Auditory Brainstem Response In Infants Research Articles

Assessment of Auditory Brainstem Response in Infants Suffering from Congenital Heart Disease

Background: Congenital heart defects are the singular most common congenital anomalies and account for a significant fraction of childhood mortality and morbidity. Hearing impairment was the most frequent sensory deficit. Auditory brainstem response (ABR) was determined to assess the maturation and function of brainstem, and hence, hearing in infants. Therefore, we used ABR for hearing assessment in infants diagnosed with congenital heart disease.
 Methods: This observational cross-sectional study was carried out on 60 infants, below or above the age of 12 months, both sexes, with CHD. Infants were furtherly divided into two equal groups: Group A with a cyanotic infant, and group B with cyanotic infants. All patients were subjected to Echocardiography.
 Results: 20% of our cases to be affected with varying degrees of hearing loss. No significant difference was found between the cyanotic and a cyanotic infant. However, cyanotic infants below 12 months had higher incidence of hearing loss when compared to those above the age of 12 months; whether the cyanotic or the cyanotic peers.
 Conclusions: High prevalence of hearing loss amongst patients with CHD warrants the addition of those patients to the high-risk registry for hearing loss, in order that they may benefit from early detection and intervention, and ergo protected against the affection of hearing impairment on their neurodevelopment. Routine follow-ups for patients with cyanotic heart disease from the age of 6 months to assess the effect of chronic hypoxemia on the inner ear and monitor the rate of improvement in ABR results, as to establish an accepted rate of improvement, and an appropriate time of intervention, if needed.

The Clinical Evaluation of a Modified Fmp in Infant Auditory Brainstem Response Tests.

The performance of a modified calculation of F statistic using multiple points (Fmp) in auditory brainstem response (ABR) tests in infants was evaluated. Using UK national guidelines, the ABR threshold was established on 50 infant ears at 4 kHz and 41 infant ears at 1 kHz. A specificity-based Fmp criterion for response presence was established from the distribution of no-response values. This criterion was then applied to determine the sensitivity of Fmp in detecting responses. A 97.5% true negative rate in no-response waveforms corresponded to an Fmp of 2.2. This criterion detected 85% of 4 kHz and 68% of 1 kHz responses at 10 dB above the ABR threshold but only 51% of 4 kHz and 32% of 1 kHz responses at the ABR threshold. Fmp has reasonable clinical utility at stimulus levels above the ABR threshold but is not an adequate replacement for strictly applied conventional waveform interpretation at the ABR threshold. A proposal is offered that should improve Fmp sensitivity.

Access to Pediatric Audiological Evaluation Facilities: Urgent Needs and Why They Matter

Access to Pediatric Audiological Evaluation Facilities: Urgent Needs and Why They Matter

Effect of Maternal Age and Anaemia on Auditory Brainstem Response of Preterm Infants in a Tertiary Care Hospital of Kolkata, West Bengal: A Cross-sectional Study

