Do currently recommended Bayley-III cutoffs overestimate motor impairment in infants born <27 weeks gestation?

OBJECTIVE: To determine whether a Bayley-III motor composite score of 85 may overestimate moderate-severe motor impairment by analyzing Bayley-III motor components and developing cut-point scores for each. STUDY DESIGN: Retrospective study of 1183 children born <27 weeks gestation at NICHD Neonatal Research Network centers and evaluated at 18-22 months corrected age. Gross Motor Function Classification System determined gross motor impairment. Statistical analyses included linear and logistic regression and sensitivity/specificity. RESULTS: Bayley-III motor composite scores were strong indicators of gross/fine motor impairment. A motor composite cut-point of 73 markedly improved the specificity for identifying gross and/or fine motor impairment (94% compared with a specificity of 76% for the proposed new cut-point of 85). A Fine Motor Scaled Score <3 differentiated mild from moderate-severe fine motor impairment. CONCLUSIONS: This study indicates that a Bayley-III motor composite score of 85 may overestimate impairment. Further studies are needed employing term controls and longer follow-up.

Characteristics of extremely low-birth-weight infant survivors with unimpaired outcomes at 30 months of age.

OBJECTIVE: To evaluate characteristics of unimpaired outcome in extremely low-birth-weight (ELBW) survivors. STUDY DESIGN: ELBW infants (n=714) with 30 months' assessments were analyzed. Logistic regression was used to develop a model for the binary outcome of unimpaired versus impaired outcome. RESULT: Thirty-three percent of infants had an unimpaired outcome. Seventeen percent of ELBW survivors had a Bayley II Mental Developmental Index score of ≥ 101 and 2% had a score of ≥ 116. Female gender, use of antenatal steroids (ANS), maternal education ≥ high school and the absence of major neonatal morbidities were independent predictors of unimpaired outcome. The likelihood of an unimpaired outcome in the presence of major neonatal morbidities was higher in infants exposed to ANS. CONCLUSION: The majority of unimpaired ELBW survivors had cognitive scores shifted toward the lower end of the normal distribution. Exposure to ANS was associated with higher likelihood of an unimpaired outcome in infants with major neonatal morbidities.

Blood stream infection is associated with altered heptavalent pneumococcal conjugate vaccine immune responses in very low birth weight infants.

OBJECTIVE: Sepsis in older children and adults modifies immune system function. We compared serotype-specific antibody responses to heptavalent pneumococcal conjugate vaccine (PCV7) in very low birth weight infants (<1500 g,VLBWs) with and without blood stream infection (BSI) during their birth hospitalization. STUDY DESIGN: Retrospective analysis of prospectively collected data for the Neonatal Research Network study of PCV7 responses among VLBWs. Infants received PCV7 at 2, 4 and 6 months after birth with blood drawn 4 to 6 weeks after third dose. Serotype antibodies were compared between infants with or without a history of BSI. Regression models were constructed with BW groups and other confounding factors identified in the primary study. RESULT: In all, 244 infants completed the vaccine series and had serum antibody available; 82 had BSI. After adjustment, BSI was not associated with reduced odds of serum antibody 0.35 µg ml(-1). CONCLUSION: BSI was not associated with reduced odds of World Health Organization-defined protective PCV7 responses in VLBWs.

Efficacy of phototherapy devices and outcomes among extremely low birth weight infants: multi-center observational study.

OBJECTIVE: Evaluate the efficacy of phototherapy (PT) devices and the outcomes of extremely premature infants treated with those devices. STUDY DESIGN: This substudy of the National Institute of Child Health and Human Development Neonatal Research Network PT trial included 1404 infants treated with a single type of PT device during the first 24±12 h of treatment. The absolute (primary outcome) and relative decrease in total serum bilirubin (TSB) and other measures were evaluated. For infants treated with one PT type during the 2-week intervention period (n=1223), adjusted outcomes at discharge and 18 to 22 months corrected age were determined. RESULT: In the first 24 h, the adjusted absolute (mean (±s.d.)) and relative (%) decrease in TSB (mg dl(-1)) were: light-emitting diodes (LEDs) -2.2 (±3), -22%; Spotlights -1.7 (±2), -19%; Banks -1.3 (±3), -8%; Blankets -0.8 (±3), -1%; (P<0.0002). Some findings at 18 to 22 months differed between groups. CONCLUSION: LEDs achieved the greatest initial absolute reduction in TSB but were similar to Spots in the other performance measures. Long-term effects of PT devices in extremely premature infants deserve rigorous evaluation.

