Auditory neuropathy spectrum disorder in late preterm and term infants with severe jaundice

Risk factors for infant hearing loss: a meta-analysis

Hearing loss is a common disability in infants that significantly impacts their cognitive, language, and literacy development. This study aimed to systematically assess the risk factors for the early identification and intervention in infant hearing loss. Databases were searched for meta-analyses of observational studies until November 2023. The quality assessment was performed using the Cochrane risk of bias tool, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess the certainty of the evidence. A meta-analysis identified 14 risk factors significantly associated with infant hearing loss. According to the GRADE approach, there were four factors with moderate-certainty evidence (low birth weight(LBW), congenital anomalies, craniofacial anomalies, intracranial hemorrhages), seven factors with low-certainty evidence (ototoxic medications, family history of hearing loss, mechanical ventilation > 5 days, intrauterine infection, admission to neonatal intensive care unit (NICU) > 5 days, mechanical ventilation and asphyxia) and six with extremely-low-certainty evidence (very low birth weight < 1500 g (VLBW), hyperbilirubinemia, sepsis or meningitis, male sex, premature birth, small for gestational age (SGA)). Nevertheless, no significant association was found between infant hearing loss and factors such as small for gestational age (SGA), male sex, and premature birth (P > 0.05).  Conclusion: The identification of these 14 interrelated risk factors can prove advantageous in clinical practice, as these findings could guide hearing screening and parental counseling. Furthermore, prospective research could be conducted to develop risk-based scoring systems based on these factors. What is Known: • Infant hearing loss is a worldwide issue. • Risk factors for this condition are debated. What is New: • This is the first meta-analysis to comprehensively evaluate perinatal and postnatal risk factors for hearing loss in infants. • Intracranial hemorrhage, mechanical ventilation, and low birth weight are associated with infant hearing loss. However, no evidence of an association was found between premature birth, being small for gestational age, or male sex and hearing loss.

Automated ABR screening for hearing loss and its clinical determinants among newborns with hyperbilirubinemia in National Hospital, Abuja, Nigeria

Background

Severe neonatal hyperbilirubinemia is a known risk factor for sensorineural hearing loss which is usually undiagnosed in our environment until school age due to a lack of routine screening programs.

Materials and Methods

This cross-sectional study conducted between August 2020 and February 2021 employed a universal sampling of consecutive eligible participants after their mothers' consent. Hearing screening was conducted using an automated auditory brainstem response (AABR) device (Otoport OAE + ABR®). The proportion of AABR screening failure was assessed while associated clinical risk factors were determined using logistic regression. Statistical significance was set at 5% for all comparative analyses.

Results

One hundred and sixty newborns below 28 days of age, delivered at 34 weeks gestation and above, who had jaundice were recruited. The prevalence of screening AABR failure in at least one ear was 26.2%. Significant risk factors for AABR screening failure in addition to extreme and hazardous hyperbilirubinemia were acute bilirubin encephalopathy (ABE) (Odds Ratio (OR) =4.44, 95% CI = 3.19-6.17), birth weight below 2500 g (OR = 3.16, 95% CI = 1.48-6.77), dull tympanic membrane (TM) (OR = 5.94, 95% CI = 2.36-14.92) and exchange blood transfusion (OR = 4.84, 95% CI = 1.87-12.58).

Conclusion and Recommendations

The prevalence of AABR screening failure was high, and a dull TM was its strongest predictor among late preterm and term neonates with hyperbilirubinemia. Otoscopy should be included in the care of newborn with hyperbilirubinemia and screening programs established to mitigate hearing loss among high-risk neonates in Abuja.