Introduction: Adolescent pregnancy and maternal anaemia have a detrimental effect on infant growth and development. They are associated with greater risk of premature births and Low Birth Weight (LBW). Wave Interpeak Latencies (IPLs) of infant Auditory Brainstem Response (ABR) indicate the degree of maturation of brainstem auditory pathways among preterm infants. Previous studies indicated that preterm infants show prolonged wave Interpeak Latencies (IPLs). Whether maternal parameters like age and haemoglobin level contributes to the changes in infant ABR is debated. Aim: To study the effect of maternal age and anaemic status on Brainstem Evoked Response Audiometry (BERA) changes among preterm infants. Materials and Methods: An observational, descriptive study of cross-sectional design was undertaken in the Neurophysiology laboratory of Department of Physiology, RG Kar Medical College and Hospital, Kolkata from December 2019 to December 2022. Total of 119 mother-preterm infant dyads were included. Click BERA was performed on the babies aged between 3 months to 1 year. Absolute and IPLs of wave I,III and V were obtained. Mothers were assigned anaemic status {Haempglobin (Hb) level<9gm/dL} based on the information in their antenatal card. Student’s t test, Fisher’s exact test, one way ANOVA test were used for data analysis. A p-value less than 0.05 was considered significant. Results: Out of 76 adolescent mothers (age between 10 to <18 years), 43 (56.6%) were anaemic. Out of 43 adult mothers (with age ≥18 years), 33 (76.7%) were anaemic. Mothers were divided into four groups, namely adolescent anaemic (n=43) and adolescent non anaemic (n=33), adult anaemic (n=33) and adult non anaemic (n=10). Distribution of data with respect to education years, social class and occupation among four mothers’ group was comparable [p-value>0.05]. Preterm infants born to both anaemic adult [Hedges g=2.51] and anaemic adolescent mothers [Hedges g=1.06] showed dyssynchronous shortening of wave latencies compared to non anaemic counterparts (p-value<0.05). Magnitude of difference with respect to infant ABR for non anaemic adolescent mothers vs non anaemic adult counterparts was large [Hedge s g=1.05] with p-value<0.05. While maternal anaemia showed either shortening or prolongation of IPLs, adolescent maternal age was related with prolongation of the wave I-V. Effect size of maternal anaemia on infant ABR was more than for adolescent maternal age. Conclusion: Maternal anaemia may exaggerate abnormal maturation of the brain stem pathways in preterm infants irrespective of maternal age.

Assessment of Auditory Brainstem response in infants in relation to type of feeding

ABSTRACT Background: Breast milk is important for brain development as it contains high concentration of long chain polyunsaturated fatty acids, also it contains cholesterol, amino acids as taurine and also lactose which broken to glucose and galactose, All are important nutrients for the brain and central nervous system tissues. Auditory Brainstem Response (ABR) is considered to reflect brain function of the infant and is widely used to determine/measure the brain development / maturation of the infant. Objective: to assess auditory brainstem maturation in breast-fed and formula fed infants as part of brain maturation using ABR. Methodology: thiscase-control was study carried out upon 100 apparently healthy infants; 50 infants of them were exclusively breast-fed and 50 infants were exclusively formula-fed, all of them aged 4-6 months. Each infant was subjected to detailed history, a full physical and neurological examination together with estimation of ABR. Results: There was statistically significant prolongation of absolute latencies of wave III and wave V of ABR of right and left ear in bottle feeding infants in comparison to breast feeding infants. Also, there was statistically significant increase of mean wave interpeak latencies I-III, III-V and I-V of right and left ear in bottle feeding infants compared to breast feeding infants. Conclusion: Better brain maturation in breast-fed infants compared to formula-fed infants evidenced by ABR.

Auditory brainstem response in infants with iron deficiency anemia

BackgroundAuditory brainstem response (ABR) in infants with Iron Deficiency Anemia (IDA) helps in understanding the auditory aspects of central nervous system. ObjectivesTo analyse and compare absolute and interpeak latencies of ABR in infants with and without IDA. MethodsABR traces were obtained from 40 anemic ears and 40 non anemic ears, aged 6–24 months. ABR was recorded with 11.1/s clicks at different intensity levels. ResultsAbsolute latencies of all the peaks were prolonged in infants with IDA at 70, 50 and 30 dBnHL except for peak I. Amplitude of peaks I, III and V was not statistically different between the two groups at 70 and 50 dBnHL. Reduced peak amplitude was noted only at 30 dBnHL in infants with IDA which was statistically significant (P < 0.05). Interpeak interval showed no significant difference between anemic and non-anemic infants at 70 dBnHL. Prolonged interpeak latency of peak III-V and I-V was noted at 50 and 30dBnHL. ConclusionFunctional development of auditory system seems to be affected due to iron deficiency. IDA has a long lasting effects on central auditory system when IDA is left untreated This will in turn lead to an alteration in the neuro-functional maturation.

Prenatal organophosphate insecticide exposure and infant sensory function.