Influence of clinical status on the association between plasma total and unbound bilirubin and death or adverse neurodevelopmental outcomes in extremely low birth weight infants.

OBJECTIVES: To assess the influence of clinical status on the association between total plasma bilirubin and unbound bilirubin on death or adverse neurodevelopmental outcomes at 18-22 months corrected age in extremely low birth weight infants. METHOD: Total plasma bilirubin and unbound bilirubin were measured in 1101 extremely low birth weight infants at 5 +/- 1 days of age. Clinical criteria were used to classify infants as clinically stable or unstable. Survivors were examined at 18-22 months corrected age by certified examiners. Outcome variables were death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death prior to follow-up. For all outcomes, the interaction between bilirubin variables and clinical status was assessed in logistic regression analyses adjusted for multiple risk factors. RESULTS: Regardless of clinical status, an increasing level of unbound bilirubin was associated with higher rates of death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss and death before follow-up. Total plasma bilirubin values were directly associated with death or neurodevelopmental impairment, death or cerebral palsy, death or hearing loss, and death before follow-up in unstable infants, but not in stable infants. An inverse association between total plasma bilirubin and death or cerebral palsy was found in stable infants. CONCLUSIONS: In extremely low birth weight infants, clinical status at 5 days of age affects the association between total plasma bilirubin and death or adverse neurodevelopmental outcomes at 18-22 months of corrected age. An increasing level of UB is associated a higher risk of death or adverse neurodevelopmental outcomes regardless of clinical status. Increasing levels of total plasma bilirubin are directly associated with increasing risk of death or adverse neurodevelopmental outcomes in unstable, but not in stable infants.

Seven-month developmental outcomes of very low birth weight infants enrolled in a randomized controlled trial of delayed versus immediate cord clamping.

OBJECTIVE: The results from our previous trial revealed that infants with delayed cord clamping (DCC) had significantly lesser intraventricular hemorrhage (IVH) and late-onset sepsis (LOS) than infants with immediate cord clamping (ICC). A priori, we hypothesized that infants with DCC would have better motor function by 7 months corrected age. STUDY DESIGN: Infants between 24 and 31 weeks were randomized to ICC or DCC and follow-up evaluation was completed at 7 months corrected age. RESULT: We found no differences in the Bayley Scales of Infant Development (BSID) scores between the DCC and ICC groups. However, a regression model of effects of DCC on motor scores controlling for gestational age, IVH, bronchopulmonary dysplasia, sepsis and male gender suggested higher motor scores of male infants with DCC. CONCLUSION: DCC at birth seems to be protective of very low birth weight male infants against motor disability at 7 months corrected age.

Fluid regimens in the first week of life may increase risk of patent ductus arteriosus in extremely low birth weight infants.

BACKGROUND: High fluid volumes may increase neonatal morbidity. However, evidence supporting fluid restriction is inconclusive and restricting fluids may restrict caloric intake. OBJECTIVE: To determine if higher fluid intake was associated with increased risk of patent ductus arteriosus (PDA) or bronchopulmonary dysplasia (BPD) in extremely low birth weight (ELBW) infants. STUDY DESIGN: A total of 204 ELBW (170 ml kg(-1) day(-1)) in the first days of life is associated with increased risk of PDA.

Association between maternal and child leptin levels 9 years after pregnancy complicated by gestational diabetes.

