Modelling the cost-effectiveness of a newborn hearing screening programme; usability and pitfalls.

OBJECTIVE: The EUSCREEN project concerns the study of European vision and hearing screening programmes. Part of the project was the development of a cost-effectiveness model to analyse such programmes. We describe the development and usability of an online tool to enable stakeholders to design, analyse or modify a newborn hearing screening (NHS) programme. DESIGN: Data from literature, from existing NHS programmes, and observations by users were used to develop and refine the tool. Required inputs include prevalence of the hearing impairment, test sequence and its timing, attendance, sensitivity, and specificity of each screening step. Outputs include the number of cases detected and the costs of screening and diagnostics. STUDY SAMPLE: Eleven NHS programmes with reliable data. RESULTS: Three analyses are presented, exploring the effect of low attendance, number of screening steps, testing in the maternity ward, or screening at a later age, on the benefits and costs of the programme. Knowledge of the epidemiology of a staged screening programme is crucial when using the tool. CONCLUSIONS: This study presents a tool intended to aid stakeholders to design a new or analyse an existing hearing screening programme in terms of benefits and costs.

Implementation of Newborn Hearing Screening in Albania.

Newborn hearing screening (NHS) was implemented in Albania in four maternity hospitals in 2018 and 2019. Implementation outcome, screening outcome, and screening quality measures were evaluated. Infants were first screened by midwives and nurses before discharge from the maternity hospital and returned for follow-up screening. Acceptability, appropriateness, feasibility, adoption, fidelity, coverage, attendance, and stepwise and final-referral rates were assessed by onsite observations, interviews, questionnaires, and a screening database. A post hoc analysis was performed to identify reasons for loss to follow up (LTFU) in a multivariate logistic regression. In total, 22,818 infants were born, of which 96.6% were screened. For the second screening step, 33.6% of infants were LTFU, 40.4% for the third, and 35.8% for diagnostic assessment. Twenty-two (0.1%) were diagnosed with hearing loss of ≥40 dB, six unilateral. NHS was appropriate and feasible: most infants are born in maternity hospitals, hence nurses and midwives could perform screening, and screening rooms and logistic support were supplied. Adoption among screeners was good. Referral rates decreased steadily, reflecting increasing skill. Occasionally, screening was repeated during a screening step, contrary to the protocol. NHS in Albania was implemented successfully, though LTFU was high. It is important to have effective data tracking and supervision throughout the screening.

Availability of data for cost-effectiveness comparison of child vision and hearing screening programmes.

OBJECTIVE: For cost-effectiveness comparison of child vision and hearing screening programmes, methods and data should be available. We assessed the current state of data collection and its availability in Europe. METHODS: The EUSCREEN Questionnaire, conducted in 2017-2018, assessed paediatric vision and hearing screening programmes in 45 countries in Europe. For the current study, its items on data collection, monitoring and evaluation, and six of eleven items essential for cost-effectiveness analysis: prevalence, sensitivity, specificity, coverage, attendance and loss to follow-up, were reappraised with an additional questionnaire. RESULTS: The practice of data collection in vision screening was reported in 36% (N = 42) of countries and in hearing screening in 81% (N = 43); collected data were published in 12% and 35%, respectively. Procedures for quality assurance in vision screening were reported in 19% and in hearing screening in 26%, research of screening effectiveness in 43% and 47%, whereas cost-effectiveness analysis was performed in 12% for both. Data on prevalence of amblyopia were reported in 40% and of hearing loss in 77%, on sensitivity of screening tests in 17% and 14%, on their specificity in 19% and 21%, on coverage of screening in 40% and 84%, on attendance in 21% and 37%, and on loss to follow-up in 12% and 40%, respectively. CONCLUSIONS: Data collection is insufficient in hearing screening and even more so in vision screening: data essential for cost-effectiveness comparison could not be reported from most countries. When collection takes place, this is mostly at a local level for quality assurance or accountability, and data are often not accessible. The resulting inability to compare cost-effectiveness among screening programmes perpetuates their diversity and inefficiency.