Hyperbilirobinemia and Its Effect on Auditory Perception and Speech Intelligibility in Cochlear Implanted Children (Cochlear Implantation Outcomes in Children Who Have Experienced Hyperbilirobinemia)

The goal of this study was to investigate the probable difference in auditory perception and speech intelligibility performance amongst cochlear implanted children who experienced hyperbilirubinemia or auditory neuropathy in comparison to the cochlear implanted children with unknown etiology for hearing loss. This case-control study was carried out on 106 cochlear implanted children with mean age of 32.36 ± 11.98 months who were purposively selected and allocated into four groups. Out of the total, 30 had no specific etiology for hearing loss, while the others had experienced auditory neuropathy or hyperbilirubinemia with/without blood exchange. The auditory perception and speech intelligibility performance of all the participants who had received auditory verbal therapy were assessed after 6 and 12 months of rehabilitation. Then, the data was analyzed, using the Statistical Package for Social Sciences-version 21(SPSS-21). Results indicated poor auditory perception and speech intelligibility performance of the cochlear implanted children with hyperbilirubinemia and blood exchange (P ≤ 0.05), while the participants in the control group with no specific etiology for hearing loss, the children with hyperbilirubinemia with no blood exchange, and those who suffered from auditory neuropathy performed better, respectively. Also, a significant correlation between auditory neuropathy and hyperbilirubinemia was observed. Despite lower improvement of auditory perception and speech intelligibility of the hearing impaired children who were experiencing moderate to severe degrees of hyperbilirubinemia or auditory neuropathy, cochlear implantation is highly recommended not only for children with unknown etiology for severe hearing loss but also for this group of hearing impaired children.

A Study of JCIH (Joint Commission on Infant Hearing) Risk Factors for Hearing Loss in Babies of NICU and Well Baby Nursery at a Tertiary Care Center

Babies in Neonatal Intensive Care Units (NICU) have an additional risk for hearing loss due to various risk factors like, prematurity, low birth weight, mechanical ventilation, hyperbillirubinemia, ototoxic drugs, low APGAR score etc. as compared to the babies from well baby nursery (WBN) who, poses risk factors mostly family history, syndromic deafness. So the present study was aimed know the risk factors responsible for hearing loss in NICU and WBN babies and to assess the incidence of deafness. A total of 800 babies from NICU (n = 402) and WBN (n = 398) underwent hearing screening from a tertiary care center. Hearing screening was done using two staged screening protocol as per JCIH guidelines with Distortion product Evoked Otoacoustic Emissions (DPOAE) and Automated Auditory Brainstem Responses (A-ABR). According to DPOAE test, 311 from NICU and 383 from WBN passed the test and during second screening, 80 out of 91 from NICU and 11 out of 13 from WBN passed the DPOAE test. Further BERA was done at the 3rd month of corrected age where 6 out of 11 showed positive responses from NICU and 3 babies from WBN had profound hearing loss. Data analysis revealed that family history of deafness, anemia and hypertension in ANC, TORCH in mother, low Apgar score and hyperbillirubinemia in newborns were a major risk factor for hearing impairment. We conclude that the diagnoses of auditory disorders at early stage due to various risk factors are important since appropriate therapeutic intervention and rehabilitation would help in better development of children.

The prevalence and risk factors for congenital hearing loss in neonates: A birth cohort study based on CHALLENGE study

OBJECTIVES

To determine the prevalence and risk factors of congenital hearing loss (HL) in neonates based on China Longitudinal Environmental, Genetic, and Economic Cohort (CHALLENGE cohort).

METHODS

Maternal and neonatal data were collected based on the CHALLENGE cohort study from July 2018 to September 2020. Total 7287 neonates underwent the universal newborn hearing screening (UNHS). Babies who did not pass the initial screening and the rescreening were given the formal audiological diagnosis for possible HL. The data was analyzed to find out the prevalence and risk factors for congenital HL in this cohort study.

RESULTS

The prevalence of congenital HL was 3.43‰, and temporary HL was 0.07‰ (5 neonates). The statistical data showed that risk factors, including craniofacial anomalies, neonatal intensive care unit (NICU) admission, family history and advanced maternal age (AMA), could be associated with congenital HL. Additionally, exchange transfusion, assisted ventilation and NICU admission, these three factors could be associated with congenital sensorineural HL (SNHL). Risk factors including craniofacial anomalies, NICU admission, family history and AMA might be contributed to congenital conductive HL(CHL).

