Radiologic imaging was performed for 37 patients (38.5%) exhibiting sensorineural hearing loss of 60 dB nHL (n = 96). Of those patients, 11 (29.7%) showed positive radiologic findings. Computed tomography had a slightly higher rate of abnormality detection (n = 33; 27%) than did MRI (n = 23; 21%).
In aural atresia, the classical malformations of the external and middle ear were found. Minor inner ear malformations at the semicircular canals were described in 3 cases, but no Mondini-like defects were observed. Electrocardiographic findings were abnormal in only 1 patient, with Jervell and Lange-Nielsen syndrome.
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DISCUSSION |
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TOPABSTRACTMETHODSRESULTSDISCUSSIONCONCLUSIONSREFERENCES |
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Hearing loss is one of the most common congenital anomalies, occurring in
1 to 2 infants per 1000. Left undetected, hearing impairment in infants can negatively affect speech and language acquisition, academic achievement, and social and emotional development. These negative effects can be diminished and even eliminated through early intervention at or before 6 months of age.3 To the best of our knowledge, this is the first report in the literature that provides data on audiologic confirmation and etiologic assessment in a large sample of newborns referred after failed UNHS. Many UNHS programs are experiencing difficulty getting all or most of the infants referred from the screening program to complete the diagnostic process and to be enrolled in intervention programs. Attrition rates as high as 60% between the initial referral and diagnostic confirmation are not unusual.10 Moreover, an important deficiency of virtually all UNHS programs is that they lack information on diagnostic evaluations.6 The current tracking system organized by the federal health care agency seems to be very effective, because virtually all patients sent by the organization were actually seen for follow-up audiologic confirmation. In addition, organizing the etiologic evaluation was quite efficient, with a dropout rate of only 25.0%. The search for an underlying cause must be undertaken through a multidisciplinary approach involving an ear, nose, and throat surgeon, a pediatrician, a geneticist, an ophthalmologist, a radiologist, and other specialists when indicated by the clinical findings. An efficiently managed diagnostic protocol decreases the burden for the parents and child and limits the risk of noncompliance.
The presence of hearing loss (either unilateral or bilateral) was confirmed in 68.2% of the referrals. In 31.8%, hearing was found to be normal after a thorough audiometric evaluation. In 60.4% of the cases, exactly analogous results were found in screening and diagnostic testing. Our results suggest that the accuracy of newborn hearing screening remains an issue, even if the positive predictive value for the UNHS program organized by the federal health care agency in Belgium has been reported to be as high as 32%.6
Children with unilateral refer results were more likely to have normal hearing, but 11.6% of those children were diagnosed as having bilateral hearing loss. These findings underscore the need for a comprehensive audiometric evaluation in both unilateral and bilateral referral cases. Limiting the audiometric protocol to bilateral referral cases cannot be justified, because unilateral referral cases with bilateral hearing loss (and the need for rehabilitation) would go undetected.
The same holds true for limiting screening to newborns with risk factors for congenital hearing loss. A total of 55.8% of children with hearing loss had no risk factors at all. The presence of >1 risk factor does not necessarily imply a cumulative risk for hearing loss, because 4 children with multiple risk factors had normal hearing.
In some European countries, such as the United Kingdom, an etiologic investigation is usually conducted only for children with bilateral hearing loss of >35 dB nHL identified through the National Newborn Hearing Screening Program.11 Interestingly, in both the GJB2 and congenital CMV groups, some children had only 1 affected ear. If an etiologic diagnosis had been sought only for children with bilateral hearing loss, then those children would have been missed.
According to the literature, prelingual hearing loss is attributed to genetic causes in 50% of cases and to environmental causes in the other 50%.12 In the present study, an etiologic diagnosis could be established in 55.2% of the cases. Of the causes identified, a genetic cause was present in 60.4% of the cases and environmental problems in 39.6%.
Among the genetic causes, 30% were reported previously to be syndromic and 70% nonsyndromic.12 Within the prelingual, nonsyndromic, hearing loss group, inheritance is reported to be 75% to 80% autosomal recessive, 20% to 25% autosomal dominant, and 15 to 1.5% X-linked. Although nonsyndromic sensorineural hearing loss is very heterogeneous, mutations in the GJB2 gene account for nearly 50% of cases of congenital, autosomal recessive, nonsyndromic, sensorineural hearing loss in the white population.13
Looking specifically at the genetic causes of hearing loss in our population (n = 29), syndromic sensorineural hearing loss accounted for 31.0% and nonsyndromic phenotypes for 69.0%. Mutations in the GJB2 gene accounted for 38% of the genetic cases, specific syndromic deafness for 7%, and chromosomal aberrations for 14%; in 41% of cases, a mendelian phenotype without known gene and/or sequence was involved. This finding is in agreement with the finding that GJB2 mutations account for 30% to 40% of genetic causes of prelingual hearing loss throughout the world.
