Universal neonatal hearing screening moving from evidence to practice

Newborn concurrent hearing and genetic screening for hearing impairment: A systematic review and meta‑analysis

Hearing loss is the most prevalent neurosensory disorder in humans, with significant implications for language, social and cognitive development if not diagnosed and treated early. The present systematic review and meta-analysis aimed to determine the rate of hearing screening pass and genetic screening failure [universal newborn hearing screening (UNHS) pass/genetic failure] and to investigate the advantages of combining newborn hearing and genetic screening for newborn hearing impairment. The PubMed, Embase and Cochrane databases were searched from inception to September 2023 to identify studies reporting the combination of neonatal hearing screening with genetic screening. Duplicate literature, unpublished literature, studies with incomplete data, animal experiments, literature reviews and systematic studies were excluded. All the data were processed by STATA15.1 statistical software. A total of nine cross-sectional studies were included in this meta-analysis. The sample sizes ranged from 1,716 to 180,469, and there were a total of 377,688 participants. The pooled results revealed that the prevalence of passing the UNHS while failing genetic screening was 0.31% (95% CI, 0.22-0.41%). The prevalence of UNHS pass and gap junction protein beta 2 and solute carrier family 26 member 4 variant screen failure was 0.01% (95% CI, 0.00-0.02%) and 0.00% (95% CI, 0.00%), respectively, while the prevalence of mitochondrially encoded 12S RRNA variant screening failure and UNHS pass was 0.21% (95% CI, 0.18-0.26%). Combined screening has a significant advantage over pure hearing screening, especially in terms of identifying newborns with mitochondrial gene mutations that render them sensitive to certain medications. In clinical practice, decision-makers can consider practical circumstances and leverage the benefits of combined newborn hearing and genetic screening for early diagnosis, early counseling, and early intervention in patients with hearing loss.

Genetic screening of 15 hearing loss variants in 77,647 neonates with clinical follow-up

BACKGROUND

To analyze the genotype distribution and frequency of hearing loss genes in newborn population and evaluate the clinical value of genetic screening policy in China.

METHODS

Genetic screening for hearing loss was offered to 84,029 neonates between March 2019 and December 2021, of whom 77,647 newborns accepted the screening program with one-year follow-up. The genotyping of 15 hot spot variants in GJB2, GJB3, SLC26A4, and MT-RNR1 was performed on microarray platform.

RESULTS

A total of 3.05% (2369/77,647) newborns carried at least one genetic hearing loss-associated variant, indicated for early preventive management. The carrier frequency of GJB2 gene was the highest, at 1.48% (1147/77,647), followed by SLC26A4 gene at 1.07% (831/77,647), and GJB3 gene at 0.23% (181/77,647). GJB2 c.235delC variant and SLC26A4 IVS7-2A>G variant were the most common allelic variants with allele frequency of 0.6304% (979/155,294) and 0.3992% (620/155,294), respectively. 10 children are identified as homozygous or compound heterozygous for pathogenic variants (4 in GJB2, 6 in SLC26A4), and 7 of these infants had passed the hearing screening. Following up of the genetically screened newborns revealed that genetic screening detected more hearing-impaired infants than hearing screening alone. Genetic screening helped identify the infants who had passed the initial hearing screening, and reduced time for diagnosis and intervention of hearing aid. In addition, we identified 234 newborns (0.30%, 234/77,647) susceptible to preventable aminoglycoside antibiotic ototoxicity undetectable by hearing screening.

CONCLUSION

We performed the largest-scale neonatal carrier screening for hearing loss genes in Southeast China. Our results indicated that genetic screening is an important complementation to conventional hearing screening. Our practice and experience may facilitate the application and development of neonatal genetic screening policy in mainland China.

Optimized concurrent hearing and genetic screening in Beijing, China: A cross-sectional study

Concurrent screening has been proven to provide a comprehensive approach for management of congenital deafness and prevention of ototoxicity. The SLC26A4 gene is associated with late-onset hearing loss and is of great clinical concern. For much earlier detection of newborns with deafness-causing mutations in the SLC26A4 gene, the Beijing Municipal Government launched a chip for optimized genetic screening of 15 variants of 4 genes causing deafness based on a chip to screen for 9 variants of 4 genes, and 6 variants of the SLC26A4 gene have now been added. To ascertain the advantage of a screening chip including 15 variants of 4 genes, the trends in concurrent hearing and genetic screening were analyzed in 2019 and 2020. Subjects were 76,460 newborns who underwent concurrent hearing and genetic screening at 24 maternal and child care centers in Beijing from January 2019 to December 2020. Hearing screening was conducted using transiently evoked otoacoustic emissions (TEOAEs), distortion product otoacoustic emissions (DPOAE), or the automated auditory brainstem response (AABR). Dried blood spots were collected for genetic testing and 15 variants of 4 genes, namely GJB2, SLC26A4, mtDNA 12S rRNA, and GJB3, were screened for using a DNA microarray platform. The initial referral rate for hearing screening decreased from 3.60% (1,502/41,690) in 2019 to 3.23% (1,124/34,770) in 2020, and the total referral rate for hearing screening dropped form 0.57% (236/41,690) in 2019 to 0.54% (187/34,770) in 2020, indicating the reduced false positive rate of newborn hearing screening and policies to prevent hearing loss conducted by the Beijing Municipal Government have had a significant effect. Positivity according to genetic screening was similar in 2019 (4.970%, 2,072/41,690) and 2020 (4.863%,1,691/34,770), and the most frequent mutant alleles were c.235 del C in the GJB2 gene, followed by c.919-2 A > G in the SLC26A4 gene, and c.299 del AT in the GJB2 gene. In this cohort study, 71.43% (5/7) of newborns with 2 variants of the SLC26A4 gene were screened for newly added mutations, and 28.57% (2/7) of newborns with 2 variants of the SLC26A4 gene passed hearing screening, suggesting that a screening chip including 15 variants of 4 genes was superior at early detection of hearing loss, and especially in early identification of newborns with deafness-causing mutations in the SLC26A4 gene. These findings have clinical significance.

Association between in vitro fertilization-embryo transfer and hearing loss: risk factors for hearing loss among twin infants in a cohort study

Assisted reproductive technologies (ART), including in vitro fertilization-embryo transfer (IVF-ET) and intracytoplasmic sperm injection (ICSI), are known to contribute a higher risk of birth defects; however, studies have rarely evaluated the association between IVF-ET and diagnostic hearing loss (HL). This study aimed to evaluate the prevalence of and risk factors for HL and to clarify the association between IVF-ET and HL among twinborn infants. We enrolled 1860 live-born twin neonates born at a hospital in China from January 2017 to December 2020. After multi-step hearing screening, participants were diagnosed with HL by pediatric audiologists at 6 months of age. The prevalence of hearing loss and the adjusted odds ratios (AORs) for specific risk factors were estimated using generalized estimation equation (GEE) models in twin-born infants. Characteristics and prevalence of failure for hearing screening and HL were measured in IVF-ET twin infants. IVF-ET conception and preterm birth conferred a higher risk of hearing loss, with increased adjusted odds ratios (AOR [95% confidence intervals (CI)] IVF-ET: 2.82 [1.17-6.80], P = 0.021; preterm birth: 6.14 [2.30-16.40], P < 0.001) than the control group, respectively. Among the 1860 twin infants, more IVF-ET twins failed in dual-step hearing screening (3.26%) and were diagnosed with hearing loss (2.21%) than those conceived by spontaneous pregnancy.