Obesity is a state of relative leptin resistance, and obesity in childhood is associated with an increased incidence of type 2 diabetes in later life. Offspring of mothers with gestational diabetes mellitus (GDM) are at increased risk of obesity. A cohort consisting of 64 mothers, 33 GDM and 31 controls screened for diabetes during the index pregnancy together with their 9-year-old offspring were studied. Our hypotheses were: 1) an elevated child leptin is associated with elevated maternal leptin in GDM mothers 9 years post delivery; and 2) child leptin at 9 years serves as a marker for incipient insulin resistance. By univariate analyses, child leptins were only significantly correlated with maternal leptins among the offspring of GDMs (OGDM) (r = 0.59; p = 0.001). By multivariate analyses, child leptin for the total study group was significantly associated with child body mass index (BMI) (R(2) = 0.65; p < 0.0001), child fasting insulin (R(2) = 0.08; p = 0.03), and female gender (R(2) = 0.28; p = 0.001). In addition, among OGDM child leptin was associated with maternal leptin (R(2) = 0.14; p = 0.005). Our results suggest that there is an association between maternal and child leptin levels 9 years after a pregnancy complicated by gestational diabetes.

Comparison of costs and referral rates of 3 universal newborn hearing screening protocols.

OBJECTIVE: To investigate the costs and referral rates of 3 universal newborn hearing screening programs: transient evoked otoacoustic emissions (TEOAE), automated auditory brainstem response (AABR), and a combination, two-step protocol in which TEOAE and AABR are used. STUDY DESIGN: Clinical outcomes (referral rates) from 12,081 newborns at 5 sites were obtained by retrospective analysis. Prospective activity-based costing techniques (n = 1056) in conjunction with cost assumptions were used to analyze the costs based on an assumed annual birth rate of 1500 births. RESULTS: Referral rates differed significantly among the 3 screening protocols (AABR, 3.21%; two-step, 4.67%; TEOAE, 6.49%; P <.01), with AABR achieving the best referral rate at discharge. Although AABR had the lowest referral rate at discharge and the highest pre-discharge costs, the total pre- and post-discharge costs per infant screened (AABR, $32.81; two-step, $33.05; TEOAE, $28.69) and costs per identified child (AABR, $16,405; two-step, $16,527; TEOAE, $14,347) were similar among programs. CONCLUSION: Although AABR incurs higher costs during pre-discharge screening, it has lower referral rates than either the TEOAE or two-step program. As a result, the total costs of newborn hearing screening and diagnosis are similar among the 3 methods studied.

Maternal worry about neonatal hearing screening.

OBJECTIVE: To identify and compare the prevalence and degree of maternal worry about neonatal hearing screening at the time of an initial neonatal hearing screen and rescreen in 1997 and 1999. STUDY DESIGN: We report on a prospective cross-sectional investigation of maternal worry about newborn hearing screening. Demographic data, maternal knowledge of hearing screening, and degree of maternal worry were collected on 307 mothers at the time of the neonatal screen and 40 mothers at the time of the rescreen. RESULTS: Degree of maternal worry was significantly greater at the rescreen compared to the screen. Mothers who reported greater worry at the time of the screen were more likely to be socioeconomically disadvantaged. Although maternal knowledge about hearing screening increased between the two time periods, degree of worry remained unchanged. CONCLUSION: Efforts to minimize the neonatal false-positive hearing screen rates and to educate mothers about hearing screening are indicated to minimize unnecessary worry.

Identification of neonatal hearing impairment: a multicenter investigation.

OBJECTIVES: This article describes the design of a multicenter study sponsored by the National Institutes of Health. The purpose of this study was to determine the accuracy of three measures of peripheral auditory system status (transient evoked otoacoustic emissions, distortion product otoacoustic emissions, and auditory brain stem responses) applied in the perinatal period for predicting behavioral hearing status at 8 to 12 mo corrected age. The influences of the infant's medical status, the test environment, and test and response parameters on test performance were examined. DESIGN: Seven institutions participated in this study. There were 7179 infants evaluated in the perinatal period. All graduates of the neonatal intensive care unit (4478) and well babies with one or more risk factor for hearing loss (353) were targeted for follow-up testing using visual reinforcement audiometry (VRA) at 8 to 12 mo corrected age. Well babies without any risk indicators (N = 2348) were not targeted for follow-up VRA testing. However, 80 of these well babies did not pass the screening protocol and thus were targeted for follow-up VRA testing as well. Perinatal test performance was evaluated using the VRA data as the "gold standard." RESULTS: The results of this study are described in a series of 11 articles following this introductory article. CONCLUSIONS: The evaluation of newborn hearing tests required a longitudinal study in which newborn test results were compared with a gold standard based on behavioral audiometric assessment. Such an evaluation was possible because all newborns, passes as well as refers, were followed up long enough to permit reliable behavioral measurements. In addition, prenatal, perinatal, and maternal history information, test environment, and test parameter information were collected to provide data that led to a complete description of factors affecting test outcomes. All of these data were obtained in a sample of sufficient ethnic, medical, and geographic diversity in efforts to increase the generalizability of the results. Finally, the data were combined in a relational data base to examine the factors that influence test performance. Specific information related to these issues is presented in the articles that follow.

