Lynn Spivak

A Multicenter Evaluation of How Many Infants With Permanent Hearing Loss Pass a Two-Stage Otoacoustic Emissions/Automated Auditory Brainstem Response Newborn Hearing Screening Protocol

Objective. Ninety percent of all newborns in the United States are now screened for hearing loss before they leave the hospital. Many hospitals use a 2-stage protocol for newborn hearing screening in which all infants are screened first with otoacoustic emissions (OAE). No additional testing is done with infants who pass the OAE, but infants who fail the OAE next are screened with automated auditory brainstem response (A-ABR). Infants who fail the A-ABR screening are referred for diagnostic testing to determine whether they have permanent hearing loss (PHL). Those who pass the A-ABR are considered at low risk for hearing loss and are not tested further. The objective of this multicenter study was to determine whether a substantial number of infants who fail the initial OAE and pass the A-ABR have PHL at ∼9 months of age. Methods. Seven birthing centers with successful newborn hearing screening programs using a 2-stage OAE/A-ABR screening protocol participated. During the study period, 86634 infants were screened for hearing loss at these sites. Of those infants who failed the OAE but passed the A-ABR in at least 1 ear, 1524 were enrolled in the study. Data about prenatal, neonatal, and socioeconomic factors, plus hearing loss risk indicators, were collected for all enrolled infants. When the infants were an average of 9.7 months of age, diagnostic audiologic evaluations were done for 64% of the enrolled infants (1432 ears from 973 infants). Results. Twenty-one infants (30 ears) who had failed the OAE but passed the A-ABR during the newborn hearing screening were identified with permanent bilateral or unilateral hearing loss. Twenty-three (77%) of the ears had mild hearing loss (average of 1 kHz, 2 kHz, and 4 kHz ≤40-decibel hearing level). Nine (43%) infants had bilateral as opposed to unilateral loss, and 18 (86%) infants had sensorineural as opposed to permanent conductive hearing loss. Conclusions. If all infants were screened for hearing loss using the 2-stage OAE/A-ABR newborn hearing screening protocol currently used in many hospitals, then ∼23% of those with PHL at ∼9 months of age would have passed the A-ABR. This happens in part because much of the A-ABR screening equipment in current use was designed to identify infants with moderate or greater hearing loss. Thus, program administrators should be certain that the screening program, equipment, and protocols are designed to identify the type of hearing loss targeted by their program. The results also show the need for continued surveillance of hearing status during childhood.

The New York State universal newborn hearing screening demonstration project: Ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention

Objective: To determine the ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention through a multi‐center, state‐wide universal newborn hearing screening project. Design: Universal newborn hearing screening was conducted at eight hospitals across New York State. All infants who did not bilaterally pass hearing screening before discharge were recalled for outpatient retesting. Inpatient screening and outpatient rescreening were done with transient evoked otoacoustic emissions and/or auditory brain stem response testing. Diagnostic testing was performed with age appropriate tests, auditory brain stem response and/or visual reinforcement audiometry. Infants diagnosed with permanent hearing loss were considered for hearing aids and early intervention. Ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention were investigated regarding nursery type, risk status, unilateral versus bilateral hearing loss, loss type, loss severity, and state regions. Results: The prevalence of infants diagnosed with permanent hearing loss was 2.0/1000 (85 of 43,311). Of the 85 infants with hearing loss, 61% were from neonatal intensive care units (NICUs) and 67% were at risk for hearing loss. Of the 36 infants fitted with hearing aids, 58% were from NICUs and 78% were at risk for hearing loss. The median age at identification and enrollment in early intervention was 3 mo. Median age at hearing aid fitting was 7.5 mo. Median ages at identification were less for infants from the well‐baby nurseries (WBNs) than for the NICU infants and for infants with severe/profound than for infants with mild/moderate hearing loss, but were similar for not‐at‐risk and at‐risk infants. Median ages at hearing aid fitting were less for well babies than for NICU infants, for not‐at‐risk infants than for at‐risk infants, and for infants with severe/profound hearing loss than for infants with mild/moderate hearing loss. However, median ages at early intervention enrollment were similar for nursery types, risk status, and severity of hearing loss. Conclusions: Early ages of hearing loss identification, hearing aid fitting, and enrollment in early intervention can be achieved for infants from NICUs and WBNs and for infants at risk and not at risk for hearing loss in a large multi‐center universal newborn hearing screening program.

The New York State universal newborn hearing screening demonstration project: outpatient outcome measures.