CONCLUSION

IVF-ET conception and premature birth were associated with a higher risk of hearing impairment. Twin infants conceived by IVF-ET tended to fail in hearing screening and be diagnosed with hearing loss. These observations provide a more comprehensive approach for the prevention and management of deafness in twin-born children.

WHAT IS KNOWN

• IVF-ET technologies conferred a higher risk of birth defects.

WHAT IS NEW

• Premature birth and IVF-ET conception were associated with a higher risk of hearing loss among twin infants. • Twin infants conceived by IVF-ET tended to fail in hearing screening and diagnosed with hearing loss.

Genetic Analysis of the LOXHD1 Gene in Chinese Patients With Non-Syndromic Hearing Loss

Non-syndromic hearing loss (NSHL) is a common neurosensory disease with an extreme genetic heterogeneity which has been linked to variants in over 120 genes. The LOXHD1 gene (DFNB77), encoding lipoxygenase homology domain 1, is a rare hearing loss gene found in several populations. To evaluate the importance of LOXHD1 variants in Chinese patients with NSHL, we performed genetic analysis on LOXHD1 in 2,901 sporadic Chinese patients to identify the aspect and frequency of LOXHD1 causative variants. Next-generation sequencing using a custom gene panel of HL was conducted on 2,641 unrelated patients and whole-exome sequencing on the remaining 260 patients. A total of 33 likely causative variants were identified in 21 patients, including 20 novel variants and 13 previously reported pathogenic variants. Each of the 20 novel variants was evaluated according to ACMG criteria. These findings showed that causative variants in LOXHD1 were found in about 0.72% (21/2,901) of Chinese NSHL patients. This study is by far the largest number of novel variants identified in this gene expanding the range of pathogenic variants in LOXHD1, and suggests that variants in this gene occur relatively commonly in Chinese NSHL patients. This extensive investigation of LOXHD1 in Chinese NSHL patients proposed six recurrent LOXHD1 variants. These findings may assist in both molecular diagnosis and genetic counseling.

Early detection of hearing loss for infants in Western Australia: Comparison to international benchmarks

AIM

To assess the degree to which timely audiological assessment of congenital hearing loss is achieved at our institution - Perth Children's Hospital, Western Australia, and to review cases which breached this timeframe in order to address barriers to timely assessment. The benchmark used to determine timely assessment is that set out by The Joint Committee on Infant Hearing (JCIH) in which diagnostic audiological testing occurs by three months of age for those who do not pass newborn hearing screening.

METHODS

A retrospective chart review of infants who underwent diagnostic auditory assessment at Perth Children's Hospital between 2016-2019. A total of 151 children were identified as meeting the inclusion criteria and their medical files were reviewed. Time to first dABR was the time point for whether testing was achieved within the 3 month timeframe.

RESULTS

Of the 151 children who underwent dABR assessments, 1 was identified as having breached the 90 day time limit (tested on day 91) for which no valid reason for delay could be identified. The timely delivery of dABR assessments in 99.3% of cases within this cohort compares favourably with the literature.

CONCLUSIONS

Conclusion Timely diagnostic audiological assessment is achievable for children with congenital hearing loss. The reasons for patients breaching this timeframe are explored in the paper along with factors which may help avoid delays.

Newborn Hearing Screening: Analysing the Effectiveness of Early Detection of Neonatal Hearing Loss in a Hospital in Greece

Introduction The introduction of newborn hearing screening programs (NHSP) has drastically contributed to the early diagnosis of hearing loss (HL) in children, with the prospect of children developing speech as early as possible. This retrospective study aims to present and discuss the preliminary results of the NHSP at the University Hospital of Patras, Greece, highlighting the strengths and weaknesses of the program. The evaluation of the implementation of NHSP is important to confirm the effectiveness of the process and elaborate system failures. Materials The study describes the results of previous data collected from the NHSP in the Rio hospital of Patra and analyzed the conditions of the sample collected. The random sample involved newborns born between November 2018 - December 2020 at the University Hospital in Patra, Greece, which was assessed using transient evoked otoacoustic emissions (TEOAEs). Testing was performed twice per week on Thursday and Friday with a random sample, specifically examining the babies in the hospital these days. From the 2014 newborns assessed, 1491 were healthy neonates, while the other 523 required hospitalization in the neonatal unit. Results In total, there were 2014 live births; 1491 healthy neonates were screened with TEOAEs. Of them, 44 did not pass the first test. After retesting one month later, 31 passed the test, while the other 13 were referred to a hearing centre for further audiological testing with auditory brainstem response (ABR) tests. Two infants never showed up for the follow-up appointment. Of the remaining 11, six infants had normal hearing, three had otitis media with effusion or other conductive HL. The last two infants had HL. Specifically, one had bilateral sensorineural HL greater than 40db, and one had unilateral sensorineural HL greater than 40db. Risk factors were identified in 523 newborns admitted to the unit. The most common risk factors identified were the use of ototoxic drugs, low Apgar scores, and prematurity. Of all the newborns, 491 passed the test the first time, and the rest 32 infants came back 1-2 months after leaving the neonatal unit. All the babies who had failed in the first screening test appeared for the follow-up appointment for the second screening test. Of these, 24 babies passed the test, but eight did not. Of these, four were diagnosed with media otitis with effusion or other conductive HL. Sensorineural HL was identified in the last four babies using ABR tests. In detail, two had unilateral sensorineural HL greater than 40db, while two had bilateral sensorineural HL greater than 40db. Conclusion In conclusion, we found that for the NHS programs to be effective, they must be implemented long-term and have monetary support. Early diagnosis and cochlear implantation are the keys to excellent outcomes. Cooperation between different specialties and a patient-centred approach will help physicians holistically face neonatal HL. Building trust between the parents and doctor is essential for the program's success and reducing the lost-to-follow-up rate. To run a successful program, trained staff, equipment, and financial support are required. However, the gold standards for the success of the program are proper implementation of the program, close follow-up, strict adherence to the guidelines in the neonatal intensive care unit (NICU), and the early detection and diagnosis of HL.

Newborn screening with targeted sequencing: a multicenter investigation and a pilot clinical study in China

Different newborn screening (NBS) programs have been practiced in many countries since the 1960s. It is of considerable interest whether next-generation sequencing is applicable in NBS. We have developed a panel of 465 causative genes for 596 early-onset, relatively high incidence, and potentially actionable severe inherited diseases in our Newborn Screening with Targeted Sequencing (NESTS) program to screen 11,484 babies in 8 Women and Children's hospitals nationwide in China retrospectively. The positive rate from preliminary screening of NESTS was 7.85% (902/11,484). With 45.89% (414/902) follow-up of preliminary positive cases, the overall clinically confirmative diagnosis rate of monogenic disorders was 12.07% (50/414), estimating an average of 0.95% (7.85% × 12.07%) clinical diagnosis rate, suggesting that monogenic disorders account for a considerable proportion of birth defects. The disease/gene spectrum varied in different regions of China. NESTS was implemented in a hospital by screening 3923 newborns to evaluate its clinical application. The turn-around time of a primary report, including the sequencing period of < 7 days, was within 11 days by our automatic interpretation pipeline. Our results suggest that NESTS is feasible and cost-effective as a first-tier NBS program, which will change the status of current clinical practice of NBS in China.