Occupational studies suggest that exposure to organophosphate insecticides (OPs) can lead to vision or hearing loss. Yet the effects of early-life exposure on visual and auditory function are unknown. Here we examined associations between prenatal OP exposure and grating visual acuity (VA) and auditory brainstem response (ABR) during infancy. 30 OPs were measured in umbilical cord blood using gas chromatography tandem mass spectrometry in a cohort of Chinese infants. Grating visual acuity (VA) (n = 179-200) and auditory brainstem response (ABR) (n = 139-183) were assessed at 6 weeks, 9 months, and 18 months. Outcomes included VA score, ABR wave V latency and central conduction time, and head circumference (HC). Associations between sensory outcomes during infancy and cord OPs were examined using linear mixed models. Prenatal chlorpyrifos exposure was associated with lower 9-month grating VA scores; scores were 0.64 (95% CI: -1.22, -0.06) points lower for exposed versus unexposed infants (p = 0.03). The OPs examined were not associated with infant ABR latencies, but chlorpyrifos and phorate were both significantly inversely associated with HC at 9 months; HCs were 0.41 (95% CI: 0.75, 0.6) cm and 0.44 (95% CI: 0.88, 0.1) cm smaller for chlorpyrifos (p = 0.02) and phorate (p = 0.04), respectively. We found deficits in grating VA and HC in 9-month-old infants with prenatal exposure to chlorpyrifos. The clinical significance of these small but statistically significant deficits is unclear. However, the disruption of visual or auditory pathway maturation in infancy could potentially negatively affect downstream cognitive development.

Auditory brainstem response in infants and children with autism spectrum disorder: A meta-analysis of wave V.

Infants with autism spectrum disorder (ASD) were recently found to have prolonged auditory brainstem response (ABR); however, at older ages, findings are contradictory. We compared ABR differences between participants with ASD and controls with respect to age using a meta‐analysis. Data sources included MEDLINE, EMBASE, Web of Science, Google Scholar, HOLLIS, and ScienceDirect from their inception to June 2016. The 25 studies that were included had a total of 1349 participants (727 participants with ASD and 622 controls) and an age range of 0–40 years. Prolongation of the absolute latency of wave V in ASD had a significant negative correlation with age (R2 = 0.23; P = 0.01). The 22 studies below age 18 years showed a significantly prolonged wave V in ASD (Standard Mean Difference = 0.6 [95% CI, 0.5–0.8]; P < 0.001). The 3 studies above 18 years of age showed a significantly shorter wave V in ASD (SMD = −0.6 [95% CI, −1.0 to −0.2]; P = 0.004). Prolonged ABR was consistent in infants and children with ASD, suggesting it can serve as an ASD biomarker at infancy. As the ABR is routinely used to screen infants for hearing impairment, the opportunity for replication studies is extensive. Autism Res 2018, 11: 355–363. © 2017 The Authors Autism Research published by International Society for Autism Research and Wiley Periodicals, Inc.Lay SummaryOur analysis of previous studies showed that infants and children with autism spectrum disorder (ASD) have a slower brain response to sound, while adults have a faster brain response to sound. This suggests that slower brain response in infants may predict ASD risk. Brain response to sound is routinely tested on newborns to screen hearing impairment, which has created large data sets to afford replication of these results.

