Conventional Auditory Brainstem Response Research Articles

A Robust Extraction Approach of Auditory Brainstem Response Using Adaptive Kalman Filtering Method.

The Auditory brainstem response (ABR) can provide valuable information on the function of the auditory pathway. However, the ABR signal has a very small amplitude, and it is easily submerged in different background noises with large amplitude. Conventional ABR extraction methods such as time-domain averaging (TDA) and Kalman filter (KF) were greatly affected by noise intensity, and the result relies on the empirical settings of parameters. ABR extraction method that can automatically adjust parameters to adapt different background noises was needed. An adaptive Kalman filtering (AKF) based ABR signal extraction method was proposed, in which two recursive rules were introduced to constantly update the parameters according to the real-time noise properties. It was used for ABR extraction from recordings in noises with different orders of larger magnitude. The AKF method demonstrated the best performance in obtaining reliable ABR waveform morphologies in the presence of large EMG noises compared with traditional methods of TDA or KF. It could extract satisfactory ABR signal with fewer trials of acoustic stimulus repetition, even from noise 10000 times larger than ABR signal. The AKF results also showed smaller absolute errors and higher correlation coefficients with the target ABR signal when different types (gum chewing, mouth opening and milk drinking) or levels of noises were introduced. The proposed AKF method is a great candidate to increase the robustness of current ABR measurements. It could provide reduced testing time and relaxed recording conditions for ABR and other evoked potentials extraction.

Effect of subject state on auditory brainstem response threshold using Kalman-weighted averaging

ObjectivesThis study aims to explore the impact of a subject's testing state on auditory brainstem response (ABR) thresholds using a novel ABR system (Vivosonic Integrity™), which incorporates Kalman-weighted averaging and bluetooth electrical isolation to address the limitation of conventional ABR limitation to obtain a stable result under non-sedated conditions, especially for infants and children. MethodTwenty-four adults (18–34 years old, 48 ears) with normal hearing were enrolled for ABR testing under three different states (lying quietly in the supine position or sleeping—lying; watching silent videos quietly in a seated position—sitting; and writing in a seated position—writing), which simulate the behaviors of young children most often encountered during non-sedated Kalman-weighted ABR testing in clinical practice. The click ABR (cABR) and tone-burst ABR (tbABR) thresholds (0.5, 1, 2, and 4 kHz) of each subject and the time taken to reach the monaural threshold for each kind of stimulus were recorded. Results(1) The cABR and tbABR thresholds were observed to increase in the following order: lying < sitting < writing. Significant threshold differences were found between any two states, except for between the sitting and lying states for the cABR and between sitting and writing for the 0.5 kHz tbABR. (2) The time required for cABR testing in the writing state was significantly longer than that in the lying and sitting states. The time required for 1 and 4 kHz tbABR testing in the lying state was significantly shorter than that in the sitting or writing state. For 2 KHz tbABR, only testing time under writing was significantly longer than that under lying. There were no significant differences in the time used for 0.5 kHz tbABR testing among different states. ConclusionsDifferent testing states have significant impacts on the thresholds of ABRs using Kalman-weighted averaging. A subject's state during ABR testing warrants consideration, and normal levels and correction values to estimate the hearing threshold from the ABR threshold should be determined for different testing states.

Auditory Brainstem Response Detection Using Machine Learning: A Comparison With Statistical Detection Methods.

The primary objective of this study was to train and test machine learning algorithms to be able to detect accurately whether EEG data contains an auditory brainstem response (ABR) or not and recommend suitable machine learning methods. In addition, the performance of the best machine learning algorithm was compared with that of prominent statistical detection methods. Four machine learning algorithms were trained and evaluated using nested k-fold cross-validation: a random forest, a convolutional long short-term memory network, a stacked ensemble, and a multilayer perceptron. The best method was evaluated on a separate test set and compared with conventional detection methods: Fsp, Fmp, q-sample uniform scores test, and Hotelling's T2 test. The models were trained and tested on simulated data that were generated based on recorded ABRs collected from 12 normal-hearing participants and no-stimulus EEG data from 15 participants. Simulation allowed the ground truth of the data ("response present" or "response absent") to be known. The sensitivity of the best machine learning algorithm, a stacked ensemble, was significantly greater than that of the conventional detection methods evaluated. The stacked ensemble, evaluated using a bootstrap approach, consistently achieved a high and stable level of specificity across ensemble sizes. The stacked ensemble model presented was more effective than conventional statistical ABR detection methods and the alternative machine learning approaches tested. The stacked ensemble detection method may have potential both in automated ABR screening devices as well as in evoked potential software, assisting clinicians in making decisions regarding a patient's ABR threshold. Further assessment of the model's generalizability using a large cohort of subject recorded data, including participants of different ages and hearing status, is a recommended next step.