[Neonatal hearing screening]

Neonatal hearing screening has been developped in a large number of countries. The rational to build such nationwide programs is robust. The prevalence of hearing impairment of various etiologies is high (1/1,000), diagnosis of hearing impairment in infants is uneasy and is made most of the time after the age of 18 months when treatment is less efficient and, last, appropriate test to screen for hearing impairment are available: Otoacoustic Emission and Auditory Evoked Potential. In France the screening is organised at the regional level. The organization of such a program is complexe. Midwifes and nurses should be trained to informed the parents and to perform the test. If the test is abnormal the infant will be oriented to a specialzed department of pediatrics for appropriate diagnosis and treatment.

Concurrent Hearing and Genetic Screening of 180,469 Neonates with Follow-up in Beijing, China

Concurrent hearing and genetic screening of newborns is expected to play important roles not only in early detection and diagnosis of congenital deafness, which triggers intervention, but also in predicting late-onset and progressive hearing loss and identifying individuals who are at risk of drug-induced HL. Concurrent hearing and genetic screening in the whole newborn population in Beijing was launched in January 2012. This study included 180,469 infants born in Beijing between April 2013 and March 2014, with last follow-up on February 24, 2018. Hearing screening was performed using transiently evoked otoacoustic emission (TEOAE) and automated auditory brainstem response (AABR). For genetic testing, dried blood spots were collected and nine variants in four genes, GJB2, SLC26A4, mtDNA 12S rRNA, and GJB3, were screened using a DNA microarray platform. Of the 180,469 infants, 1,915 (1.061%) were referred bilaterally or unilaterally for hearing screening; 8,136 (4.508%) were positive for genetic screening (heterozygote, homozygote, or compound heterozygote and mtDNA homoplasmy or heteroplasmy), among whom 7,896 (4.375%) passed hearing screening. Forty (0.022%) infants carried two variants in GJB2 or SLC26A4 (homozygote or compound heterozygote) and 10 of those infants passed newborn hearing screening. In total, 409 (0.227%) infants carried the mtDNA 12S rRNA variant (m.1555A>G or m.1494C>T), and 405 of them passed newborn hearing screening. In this cohort study, 25% of infants with pathogenic combinations of GJB2 or SLC26A4 variants and 99% of infants with an m.1555A>G or m.1494C>T variant passed routine newborn hearing screening, indicating that concurrent screening provides a more comprehensive approach for management of congenital deafness and prevention of ototoxicity.

Preserving Inhibition during Developmental Hearing Loss Rescues Auditory Learning and Perception

Transient periods of childhood hearing loss can induce deficits in aural communication that persist long after auditory thresholds have returned to normal, reflecting long-lasting impairments to the auditory CNS. Here, we asked whether these behavioral deficits could be reversed by treating one of the central impairments: reduction of inhibitory strength. Male and female gerbils received bilateral earplugs to induce a mild, reversible hearing loss during the critical period of auditory cortex development. After earplug removal and the return of normal auditory thresholds, we trained and tested animals on an amplitude modulation detection task. Transient developmental hearing loss induced both learning and perceptual deficits, which were entirely corrected by treatment with a selective GABA reuptake inhibitor (SGRI). To explore the mechanistic basis for these behavioral findings, we recorded the amplitudes of GABA_A and GABA_B receptor-mediated IPSPs in auditory cortical and thalamic brain slices. In hearing loss-reared animals, cortical IPSP amplitudes were significantly reduced within a few days of hearing loss onset, and this reduction persisted into adulthood. SGRI treatment during the critical period prevented the hearing loss-induced reduction of IPSP amplitudes; but when administered after the critical period, it only restored GABA_B receptor-mediated IPSP amplitudes. These effects were driven, in part, by the ability of SGRI to upregulate α1 subunit-dependent GABA_A responses. Similarly, SGRI prevented the hearing loss-induced reduction of GABA_A and GABA_B IPSPs in the ventral nucleus of the medial geniculate body. Thus, by maintaining, or subsequently rescuing, GABAergic transmission in the central auditory thalamocortical pathway, some perceptual and cognitive deficits induced by developmental hearing loss can be prevented.SIGNIFICANCE STATEMENT Even a temporary period of childhood hearing loss can induce communication deficits that persist long after auditory thresholds return to normal. These deficits may arise from long-lasting central impairments, including the loss of synaptic inhibition. Here, we asked whether hearing loss-induced behavioral deficits could be reversed by reinstating normal inhibitory strength. Gerbils reared with transient hearing loss displayed both learning and perceptual deficits. However, when animals were treated with a selective GABA reuptake inhibitor during or after hearing loss, behavioral deficits were entirely corrected. This behavioral recovery was correlated with the return of normal thalamic and cortical inhibitory function. Thus, some perceptual and cognitive deficits induced by developmental hearing loss were prevented with a treatment that rescues a central synaptic property.

Comparison of auditory brainstem response and auditory steady state response audiometry by evaluating the hearing thresholds obtained in children with different severity of hearing loss

Objectives:

To compare the hearing thresholds obtained with auditory brainstem response (ABR) and auditory steady state response (ASSR) audiometry in children with hearing loss.

Methods:

Hearing thresholds were obtained by ABR and ASSR in children who presented with suspicion of deafness at Ear, nose & throat department of Al-Nafees Medical College Hospital Islamabad, between January to August 2018. The mean hearing thresholds obtained by two tests were compared within each category of severity of deafness. Time taken by both tests was also compared.

Results:

A total of 57 patients (114 ears) were included in the study. Among them 27 (47.4%) were male and 30 (52.6%) were female. The mean age of patients at presentation was 42 months (±30.9) with age range from one to 12 years. Mean hearing thresholds obtained by click ABR, chirp ABR, ASSR (1, 2, 4 kHz) & ASSR (0.5, 1, 2, 4 kHz) was 56.25 (±27.61), 58.88 (±27.44), 58.03 (±21.26) & 56.35 (±22.86) respectively. Mean thresholds were comparable between click ABR & ASSR (1, 2, 4 kHz) and between chirp ABR & ASSR (0.5, 1, 2, 4 kHz) in all degrees of hearing loss categories except in those patients with normal hearing thresholds. The mean time taken by clicks ABR, chirp ABR and ASSR were four minutes seven seconds, three minutes 15 seconds and 16 minutes and 7 seconds respectively.

Conclusions:

Hearing thresholds obtained by ABR and ASSR are comparable in all categories of severity of hearing loss. The time taken by ABR is less as compared to ASSR.

Pilot Study of Universal Newborn Hearing Screening in Japan: District-Based Screening Program in Okayama

Objectives: Newborn hearing screening was started in Okayama Prefecture in 2001 as part of a nationwide pilot study in Japan. Nearly 50,000 infants have been screened to date, and an observational study and more than 2 years of follow-up of this population are described in this report.

Methods: Between June 2001 and March 2005 (45 months), 47,346 neonates were screened with automated auditory brain stem response systems and followed up for at least 2 years. This total corresponds to 95% of the infants born in the 44 gynecologic institutions in this district.

Results: After undergoing the screening process twice, 248 infants (0.52%) received referrals; 108 of them had apparent bilaterally affected hearing, and 140 had apparent unilaterally affected hearing. Among the bilateral cases, hearing impairment was diagnosed in 40 infants, for a total prevalence of hearing impairment of 0.08%. In 3 additional infants who received a bilateral pass result and 1 infant who received a unilateral pass result, hearing impairment that was progressive or of late onset was subsequently diagnosed. The positive and negative predictive values were calculated as 40% and 99.993%, respectively.

Conclusions: The screening program was carefully designed to work in the Japanese society and to be well managed in Okayama Prefecture.