Protocol and programme factors associated with referral and loss to follow-up from newborn hearing screening: a systematic review.

BACKGROUND: An effective newborn hearing screening programme has low referral rate and low loss to follow-up (LTFU) rate after referral from initial screening. This systematic review identified studies evaluating the effect of protocol and programme factors on these two outcomes, including the screening method used and the infant group. METHODS: Five databases were searched (latest: April 2021). Included studies reported original data from newborn hearing screening and described the target outcomes against a protocol or programme level factor. Studies were excluded if results were only available for one risk condition, for each ear, or for < 100 infants, or if methodological bias was observed. Included studies were evaluated for quality across three domains: sample, screening and outcome, using modified criteria from the Ottawa-Newcastle and QUADAS-2 scales. Findings from the included studies were synthesised in tables, figures and text. RESULTS: Fifty-eight studies reported on referral rate, 8 on LTFU rate, and 35 on both. Only 15 studies defined LTFU. Substantial diversity in referral and LTFU rate was observed across studies. Twelve of fourteen studies that evaluated screening method showed lower referral rates with aABR compared to TEOAE for well babies (WB). Rescreening before hospital discharge and screening after 3 days of age reduced referral rates. Studies investigating LTFU reported lower rates for programmes that had audiologist involvement, did not require fees for step 2, were embedded in a larger regional or national programme, and scheduled follow-up in a location accessible to the families. In programmes with low overall LTFU, higher LTFU was observed for infants from the NICU compared to WB. CONCLUSION: Although poor reporting and exclusion of non-English articles may limit the generalisability from this review, key influential factors for referral and LTFU rates were identified. Including aABR in WB screening can effectively reduce referral rates, but it is not the only solution. The reported referral and LTFU rates vary largely across studies, implying the contribution of several parameters identified in this review and the context in which the programme is performed. Extra attention should be paid to infants with higher risk for hearing impairment to ensure their return to follow-up.

Assessment of hearing screening programmes across 47 countries or regions III: provision of childhood hearing screening after the newborn period.

OBJECTIVE: To inventory provision and features of childhood hearing screening after the newborn period (CHS), primarily in Europe. DESIGN: From each participating country or region, experts provided information through an extensive questionnaire: implementation year, age at screening, test method, pass criteria, screening location, screener profession, and quality indicators: coverage, referral, follow-up and detection rates, supplemented by literature sources. STUDY SAMPLE: Forty-two European countries or regions, plus Russia, Malawi, Rwanda, India, and China. RESULTS: CHS was performed universally with pure-tone audiometry screening (PTS) in 17 countries or regions, whereas non-universal CHS was performed in eight with PTS or whisper tests. All participating countries with universal PTS had newborn hearing screening. Coverage rate was provided from three countries, detection rate from one, and referral and follow-up rate from two. In four countries, universal PTS was performed at two ages. Earliest universal PTS was performed in a (pre)school setting by nurses (n = 9, median age: 5 years, range: 3-7), in a healthcare setting by doctors and nurses (n = 7, median age: 4.5 years, range: 4-7), or in both (n = 1). CONCLUSIONS: Within universal CHS, PTS was mostly performed at 4-6 years by nurses. Insufficient collection of data and monitoring with quality indicators impedes evaluation of screening.

Assessment of hearing screening programmes across 47 countries or regions II: coverage, referral, follow-up and detection rates from newborn hearing screening.

OBJECTIVES: To assess the performance of newborn hearing screening (NHS) programmes, through selected quality measures and their relationship to protocol design. DESIGN: NHS coverage, referral, follow-up and detection rates were aggregated. Referral rates were compared to age at screening step 1, number of steps, and test method: OAE or aABR. STUDY SAMPLE: A questionnaire on existing hearing screening was completed by experts from countries in Europe, plus Russia, Malawi, Rwanda, India and China. RESULTS: Out of 47 countries or regions, NHS coverage rates were reported from 26, referral rates from 23, follow up from 12 and detection rates from 13. Median coverage rate for step 1 was 96%. Referral rate from step 1 was 6-22% where screening may be performed <24 h from birth, 2-15% for >24 h, and 4% for >72 h. Referral rates to diagnostic assessment averaged 2.1% after one to two steps using OAE only, 1.7% after two steps including aABR, and 0.8% after three to four steps including aABR. Median detection rate for bilateral permanent hearing impairment ≥40dB was 1 per 1000 infants. CONCLUSION: Referral rates were related to age, test method and number of screening steps. Quality measures were not available for many NHS programmes.