Objective: To investigate outpatient outcome measures of a multi‐center, state‐wide, universal newborn hearing screening project. Design: Eight hospitals participated in a 3‐yr, funded project. Each hospital designed its own protocol using common criteria for judging whether an infant passed a hearing screening. Infants were tested in the hospital, and those either failing the in‐hospital screening or who were not tested in the hospital (missed) were asked to return 4 to 6 wk after hospital discharge for outpatient rescreening. Those infants failing the outpatient rescreening were referred for diagnostic auditory brain stem response testing. Each hospital used its own audiological equipment and criteria to determine whether a particular infant had a hearing loss. All data were collected and analyzed for individual hospitals, as well as totaled across all hospitals. Data were analyzed in terms of year of program operation, nursery type, and geographic region. Results: Seventy‐two percent of infants who failed the in‐hospital screening returned for outpatient testing. The percentage of in‐hospital fails returning for retesting was significantly higher than the percentage of in‐hospital misses returning for retesting. The percentage of infants returning for retesting increased with successive years of program operation. Some differences were noted in the percentage of infants returning for retesting among hospitals and geographic regions of the state. Some differences in outpatient outcome measures also were noted between infants originally born into the neonatal intensive care unit (NICU) and the well‐baby nursery (WBN). The percentage of infants from the NICU who returned for retesting was slightly higher than that for infants from the WBN. The percentage of infants from the WBN passing the outpatient rescreening was higher than that for the NICU infants. The overall prevalence of hearing loss was 1.96/1000, with that in the NICU being 8/1000 and that in the WBN being 0.9/1000. Positive predictive value for permanent hearing loss based on inpatient screening was approximately 4% and based on outpatient rescreening was approximately 22%. Conclusions: Several outpatient outcome measures changed with successive years of program operation, suggesting that programs improve over time. Also, some outpatient outcome measures differ between NICU and WBN populations. The differences noted across regions of the state in the percentage of infants returning for outpatient retesting require further research to determine whether differences are due to demographic and/or procedural differences.

New York State universal newborn hearing screening demonstration project: effects of screening protocol on inpatient outcome measures.

Objective: To examine differences among various test protocols on the fail rate at hospital discharge for infants in the well‐baby nursery (WBN) and neonatal intensive care unit (NICU) who received hearing screening through a universal newborn hearing screening demonstration project. Design: The outcomes of several screening protocols were examined. Two technologies were used: transient evoked otoacoustic emissions (TEOAEs) alone or in combination with the auditory brain stem response (ABR). The performance of test protocols in both nurseries within eight hospitals was examined over a 2‐ to 3‐yr period. In the WBN, six hospitals used a screening protocol of TEOAE technology first followed by an ABR (automated or conventional) technology screening for newborns who referred on TEOAE screening. Two hospitals used TEOAE only in the WBN. Seven hospitals used screening protocols in the NICU that used a combination of TEOAE and ABR technologies (TEOAE technology administered first or second, before or after TEOAE, or TEOAE and ABR tests on all infants). Only one hospital used TEOAE technology exclusively for hearing screening. Results: Significant differences among screening protocols were found across hospitals in the first, second, and third years of the program. The combination of TEOAE technology and ABR technology (a two‐technology screening protocol) resulted in a significantly lower fail rate at hospital discharge than the use of a single‐technology (TEOAE). Fail rates at discharge were twice as high using the one‐technology protocol versus two‐technology protocol, even when the best outcomes from program year 3 were considered exclusively. Results of two‐technology versus one‐technology protocols were similar in the NICU. Use of a second technology for screening TEOAE fails significantly reduced every hospital that used the protocols fail rate at discharge. Conclusions: A two‐technology screening protocol resulted in significantly lower fail rates at hospital discharge in both the WBN and NICU nurseries than use of a single‐technology (TEOAE) hearing screening protocol.

The relationship between electrical acoustic reflex thresholds and behavioral comfort levels in children and adult cochlear implant patients.

The accuracy with which behavioral comfort levels could be predicted by the electrically elicited acoustic reflex threshold (EART) was examined in 35 Nucleus Cochlear Implant patients (16 adults and 19 children). EARTs were obtained by stimulating bipolar pairs of electrodes through the Nucleus Diagnostic Programming System and monitoring the change in middle ear admittance in the ear contralateral to the implanted ear. EARTs were successfully elicited in 24 patients. EARTs differed from behavioral comfort levels by a mean of 19.4 stimulus level units for adults and 9.6 stimulus level units for children. While EARTs were found to be acceptably close to behavioral comfort levels in four adults and eight children, EARTs significantly overestimated or underestimated comfort levels in the rest. The results of this study suggested that while the EART does not accurately predict comfort levels in all cases, it may provide valuable information regarding levels which should not be exceeded when programming the cochlear implant. Cautious use of information available from the EART may prove useful for programming the cochlear implant in children or adults who are unable to make reliable psychophysical judgments.

Electrical compound action potentials recorded with automated neural response telemetry: threshold changes as a function of time and electrode position.