Showing Value in Newborn Screening: Challenges in Quantifying the Effectiveness and Cost-Effectiveness of Early Detection of Phenylketonuria and Cystic Fibrosis

Decision makers sometimes request information on the cost savings, cost-effectiveness, or cost-benefit of public health programs. In practice, quantifying the health and economic benefits of population-level screening programs such as newborn screening (NBS) is challenging. It requires that one specify the frequencies of health outcomes and events, such as hospitalizations, for a cohort of children with a given condition under two different scenarios-with or without NBS. Such analyses also assume that everything else, including treatments, is the same between groups. Lack of comparable data for representative screened and unscreened cohorts that are exposed to the same treatments following diagnosis can result in either under- or over-statement of differences. Accordingly, the benefits of early detection may be understated or overstated. This paper illustrates these common problems through a review of past economic evaluations of screening for two historically significant conditions, phenylketonuria and cystic fibrosis. In both examples qualitative judgments about the value of prompt identification and early treatment to an affected child were more influential than specific numerical estimates of lives or costs saved.

Management challenges of congenital & early onset childhood hearing loss in a sub-Saharan African country

BACKGROUND

Hearing impairment is a hidden human disability with potentially catastrophic and age long consequences. This study highlighted the challenges associated with the management of congenital and early onset childhood hearing loss in a sub-Saharan African country.

METHODS

A retrospective descriptive study of children seen between January 2008 and December 2013 RESULT: A total of 223 children consisting of 124 (55.6%) males with (M:F) of 1.3:1. Age ranged 1-15 years (mean±SD; 6.39±4.37 years) and age group 1-5 years constituted the largest proportion (56.5%). Congenital causes, febrile illness and hypoxia were the leading causes of HI. Over 93% had moderately severe to profound hearing loss and 64.6% had delayed speech development. Majority (99.3%) with congenital/perinatal onset of HL had significantly delayed speech development and 99.3% of HL due to ototoxicity and infective causes had peri/post lingual speech impairment. Larger percentage of patients presented late; 16.6% of patients with congenital/perinatal onset of HL presented within the first year, >41% presented after the fifth year. Less than 5% had hearing aid fitted and patients with profound hearing impairment were referred for cochlear implant

CONCLUSION

The burden of congenital and early onset hearing impairment is high and management outcomes are unsatisfactory in our locality, Challenges associated with managing such children were discussed, and suggestions/strategies for better management and outcome were made.

Cordblood-Based High-Throughput Screening for Deafness Gene of 646 Newborns in Jinan Area of China

Objectives

Infants with slight/mild or late-onset hearing impairment might be missed in universal newborn hearing screening (UNHS). We identified the mutation hot spot of common deaf gene in the newborns in Jinan area population by screening the mutation spot with neonate cord blood, in order to make clear whether the neonate cord blood for screening is feasible.

Methods

Six hundred and forty-six newborns were subjected to both UNHS and genetic screening for deafness by using neonate cord blood. The newborn genetic screening targeted four deafness-associated genes, which were commonly found in the Chinese population including gap junction beta-2 protein (GJB2), gap junction beta-3 protein (GJB3), solute carrier family 26 member 4 (SLC26A4), and mtDNA 12S rRNA. The most common 20 spot mutations in 4 deaf genes were detected by MassARRAY iPLEX platform and mitochondrial 12S rRNA A1555G and C1494T mutations were sequenced using Sanger sequencing.

Results

Among the 646 newborns, 635 cases passed the UNHS and the other 11 cases (1.7%) did not. Of the 11 failures, two cases were found to carry homozygous GJB2 p.R143W pathogenic mutation, one case was found to have heterozygous GJB2 235delC mutation, and another one case carried heterozygous GJB3 p.R180X pathogenic mutation. Six hundred and thirty-five babies passed the newborn hearing screening, in which 25 babies were identified to carry pathogenic mutations, including 12 heterozygotes (1.9%) for GJB2 235delC, eight heterozygotes (1.3%) for SLC26A4 IVS7-2A>G, one heterozygote (0.2%) for p.R409H, two homozygotes (0.3%) for m.1494C>T, and two homozygotes (0.3%) for m.1555A>G.

Conclusion

Newborn genetic screening through the umbilical cord blood for common deafness-associated mutations may identify carriers sensitive to aminoglycoside antibiotic, and can effectively prevent or delay hearing loss occurs.

Analysis of audiological results of patients referred from newborn hearing screening program

CONCLUSION

As tools of confirmation of sensorineural hearing loss in neonates who are 'referred' from a newborn hearing screening program, both ASSR and DPOAE have high sensitivity and specificity. In addition, ASSR can be used as a substitute for ABR.

OBJECTIVES

To analyze the confirmative audiological results of patients referred from a newborn hearing screening program.

PATIENTS AND METHOD

From January 2007 to December 2013, hearing tests were performed on 474 babies (804 ears) who were 'referred' from the hospital or other maternity centers. Auditory brainstem response (ABR), auditory steady-state response (ASSR), and distortion product otoacoustic emissions (DPOAE) were used for hearing evaluation.

RESULTS

Of 474 babies (804 ears), 232 had normal hearing, while 242 babies (358 ears) had over 30 dB nHL threshold from ABR. Among the 156 babies (312 ears) who underwent both ABR and ASSR, the mean ASSR threshold had a strong correlation with ABR threshold (r = 0.942, p < 0.001). Assuming that ABR results were the yardstick of abnormal hearing, sensitivity and specificity of ASSR to ABR were 90.6% and 95%. DPOAE tests were performed on 180 babies (360 ears), with sensitivity of 85.9% and specificity of 84.4%.

Separating the contributions of olivocochlear and middle ear muscle reflexes in modulation of distortion product otoacoustic emission levels

OBJECTIVES

Mediated by the medial olivocochlear system (MOCS), distortion product otoacoustic emission (DPOAE) levels are reduced by presentation of contralateral acoustic stimuli. Such acoustic signals can also evoke a middle ear muscle reflex (MEMR) that also attenuates recorded DPOAE levels. Our aim is to clearly differentiate these two inhibitory mechanisms and to analyze each separately, perhaps allowing the development of novel tests of hearing function.

METHODS

DPOAE were recorded in real time from chinchillas with normal auditory brainstem response thresholds and middle ear function. Amplitude reduction and its onset latency caused by contralateral presentation of intermittent narrow-band noise (NBN) were measured. Stapedius and tensor tympani muscle tendons were divided without disturbing the ossicular chain, and DPOAE testing was repeated.

RESULTS

Peak reduction of (2f1 - f2) DPOAE levels occurred when the center frequency of contralateral NBN approximated the primary tone f2, indicating an f2-frequency-specific response. For a 4.5-kHz centered NBN, DPOAE (f2 = 4.4 kHz) inhibition was 0.1 dB (p < 0.001). This response remained present after tendon division, consistent with an MOCS origin. Low-frequency NBN (center frequency: 0.5 kHz) reduced otoacoustic emission levels (0.1 dB, p < 0.001) across a wide range of DPOAE frequencies. This low-frequency response was abolished by division of the middle ear muscle tendons, clearly indicating MEMR involvement.

CONCLUSIONS

Following middle ear muscle tendon division, DPOAE inhibition by contralateral stimuli approximating the primary tone f2 persists, whereas responses evoked by lower contralateral frequencies are abolished. This distinguishes the different roles of the MOCS (f2 frequency specific) and MEMR (low frequency only) in contralateral modulation of DPOAE. This analysis helps clarify the pathways involved in an objective test that might have clinical benefit in the testing of neonates.