Identification of neonatal hearing impairment: experimental protocol and database management.

OBJECTIVE: The purposes of this article are to describe the overall protocol for the Identification of Neonatal Hearing Impairment (INHI) project and to describe the management of the data collected as part of this project. A well-defined protocol and database management techniques were needed to ensure that data were 1) collected accurately and in the same way across sites; 2) maintained in a database that could be used to provide feedback to individual sites regarding enrollment and the extent to which the protocol was complete on individual subjects; and 3) available to answer project questions. This article describes techniques that were used to meet these needs. DESIGN: This study was a prospective, randomized study that was designed to evaluate auditory brain stem responses, transient evoked otoacoustic emissions, and distortion product otoacoustic emissions as hearing-screening tools, and to relate neonatal test findings to hearing status, defined by visual reinforcement audiometry at 8 to 12 mo of age. Measures of middle-ear function also were obtained at some sites as part of the neonatal test battery. In addition, other clinical and demographic data were gathered to determine the extent to which factors, other than auditory status, influenced test behavior. Three groups were evaluated: neonatal intensive care unit (NICU) infants (those who spent 3 or more days in a NICU), well babies with risk factors for hearing loss, and well babies without risk factors. Six centers participated in the trial. The testers for the project included audiologists, technicians, audiology graduate students, and medical research staff. The same computerized neonatal test program was applied at each center. This program generated the neonatal test database automatically. Clinical and demographic data were collected by means of concise data collection forms and were entered into a database at each site. After the neonatal test, subjects from the NICU and at-risk well babies were evaluated with visual reinforcement audiometry starting at 8 to 12 mo of age. All data were electronically transmitted to the core site where they were merged into one overall database. This database was exercised to provide feedback and to identify discrepancies throughout the course of the study. In its final form, it served as the database on which all analyses were performed. RESULTS AND CONCLUSION: The protocol was a departure from typical hearing screening procedures in terms of 1) its regimented application of three screening measures; 2) the detailed information that was obtained regarding subject clinical and demographic factors; and 3) its application of the same procedures across six centers having diverse geographic location and subject demographics. A learning curve for successfully executing the study protocols was observed. Throughout the study, monthly reports were generated to monitor subject enrollment, check for data completeness, and to perform data integrity checks. In combination with monthly data reports and checks that occurred throughout the progression of the study, miscellaneous data audits were performed to check accuracy of neonatal testing programs and to cross-check information entered in the clinical and demographic database. The data management techniques used in this project helped to ensure the quality of the data collection process and also allowed for detailed analyses once data were collected. This was particularly important because it enabled us to evaluate not only the performance of individual measures as screening tools, but also permitted an evaluation of the influence of other variables on screening test results.

Identification of neonatal hearing impairment: distortion product otoacoustic emissions during the perinatal period.