Towards effective assessment of normal hearing function from ABR using a time-variant sweep-tone stimulus approach

Objective. The auditory brainstem response (ABR) audiometry is a means of assessing the functional status of the auditory neural pathway in the clinic. The conventional click ABR test lacks good neural synchrony and it mainly evaluates high-frequency hearing while the common tone-burst ABR test only detects hearing loss of a certain frequency at a time. Additionally, the existing chirp stimuli are designed based on average data of cochlear characteristics, ignoring individual differences amongst subjects. Approach. Therefore, this study designed a new stimulus approach based on a sweep-tone concept with a time variant and spectrum characteristics that could be customized based on an individual’s cochlear characteristics. To validate the efficiency of the proposed method, we compared its performance with the click and tone-bursts using ABR recordings from 11 normal-hearing adults. Main results. Experimental results showed that the proposed sweep-tone ABR achieved a higher amplitude compared with those elicited by the click and tone-bursts. When the stimulus level or rate was varied, the sweep-tone ABR consistently elicited a larger response than the corresponding click ABR. Moreover, the sweep-tone ABR appeared earlier than the click ABR under the same conditions. Specifically, the mean wave V peak-to-peak amplitude of the sweep-tone ABR was 1.3 times that of the click ABR at 70 dB nHL (normal hearing level) and a rate of 20 s−1, in which the former saved 40% of test time. Significance. In summary, the proposed sweep-tone approach is found to be more efficient than the traditional click and tone-burst in eliciting ABR.

Click-evoked and speech-evoked auditory brainstem responses from individuals with multiple sclerosis

PurposeTo determine whether speech-evoked auditory brainstem response (ABR) is more sensitive to the effects of multiple sclerosis (MS) than click-evoked ABR. Materials and MethodsEleven previously-confirmed MS patients (8 females, 3 males) and nine controls (7 females, 2 males), matched in age and gender, participated in a repeated-measures design. Stimuli were presented monaurally to the right ear via insert earphone. All evoked potential responses were collected by a single-channel montage where three electrodes were placed on the center of the head (Cz: non-inverting/ active), the ipsilateral earlobe (inverting/ reference) and the contralateral earlobe (ground). Rarefaction clicks of 0.1 ms duration were presented at rates of 13.30 and 91.1 clicks per second. Speech-evoked ABRs were obtained using the BioMARK software and the Bio-Logic Navigator PRO hardware. A synthesized /da/ syllable of 40-ms duration was presented via alternating polarity and at a rate of 10.9 stimuli per second. Stimuli were presented at 80 dB SPL. Speech-evoked ABR responses were obtained in quiet and in noise. ResultsConventional click ABR responses were absent more often at high presentation rates in control subjects than in MS patients. Speech-evoked ABR peak amplitudes, wave E latency and VA complex slope variables separated the MS patients from controls. Group differences were also found in speech-evoked ABR response correlations in quiet versus noise conditions. ConclusionsThe speech-evoked ABR is as or more sensitive to MS than conventional ABR measures without resort to simply noting missing peaks. Comparison of speech-evoked ABR responses in quiet and in noise highlight loss of neural synchrony in MS.

Detection of binaural interaction in free-field evoked auditory brainstem responses by time-scale representations.

The so called β-wave of the binaural interaction component (BIC) in auditory brainstem responses (ABR) has been shown to be an objective measure for binaural interaction (BI). This component is the arithmetical difference between the sum of the monaurally evoked ABRs and the binaurally evoked ABR. Unfortunately, these neural responses are known to be very fragile and as a result the calculated BIC. An additional issue is, that the findings of this measurement are predominantly needed in people with hearing loss who may use hearing devices like hearing aids (HA) or cochlear implants (CI), thus they are not able to use headphones (like in conventional ABR measurements) during the detection of possible BI. This is a crucial problem, because it is known that factors like the interaural time delay (ITD) between the receiving ears are responsible for solving tasks like sound source localization or sound source separation, but specially designed measurements to coordinate the fitting of HAs or CIs with respect to BI are still missing. In this paper, we introduce a new measurement setup that is able to detect BI depending on different ITDs in free-field evoked responses by using the more reliable instantaneous phase in the time-scale representation. With this pilot study we are able to demonstrate a decreasing BI with an increasing ITD using the wavelet phase synchronization stability analysis in ten normal hearing subjects.