Newborn hearing screening in the Campania region (Italy): early language and perceptual outcomes of infants with permanent hearing loss

Hearing loss in children causes a deficit in early perceptive and language skills. The objective of this study was to evaluate early receptive and expressive language outcomes in children with hearing loss, identified by hearing screening, compared to the time of diagnosis. We studied 18 severely hearing impaired children who were divided into two groups according to the time of diagnosis. Evaluation of communicative language ability was carried out at 18 month of age using the "MacArthur Child Development Inventory" questionnaire, while evaluation of acoustic-perceptual abilities was assessed with the Genovese-Arslan protocol every three months following diagnosis. The linguistic communicative and acoustic-perceptual outcomes of hearing impaired children diagnosed before 6 months of age followed those expected for normally hearing children, with a trend of temporal progression of skills that were faster than those of children diagnosed after 6 months of age.

Frequency of Hearing Impairment among Full-term Newborns in Yazd, Iran

OBJECTIVE

Permanent congenital hearing loss, a common congenital anomaly, may affect speech and language acquisition, academic achievement and social development. Current standards emphasize early recognition of congenital hearing loss. This study was conducted to find the prevalence of hearing impairment in term newborns in Yazd, Iran.

METHODS

This was a descriptive-analytic study conducted in Yazd on 7250 term newborns. Otoacoustic emissions (OAEs) test was performed in all newborns during the first 24 hours after birth. Those who failed to respond at the first step were retested 15 days later. Those who failed to respond at the second step too, were tested by acoustic brainstem responses (ABR) test. Chi square test was used for data analysis.

FINDINGS

From 7250 newborns in the first step 598 (8.2%) and 682 (9.4%) ears (right and left, respectively) failed. In the second step 51 (0.7%) and 58 (0.8%) ears (right and left, respectively) failed. Consanguinity and route of delivery had significant effect on the frequency of hearing loss.

CONCLUSION

The overall frequency of congenital hearing loss in this study was found high.

Dynamic characteristics of the middle ear in neonates

OBJECTIVE

Early diagnosis and treatment of hearing disorders in neonates is highly effective for realization of linguistic competence and intellectual development. To objectively and quickly evaluate the dynamic characteristics of the middle ear, a sweep frequency impedance (SFI) meter was developed, which allowed the diagnosis of middle-ear dysfunctions in adults and children. However, this SFI meter was not applicable to neonates since the size of the measurement probe was too large. In the present study, therefore, the SFI meter was improved, i.e., the diameter of the probe was reduced to that of the neonatal external ear canal. By using this newly designed SFI meter, SFI tests were performed in healthy neonates.

METHODS

A sound of the sweeping sinusoidal frequency between 0.1 kHz and 2.0 kHz in 0.02-kHz step intervals is presented to the ear canal by an SFI probe while the static pressure of the ear canal is kept constant. During this procedure, the sound pressure level (SPL) is measured. The measurements are performed at 50-daPa intervals of static pressure from 200 daPa to -200 daPa.

RESULTS

Measurements were conducted in 10 ears of 9 neonates. The SPL showed two variations at 0.26 ± 0.03 kHz and 1.13 ± 0.12 kHz. Since the SPL is known to show a variation at frequencies from 1.0 kHz to 1.6 kHz due to the resonance of the middle ear in adults and children with normal hearing, the second variation is probably related to such resonance in neonates. The measurement of gel models, which mimics the neonatal external ear canal, showed a variation in SPL at around 0.5 kHz. This implies that the source of the first variation may possibly be related to the resonance of the external ear canal wall.

CONCLUSIONS

SFI tests revealed that there were two variations in the SPL curve in neonates, one at 0.26 ± 0.03 kHz and the other at 1.13 ± 0.12 kHz, the former and the latter being possibly related to the resonance of the external ear canal wall and that of the middle ear, respectively. This result suggests that the dynamic characteristics of the middle ear in neonates are different from those in adults.

Feasibility and effectiveness of a population-based newborn hearing screening in an economically deprived region of Italy

AIM

To describe the effectiveness of a population-based newborn hearing screening program in an economically deprived region of southern Italy.

METHODS

A screening protocol was proposed for all newborns of the Campania region, starting on January, 2007. For infants identified with hearing loss, information on degree and type of hearing loss and presence of risk factors was collected.

RESULTS

The infants born in the 3-year study period were 182,188. Among them, 146,026 (80%) were tested with OAE. Sensorineural hearing loss ≥40dBnHL was established for 159 infants (1.1×1000). Among the NICU and WIN infants, the rate of hearing loss was respectively 9×1000 and 0.67×1000. Follow-up information was available for 111 children (70%), as 48 (30%) got care in other regions or health facilities. Most infants were fitted hearing aids by 1 month after diagnosis and 15 children (13.5%) received a cochlear implant at a mean age of 25 months (SD 10).

CONCLUSIONS

Even in a setting of population poverty, a universal newborn screening program can deliver satisfactory outcomes. The coverage and the tracking system of the program need to be improved, as well as the cooperation between public and private health services.

Auditory screening concurrent deafness predisposing genes screening in 10,043 neonates in Gansu province, China

OBJECTIVE

The aim of our study was to evaluate the effectiveness of combining newborn hearing screening with screening for genetic mutations associated with deafness.

METHODS

Ten thousand forty-three newborn babies, born between December 2009 and April 2011 in Gansu province, China, were screened for hearing loss using the otoacoustic emissions test or automatic auditory brainstem response test and genetic mutations associated with deafness using a standard protocol.

RESULTS

In the hearing screening, the referral rate for hearing loss in the first-step screening was 14.4% (1409/9786), decreasing significantly to 3.8% (362/9506) upon retesting. After the second-step screening, a total of 537 newborns were lost to follow-up. The genetic screening found that about 2.29% (230/10,043) individuals carried one or more recessive risk alleles or the mitochondrial mutation. Among them, 18 babies had the pathogenic mitochondrial DNA mutation, 92 babies were SLC26A4 heterozygote carriers, one case with both SLC26A4 and 12S rRNA 1555A>G mutation, 117 babies were GJB2 heterozygote carriers, and two babies were GJB2 homozygote carriers. However, 83.5% (192/230) neonates passed the conventional hearing screening among these carriers.

CONCLUSIONS

It might be effective to complement the conventional hearing screening with gene screening for the purpose of early diagnosis and discovery of the late-onset hearing loss.

Newborn hearing concurrent gene screening can improve care for hearing loss: a study on 14,913 Chinese newborns

OBJECTIVE

Newborn hearing screening has been widely adopted and made an achievement to some degree. Current screening protocols rely solely on detecting existing auditory disorders at the time of screening and are unable to identify individuals susceptible to auditory disorders in later life. Even if the hearing loss newborn is referred, most cases could not be diagnosed until 6-12 months old with no etiology being elucidated. This study reports the first effort to combine traditional hearing screening with genetic screening to improve the efficacy of newborn hearing screening.

METHODS

This study was undertaken in 12 regional hospitals located in 11 provinces of China. 14,913 newborn babies received hearing concurrent genetic screening. The hearing screening was performed with OAE or AABR. Blood sample was collected with a universal newborn genetic screening card. And three common gene, mtDNA 12S rRNA, GJB2 and SLC26A4 were screened with standard protocol.