Non-persistent Insecticide Exposure and Auditory Brainstem Response in Infants

Introduction Occupational studies suggest that exposure to insecticides may lead to hearing loss, yet effects of early-life exposure on auditory function are unknown. We examined effects of prenatal organophosphate (OP) and pyrethroid (PYR) exposure on infant auditory brainstem response (ABR). Methods 36 OP and PYR and 7 metabolites were measured in umbilical cord blood plasma from a cohort of infants in Fuyang County, China (n=234). ABR latencies for waves I, III, V were measured during unsedated sleep at 3 time points: 6wk, 9m, and18m. ABR outcomes included wave V latency, central conduction time (CCT [wave V- wave I]), and wave III-V interpeak interval (IPI [wave V-wave III]). Higher values indicate slower transmission. Composite variables were created for total OP and PYR detects. Individual insecticides were analyzed as continuous, 3-level ordinal (ND/medium/high), or dichotomous (non-detect [ND]/detect), depending on detection rates. Multivariate linear regression was used to evaluate relationships between insecticides and ABR. Results are reported as β (95%CI). Results 26 OP and PYR and 5 metabolites were detected. For OP, infants with high methamidophos (vs. ND) had longer CCT at 18m (0.11 [0.01-0.22], p=0.03) and infants with medium trichlorfon (vs. ND) had longer III-V IPI at 18m (0.06 [0.00-0.12], p=0.05). For PYR, log-3-phenoxybenzoic acid was positively associated with III-V IPI at 6wk (0.02 [0.01-0.04]), 9m (0.01 [0.00-0.03]), and 18m (0.01 [0.00-0.03]), p=0.01, 0.05, and 0.05. Infants with high cis-permethrin (vs. ND) had longer III-V IPI at 6wk (0.07 [0.01-0.14], p=0.03). Infants with medium lambda-cyhalothrin (vs. ND) had longer wave V latencies (0.08 [0.00-0.15], p=0.05), CCT (0.12 [0.02-0.22], p=0.02), and III-V IPI (0.07 [0.01-0.13], p=0.02) at 18m. Conclusions Prenatal exposure to certain OP and PYR insecticides was associated with slower auditory signal transmission in infants. Longer III-V IPI may reflect impaired auditory pathway myelination.

Transient evoked otoacoustic emissions and auditory brainstem response in infants with perinatal asphyxia

ObjectiveThe objective of this study was to verify the effects of perinatal asphyxia on different parts of the auditory system. MethodsThis was a non-concurrent cohort study conducted on a fixed population in a tertiary public hospital. Participants included 181 infants born at term who underwent the transient evoked otoacoustic emission test as a part of a neonatal hearing screening program, with a “pass” result in both ears, and by auditory brainstem response testing. The infants were divided into 3 groups: G1, 20 infants who had perinatal asphyxia; G2, 111 infants with an Apgar score lower than 4 in the first minute and/or lower than 6 in the fifth minute (called “low Apgar” at birth); and G3, 50 infants with first- and fifth-minute Apgar scores ≥7. ResultsThe signal-to-noise ratio of transient evoked otoacoustic emissions were greater in G3 compared with G1 and G2 at 4 kHz frequency for males. An increased latency of waves I and III in the auditory brainstem response of male infants in G1 was observed. ConclusionThis study demonstrated that alterations occurred in both the cochlear and the neural components in male infants who had perinatal asphyxia.

Chloral hydrate sedation for auditory brainstem response (ABR) testing in children: Safety and effectiveness

IntroductionThe auditory brainstem response (ABR) test is used to identify hearing loss and measure hearing thresholds of infants and children who cannot be tested using standard behavioral hearing testing methods. In order for the ABR to yield useful data, a child must be asleep throughout the duration of the test. In many centers, this is achieved through the use of a general anesthetic, with its inherent risks and costs. Since 2004, ABRs have been routinely conducted at BC Children's Hospital in an ambulatory care setting under oral chloral hydrate sedation, with monitoring by a specialist nurse. The aim of this retrospective study was to assess the effectiveness and safety of nurse-led sedation with chloral hydrate for ABR testing at our tertiary pediatric center. MethodsMedical and audiology records were reviewed for children aged 6 months to 17 years who underwent ABR testing from 2004 to 2012. We reviewed the dosage of drug used, condition of the child after chloral hydrate administration, adverse effects, audiological results, patients’ vital signs, and the effectiveness of the sedative in keeping the child asleep throughout the duration of the test. Frequency distributions were derived for adverse outcomes. Results725 ABR records encompassing 635 children (multiple ABR tests in some children) were reviewed. The average dose of chloral hydrate used was 52mg/kg. The majority of sedated ABR's (80.8%) were completed without any incident. Significant events [apnea and/or bradycardia], minor complications [vomiting, hypoxemia, prolonged sedation, and/or tachypnea] and restlessness were noted in 3.4%, 6.2%, and 5.0% of the cases, respectively. The majority of these issues resolved without medical intervention, such as the need to provide supplementary oxygen. In 95.9% of ABRs, chloral hydrate was successful in sedating the child adequately to answer the audiological question. ConclusionsThis forms the largest study to date on oral sedation for ABR testing. Based on our results, the use of chloral hydrate in the presence of a sedation nurse was a safe and reliable method of performing ABR in infants and children. This may be of significant value to centres worldwide exploring alternatives to general anesthesia for ABR testing.