Assessment of hearing screening programmes across 47 countries or regions I: provision of newborn hearing screening.

OBJECTIVES: Newborn hearing screening (NHS) varies regarding number and type of tests, location, age, professionals and funding. We compared the provision of existing screening programmes. DESIGN: A questionnaire containing nine domains: demography, administration, existing screening, coverage, tests, diagnosis, treatment, cost and adverse effects, was presented to hearing screening experts. Responses were verified. Clusters were identified based on number of screening steps and use of OAE or aABR, either for all infants or for well and high-risk infants (dual-protocol). STUDY SAMPLE: Fifty-two experts completed the questionnaire sufficiently: 40 European countries, Russia, Malawi, Rwanda, India and China. RESULTS: It took considerable effort to find experts for all countries with sufficient time and knowledge. Data essential for evaluation are often not collected. Infants are first screened in maternity wards in most countries. Human development index and health expenditure were high among countries with dual protocols, three screening steps, including aABR, and low among countries without NHS and countries using OAE for all infants. Nationwide implementation of NHS took 6 years, on average. CONCLUSION: The extent and complexity of NHS programmes are primarily related to health expenditure and HDI. Data collection should be improved to facilitate comparison of NHS programmes across borders.

Cost-Effectiveness of Neonatal Hearing Screening Programs: A Micro-Simulation Modeling Analysis.

OBJECTIVES: Early detection of neonatal hearing impairment moderates the negative effects on speech and language development. Universal neonatal hearing screening protocols vary in tests used, timing of testing and the number of stages of screening. This study estimated the cost-effectiveness of various protocols in the preparation of implementation of neonatal hearing screening in Albania. DESIGN: A micro-simulation model was developed using input on demography, natural history of neonatal hearing impairment, screening characteristics and treatment. Parameter values were derived from a review of the literature and expert opinion. We simulated multiple protocols using otoacoustic emissions (OAE) and automated auditory brainstem response (aABR), varying the test type, timing and number of stages. Cost-effectiveness was analyzed over a life-time horizon. RESULTS: The two best protocols for well infants were OAE followed by aABR (i.e., two-stage OAE-aABR) testing in the maternity ward and single-aABR testing. Incremental cost-effectiveness ratios were €4181 and €78,077 per quality-adjusted life-year gained, respectively. Single-aABR screening led to more cases being detected compared to a two-stage screening program. However, it also resulted in higher referral rates, which increased the total costs of diagnostics. Multi-staged screening decreased referral rates but may increase the number of missed cases due to false-negative test results and nonattendance. CONCLUSIONS: Only the 2-stage OAE-aABR (maternity ward) protocol was below the willingness-to-pay threshold of €10,413 for Albania, as suggested by the World Health Organization, and was found to be cost-effective. This study is among the few to assess neonatal hearing screening programs over a life-time horizon and the first to predict the cost-effectiveness of multiple screening scenarios.

Prevalence of permanent neonatal hearing impairment: systematic review and Bayesian meta-analysis.

Objective: To investigate the variance in reported prevalence rates of permanent neonatal hearing impairment (HI) worldwide.Design: A systematic review and meta-analysis was performed on reported prevalence rates of sensorineural and permanent conductive or mixed HI worse than 40 dB in neonates, detected as a result of a screening programme or audiometric study.Study sample: For meta-analysis, 35 articles were selected, 25 from high-income countries and 10 from middle-income countries according to the world bank classification system.Results: The prevalence rate of permanent uni- and bilateral HI worse than 40 dB in neonates varied from 1 to 6 per 1000, the overall prevalence was 2.21 per 1000 [1.71, 2.8]. In NICU populations the prevalence rate was higher with a larger fraction of bilateral cases. Although not significant, prevalence rates were slightly higher in Asia compared to Europe and the number of infants lost to follow-up appeared higher in countries with lower gross national income.Conclusion: Substantial variations exist in prevalence rates of neonatal permanent HI across countries and regions. There is a strong need for more data from low-income countries to identify demographic factors that account for this variability in reported prevalence rates. Reporting these data in a uniform way is advocated.