RESULTS

Among all the 14,913 newborns, 86.1% (12,837/14,913) individuals passed the first-step hearing screening, 7.8% (1168/14,913) babies passed only one side, and the other 6.1% (908/14,913) were bilaterally referred. Gene screening found 306 individuals had one or two mutant alleles, the carrier rate is 2.05% (306/14,913) among the entire newborn population. The risk for hearing loss was 100% (7/7) for those newborns carrying causative GJB2 or SLC26A4 mutations (homozygotes or compound heterozygotes), 14.4% (23/160) for GJB2 heterozygote carriers, 12.3% (15/122) for SLC26A2 heterozygous carriers, and the total prevalence of referral hearing screening was approximately 14.7% (45/306). However, 85.3% (261/306) newborns passed hearing screening among these carriers including 18 newborns with 12S rRNA mt.1555A>G pathogenic mutation, who would suffer from sudden hearing loss once applying aminoglycoside drugs.

CONCLUSION

The cohort studies provided the essential population parameters for developing effective programs for hearing care of newborns in China. Hearing concurrent gene screening in newborns may confirm the abnormal results from hearing screening tests, help to find the etiologic of the hearing loss, and better recognize infants at risk for late-onset hearing loss occurring prior to speech and language development. In conclusion, a survey on 14,913 Chinese newborns proved that concurrent genetic screening could improve newborn hearing screening for hearing defects.

Clinical practice: The approach to the deaf or hard-of-hearing paediatric patient

Approximately 1 child in 1,000 is deaf or severely hard of hearing from birth, and the prevalence rises to about 1.6 per 1,000 in adolescents. Providing medical care for this group of children poses special challenges for professionals. To allow a medical consultation to proceed successfully and to the satisfaction of the patient, it is essential that physicians are aware of the different linguistic and cultural background of these patients. Healthcare workers should be aware of the possible higher incidence of comorbidities, sexual abuse and (psycho)social problems, of the possible pitfalls in obtaining informed consent and higher frequency of medical mistakes. This review describes the communication challenges and medical, ethical and legal issues a physician can experience when faced with these patients.

Analysis of a large-scale screening of mitochondrial DNA m.1555A>G mutation in 2417 deaf-mute students in northwest of China

The ancient Silk Road (also called "Northwest Silk Road") in Northwest China, starting from Xi'an, passes through Gansu, Xinjiang, Central Asia, West Asia, and the land passage connecting the Mediterranean countries. The aim of the present study was to determine the frequency of mitochondrial DNA12SrRNA m.1555A>G mutation in a total of 2417 cases of nonsyndromic deaf-mute patients representative of the general population of Shaanxi, Gansu, Qinghai, Ningxia, and Xinjiang along the Silk Road. Enzyme digestion and direct sequencing were applied to identify sequence variations. The carrier frequency of mitochondrial DNA12S rRNA m.1555A>G mutation was estimated to be 5.21% (126/2417) in the studied population. In detail, the carrier frequency of Uighur and Hui was 1.62% (3/185) and 3.29% (10/304), respectively, compared with 6.09% (113/1856) that of Han. There was a statistically significant difference between Uighur and Han (chi-square test, chi(2) = 6.437, p = 0.011 and p < 0.05), whereas no significant difference in m.1555A>G mutation spectrum or prevalence of mitochondrial DNA12SrRNA was found between Uighur and Hui or Hui and Han. In the 126 m.1555A>G mutation carriers, 52 cases were found to have a clear history of using aminoglycoside antibiotics. Results suggested that the application of aminoglycoside antibiotics in this region is an important reason for higher incidence of m.1555A>G mutation in the deaf-mute population.

Neonatal cochlear function: measurement after exposure to acoustic noise during in utero MR imaging

PURPOSE

To establish whether fetal exposure to the operating noise of 1.5-T magnetic resonance (MR) imaging is associated with cochlear injury and subsequent hearing loss in neonates.

MATERIALS AND METHODS

The study was performed with local research ethics committee approval and written informed parental consent. Neonatal hearing test results, including otoacoustic emission (OAE) data, were sought for all neonates delivered in Sheffield who had previously undergone in utero MR imaging between August 1999 and September 2007. The prevalence of hearing impairment in these neonates was determined, with corresponding 95% confidence intervals calculated by using the binomial exact method, and mean OAE measurements were compared with anonymized local audiometric reference data by using the t test.

RESULTS

One hundred three neonates who had undergone in utero MR imaging were identified; 96 of them had completed hearing screening assessment. Thirty-four of these babies were admitted to the neonatal intensive care unit (NICU), and one of them had bilateral hearing impairment. The prevalence of hearing impairment was 1% (one of 96; 95% confidence interval: 0.03%, 5.67%), which is in accordance with the prevalence expected, given the high proportion of babies in this study who had been in the NICU (ie, NICU graduates). In addition, for the well babies, there was no significant difference in mean OAE cochlear response compared with that for a reference data set of more than 16,000 OAE results. When NICU graduates were included in the comparison, a significant difference (P = .002) was found in one of four frequency bands used to analyze the cochlear response; however, this difference was small compared with the normal variation in OAE measurements.

CONCLUSION

The findings in this study provide some evidence that exposure of the fetus to 1.5-T MR imaging during the second and third trimesters of pregnancy is not associated with an increased risk of substantial neonatal hearing impairment.

Factors influencing parental decision about genetics evaluation for their deaf or hard-of-hearing child

PURPOSE

To identify factors that are associated with why parents of deaf children who have had GJB2/GJB6 testing as part of a genetics research study do or do not take their children for genetics evaluation.

METHODS

Self-administered questionnaire was completed by parents of a deaf child participating in a GJB2/GJB6 testing study.

RESULTS

A total of 30 parents (representing 24 children) completed the questionnaire; 11 of 24 children (46%) underwent a genetics evaluation. Compared with parents who did not take their child for a genetics evaluation, those who did were more likely to (1) have supportive pediatricians, (2) feel it was important or would be helpful to their child, (3) recall the recommendation for evaluation, (4) have family members who wanted the child to have an evaluation, and (5) be Hispanic or Asian. Genetic test results, knowledge of genetics evaluation, psychosocial factors, language concerns, or structural factors were not substantively associated with attending a genetics evaluation.

CONCLUSION

Parental perceptions, family environment, and pediatricians play a role in decisions regarding genetics evaluation. Because genetic testing for deafness likely will occur outside of traditional genetics clinics and without comprehensive genetics evaluation, efforts to increase pediatricians' awareness of the usefulness of genetics evaluation may be essential to ensure appropriate care for deaf and hard-of-hearing children as recommended by the American College of Medical Genetics.

Triagem auditiva neonatal universal: índice de efetividade no reteste de neonatos de um hospital da rede pública de Campinas

OBJETIVOS: conhecer o índice de bebês avaliados na Triagem Auditiva Neonatal Universal de um hospital da rede pública de Campinas - São Paulo que concluíram o processo diagnóstico tendo falhado no teste de Emissões Otoacústicas Evocadas Transientes. MÉTODOS: a amostra é composta por 1146 protocolos de bebês avaliados no Programa de Triagem Auditiva Neonatal Universal desse hospital, no período de julho de 2007 a abril de 2008. RESULTADOS: a Triagem Auditiva Neonatal Universal mostrou efetividade de 69,4%, porém, a partir do reteste dos bebês que falharam, o índice de sucesso no seguimento cai acentuadamente. Do total da amostra, 11 bebês apresentaram suspeita de perda auditiva, dos quais quatro apresentaram alteração. CONCLUSÃO: os dados sugerem a necessidade de aperfeiçoamento do programa.