Prolonged auditory brainstem responses in infants with autism.

Numerous studies have attempted to identify early physiological abnormalities in infants and toddlers who later develop autism spectrum disorder (ASD). One potential measure of early neurophysiology is the auditory brainstem response (ABR), which has been reported to exhibit prolonged latencies in children with ASD. We examined whether prolonged ABR latencies appear in infancy, before the onset of ASD symptoms, and irrespective of hearing thresholds. To determine how early in development these differences appear, we retrospectively examined clinical ABR recordings of infants who were later diagnosed with ASD. Of the 118 children in the participant pool, 48 were excluded due to elevated ABR thresholds, genetic aberrations, or old testing age, leaving a sample of 70 children: 30 of which were tested at 0–3 months, and 40 were tested at toddlerhood (1.5–3.5 years). In the infant group, the ABR wave‐V was significantly prolonged in those who later developed ASD as compared with case‐matched controls (n = 30). Classification of infants who later developed ASD and case‐matched controls using this measure enabled accurate identification of ASD infants with 80% specificity and 70% sensitivity. In the group of toddlers with ASD, absolute and interpeak latencies were prolonged compared to clinical norms. Findings indicate that ABR latencies are significantly prolonged in infants who are later diagnosed with ASD irrespective of their hearing thresholds; suggesting that abnormal responses might be detected soon after birth. Further research is needed to determine if ABR might be a valid marker for ASD risk. Autism Res 2016, 9: 689–695. © 2015 The Authors Autism Research published by Wiley Periodicals, Inc. on behalf of International Society for Autism Research

Measuring the Advantage of Kalman-Weighted Averaging for Auditory Brainstem Response Hearing Evaluation in Infants.

The purposes of this study were to (a) measure the effects of Kalman-weighted averaging methods on auditory brainstem response (ABR) threshold, latency, and amplitude; (b) translate lab findings to the clinical setting; and (c) estimate cost savings when ABRs can be obtained in nonsedated infants. ABRs were recorded in 40 adults with normal hearing during induced motor noise conditions using the Kalman-weighted averaging method implemented on a commercial system, the Vivosonic Integrity (Vivosonic Inc., Toronto, Ontario, Canada). The device was then used to test 34 infants in awake and asleep states. The advantages of the Kalman-weighted averaging method were modeled in terms of time saved for conducting an ABR evaluation. Kalman-weighted ABR threshold estimates were 6-7 dB lower than with conventional methods during induced motor noise. When used to obtain ABRs in infants who were awake, the number of sweeps required to obtain a result was significantly greater than that required for a sleeping infant but well within the range for clinical application. The use of Kalman-weighted averaging provides a measurable advantage over conventional methods and may reduce costs for the pediatric audiology practice.

Prediction of frequency-specific hearing threshold using chirp auditory brainstem response in infants with hearing losses

ObjectivesTo investigate the clinical usefulness of the LS-chirp auditory brainstem response for estimation of behavioral thresholds in young children with mild to severe hearing losses. Methods68 infants (136 ears) aged 6–12 months (mean age=9.2 months) with bilateral mild to severe hearing losses were studied at Children's Hospital of Fudan University. In all cases, the children were referred for LS-chirp ABR and visual reinforcement audiometric (VRA) measurements. The low-frequency band chirp (LF-chirp) thresholds (frequency band=0.1–0.85kHz) were compared to the average VRA thresholds (frequency band=0.25–0.5kHz), whereas the high-frequency band chirp (HF-chirp) thresholds (frequency band=1–10kHz) were compared to the average VRA thresholds (frequency band=1–4kHz) using statistical correlation coefficient values. ResultsThe LS-chirp ABR thresholds are very close to behavioral hearing levels. The mean differences between chirp-ABR and VRA thresholds were within 5dBHL for all measurements. The smallest mean threshold difference (<3dBHL) was obtained for the severe hearing loss group. The correlation coefficient values (r) were 0.97 at low-frequency and high-frequency bands. For each carrier frequency, the best correlations between chirp-ABR thresholds and VRA thresholds were obtained at VRA frequency of 0.25kHz/LF-chirp (r=0.98) and VRA frequency of 1kHz/HF-chirp (r=0.98). ConclusionsThis study demonstrates the effectiveness using chirp-ABR predicted frequency-specific thresholds, especially of low and middle frequencies. LS-chirp ABR thresholds determined behavioral thresholds in patients with severe hearing losses were better than for mild hearing losses. The use of a chirp-ABR testing ensures higher sensitivity and accuracy than that of auditory stead-state evoked response (ASSR) for measuring frequency-specific thresholds in young children.