OBJECTIVES: 1) To describe distortion product otoacoustic emission (DPOAE) levels, noise levels and signal to noise ratios (SNRs) for a wide range of frequencies and two stimulus levels in neonates and infants. 2) To describe the relations between these DPOAE measurements and age, test environment, baby state, and test time. DESIGN: DPOAEs were measured in 2348 well babies without risk indicators, 353 well babies with at least one risk indicator, and 4478 graduates of neonatal intensive care units (NICUs). DPOAE and noise levels were measured at f2 frequencies of 1.0, 1.5, 2.0, 3.0, and 4.0 kHz, and for primary levels (L1/L2) of 65/50 dB SPL and 75/75 dB SPL. Measurement-based stopping rules were used such that a test did not terminate unless the response was at least 3 dB above the mean noise floor + 2 SDs (SNR) for at least four of five test frequencies. The test would terminate, however, if these criteria were not met after 360 sec. Baby state, test environment, and other test factors were captured at the time of each test. RESULTS: DPOAE levels, noise levels and SNRs were similar for well babies without risk indicators, well babies with risk indicators, and NICU graduates. There was a tendency for larger responses at f2 frequencies of 1.5 and 2.0 Hz, compared with 3.0 and 4.0 kHz; however, the noise levels systematically decreased as frequency increased, resulting in the most favorable SNRs at 3.0 and 4.0 kHz. Response levels were least and noise levels highest for an f2 frequency of 1.0 kHz. In addition, test time to achieve automatic stopping criteria was greatest for 1.0 kHz. With the exception of "active/alert" and "crying" babies, baby state had little influence on DPOAE measurements. Additionally, test environment had little impact on these measurements, at least for the environments in which babies were tested in this study. However, the lowest SNRs were observed for infants who were tested in functioning isolettes. Finally, there were some subtle age affects on DPOAE levels, with the infants born most prematurely producing the smallest responses, regardless of age at the time of test. CONCLUSIONS: DPOAE measurements in neonates and infants result in robust responses in the vast majority of ears for f2 frequencies of at least 2.0, 3.0 and 4.0 kHz. SNRs decrease as frequency decreases, making the measurements less reliable at 1.0 kHz. When considered along with test time, there may be little justification for including an f2 frequency at 1.0 kHz in newborn screening programs. It would appear that DPOAEs result in reliable measurements when tests are conducted in the environments in which babies typically are found. Finally, these data suggest that babies can be tested in those states of arousal that are most commonly encountered in the perinatal period.

Identification of neonatal hearing impairment: characteristics of infants in the neonatal intensive care unit and well-baby nursery.

OBJECTIVE: The objective of this study was to describe the demographic data, medical status, and incidence of risk factors for hearing impairment in the neonatal intensive care unit (NICU) and well-baby populations in a multicenter prospective study designed to assess neonatal hearing impairment and to evaluate factors that might affect neonatal hearing test performance. DESIGN: This was a prospective multicenter study funded by the National Institutes of Health-National Institute on Deafness and Other Communication Disorders to evaluate the effectiveness of auditory brain stem response, transient evoked otoacoustic emissions, and distortion product otoacoustic emissions for newborn hearing screening. Research staff at each site obtained informed consent and detailed demographic and medical data, including information on established risk factors for hearing loss on 4478 high-risk infants cared for in the NICU, 2348 infants from the well-baby nurseries with no risk factor, and 353 infants from the well-baby nurseries with risk factors. For follow-up purposes the sample was divided further to include a subgroup called selects. Selects were either infants from the well-baby nursery who had an established risk factor for hearing impairment (N = 353) or did not pass the neonatal hearing screen protocol (N = 80). In this study, we focus on the distribution of infants by nursery and risk factors only. Particular effort was made to enroll infants with risk factors for hearing loss in both the NICU and well-baby nurseries. Descriptive analyses are used to describe characteristics of this sample. RESULTS: All 10 of the risk factors established by the Joint Committee on Infant Hearing in 1994 were identified in the NICU population. The four most common were ototoxic medications (44.4%), very low birth weight (17.8%), assisted ventilation > 5 days (16.4%), and low Apgar scores at 1 or 5 min (13.9%). In contrast, only six risk factors were present in the well-baby nurseries: family history (6.6%), craniofacial abnormalities (3.4%), low Apgar scores (2.8%), syndromes (0.5%), ototoxic medications (0.2%), and congenital infection (0.1%). CONCLUSION: These descriptive risk factor data reflect both the newborn populations at the study sites and the bias for enrolling infants at risk for hearing loss. The high-risk NICU sample reflects the characteristics typically found in graduates of the NICU. The data summarized in this study will be used to assess the relationships between risk factor and hearing test outcome.

Identification of neonatal hearing impairment: transient evoked otoacoustic emissions during the perinatal period.