A prospective, longitudinal study of the impact of GJB2/GJB6 genetic testing on the beliefs and attitudes of parents of deaf and hard-of-hearing infants

There are limited data on the impact of incorporating genetic counseling and testing into the newborn hearing screening process. We report on results from a prospective, longitudinal study to determine the impact of genetic counseling and GJB2/GJB6 genetic testing on parental knowledge, attitudes, and beliefs about genetic testing. One hundred thirty culturally hearing parents of 93 deaf or hard-of-hearing children ages 0-3 years primarily identified through newborn hearing screening received pre- and post-test genetic counseling for GJB2 and GJB6. Parents completed questionnaires following pre-test counseling, and 1- and 6-month post-test result disclosure. Results indicate that following pre-test counseling all parents perceived benefits to genetic testing. While parents who received positive results continued to perceive benefits from testing, perceived benefit declined among parents who received inconclusive or negative results. Parents did not perceive genetic testing as harmful following pre-test counseling or receipt of test results. Parents who received positive test results performed better in understanding recurrence and causation of their child's deafness and indicated greater interest in prenatal genetic testing than those who received inconclusive or negative test results. Parents felt that pediatricians and audiologists should inform parents of genetic testing availability; however, there was no consensus on timing of this discussion. Thus culturally hearing parents do not perceive genetic testing of their deaf or hard-of-hearing infants/toddlers as harmful; they feel that primary care providers should discuss genetic testing with them; and positive genetic test results with genetic counseling give rise to better understanding and perceived benefit than negative or inconclusive results.

Neonatal hearing screening model: An Italian regional experience

OBJECTIVE

To produce a model for routine centralized hearing screening including all aspects of the screening, from diagnosis to psychological counseling and early rehabilitation.

METHODS

A prospective observational study on a geographically defined pediatric population (Liguria region, northwestern Italy) and data collection in a data bank. The model proposed was created for the audiological screening of all newborns of the Liguria region. The model includes four phases: (1) preliminary identification of contractual, administrative, legal aspects; (2) screening for identification of congenital hearing impairment; (3) therapy and rehabilitation of identified subjects and genetic analysis; (4) epidemiology, data management, and workload management. To test the feasibility of the model proposed and to establish the workload required according to the resources available in the regional health plan, we performed a pilot study on all infants born in four of the 13 regional birth centers of Liguria region from 1 April 2001 to 30 September 2001.

RESULTS

Out of the 3268 newborns enrolled during the 6-month pilot study, 3238 (99.1%) were screened with otoacoustic emissions (OAE), while screening was refused in 30 newborns (0.9%). OAE resulted in a 'pass' for 3180 newborns (98.2%) and a 'refer' in 58 (1.8%). The standard auditory brainstem response (ABR) test was performed in 156 newborns, 58 of them as a result of the 'refer' at the second OAE and 98 others at audiological risk. Results were positive or uncertain at first ABR in 45 patients. Workload was calculated on the basis of the data obtained in the pilot study to allocate financial and organizational resources.

CONCLUSIONS

The results of the pilot study allowed project planning. We think that the screening model proposed is an example of how a regional organization can deliver improved quality care through a rationalization and optimization process.

Screening to detect permanent childhood hearing impairment in neonates transferred from the newborn nursery

OBJECTIVES

The focus of this report is hearing screening of newborns transferred from the regular nursery to a specialized area. The purpose of the study undertaken was: (1) to determine whether screening coverage in this population was achieved; (2) to establish whether the linkage between neonatal screening and the diagnostic follow-up was carried out correctly; (3) to better determine the incidence of permanent childhood hearing impairment (PCHI) in this at-risk population.

METHODS

Six population centres averaging 12,000 births annually participated (Bordeaux, Lille, Paris, Marseille, Toulouse and Lyon). Automated auditory brainstem response (AABR) (Natus ALGO 3i) screening was performed in two stages: i.e. infants with initial "positive" results were screened a second time using the same technique. Of the 117,103 babies born during the study period, 4972 neonates were "transferred" and comprised the population for this report (4.2% of the total births).

RESULTS AND DISCUSSION

Screening results for 4972 "transferred" neonates were compared with those of non-transferred neonates (N=112,131). Screening coverage of eligible infants was significantly lower (75.4%) in "transferred" neonates (3750 infants screened) compared to 97.5% coverage of non-transferred neonates (109,349 infants screened). The rate of positive results after the first stage AABR was higher in the "transferred" population (11.1%) than in the non-transferred population (6.5%). Of the 415 "transferred" newborns with initial positive screens, 91.3% were rechecked as stipulated in the project protocol. The second pre-discharge AABR ascertained that in half of the cases auditory function had normalized in the day. Of the 183 "transferred" infants whose result remained suspect at the conclusion of both stages of the neonatal screen (4.9% of the tested population), only 70.5% returned to the audiology centre for diagnostic follow-up. The incidence of bilateral PCHI was markedly higher (4/1000) in "transferred" infants than in the non-transferred population (1.08/1000).

CONCLUSIONS

The difficulty of obtaining universal screening coverage in "transferred" infants was, unfortunately, verified in this prospective, multicentre study. Further, the diversity of our "transferred" population was not much greater than that revealed by careful analysis of published hearing screening studies in neonatal intensive care unit (NICU) infants. The influence of risk factors and their more or less complex combinations is apparent.

Clinical comparison of the auditory steady-state response with the click auditory brainstem response in infants

OBJECTIVES

Our goal was to determine the effectiveness of using the auditory steady state response (ASSR) as a measure of hearing thresholds in infants who are suspected of having significant hearing loss, as compared with using the click-auditory brainstem response (C-ABR).

METHODS

We retrospectively analyzed the audiologic profiles of 76 infants (46 boys and 30 girls, a total of 151 ears) who ranged in age from 1 to 12 months (average age: 5.7 months). The auditory evaluations in 76 infants who were suspected of having hearing loss were done via the C-ABR and ASSR. In addition, for reference, the mean ASSR thresholds were compared to those of 39 ears of infants and 39 ears of adults with normal hearing at 0.5, 1, 2, and 4 kHz.

RESULTS

The highest correlation between the C-ABR and ASSR thresholds was observed at an average of 2-4 kHz (r=0.94). On comparison between the hearing of infants and adults at 0.5, 1, 2, and 4 kHz, the mean ASSR threshold in infants was 12, 7, 8, and 7 dB higher, respectively, than that in adults.

CONCLUSION

ASSR testing may provide additional audiometric information for accurately predicting the hearing sensitivity, and this is essential for the management of infants with severe to profound hearing loss.

Language ability in children with permanent hearing impairment: the influence of early management and family participation

OBJECTIVE

The goal was to examine the relationships between management after confirmation, family participation, and speech and language outcomes in the same group of children with permanent childhood hearing impairment.

METHODS

Speech, oral language, and nonverbal abilities, expressed as z scores and adjusted in a regression model, and Family Participation Rating Scale scores were assessed at a mean age of 7.9 years for 120 children with bilateral permanent childhood hearing impairment from a 1992-1997 United Kingdom birth cohort. Ages at institution of management and hearing aid fitting were obtained retrospectively from case notes.

RESULTS

Compared with children managed later (> 9 months), those managed early (< or = 9 months) had higher adjusted mean z scores for both receptive and expressive language, relative to nonverbal ability, but not for speech. Compared with children aided later, a smaller group of more-impaired children aided early did not have significantly higher scores for these outcomes. Family Participation Rating Scale scores showed significant positive correlations with language and speech intelligibility scores only for those with confirmation after 9 months and were highest for those with late confirmed, severe/profound, permanent childhood hearing impairment.

