The hearing-impaired infant: patterns of identification and habilitation

Lessons From an Analysis of Newborn Hearing Screening Data for Children With Cochlear Implants

OBJECTIVES

The aims of the study are to identify the limitations of the current newborn hearing screening (NHS) programs and provide recommendations for better protocols.

STUDY DESIGN

Retrospective analysis.

SETTING

Tertiary referral center.

PATIENTS

The study participants were 185 children who received cochlear implants (CIs) at ≤5 years of age.

INTERVENTIONS

Therapeutic and rehabilitative.

MAIN OUTCOME MEASURES

The results of NHS, screening tools used, age, and hearing thresholds at which hearing loss was confirmed, causes of the hearing loss, age of CI insertion, aided pure-tone audiogram findings, and language development level were analyzed.

RESULTS

NHS data was available for 109 children, and 24 patients (22.0%) had passed NHS for both ears. Hearing loss was confirmed considerably later in children who had passed NHS than in children who were referred for further evaluation (p < 0.01). The most common cause for hearing loss in the NHS-pass group was SLC26A4 mutations (41.7%). Patients in the NHS-pass group received CIs considerably later than those in the NHS-referred group (p < 0.01). Among patients with SLC26A4 mutations, the language development level was significantly lower in the NHS-pass group than in the NHS-referred group (p < 0.01).

CONCLUSIONS

Careful counseling regarding NHS results is necessary for parents to understand that the absence of hearing loss at birth does not mean that the child will not develop hearing loss later in life. Genetic testing for SLC26A4 mutations may be necessary in regions with a high incidence of these mutations, such as East Asia.

Practicality, Validity, and Cost-Efficiency of Universal Newborn Hearing Screening Using Transient Evoked Otoacoustic Emissions

Although the importance of identifying significant hearing loss at an early age has long been recognized, it is generally acknowledged that newborn hearing screening programs in the United States have not been very successful. The problem has been that available techniques were impractical, too expensive, or invalid. This article summarizes the data regarding the use of transient evoked otoacoustic emissions (TEOAE) in a universal newborn hearing screening program and describes various facets of program implementation. It is concluded that available data provide clear evidence that TEOAE can be used to significantly reduce the average age of identification for hearing loss in the U.S.

Timeliness of service delivery for children with later-identified mild-to-severe hearing loss

PURPOSE

In this study, the authors examined diagnostic and intervention services for children identified with hearing loss (HL) after the newborn period.

METHOD

The authors compared ages at service delivery and length of delays between service delivery steps for 57 later-identified children with HL and 193 children who referred for assessment from the newborn hearing screen (NHS). For only later-identified children, regression models were used to investigate relationships among predictor variables and dependent variables related to service delivery.

RESULTS

Children who referred from the NHS received follow-up services at younger ages than later-identified children. Later-identified children had significantly longer delays from HL confirmation to entry into early intervention, compared to children who referred from the NHS. For later-identified children, degree of HL predicted ages at follow-up clinical services. Children with more severe HL received services at younger ages compared to children with milder HL. Gender predicted the length of the delay from confirmation to entry into early intervention, with girls demonstrating shorter delays.

CONCLUSIONS

The current results lend support to the need for ongoing hearing monitoring programs after the neonatal period, particularly when children enter early intervention programs because of language/developmental delays.

Screening methods: current status

Two technologies are currently used to screen newborn infants for hearing, auditory brainstem response (ABR), and otoacoustic emissions (OAEs). Each technology is based on detecting the infant's physiologic response to auditory stimulation. ABR is a short-latency auditory evoked response originating from eighth nerve and brainstem auditory pathway structures and detected by scalp surface electrodes. OAEs are auditory signals generated by cochlear outer hair cells in response to acoustic stimulation and detected by a miniature microphone coupled to the infant's ear. Although each technique requires specific sound generation and response recording technologies, advances in computerized stimulus delivery and response detection algorithms allow these tests to be performed by trained technicians or volunteers under the supervision of an audiologist. Results of test performance, and the advantages and disadvantages of each technique are described.