OBJECTIVES: 1) To describe transient evoked otoacoustic emission (TEOAE) levels, noise levels and signal to noise ratios (SNRs) for a range of frequency bands in three groups of neonates who were tested as a part of the Identification of Neonatal Hearing Impairment multi-center consortium project. 2) To describe the relations between these TEOAE measurements and age, test environment, baby state, and test time. DESIGN: TEOAEs were measured in 4478 graduates of neonatal intensive care units (NICUs), 353 well babies with at least one risk indicator, and 2348 well babies without risk factors. TEOAE and noise levels were measured for frequency bands centered at 1.0, 1.5, 2.0, 3.0, and 4.0 kHz for a click stimulus level of 80 dB SPL. For those ears not meeting "passing" stopping criteria at 80 dB pSPL, a level of 86 dB pSPL was included. Measurement-based stopping rules were used such that a test did not terminate unless the response revealed a criterion SNR in four out of five frequency bands or no response occurred after a preset number of averages. Baby state, test environment, and other test factors were captured at the time of test. RESULTS: TEOAE levels, noise levels and SNRs were similar for NICU graduates, well babies with risk factors and well babies without risk factors. There were no consistent differences in response quality as a function of test environment, i.e., private room, unit, open crib, nonworking isolette, or working isolette. Noise level varied little across risk group, test environment, or infant state other than crying, suggesting that the primary source of noise in TEOAE measurements is infant noise. The most significant effect on response quality was center frequency. Responses were difficult to measure in the half-octave band centered at 1.0 kHz, compared with higher frequencies. Reliable responses were measured routinely at frequencies of 1.5 kHz and higher. CONCLUSIONS: TEOAEs are easily measured in both NICU graduates and well babies with and without risk factors for hearing loss in a wide variety of test environments. Given the difficulties encountered in making reliable measurements for a frequency band centered at 1.0 kHz, its inclusion in a screening program may not be justified.

Identification of neonatal hearing impairment: auditory brain stem responses in the perinatal period.

OBJECTIVES: 1) To describe the auditory brain stem response (ABR) measurement system and optimized methods used for study of newborn hearing screening. 2) To determine how recording and infant factors related to the screening, using well-defined, specific ABR outcome measures. DESIGN: Seven thousand one hundred seventy-nine infants, 4478 from the neonatal intensive care unit (NICU) and the remaining from the well-baby nursery, were evaluated with an automated ABR protocol in each ear. Two channel recordings were obtained (vertex to mastoid or channel A and vertex to nape of neck or channel B) in response to click stimuli of 30 and 69 dB nHL in all infants as well as 50 dB nHL in infants who did not meet criteria for response at 30 dB. Criteria for response included F(SP) > or =3.1 and a tester-judgment of response. Criteria could be met in the first or repeat test with a maximum of 6144 accepted sweeps per test. RESULTS: More than 99% of infants could complete the ABR protocol. More than 90% of NICU and well-baby nursery infants "passed" given the strict criteria for response, whereas 86% of those with high risk factors met criterion for ABR response detection. The number of infants who did not meet ABR response criteria in one or both ears was systematically related to stimulus level with the largest group not meeting criteria at 30 dB followed by 50 and 69 dB nHL. Meeting criteria on the ABR was positively correlated with the amplitude of wave V, with low noise and low electrode impedance. Factors that predicted how many sweeps would be needed to reach criterion F(SP) included noise level of the test site, state of the baby (for example, quiet sleep versus crying), recording noise, electrode impedance and response latency. Channel A (vertex to mastoid) reached criterion more often than channel B (vertex to nape of neck) due to higher noise in channel B. Average total test time for 30 dB nHL screening in both ears was under 8 minutes. Well babies with risk factors took slightly longer to evaluate than other groups with this automated ABR procedure and have higher noise levels. CONCLUSIONS: ABR implemented with an automated detection algorithm using a 30 dB nHL click stimulus is reliable technique for rapid assessment of auditory status in newborns. Factors other than hearing loss that influenced the test result include infant state, electrode location and impedance, testing site, and infant risk status. Even so, ABRs were reliably recorded in the vast majority of babies under circumstances in which most babies are found in the perinatal period.

Identification of neonatal hearing impairment: ear-canal measurements of acoustic admittance and reflectance in neonates.