Hearing Loss by Week of Gestation and Birth Weight in Very Preterm Neonates

To gain insight into health and related costs associated with very preterm births, one needs accurate information about the prevalence of the disabling conditions, including neonatal hearing loss (NHL). We assessed the prevalence of NHL by week of gestation and categories of birth weight in very preterm neonates. Results of the 2-stage Automated Auditory Brainstem Response nationwide Newborn Hearing Screening Program in Dutch Neonatal Intensive Care Units and diagnostic examinations were centrally registered between October 1998 and December 2012 and included in this study. NHL was defined as impaired when the neonate conventional Auditory Brainstem Response level exceeded 35 dB near Hearing Level at diagnostic examination. Birth weight was stratified into <750 g, 750-999 g, 1000-1249 g, 1250-1499 g, and ≥ 1500 g, and by small for gestational age (SGA; <10th percentile) vs appropriate for gestational age. Logistic regression analyses and recursive partitioning were performed. In total, 18,564 very preterm neonates were eligible. The prevalence of NHL consistently increased with decreasing week of gestation (1.2%-7.5% from 31 to 24 weeks) and decreasing birth weight (1.4%-4.8% from ≥ 1500 g to <750 g, all P < .002). Most vulnerable to NHL were girls <28 weeks, boys <30 weeks, and SGA neonates. The SGA effect started at 27 weeks. Gestational age and birth weight quantify the risk of NHL. This information can be used at the individual level for parent counseling and at the population level for medical decision making.

O-036 Hearing Loss By Week Of Gestation And Categories Of Birth Weight In Very Preterm Neonates: A Population-based Study

Background and aims Studies have shown an association between Neonatal hearing loss (NHL) and preterm birth and low birth weight, but the prevalence of NHL more specific within these categories is not known. Aim of this study is to present the risk of NHL by week of gestation and categories of birth weight in an nationwide cohort of neonates born Methods Results of the two-stage Automated Auditory Brainstem Response (AABR) Universal Newborn Hearing Screening Program in Dutch neonatal intensive care units and diagnostic examination were centrally registered between October 1998 and December 2012 and included in this study. NHL was defined as impaired when the neonates’ conventional Auditory Brainstem Response (ABR) level exceeded 35 dB in one (unilateral) or two (bilateral) ears at diagnostic examination. Birth weight was stratified into Results In total 18,564 neonates with a gestational age between 24.0 and 31.9 weeks were eligible for this study. Logistic regression analyses revealed significant associations between gestational age, birth weight and both unilateral and bilateral NHL (all p Conclusions Gestational age and birth weight are independently associated with NHL in a dose-response relationship. This information can be used to gain insight into health and related costs associated with very preterm births.

Preservation of Hearing in Vestibular Schwannoma Surgery

Introduction: Besides facial nerve function, patients claim hearing to be of great subjective importance especially in the case of “the last hearing ear.” The influence of the microsurgical technique under neurophysiological monitoring was the focus of this study. Methods: In a consecutive series of 400 patients with vestibular schwannomas, 274 presented with some residual hearing. The goal of hearing preservation was indicated depending on the patient's individual clinical signs, wishes, and needs. Also in case of only moderate hearing rest, but the last hearing ear, an attempt for preservation was undertaken. In these cases, double or triple modality monitoring of auditory brainstem responses (ABR) was performed by conventional ABR and near field techniques at the cochlea and brainstem. Results: Independent of tumor size and preoperative hearing function, overall preservation rate was 30%, but increased to 47% in case of multimodality ABR control. This provided a useful support especially in phases with increased artifacts and therefore enabled preservation also in difficult cases. Conclusion: Functional nerve preservation is an important factor in patients' subjective outcome after VS treatment. The high vulnerability of the auditory pathway and of ABR may, in part, be overcome by the multimodality monitoring control, which provides more reliable and faster feedback to the surgeon.