Epidemiology of hearing impairment at three Flemish Institutes for Deaf and Speech Defective Children

A retrospective analysis of 190 records of hearing impaired children up to the age of 14, all educated at one of three Flemish Institutes for Deaf and Speech Defective Children in Belgium, was performed. Until 1999, the well-known behavioral test (Ewing test) was used in the Flemish national screening program for hearing losses. Because it presented a lot of disadvantages, it has been replaced by Automated Auditory Brainstem Responses (AABR), enabling the Flemish national neonatal screening program to commence. This study is an extension of the preliminary results of a recently performed retrospective analysis in one Flemish institute of the hearing loss of patients that were diagnosed in the pre-AABR era. The authors analyzed the following data: etiology, risk factors of congenital hearing impairment, the patient's history from the moment of the first suspicion to diagnosis and treatment. The median age of the children was 8.5 years (2-14 year). In 66.5% the parents and/or grandparents were the first to raise suspicion, this was at a median age of approximately 9 months. The diagnosis was often made late, at a median age of 15 months (0-88 months). The etiology was unknown in 32.6% of the cases. The only cast-iron certain diagnoses were pre- and perinatal infections, syndromal and genetic hearing loss, and acquired infections (meningitis and measles). No risk factors of hearing loss, as they are stated by the Joint Committee on Infant Hearing, were found in more than 50% of the cases. Audiometry was performed in all cases, often supplemented with Auditory Brainstem Responses and/or click-evoked otoacoustic emissions, while other diagnostic investigations (imaging, genetics, etc.) were only variably performed. Finally, the authors confirm the need for universal neonatal screening, which only recently started in Belgium, and suggest that a detailed protocol should be established to pursue a coherent diagnostic policy.

Parents' reactions and recommendations after diagnosis and hearing aid fitting

This study was designed to explore parent reactions to the early stages of audiologic assessment and intervention. A total of 213 parents whose children were under the age of 6 years returned a mail survey. Respondents from 45 states participated. Parents were asked to (1) report the approximate age of diagnosis and hearing aid fitting; (2) comment on reasons for any delays encountered from diagnosis to fitting; and (3) respond to questions concerning their reactions to the initial fitting of amplification. The median age of identification was earlier than some previous investigations; however, substantial delays occurred between diagnosis and hearing aid fitting. Reasons for delay included the need for further audiologic evaluation, problems obtaining return appointments, illness of the child, and difficulties obtaining adequate earmolds. Parent reactions to hearing aids, once fitted, included concerns about appearance and questions about maintenance and use, but attitudes regarding hearing aids and their perceived benefits improved over time.

Universal newborn hearing screening in an inner-city, managed care environment

OBJECTIVES/HYPOTHESIS

Universal neonatal hearing screening (UNHS) programs aim to identify and treat educationally significant hearing loss in the first months of life. Several states have mandated UNHS for all newborns. Such programs have been successful in small, homogeneous populations. As larger states attempt to implement such programs, important obstacles have arisen, particularly in sparsely populated rural environments and in the inner city, where poverty, unstable living situations, and inadequate access to health care make follow-up of infants failing initial testing difficult.

STUDY DESIGN

We performed a prospective longitudinal study examining the effects of increasingly complex and expensive interventions designed to ensure that children failing initial hearing screening returned for complete evaluation and habilitation.

METHODS

A UNHS program based on transient evoked otoacoustic emissions testing was implemented at Temple University Hospital, with 2,000 births per year. At 6 months into the program, efficacy was assessed and modifications in follow-up methodology were made in an attempt to improved rate of return of infants failing newborn screening. The effect of these interventions was reassessed 6 months later.

RESULTS

In its first 12 months, the Temple University Infant and Young Child Hearing Intervention Initiative successfully screened 95% (2,031) of all newborns using transient evoked otoacoustic emissions. Collecting a complete database profile for each newborn, establishing rapport with the family, and offering immediate follow-up appointments yielded a 61% return rate after discharge. The addition of a dedicated project secretary, free day-care for siblings, and cab vouchers for transportation and the elimination of a requirement for health maintenance organization referrals increased follow-up yield to 75%.

CONCLUSION

Given adequate resources and planning, UNHS can be successful, even in economically depressed environments.

The New York State universal newborn hearing screening demonstration project: introduction and overview

OBJECTIVE

To determine the feasibility of universal newborn hearing screening, including intervention of identified infants, in the state of New York.

DESIGN

The New York State Department of Health issued a request for proposals that invited regional perinatal centers to apply for funding to implement universal newborn hearing screening. Hospitals were free to choose their own protocols but were to use physiologically based measures to screen infants for possible hearing loss. Criteria for passing the screening measures were common across sites. Infants failing the screening were to have diagnostic testing. Identified infants were to be followed by the state's Early Intervention Program and its associated Infant-Child Health Assessment Program.

RESULTS

Seven regional perinatal centers (eight hospitals) representing the various regions of the state were funded for 3 yr to implement universal newborn hearing screening and follow-up of identified infants. Detailed data analysis was performed for inpatient, outpatient, and intervention outcome measures and for the various protocols. Most of the outcome measures were analyzed in terms of year of program operation, nursery type, and geographic region of the state.