OBJECTIVES: 1) To describe broad bandwidth measurements of acoustic admittance (Y) and energy reflectance (R) in the ear canals of neonates. 2) To describe a means for evaluating when a YR response is valid. 3) To describe the relations between these YR measurements and age, gender, left/right ear, and selected risk factors. DESIGN: YR responses were obtained at four test sites in well babies without risk indicators, well babies with at least one risk indicator, and graduates of neonatal intensive care units. YR responses were measured using a chirp stimulus at moderate levels over a frequency range from 250 to 8000 Hz. The system was calibrated based on measurements in a set of cylindrical tubes. The probe assembly was inserted in the ear canal of the neonate, and customized software was used for data acquisition. RESULTS: YR responses were measured in over 4000 ears, and half of the responses were used in exploratory data analyses. The particular YR variables chosen for analysis were energy reflectance, equivalent volume and acoustic conductance. Based on the view that unduly large negative equivalent volumes at low frequencies were physically impossible, it was concluded that approximately 13% of the YR responses showed evidence of improper probe seal in the ear canal. To test how these outliers influenced the overall pattern of YR responses, analyses were conducted both on the full data set (N = 2081) and the data set excluding outliers (N = 1825). The YR responses averaged over frequency varied with conceptional age (conception to date of test), gender, left/right ear, and selected risk factors; in all cases, significant effects were observed more frequently in the data set excluding outliers. After excluding outliers and controlling for conceptional age effects, the dichotomous risk factors accounting for the greatest variance in the YR responses were, in rank order, cleft lip and palate, aminoglycoside therapy, low birth weight, history of ventilation, and low APGAR scores. In separate analyses, YR responses varied in the first few days after birth. An analysis showed that the use of a YR test criterion to assess the quality of probe seal may help control the false-positive rate in evoked otoacoustic emission testing. CONCLUSIONS: This is the first report of wideband YR responses in neonates. Data were acquired in a few seconds, but the responses are highly sensitive to whether the probe is fully sealed in the ear canal. A real-time acoustic test of probe fit is proposed to better address the probe seal problem. The YR responses provide information on middle-ear status that varies over the neonatal age range and that is sensitive to the presence or absence of risk factors, ear, and gender differences. Thus, a YR test may have potential for use in neonatal screening tests for hearing loss.

Identification of neonatal hearing impairment: recruitment and follow-up.

OBJECTIVE: The purpose of this study is to describe the recruitment and retention strategies as well as the sample demographics for families with infants completing the neonatal examination and returning for follow-up. These data are compared to those infants inactivated from the study. DESIGN: This study was a prospective, randomized clinical study. All infants who were confined to the neonatal intensive care unit (NICU) and well babies with at least one risk indicator were targeted for behavioral audiometric follow-up testing. In addition, infants without risk factors from the well-baby nursery, but who failed a newborn test, were also followed. Several variables were evaluated to determine those factors, if any, that might predict which families returned for follow-up testing. RESULTS: Recruitment was achieved as per study design with 4911 high-risk infants and 2348 well-baby nursery infants (without risk indicators for hearing) enrolled. Of the 4911 high-risk infants enrolled, 64% were successfully recruited into the follow-up portion of the study. This was less than the projected rate of 80%. Factors predicting noncompliance with the study protocol for follow-up were predominantly sociodemographic and included nonwhite race, no insurance, substance abuse, young maternal age, more than two children at home, and late onset of prenatal care. CONCLUSIONS: Factors related to low socioeconomic status and increased social risk were the strongest predictors of poor study protocol compliance. Despite retention challenges, 64% of the targeted, high-risk infants subsequently returned for the 8-to 12-mo behavioral hearing assessment protocols for validation purposes.

Identification of neonatal hearing impairment: hearing status at 8 to 12 months corrected age using a visual reinforcement audiometry protocol.