Protective Role of Hydrogen Sulfide against Noise-Induced Cochlear Damage: A Chronic Intracochlear Infusion Model

BackgroundA reduction in cochlear blood flow plays an essential role in noise-induced hearing loss (NIHL). The timely regulation of cochlear perfusion determines the progression and prognosis of NIHL. Hydrogen sulfide (H2S) has attracted increasing interest as a vasodilator in cardiovascular systems. This study identified the role of H2S in cochlear blood flow regulation and noise protection.Methodology/Principal FindingsThe gene and protein expression of the H2S synthetase cystathionine-γ-lyase (CSE) in the rat cochlea was examined using immunofluorescence and real-time PCR. Cochlear CSE mRNA levels varied according to the duration of noise exposure. A chronic intracochlear infusion model was built and artificial perilymph (AP), NaHS or DL-propargylglycine (PPG) were locally administered. Local sodium hydrosulfide (NaHS) significantly increased cochlear perfusion post-noise exposure. Cochlear morphological damage and hearing loss were alleviated in the NaHS group as measured by conventional auditory brainstem response (ABR), cochlear scanning electron microscope (SEM) and outer hair cell (OHC) count. The highest percentage of OHC loss occurred in the PPG group.Conclusions/SignificanceOur results suggest that H2S plays an important role in the regulation of cochlear blood flow and the protection against noise. Further studies may identify a new preventive and therapeutic perspective on NIHL and other blood supply-related inner ear diseases.

Evaluation of wavelet techniques in rapid extraction of ABR variations from underlying EEG

The aim of this study is to analyse an effective wavelet method for denoising and tracking temporal variations of the auditory brainstem response (ABR). The rapid and accurate extraction of ABRs in clinical practice has numerous benefits, including reductions in clinical test times and potential long-term patient monitoring applications. One method of achieving rapid extraction is through the application of wavelet filtering which, according to earlier research, has shown potential in denoising signals with low signal-to-noise ratios. The research documented in this paper evaluates the application of three such wavelet approaches on a common set of ABR data collected from eight participants. We introduced the use of the latency–intensity curve of ABR wave V for performance evaluation of tracking temporal variations. The application of these methods to the ABR required establishing threshold functions and time windows as an integral part of the research. Results revealed that the cyclic-shift-tree-denoising performed superior compared to other tested approaches. This required an ensemble of only 32 epochs to extract a fully featured ABR compared to the 1024 epochs with conventional ABR extraction based on linear moving time averaging.

Evaluation of an automated auditory brainstem response in a multi-stage infant hearing screening

An automated auditory brainstem response (AABR) method, the Maico MB-11 with BERAphone, has been developed for hearing screening in newborns. The aim of this study was to test the validity of this automated ABR screening method in a multistage newborn hearing screening (NHS). We applied a "five level" protocol using transient evoked otoacoustic emission (TEOAE), AABR-MB-11 with BERAphone and conventional auditory brainstem response (ABR). TEOAE, AABR, and conventional ABR testing were performed by ENT specialists experienced in neonatal screening techniques. Among the 8,671 newborns tested (males 3,889; females 4,782), only 42 newborns were lost to follow-up and the final false-positive rate was of 0.03%. Our experience highlights that for the neonatal period, conventional auditory brainstem response is the most reliable method for assessing the hearing level and minimizing the false-positive rate. Although AABR (performed by ENT specialists experienced in neonatal screening techniques) is easy to use, fast and with a good compliance, the device is unable to provide accurate and certain diagnosis on the degree of hearing loss to allow a proper treatment.

Zur Beziehung zwischen den binauralen Differenzpotentialen und dem Richtungshörvermögen

Central auditory processing disorders (CAPD) are associated with reduced discriminatory abilities of the auditory system. One of these abilities is directional hearing, which is based on the evaluation of interaural signal differences. Since these differences affect also the binaural difference potentials (BDP), these derived evoked potentials could be suitable for the objective detection of disabilities in acoustic localization. Auditory brainstem responses (ABR) evoked by monaural and binaural stimulation were recorded in 32 adult normal-hearing volunteers at stimulus levels between 10 and 80 dB nHL and the BDP were derived. Additionally, a test of directional hearing was performed and evaluated. BDP are detectable at all stimulus levels without difficulties, with acceptable examination times and with satisfactory reliability in a routine clinical environment. The electrodes can be positioned at the mastoid (A1 and A2) and vertex (Cz) as for conventional ABR recording. Normal ranges are given for latency and amplitude as well as for their lateral differences. The spectrum in directional hearing ability as covered by normal-hearing subjects is not mirrored in the parameters of their BDP. Nevertheless, it cannot be ruled out that a real impairment of directional hearing goes along with significantly altered BDP.