Objective: Since the introduction of neural response telemetry (NRT) for the Nucleus 24 cochlear implant (CI24), researchers and clinicians have investigated the feasibility of using the electrically evoked compound action potential (ECAP) threshold to objectively predict psychophysical measurements that are used in the programming of the speech processor. The ability to substitute objective for behavioral measurements, particularly measurements made at the time of surgery, would greatly facilitate programming the MAP for young children and other individuals who are not able to provide reliable behavioral data required for MAP programming. There have been a number of studies that have examined characteristics of the ECAP measured at the time of surgery and postoperatively; however, all the available published data are based on the CI24. With the introduction of the Nucleus Freedom device, an automated NRT (AutoNRT) program became available, which was capable of measuring ECAP thresholds at lower levels than was previously possible with NRT software associated with the CI24 device. It was hypothesized that the enhancements to the NRT program may improve the predictability of postoperative measurements from intraoperatively recorded ECAP thresholds. The purpose of this study was to track ECAP thresholds obtained using AutoNRT as a function of time and electrode position. Design: ECAP thresholds were recorded from 71 children and adults implanted with the Nucleus Freedom device using the AutoNRT test protocol. ECAP thresholds were obtained at the time of surgery, at initial stimulation, and 3 mos poststimulation. Five electrodes located at basal, middle, and apical positions in the cochlea were tested at each time interval and thresholds were compared. Results: Significant differences were found in ECAP thresholds measured with AutoNRT as a function of both time and electrode position. Basal electrodes had higher ECAP thresholds than apical electrodes and that relationship was consistent for each time period. Thresholds for all electrodes decreased between surgery and initial stimulation and remained relatively stable at 3 mos poststimulation. ECAP thresholds were consistently lower for children compared with adults at each time point. Mid-array electrodes (11 and 16) showed the least amount of change over time. Conclusions: AutoNRT thresholds demonstrated significant change over time, limiting the ability to use intraoperatively recorded ECAP thresholds to predict postoperative measurements. In this study, electrodes 11 and 16 showed the least amount of change in ECAP threshold over time and therefore would be the best choices for estimating postoperative ECAP thresholds. Although not an ideal solution, mid-array ECAP thresholds obtained intraoperatively may prove to be helpful in creating a first MAP when no other behavioral or electrophysiological data are available.

Response asymmetry and binaural interaction in the auditory brain stem evoked response

Asymmetry in the auditory brain stem evoked response (ABR) and its effect on measurements of binaural interaction were studied. Monaural and binaural ABRs were recorded from 24 normal hearing subjects at two sensation levels: 70 and 50 dB. Monaural responses were judged to be asymmetrical when the right response minus the left response resulted in a difference trace which was significantly greater than the level of the background noise in the ABR. It was found that sensation level significantly affected the frequency of monaural response asymmetry and that the amplitude of the derived binaural interaction component (BIC) was positively correlated with the degree of asymmetry present. Offsetting the asymmetry by introducing an interaural intensity difference resulted in a significant reduction in the amplitude of the BIC. It was concluded that the BIC is affected by factors other than those which can be attributed solely to binaural interaction.

Spectral Differences in the ABRs of Old and Young Subjects

The purpose of the present study was to analyze and compare the amplitude spectra of ABRs recorded from 40 elderly and 40 young subjects in order to determine if there are any age related differences. A spectral analysis was performed on each subjects ABR. It was found that the ABRs recorded from older subjects have a significantly greater amount of low frequency spectral energy than ABRs recorded from young subjects. This difference was attributed to the greater amount of low frequency background noise found in the ABRs of older subjects. Modification of standard recording procedures should be considered when ABRs are recorded from older subjects.

Effect of stimulus parameters on auditory brainstem response spectral analysis.

A recent increase of interest in spectral analysis has been prompted by the suggestion that spectral components of the ABR may contribute to differential diagnosis. Knowledge of the effects of stimulus parameters on the spectral content of the ABR is essential. The present study examined the effect of intensity, rate, and polarity on the spectral content of ABRs of 15 normal-hearing subjects. The effects of intensity were significant at all spectral frequencies examined while the effects of rate and polarity were frequency specific. These results indicate that the effects of stimulus parameters must be considered in examining the ABR spectral analysis.

Factors Related to Not Following Up with Recommended Testing in the Diagnosis of Newborn Hearing Loss

Childrens hearing is a public health concern, and universal newborn hearing screenings are the first step in detecting and treating congenital hearing loss. Despite the high rate of participation in such programs, loss to follow-up (LTF) with additional recommended diagnosis and treatment has been a persistent problem. The current research seeks to expand the knowledge base at the point of diagnosis, where there is a large drop-off in parents following through with recommended care. This research was organized around the following question: What biopsychosocial factors are associated with LTF between screenings and diagnostic evaluations? A prospective quantitative longitudinal study tracked 203 families whose newborns were referred for additional testing at discharge from the hospital after birth. Binary logistic regression was used to determine what constellation of factors best predicted LTF. Psychosocial factors related to being lost to follow-up at diagnosis included race and ethnicity and access to health care professionals, with African American babies being most at risk for LTF; however, the impact of race and ethnicity declined when parents believed they had more health care professionals with whom to consult.