CONCLUSIONS

Universal newborn hearing screening was feasible in regional perinatal centers across the state of New York. The average ages of identification of hearing loss, hearing aid fitting, and enrollment in early intervention were less than those reported in published studies where universal newborn hearing screening was not in place.

The role of the pediatrician in hearing loss. From detection to connection

The advocacy by pediatricians is imperative if early hearing detection and intervention (EHDI) programs are to be effective, efficient, and successful over the long term. Some pediatricians remain unfamiliar with the rationale for universal screening of all newborns prior to hospital discharge. Pediatricians' questions regarding universal screening are data- and quality-driven. Discussion of the components of the EHDI program, answers to pediatricians' most frequently asked questions, supported by data, and the quality indicators used to monitor EHDI programs in Texas are provided.

Risk factors associated with hearing loss in neonates

PURPOSE

To identify the risk factors associated with hearing loss in our neonatal patient population and compare them to the ones listed by the Joint Committee on Infant Hearing.

PATIENTS AND METHODS

The medical records of 50 consecutive infants with hearing impairment by auditory brainstem response (ABR) audiometry were reviewed retrospectively and were compared with the records of 50 randomly selected newborns that had normal hearing.

RESULTS

In our review, only five of 18 variables were found to be associated with hearing impairment. These are: hyperbilirubinemia, craniofacial anomalies (CFA), length of stay in the intensive care unit, respiratory distress syndrome, and retrolental fibroplasia. The last three variables are not listed in the high-risk register published by the Joint Committee on Infant Hearing.

CONCLUSION

The results of this study provide for additional risk factors that may be used in infant-hearing screening programs.

Risk factors for childhood sensorineural hearing loss in the Oxford region

We have used a comprehensive register of hearing-impaired children born in the former Oxford Health Region to study risk factors for sensorineural hearing loss. The occurrence of a wide variety of risk factors was documented from the case notes of 145 children; these were all the cases known at the time of the study with all degrees of hearing loss born between 1984 and 1988. Comparison with the normal Regional population showed that maternal age over 35 years and Asian ethnic origin were significant risk factors for congenital (non-acquired) hearing loss (odds ratio 1.7 and 2.5 respectively). Black/Asian children were also significantly more likely to have acquired losses. Low birthweight (below 2500 g) also gave a significantly increased risk, with an odds ratio of 4.5, rising to 9.6 for birthweight less than 1500 g. We also found that significantly more hearing-impaired cases were in lower social classes compared with the general population. A high proportion of cases (24%) had cranio-facial abnormalities (CFA), including many non-aural abnormalities and dysmorphic features, which therefore should be counted as high risk. Hearing losses acquired due to perinatal causes were almost all mild or moderate. Four factors-admission to special care baby unit for more than 72 hours, CFA, family history, and meningitis-accounted for 69% of all cases in this study. Targeted neonatal screening based on the first three factors, plus obligatory testing following meningitis, therefore, should be highly efficient at detecting deafness early.

Auditory brainstem response screening for hearing loss in high risk neonates

The present paper reports the findings of a 7 year study evaluating the use of the auditory brainstem response (ABR) as the basis of a hearing screening procedure in a group of newborns at increased risk of hearing impairment. A Special Care Baby Unit (SCBU) population of 417 infants with diverse clinical backgrounds and treatment histories was tested for hearing impairment at birth using ABR audiometry. Some 332 passed the original screen at 30 dBnHL test level in both ears. Of the failure group, 18 did not survive and 32 had some degree of hearing impairment confirmed, nine of which were sensorineural in origin. An increased incidence of persistent middle ear disease was also noted in the failure group. A detailed operational analysis demonstrates that provided appropriate pass/fail criteria are adopted, the ABR technique offers excellent sensitivity and specificity for the detection of significant hearing loss in the test population. Furthermore, the study establishes that implementation of an ABR-based screening programme could reduce the average age at detection of permanent hearing loss by 7 months. A cost assessment shows that the introduction of such a targetted screening procedure could be done at a reasonable outlay.

Age of suspicion, identification, and intervention for infants and young children with hearing loss: a national study

OBJECTIVE

This study was designed to seek a nationwide perspective on the status of identification and intervention for infants and young children with hearing loss.

DESIGN

Three hundred thirty-one parents, whose children ranged from infancy to 5 yr of age, returned a mail survey that included respondents from 35 states. Parents were asked to report the approximate age of suspicion, diagnosis, hearing aid fitting, and initiation of early intervention services. Demographic information, risk factors, if known, and reasons for delay were also investigated.