Reliability of hearing screening in high-risk neonates: Comparative study of otoacoustic emission, automated and conventional auditory brainstem response

Objective To compare the diagnostic reliability of automated transient evoked otoacoustic emissions (a-TEOAE), automated auditory brainstem response (a-ABR) and conventional brainstem auditory evoked potential (BAEP/ABR) for identification of hearing loss in high-risk neonates. Methods Two hundred and six neonatal intensive care unit (NICU) admitted neonates were tested pre-discharge. Follow-up included a-TEOAE in all children, repetition of a-ABR or BAEP if failed in NICU. Sensitivity and specificity were compared and correlated with auditory risk factors. Results BAEP had the highest sensitivity (100%) and specificity (90.8%), a-ABR the lowest (88.9% and 70.6%). A statistically significant difference in risk factors for temporary hearing loss was observed between normal and false positive a-TEOAE and BAEP, but not a-ABR outcome. Differences in specificity between a-ABR and a-TEOAE explain the pattern of ‘absent a-ABR/present a-TEOAE’ in 13.8% of ears. Conclusions The BAEP appears the more reliable test for hearing screening of high-risk neonates because of highest sensitivity and specificity and should be used to confirm the diagnosis of ‘auditory neuropathy’ in high-risk neonates. The reliability of a-ABR devices in critically ill neonates needs further investigation. Significance This is, to our knowledge, the first attempt to compare the diagnostic reliability of a-TEOAE, a-ABR and BAEP in high-risk neonates.

The Milan Project: A newborn hearing screening programme

Since 1997 a newborn hearing screening programme has been implemented by the U.O. Neurologia-Neurofisiopatologia and Dipartimento di Neonatologia of the Istituti Clinici di Perfezionamento ICP in Milan for both babies with no risk and those at risk of hearing impairment. This programme was named the Milan Project. The protocol for no-risk babies consisted of three stages: in the first two stages, newborns were tested with transient click-evoked otoacoustic emissions (TEOAE), in the third one with conventional auditory brainstem responses (ABR). The first TEOAE test was performed by 36 h of age, before discharge, the second one after 15-30 d in case of referral, and the third one, by ABR, for those babies who failed the second TEOAE stage. Newborns at audiological risk were submitted to conventional ABR before the third month of corrected age. Some of this latter population was also submitted to the TEOAE test. The entire tested population (no-risk babies and newborns at audiological risk) consisted of 19 777 babies: 19 290 without risk ("no risk") and 487 at risk ("at risk"). During the course of the Milan Project, hearing impairment (ABR threshold equal to or greater than 40 dB nHL) was identified in 63 newborns (19 from the no-risk and 44 from the at-risk population), with a prevalence of 0.32%. Bilateral hearing impairment (BHI) was found in 33 newborns (10 from the no-risk and 23 from the at-risk population), corresponding to 0.17%. Among infants with bilateral hearing impairment, 30.3% had no risk factors. The prevalence of hearing impairment was determined on days 15-30 after birth. The results show that the implementation of a hospital-based, universal neonatal hearing screening programme for babies with and without audiological risk is feasible and effective. The effectiveness of the programme has increased as a function of the years since its inception, with a strong decrease in the referral rate. Further improvement is obtained if the TEOAE measurements are repeated in cases of referral scoring before discharge.

Auditory steady-state response testing in children: evaluation of a new technology

The purpose of this study was to evaluate auditory steady-state responses (ASSR) for determining frequency-specific hearing impairment and to compare this technology with conventional auditory brainstem responses (ABR). Study design The study was a prospective clinical trial. Twenty-eight pediatric patients ranging in age from 7 to 61 months who were undergoing sedated ABR testing for evaluation of hearing impairment were also evaluated using ASSR. Estimated audiograms of the ASSR are compared with the ABR results. ASSR estimated audiograms with frequency-specific information were produced for all patients in whom an ABR recording was obtained. In 20 ears in which an ABR tracing was absent at the maximum level of 90 dB, 13 ears had measurable ASSR thresholds with an average threshold of 98.9 dB at 250 to 8000 Hz. ASSR showed sensitivity equal to that of ABR for individuals with hearing levels (HL) from 0 to 90 dB HL. In patients with hearing impairment greater than 90 dB normal HL (nHL), ASSR showed distinct advantage over ABR testing in that recordings were reliably produced up to 127 dB nHL.