Maturation of bone-conduction transcranial and forehead attenuation using a measure of sound pressure in the ear canal.

OBJECTIVE: Although it is understood that bone-conduction (BC) hearing is different between infants and adults, few studies have attempted to explain why these differences exist. The main objective in this study was to better understand how properties of the developing skull contribute to the maturation of BC sensitivity through an indirect measurement of BC attenuation across the skull. DESIGN: Estimation of transcranial and forehead attenuation of pure-tone BC stimuli was conducted using sound pressure in the ear canal for a transducer placed on the skull ipsi- and contralateral to the probe ear and at the forehead. STUDY SAMPLE: Seventy-six individuals participated in the study, including 59 infants and children (1 month-7 years) and 17 adults. RESULTS: BC attenuation was greatest for young infants, and decreased throughout maturation. Attenuation from the forehead to the ipsilateral temporal bone was also greater compared to the transcranial measures for infants and children older than 10 months. CONCLUSIONS: These results provide evidence that physical maturation of the skull contributes to infant-adult differences in BC attenuation. Clinicians may consider these results, in combination with previous studies using physiological measures, when fitting infants and young children with bone-anchored hearing systems.

Maturation of Mechanical Impedance of the Skin-Covered Skull: Implications for Soft Band Bone-Anchored Hearing Systems Fitted in Infants and Young Children.

OBJECTIVES: Little is known about the maturational changes in the mechanical properties of the skull and how they might contribute to infant-adult differences in bone conduction hearing sensitivity. The objective of this study was to investigate the mechanical impedance of the skin-covered skull for different skull positions and contact forces for groups of infants, young children, and adults. These findings provide a better understanding of how changes in mechanical impedance might contribute to developmental changes in bone conduction hearing, and might provide insight into how fitting and output verification protocols for bone-anchored hearing systems (BAHS) could be adapted for infants and young children. DESIGN: Seventy-seven individuals participated in the study, including 63 infants and children (ages 1 month to 7 years) and 11 adults. Mechanical impedance magnitude for the forehead and temporal bone was collected for contact forces of 2, 4, and 5.4 N using an impedance head, a BAHS transducer, and a specially designed holding device. Mechanical impedance magnitude was determined across frequency using a stepped sine sweep from 100 to 10,000 Hz, and divided into low- and high-frequency sets for analysis. RESULTS: Mechanical impedance magnitude was lowest for the youngest infants and increased throughout maturation in the low frequencies. For high frequencies, the youngest infants had the highest impedance, but only for a temporal bone placement. Impedance increased with increasing contact force for low frequencies for each age group and for both skull positions. The effect of placement was significant for high frequencies for each contact force and for each age group, except for the youngest infants. CONCLUSIONS: Our findings show that mechanical impedance properties change systematically up to 7 years old. The significant age-related differences in mechanical impedance suggest that infant-adult differences in bone conduction thresholds may be related, at least in part, to properties of the immature skull and overlying skin and tissues. These results have important implications for fitting the soft band BAHS on infants and young children. For example, verification of output force form a BAHS on a coupler designed with adult values may not be appropriate for infants. This may also hold true for transducer calibration when assessing bone conduction hearing thresholds in infants for different skull locations. The results have two additional clinical implications for fitting soft band BAHSs. First, parents should be counseled to maintain sufficient and consistent tightness so that the output from the BAHS does not change as the child moves around during everyday activities. Second, placement of a BAHS on the forehead versus the temporal bone results in changes in mechanical impedance which may contribute to a decrease in signal level at the cochlea as it has been previously demonstrated that bone conduction thresholds are poorer at the forehead compared with a temporal placement.