RESULTS

Results revealed substantial delays between parental suspicion, audiologic-medical diagnosis, fitting of acoustic amplification, and initiation of early intervention services; however, the pattern of delay was different for children with known risk factors than it was for those without known risk factors. The median age of identification and intervention was lower than that reported by some previous investigators, although a considerable range was reported for each category.

CONCLUSIONS

The median age of identification and intervention, although still higher than optimal, may be improving. Further research is needed to identify the many factors that continue to delay the timely management of hearing loss in young children.

Early identification of hearing loss: listen to parents

Families of 49 hearing-impaired children responded to a questionnaire requesting information about the identification of their child's hearing loss. Parents were the first to suspect the hearing loss in 48 cases but more often than not were told that the child would outgrow it or was too young to test. When professionals agreed with the parents and attended to their concerns, confirmation of the hearing loss occurred significantly more rapidly than when they disagreed with parents and ignored their concerns. A child whose hearing loss is not clearly identified and whose communication is inadequate or nonexistent, causes frustration and stress within the family and prevents the child from receiving the maximum benefit from early language input and amplification. It would benefit both the child and family if professionals would listen to parental concerns regarding their child and assist in the early identification process.

Delayed detection of congenital hearing loss in high risk infants

OBJECTIVE

To examine the methods used to investigate children at high risk of congenital hearing impairment, and to see whether the introduction of evoked response audiometry has reduced the mean age at which hearing loss is identified.

DESIGN

Clinicians who notified children to the national congenital rubella surveillance programme were asked retrospectively to complete a questionnaire examining the methods used to identify hearing impairment and the age at testing in two consecutive five year cohorts. The presence or absence of hearing loss was confirmed by obtaining the results of audiometric evaluations and, whenever possible, a recent pure tone audiogram.

SETTING

The United Kingdom.

PATIENTS

Children notified to the national congenital rubella surveillance programme and born in 1978-87 in whom IgM specific for rubella was detected shortly after birth.

MAIN OUTCOME MEASURES

The age at which hearing loss was identified and the degree of loss in decibels at 250, 500, 1000, 2000, and 4000 Hz measured by pure tone audiometry.

RESULTS

61 (52%) Of 117 children born in 1978-82 had a hearing impairment of 40 dB or greater in both ears. The mean loss was 93 dB. In the following five years 75 (47%) of 159 children had impaired hearing, their mean loss being 96 dB. The age at which the hearing loss was confirmed decreased from 11.6 to 9.8 months as a result of earlier auditory evoked response testing. Nevertheless, only eight (13%) of the children with hearing impairment born in 1978-82 and 16 (21%) of those born in 1983-7 had these tests performed in the first six months of life.

CONCLUSIONS

Unacceptable delays in identifying hearing loss occurred in this high risk group because of failure to arrange auditory evoked response testing in early infancy. Evoked response audiometry is sensitive and specific and should be undertaken within the first few months of life for all infants known to be at risk of sensorineural hearing loss.

Review of a high risk register for congenital or early-onset deafness

This paper is an attempt to assess the success of a high risk register for congenital or early onset of severe to profound hearing impairment. With some years experience, and a large number of publications, it is possible to evaluate (at least in part) the extent to which such a register actually does permit us to identify these infants. To that end, an extensive review is reported here and some recommendations are made.

Neonatal status and hearing loss in high-risk infants

Neurophysiologic and behavioral assessments of auditory function were performed on 224 very low birth weight (less than or equal to 1500 gm) infants requiring intensive care in the nursery. The subjects were studied prospectively from 36 weeks to 4 years of age, as available for follow-up. To classify them according to their neonatal status, we applied a principal components analysis to a number of variables representative of the extent of illness and of patient care in early postnatal life. The subjects were then divided into neonatal status quartiles and evaluated for hearing outcome. All those with sensorineural hearing loss fell exclusively into the lowest neonatal status quartile. Sensorineural hearing loss was statistically associated (1) with greater amounts of furosemide administration for longer durations and in combination with aminoglycoside antibiotics and (2) with more episodes of low pH, hypoxemia, or both, higher total bilirubin levels, and substantially lower neonatal status scores. Birth weight, gestational age, highest creatinine level, Apgar score, and aminoglycosides alone were not systematically related to hearing capacity. Subjects in the lowest neonatal status quartile also had a considerably higher incidence of middle ear disorders, characterized by elevated thresholds and prolonged auditory brain stem-response latencies reflective of conductive hearing loss. We conclude that protracted illness and its associated treatment, independently of specific diagnostic categories, constitute important risk factors for permanent hearing loss and for transient hearing loss in early life.