CONCLUSIONS

Early management of permanent childhood hearing impairment results in improved language. Family participation is also an important factor in cases that are confirmed late, especially for children with severe or profound permanent childhood hearing impairment.

Receptive (aural) vocabulary development in children with permanent bilateral sensorineural hearing impairment

Objective:

The receptive (aural) vocabulary development of children with binaural-aided residual hearing was investigated in a prospective longitudinal analysis (repeated measures).

Patient and methods:

Thirty-three children with sensorineural hearing loss, without major co-morbidities (mean age at the first testing point, 56.2 months, standard deviation 19.0 months) were recruited from the 1994 German Goettinger Hearing Language Register. Their receptive vocabulary was measured using standardised tests (with reference to normal hearing child performance) on three separate test points (mean follow up, 18.7 months, standard deviation 5.0 months).

Results:

On average, the study group scored below the normal range at the first and second tests and made a significant improvement at the last test. The degree of hearing loss was found to be significantly correlated to vocabulary performance at all time points, with increasing correlation coefficients. At the third test, significant predictive variables for successful receptive vocabulary outcome were found to be: degree of hearing loss (t = 5.43; p < 0.0001); age at diagnosis (t = 2.29; p = 0.03); and nonverbal intelligence (t = 2.82; p = 0.009).

Conclusion:

If permanent childhood hearing impairment is mild and/or is detected early, and if the child grows up in a monolingual environment, the development of receptive vocabulary within the normal range is possible.

Universal newborn hearing screening in Mexico: results of the first 2 years

OBJECTIVE

The purpose of this study is to present the results of the first 2 years of universal newborn hearing screening and the prevalence of congenital hearing loss in Monterrey, Mexico.

MATERIALS AND METHODS

We performed a descriptive study of the first 2 years after starting of the newborn screening program in a private hospital in Mexico. The program is organized into levels. We using for initial evaluation an automated auditory brainstem response (AABR). If the test was positive, the audiologist conducted and auditory brainstem response (ABR) test and other specialized testing was performed. Babies with hearing impairment were referred for early intervention.

RESULTS

A total of 3066 newborns were screened (99.9%). The prevalence of sensorineural and bilateral hearing loss was of 0.65/1000 newborns. Seventy-three neonates (2.37%) had a risk factor for hearing impairment. A total of 0.22% (n=7) of those studied were referred for ABR testing. Of the patients referred to the audiologist, 100% were seen. The positive predictive value for sensorineural hearing loss was 71.4% (95% CI 30.2-94.8) and the false positive rate was 0.065%. Of the subjects screened, 100% were diagnosed before the age of 3 months, but all babies began treatment after the age of 6 months. No cochlear implants were indicated.

CONCLUSION

This is the first report of a universal hearing screening program in Mexico. Even though this study had a reduced sample, the findings of hearing loss rate in this study are similar to the results found in other countries.

Maturation of auditory steady-state responses in normal babies

OBJECTIVE

To track the development of the auditory steady-state response (ASSR) through the neonatal and early infant periods in a group of normal-hearing babies.

DESIGN

This longitudinal study involved assessment at four data collection points. ASSR thresholds to modulated 500 Hz and 4 kHz tones were established in 20 full-term subjects at 0, 2, 4, and 6 wks of age.

RESULTS

Significant developmental changes were observed for both test frequencies. Mean ASSR threshold levels decreased by approximately 10 dB between the week 0 and week 6 data collection points.

CONCLUSIONS

The results of this study indicate that ASSR threshold levels in normal-hearing neonates and young infants are different from those observed in older subjects. Clinical application of the ASSR procedure in this population will need to take into account developmental changes occurring in the first weeks of life. Furthermore, the findings indicate that ASSR thresholds in normal-hearing babies at 6 wks of age are not yet mature.

The economic costs of congenital bilateral permanent childhood hearing impairment

OBJECTIVE

The objective of this study was to estimate the economic costs of bilateral permanent childhood hearing impairment (PCHI) in the preceding year of life for children aged 7 to 9 years.

METHODS

A cost analysis was conducted by using a birth cohort of children born between 1992 and 1997 in 8 districts of Southern England, of which half had been born into populations exposed to universal newborn screening (UNS). Unit costs were applied to estimates of health, social, and broader resource use made by 120 hearing-impaired children and 63 children in a normally hearing comparison group. Associations between societal costs per child and severity of hearing impairment, language ability score, exposure to UNS, and age of confirmation were analyzed, including adjustment for potential confounders in a linear regression model.

RESULTS

The mean societal cost in the preceding year of life at 7 to 9 years of age was 14092.5 pound sterling for children with PCHI, compared with 4206.8 pound sterling for the normally hearing children, a cost difference of 9885.7 pound sterling. After adjusting for severity and other potential confounders in a linear regression model, mean societal costs among children with PCHI were reduced by 2553 pound sterling for each unit increase in the z score for receptive language. Using similar regression models, exposure to a program of UNS was associated with a smaller cost reduction of 2213.2 pound sterling, whereas costs were similar between children whose PCHI was confirmed at <9 or >9 months. CONCLUSIONS. The study provides rigorous evidence of the annual health, social, and broader societal cost of bilateral PCHI in the preceding year of life at 7 to 9 years of age and shows that it is related to its severity and has an inverse relationship with language abilities after adjustment for severity.

[The model project "newborn auditory screening" in the Upper Palatinate: high process and result quality of an interdisciplinary concept]

BACKGROUND

In May 2003, a newborn auditory screening program was initiated in the Upper Palatinate.

METHODS

Sequential OAE- and BERA-screening was conducted in all hospitals with obstetric facilities. The Screening Center at the Public Health Authority was responsible for the coordination of the screening process, completeness of participation, the follow-up of all subjects with a positive screening test and the quality of instrumental screening.

RESULTS

A total of 96% of 17,469 newborns were screened. The referral rate at discharge was 1.6% (0.4% for bilateral positive findings). For 97% of the positive screening results, a definite diagnosis to confirm or exclude hearing loss was achieved; for 43% only after intervention by the Screening Center. Fifteen children with profound bilateral hearing impairment were identified of whom eight were only detected by the intervention of the Screening Center.

CONCLUSION

The effective structures established in the Upper Palatinate provide a standard for the quality of neonatal auditory screening achievable in Germany.

Importance of congenital cytomegalovirus infections as a cause for pre-lingual hearing loss

BACKGROUND

No large population based studies of newborn hearing screening have reported the population frequency of more than one specific form of deafness.

OBJECTIVES

To combine available data on the overall incidence of pre-lingual deafness with estimates for specific causes to gain insight into age-related changes in the prevalence of the major causes of pre-lingual deafness.

STUDY DESIGN

The incidence of deafness in England was adjusted for the exclusion of unilateral losses to obtain an overall estimate of 1.86 per 1000 births in the United States. Longitudinal data were used to estimate that the prevalence rises to 2.70 per 1000 at age 4. The genetic component was estimated sentinel phenotype analysis, and studies of single entities were integrated to estimate the prevalence of specific causes.

RESULTS AND CONCLUSIONS

Congenital CMV infections and connexin mutations are the two major causes of deafness at birth, while causes for enlarged vestibular aqueduct along with congenital CMV infection are the major causes of pre-lingual hearing loss that is not expressed at birth. By molecular screening tests on newborn blood spots for four known causes, 60% of the infants who develop late onset pre-lingual hearing loss could be identified at birth.