The effects of stimulus rate and electrode montage on the auditory brainstem response in infants

PurposeThis study investigates the effects of different stimulus repetition rates and multiple electrode recording montages (ipsilateral, contralateral, horizontal, and vertical) on the auditory brainstem response (ABR) wave V amplitude and latency in infants.MethodologyEleven healthy infants with the mean age of 4.36 ± 1.95 months were involved in this repeated-measure design study. Prior to the actual data collection, several preliminary audiological assessments (otoscopic examination, tympanometry, otoacoustic emission and ABR screening at 35 dB normalized hearing level (dBnHL)) were conducted to ensure that all participants had normal auditory functions. Once qualified, the participants were tested with the ABR using 100-microsecond clicks recorded under the four electrode montages at two stimulus repetition rates (19.1 and 61.1 Hz) and at an intensity level of 35 dBnHL.ResultsThe ABR was shown as present in all participants in all four electrode montages and both stimulus repetition rates. The largest wave V amplitude was recorded in the vertical montage for both stimulus repetition rates. No significant changes (P > 0.05) were noted in the wave V amplitudes in all electrode montages when the stimulus repetition rate was changed from 19.1 to 61.1 Hz.ConclusionThis study confirmed that combining the vertical montage with high stimulus repetition rates of 61.1 Hz at 35 dBnHL has the potential for detecting auditory dysfunction in infants, because of the larger and more stable wave V amplitude.

Auditory brainstem responses to broad-band chirps: Amplitude growth functions in sedated and anaesthetised infants

ObjectiveRecently an optimized broad-band chirp stimulus has been proposed for the objective estimation of hearing thresholds with auditory brainstem responses (ABRs). Several studies have demonstrated that this stimulus, compensating for the travelling wave delay of the frequency components of a click stimulus at the basilar membrane, evokes larger ABR amplitudes in adults. This study analyses the amplitude of chirp-evoked ABRs recorded in infants below 48 month of age under clinical conditions and compares these results with literature data. MethodsChirp-evoked ABR recordings in 46 infants under chloral hydrate sedation or general anaesthesia were analysed retrospectively. The amplitude of the wave V was measured as a function of the stimulus intensity. To compare ABR amplitudes across infants with different hearing losses, the stimulus intensity was readjusted to the subjects’ individual physiological threshold in dB SL (sensation level). Individual wave V amplitudes were plotted against stimulus intensity and individual amplitude growth functions were calculated. To investigate the maturation of chirp-evoked ABR, data from infants below and above 18 months of age were analysed separately. ResultsChirp-evoked ABR amplitudes in both age groups were larger than the click-evoked ABR amplitudes in young infants from the literature. Amplitudes of chirp-evoked ABR in infants above 18 months of age were not substantially smaller than those reported for normal hearing adults. Amplitudes recorded in infants below 18 months were significantly smaller than those in infants above 18 months. A significant difference between chirp-evoked ABR amplitudes recorded in sedation or under general anaesthesia was not found. ConclusionsThe higher amplitudes of ABR elicited by a broadband chirp stimulus allow for a reduction of the recording time in young infants.