Hearing impairment in subjects in the biallellic nontruncating GJB2 mutations ranges from mild to profound and is usually nonprogressive.14,15 The c35delG (35delG mutation) variant is the most common in children of northern European ancestry and has a carrier frequency of 2.5% in the general population. It was also the most common allele variant of GJB2 in our population. As illustrated in Table 5, there was a variable genotype-phenotype correlation even among children homozygous for 35delG, which is known to be associated with profound hearing loss. Our data are in accordance with those from a large multicenter study reported by Snoeckx et al.16 Those authors found that the degree of hearing loss associated with biallellic truncating mutations (such as 35delG) was more severe than that associated with biallellic nontruncating mutations. A diagnosis of GJB2 mutations has important implications for parental counseling. Hearing loss attributable to GJB2 mutations is usually nonprogressive, and prenatal diagnosis is possible in the case of future children.14–16
WS is the most common type of autosomal dominant syndromic hearing loss, in association with minor defects in structures arising from the neural crest and pigmentation anomalies.17 It consists of variable degrees of sensorineural hearing loss and pigmentary abnormalities of the skin, hair (white forelock), and eyes (heterochromia iridis). Four types are recognized (ie, WS I, WS II, WS III, and WS IV), on the basis of the presence of other abnormalities. WS I and WS II share many features but have an important phenotypic difference; WS I is characterized by the presence of dystopia canthorum, whereas WS II is characterized by its absence. In WS III, upper-limb abnormalities are present. In WS IV, Hirschsprung disease is present. Mutations in PAX3 cause WS I and WS III. Mutations in MITF cause some cases of WS II. Mutations in EDNRB, EDN3, and SOX10 cause WS IV.
Jervell and Lange-Nielsen syndrome is an autosomal recessive form of profound bilateral congenital deafness associated with prolongation of the QT interval, as detected through electrocardiography (the abnormal QTc is >440 milliseconds). It is caused specifically by mutation of the KCNE1 and KCNQ1 genes. Among untreated individuals with Jervell and Lange-Nielsen syndrome, 50% die by the age of 15 years, as a result of ventricular arrhythmias.18
Fetal alcohol spectrum disorder describes a spectrum of permanent and often devastating birth defect syndromes caused by maternal consumption of alcohol during pregnancy. The main effect of fetal alcohol exposure is brain damage. Church and Abel19 observed that fetal alcohol spectrum disorder is associated with 4 kinds of hearing disorders, that is, (1) developmentally delayed speech and language development, (2) sensorineural hearing loss, (3) intermittent conductive hearing loss attributable to recurrent serous otitis media, and (4) central hearing loss. As is the case with other syndromes associated with craniofacial anomalies and hearing impairments, speech and language pathologic conditions also are common in patients with fetal alcohol spectrum disorder. In our population, 1 child demonstrated clinical signs of fetal alcohol spectrum disorder.
Craniofacial malformations were observed in 12.5% of cases (n = 6). In 4 cases, aural atresia was determined.
According to Das,20 chromosomal aberrations may account for 3.8% of congenital hearing loss. In our population, trisomies 18, 21, and 19p accounted for 8.3% (n = 4) of the identified causes of prelingual hearing loss.
In the literature, the most important environmental factors responsible for prelingual hearing loss are congenital infections (mainly rubella in nonvaccinated areas and CMV), ototoxicity, prematurity, and asphyxiation.12 In our study group, 39.6% of the cases of permanent hearing loss were attributable to environmental causes.