OBJECTIVES: 1) To describe the hearing status of the at-risk infants in the National Institutes of Health-Identification of Neonatal Hearing Impairment study sample at 8 to 12 mo corrected age (chronologic age adjusted for prematurity). 2) To describe the visual reinforcement audiometry (VRA) protocol that was used to obtain monaural behavioral data for the sample. DESIGN: All neonatal intensive care unit infants and well babies with risk factors (including well babies who failed neonatal tests) were targeted for follow-up behavioral evaluation once they had reached 8 mo corrected age. Three thousand one hundred and thirty-four (64.4%) of the 4868 surviving infants returned for at least one behavioral hearing evaluation, which employed a well-defined VRA protocol. VRA thresholds or minimum response levels (MRLs) were determined for speech and pure tones of 1.0, 2.0, and 4.0 kHz for each ear using insert earphones. RESULTS: More than 95% of the infants were reliably tested with the VRA protocol; 90% provided complete tests (four MRLs for both ears). Ninety-four percent of the at-risk infants were found to have normal hearing sensitivity (MRLs of 20 dB HL) at 1.0, 2.0, and 4.0 kHz in both ears. Of the infants, 2.2% had bilateral hearing impairment, and 3.4% had impairment in one ear only. More than 80% of the impaired ears had losses of mild-to-moderate degree. CONCLUSIONS: This may be the largest study to attempt to follow all at-risk infants with behavioral audiometric testing, regardless of screening outcome, in an effort to validate the results of auditory brain stem response, distortion product otoacoustic emission, and transient evoked otoacoustic emission testing in the newborn period. It is one of only a few studies to report hearing status of infants at 1 yr of age, using VRA on a clinical population. Successful testing of more than 95% of the infants who returned for the VRA follow-up documents the feasibility of obtaining monaural behavioral data in this population.

Identification of neonatal hearing impairment: infants with hearing loss.

OBJECTIVE: This article describes the audiologic findings and medical status of infants who were found to have hearing loss, detected as part of the Identification of Neonatal Hearing Impairment (INHI) project. In addition, the neonatal and maternal health variables for the group of infants who could not be tested with visual reinforcement audiometry (VRA) due to developmental and visual disability are presented. DESIGN: The overall goal of the INHI project was to evaluate the test performance of auditory brain stem response and evoked otoacoustic emission (OAE) tests given in the newborn period. These tools were evaluated on the basis of the infants' hearing when tested behaviorally with VRA at 8 to 12 mo corrected age. The neonatal test results, VRA results, medical history information and a record of intercurrent events occurring between the neonatal period and the time of VRA were collated and reviewed. The purpose of this article is to review the characteristics of those infants who were found to have hearing loss. RESULTS: Of 2995 infants who had VRA tests judged to be of good or fair reliability, 168 had a finding of hearing loss for at least one ear, an incidence of 5.6%. Sixty-six infants had bilateral losses, an incidence of 2%, and 22 infants had bilateral hearing losses in the moderate to profound range, an incidence 0.7%. The prevalence of middle ear problems was greater than 50% among these infants with hearing loss. From the larger group of 168 infants with hearing loss, a group of 56 infants (86 ears) was chosen as those with a low probability that the hearing loss was due to transient middle ear pathology and was more likely hearing loss of a permanent nature. These were the infants used for the analyses of neonatal test performance (Norton et al., 2000). In this selected group there were 30 infants with bilateral impairment of at least mild degree, which is an incidence of 1%. There were approximately equal numbers of ears in the mild, moderate, severe and profound range of hearing loss. Risk factors associated with hearing loss were reviewed for the total sample of infants tested with VRA and for those infants with hearing loss. A history of treatment with aminoglycosides was the risk factor most often reported in the entire sample; however, there was no difference in prevalence of this risk factor for the normal-hearing and hearing-impaired groups. The risk factor associated with the highest incidence of hearing loss was stigmata of syndromes associated with sensorineural hearing loss and other neurosensory disorders. Sixty-seven infants who returned for follow-up could not be tested with VRA due to severe developmental delay or visual disability. Many of these infants had medical histories indicating the sequelae of extreme prematurity and/or very low birthweight. CONCLUSIONS: Most of the hearing losses found in this study were mild and, based on clinical history and tympanometry tests, many of the mild and some of the moderate impairments may have been acquired in early infancy due to middle ear effusion. In the group of infants used for determination of neonatal test performance there were approximately equal numbers of mild, moderate, severe and profound losses. Only a small percentage of infants with a conventional risk indicator for hearing loss actually had a hearing loss, and there were a significant number of infants with hearing loss who did not have a risk indicator. These findings support the need for an early identification program based on universal neonatal hearing screening rather than by targeted testing of those with risk indicators.