A comparison of the three-dimensional auditory brainstem response and the conventional auditory brainstem response in children

For measurement of neural activity in the brainstem auditory pathway, the conventional two-dimensional (2D) auditory brainstem response (ABR) does not provide a true response, because the equivalent dipoles originate from the stereoregularity pathway. It is thus necessary to use three-dimensional (3D) ABR to estimate the true response of the brainstem. We recorded 3D ABR in a group of children and adults, and compared the results with those of the conventional 2D ABR. The subjects were 22 children (age range 3–10 years) and 10 adults with no neurological disorders, and three patients: a boy and a girl who had experienced sudden brainstem dysfunction, and a girl who had sudden deafness. 3D ABR was recorded for all subjects, and the results were displayed on a computer screen for off-line analysis using an original 3D ABR analysis program. Four leaf-like vector segments of 3D ABR existed during the first 8 ms after stimulation. Each vector segment corresponded to a peak of the conventional ABR, and showed the original directivity. The amplitudes of waves II and IV of the 3D ABR were significantly larger than those of the conventional ABR. 3D ABR was shown to be superior to the conventional ABR in obtaining absolute amplitude. We were able to clarify the development of brainstem function using 3D ABR. In one patient in whom only one wave was obtained, 3D ABR was able to identify the wave as wave V. These results indicate that ABR is useful both for identifying the kind of wave produced and for suggesting the wave origin.

Hearing screening.

Hearing screening.

Vestibular-Evoked Myogenic Potentials as a Test of Otolith Function

Objectives: To evaluate the use of 75 auditory clicks rather than the usual 100–256 for production of the vestibular-evoked myogenic potential (VEMP) response and to assess if the VEMP correlates with measures of cochlear function such as hearing loss (decibels on pure-tone testing) or auditory brainstem response (ABR). Subjects and Methods: Testing of the VEMP was carried out on 24 subjects: 7 normal individuals and 13 hard-of-hearing patients, 2 patients with known vestibular lesions, 1 with profound sensorineural hearing loss and 1 patient with unilateral acoustic neuroma prior to resection. The recording was performed using a conventional ABR machine. Using 75 refraction clicks as auditory stimuli, VEMP responses were measured from a surface electrode applied to the sternocleidomastoid muscle. The 75 responses were averaged. Results: A consistent unilateral biphasic response, the first negative and the second positive (nI, pII), was elicited from 39 of 40 ears (7 normal and 13 hard-of-hearing subjects with no known vestibular dysfunction). No statistical difference was found between the right and left ear responses for nI or pII wave latencies. Two patients with loss of peripheral vestibular function showed no VEMP responses on the affected side. The responses, however, were elicited bilaterally in a patient with congenital profound sensorineural hearing loss. In addition, ABR latencies did not correlate with VEMP latencies. Conclusion: Clear VEMP responses were elicited by using only 75 auditory clicks. This shortens the testing time and facilitates the procedure for the tested subject. Our data also indicate that the VEMP is generated secondary to auditory stimulation of the vestibular end organs (specifically the saccule) and does not correlate with cochlear function.

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

To evaluate the feasibility of universal newborn hearing screening by examining inpatient outcome measures from 8 hospitals located in geographically diverse areas of New York State over a 3-yr period. Funding was provided by the New York State Department of Health to implement predischarge hearing screening programs in the neonatal intensive care units (NICUs) and well-baby nurseries (WBNs) of eight hospitals. Various screening protocols including transient evoked otoacoustic emissions alone or in combination with conventional auditory brain stem response or screening auditory brain stem response were implemented by each site. Measured outcomes included rate of misses, refusals, and fails. Results were analyzed as a function of year of operation, nursery type, and geographic location. Six out of eight hospitals successfully implemented universal hearing screening during the first year, and the remaining 2 hospitals implemented programs during the second year of the project. Over a period of 3 yr, 69,761 newborns were screened at the eight hospitals representing 96.9% of all live births. The overall fail rate (4.04%) combined with the miss rate (2.61%) resulted in 6.63% of infants referred for outpatient follow-up. Mean data indicated that inpatient outcome measures improved with year of operation, with most individual hospitals also showing improvements. Both fail and miss rates were higher in the NICU than in the WBN and for hospitals located in New York City than in other regions of the state. Inpatient outcome measures of a universal newborn hearing screening project, which involved multiple centers across geographically diverse regions of New York State, were acceptable in terms of successfully screening a high percentage of live births and attaining low refer rates for outpatient screening. This study adds to the growing body of literature supporting the feasibility of screening all newborns before hospital discharge.