Normalization or improvement of auditory brainstem responses in infants and children who were suspected deafness

Normalization or improvement of auditory brainstem responses in infants and children who were suspected deafness

The role of intraoperative auditory brainstem response testing for infants and difficult-to-test children

Objective To assess the validity of intraoperative auditory brainstem response in infants and difficult-to-treat older children. Study Design Case series with chart review. Setting Tertiary-level children's hospital. Subjects and Methods Twenty-six patients were identified (mean age, 20 ± 18 months) who underwent both intraoperative auditory brainstem response (ioABR) testing and a follow-up hearing evaluation at five (standard deviation 4) months. Ears were analyzed separately for mean threshold change, and a sub-analysis was performed accounting for the presence or absence of fluid at the time of surgery. Results A paired t test analysis indicated a statistically significant difference at 1 kHz. There was not a statistically significant difference between the two groups with click or 4-kHz testing. Fifteen ears (58%) at 1 kHz and 17 ears (49%) at 4 kHz frequencies, however, improved by 10 dB or more; 67 percent and 65 percent of these ears, respectively, had middle ear fluid intraoperatively. Eight ears (35%) in the click ABR group had a similar improvement, four of which had fluid at the time of surgery. Four ears in the 1-kHz (11.5%), in the 4-kHz (11.4%), and in the click ABR group (17.4%) demonstrated a 10-dB or worse threshold. The range of the discrepancy varied from a worsening in thresholds up to 20 dB and improvement in thresholds up to 45 dB. Conclusions We observed a significant discrepancy between ioABR and follow-up hearing thresholds. If ioABR indicates a hearing loss, audiologic testing should be performed at least several weeks later to confirm the results.

Clinical Comparison of the Auditory Steady-State Response with the Click Auditory Brainstem Response in Infants

ObjectivesOur goal was to determine the effectiveness of using the auditory steady state response (ASSR) as a measure of hearing thresholds in infants who are suspected of having significant hearing loss, as compared with using the click-auditory brainstem response (C-ABR).MethodsWe retrospectively analyzed the audiologic profiles of 76 infants (46 boys and 30 girls, a total of 151 ears) who ranged in age from 1 to 12 months (average age: 5.7 months). The auditory evaluations in 76 infants who were suspected of having hearing loss were done via the C-ABR and ASSR. In addition, for reference, the mean ASSR thresholds were compared to those of 39 ears of infants and 39 ears of adults with normal hearing at 0.5, 1, 2, and 4 kHz.ResultsThe highest correlation between the C-ABR and ASSR thresholds was observed at an average of 2-4 kHz (r=0.94). On comparison between the hearing of infants and adults at 0.5, 1, 2, and 4 kHz, the mean ASSR threshold in infants was 12, 7, 8, and 7 dB higher, respectively, than that in adults.ConclusionASSR testing may provide additional audiometric information for accurately predicting the hearing sensitivity, and this is essential for the management of infants with severe to profound hearing loss.

Follow-up study of auditory brainstem responses in infants with high unbound bilirubin levels treated with albumin infusion therapy.

Several authors reported that there was a close relationship between unbound bilirubin concentrations and abnormal results of auditory brainstem responses. Full-term infants with high-unbound bilirubin concentrations who were treated with human albumin were followed to evaluate their hearing abilities by using auditory brainstem responses. Fifty-eight infants (gestational age, 39.4 +/- 1.4 weeks; birthweight, 3,245 +/- 435 g) with high unbound bilirubin concentrations (> or = 0.9 micro g/dL) were treated with intensive phototherapy. Twenty infants (control group) received only phototherapy, while 38 others (albumin-treated group) were also given i.v. human albumin administration (1 g/kg bodyweight) during the first 2 h of phototherapy. The follow-up study of auditory brainstem responses was carried out at 6 and 12 months of age. Development quotient tests were carried out at 18 months of age. Abnormalities of auditory brainstem response were detected in three infants in the albumin-treated group and six infants in the control group at 6 months. Two infants in the albumin-treated group and four infants in the control group had improved at 12 months. The results of the follow-up study at 18 months of age in the both groups were normal with development quotient >85. No patients with hearing disability and cerebral palsy were clinically detected at the age of 2 years. The results suggest that albumin priming might be effective for decreasing the rate of auditory brainstem response abnormalities at 6 months.