Congenital CMV infection was recognized as the most frequent cause of acquired hearing loss in neonates. In our population, congenital CMV infection was present in 18.8% of cases. A diagnosis of congenital CMV infection was based on PCR assays with dried blood spots on Guthrie cards, viral cultures from urine or saliva samples, and the presence of specific IgM antibodies. Congenital CMV infection is a challenging diagnosis.21 Once children are older than 2 to 3 weeks, the diagnosis becomes sometimes difficult, because viral excretion in the urine might be intermittent and a postnatal infection cannot be ruled out. In more-recent years, implementation of PCR analysis of viral DNA in dried blood spots has significantly improved the diagnostic power for congenital CMV infection.22,23 An early diagnosis of congenital CMV has important implications from a therapeutic point of view. Clinical studies with treatment protocols based on ganciclovir are underway and promising, although not applied in the present study.24,25 Hearing loss attributable to congenital CMV may be progressive in >50% of cases,26 and regular audiometric follow-up monitoring is required until the age of 6 years. Both aspects underscore the need for correct early diagnosis and appropriate counseling of the parents.
According to Fortnum and Davis,27 bacterial meningitis accounts for 6% of sensorineural hearing loss in children. In a study by Koomen et al, 75% of patients were <2 years of age.28 Bacterial meningitis was a cause of acquired neonatal hearing loss in 1 child (2.1%) in our population.
A diagnosis of auditory dyssynchrony was established for 2 children (4.2%). This disorder is characterized by a dysfunction in neural/brainstem transmission of auditory stimuli in the presence of normal outer hair cell function. This condition translates into absent or abnormal ABR responses and normal otoacoustic emissions. The clinical significance is that this may result in impaired development of normal auditory behavior or oral language, often leading to cochlear implantation. According to Foerst et al,29 a prevalence of 0.94% was found within the group at risk for hearing loss, compared with 8.44% among profoundly hearing-impaired children. Protocols that use otoacoustic emission screening should refer infants with hyperbilirubinemia for ABR testing, because there is mounting evidence in the literature showing linkage between auditory dyssynchrony and hyperbilirubinemia.30 In the present study, every child who needed at least phototherapy was considered at risk for hearing loss.
Mutations in the gene encoding otoferlin (OTOF), known as DFNB9, also may cause a pattern of auditory dyssynchrony.31 In this particular case, the disorder is attributed to functional alterations in the inner hair cells.
In 1 child, auditory dyssynchrony was caused by hyperbilirubinemia attributable to Rh factor incompatibility. The child was treated with exchange transfusion during the newborn period, and later she received a cochlear implant. For the other child, no risk factors were present and mutations in the OTOF gene were excluded.
It is obvious that identification of the cause of the hearing loss provides new information relevant to hearing loss management, coexisting medical problems, and the prognosis for the child and family. In addition, these investigations clarify the epidemiological features of congenital deafness, which may facilitate the planning of effective hearing loss prevention and surveillance programs.
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CONCLUSIONS |
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TOPABSTRACTMETHODSRESULTSDISCUSSIONCONCLUSIONSREFERENCES |
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A diagnosis of congenital hearing loss (either unilateral or bilateral) was made for 68.2% of neonates referred for audiometric evaluation after failed UNHS. For 55.2% of those children, an etiologic diagnosis could be made after a comprehensive etiologic evaluation. This evaluation allows for appropriate, individually tailored rehabilitation, audiometric follow-up monitoring, and parental counseling. Our diagnostic abilities are likely to improve in the near future, with advances in molecular genetics and the rapidly expanding knowledge concerning genes involved in nonsyndromic sensorineural hearing loss. This would significantly improve the strength of UNHS programs and allow for the rapid identification of prelingual hearing loss.
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ACKNOWLEDGMENTS |
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We thank the audiologists in our department for their outstanding professional help and diligence in screening newborns.
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FOOTNOTES |
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Accepted Sep 27, 2007.
Address correspondence to Frank Declau, MD, PhD, Department of Otorhinolaryngology, Head and Neck Surgery, and Communication Disorders, University Hospital Antwerp, Wilrijkstraat 10, B-2650 Edegem, Belgium. E-mail: nko{at}telenet.be
The authors have indicated they have no financial relationships relevant to this article to disclose.
| What's Known on This Subject Hearing loss is one of the most common congenital anomalies. Hearing impairment in infants can negatively affect speech and language acquisition, academic achievement, and social and emotional development. These negative effects can be diminished through early intervention.
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| What This Study Adds To the best of our knowledge, this is the first report in the literature that provides data on both audiologic confirmation and etiologic assessment in a large sample of newborns referred after failed screening.
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PEDIATRICS (ISSN 1098-4275). ©2008 by the American Academy of Pediatrics
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