CONCLUSION

There were several common risk factors could be contributed to congenital HL, which were consistent with previous studies. However, some risk factors were no longer causing congenital HL due to the improvement of medical treatment and prenatal care. This study has not only helped explain the status quo of the prevalence of congenital HL in China but also laid foundation for future studies.

Effects of ‘Perinatal Risk Factors Associated with Hearing Loss’ on Auditory Outcomes in Cochlear Implant Recipient Children

Cochlear implantation (CI) is used for rehabilitation of children with bilateral severe to profound permanent childhood hearing loss (PCHL). Recently, treatment of such children has been influenced by diagnostic technological advances. Children with perinatal risk factors associated with PCHL can undergo CI. The primary aim of this study was to determine the effects of 'perinatal risk factor associated with PCHL' on post-CI auditory outcomes. In this prospective study at a tertiary care centre we evaluated 50 cochlear implanted children from October 2011 to March 2013. The case group consisted of 6 (12%) children who had presence of 'perinatal risk factor associated with PCHL' and control group consisted of 44 (88%) children without any 'perinatal risk factor associated with PCHL'. All patients received auditory and speech rehabilitation and we evaluated their auditory perception outcomes by categories of auditory performance (CAP) and meaningful auditory integration scale (MAIS) scores at 1 year post-CI. There were significantly decreased mean MAIS scores (decrease of 8.6%) and mean CAP scores (decrease of 6.7%) in CI recipient children with 'perinatal risk factor associated with PCHL' as compared to those who were without any 'perinatal risk factor associated with PCHL' at 1 year after CI. However, in children with 'perinatal risk factor associated with PCHL', mean CAP & MAIS scores (auditory perception outcomes) were still more than 80% of maximum achievable CAP & MAIS scores. In this study, CI recipient children who were without any 'perinatal risk factor associated with PCHL' had significantly better mean MAIS & CAP scores (auditory perception outcomes) 1 year post-CI. However, even in children who had 'perinatal risk factor associated with PCHL', there was substantial improvement in auditory perception outcomes at 1 year post-CI and CI was still helpful in these children. Hence, knowledge of 'perinatal risk factor associated with PCHL' can provide reasonable help in predicting the auditory perception outcome and optimal counselling of families of CI candidates.

Prevalence, risk factors, and audiological characteristics of auditory neuropathy

OBJECTIVE

The objective of this study was to determine the prevalence, risk factors, and audiological characteristics of auditory neuropathy spectrum disorder (ANSD) in the pediatric population.

DESIGN

A retrospective review of medical charts was conducted for children visiting two hospitals in Saudi Arabia.

STUDY SAMPLE

Medical records of 1025 patients with sensorineural hearing loss (SNHL) were reviewed. We analyzed the databases for results of audiological examinations, risk factors, and outcomes of intervention including hearing aid (HA) and cochlear implantation (CI).

RESULTS

Out of 1025 children with SNHL, 101 patients (9.85%) were identified to have ANSD. Audiological characteristics of the ANSD group revealed a severe-to-profound degree of hearing loss, all showed type A tympanogram and absent reflexes, absent auditory brainstem response (ABR) findings with present cochlear microphonic while otoacoustic emissions were absent in 54.5% of patients. The most prevalent risk factors for ANSD in this group were family history of hearing loss, consanguinity, hyperbilirubinemia, and low birth weight. Pure tone and speech detection thresholds improved significantly with CI compared to HA use in this sample of patients with ANSD.

CONCLUSION

This study shows that ANSD is not extremely rare among Saudi children with severe to profound hearing loss, with a prevalence of 9.85%.

Breastfeeding Insufficiencies: Common and Preventable Harm to Neonates

Insufficient milk intake in breastfed neonates is common, frequently missed, and causes preventable hospitalizations for jaundice/hyperbilirubinemia, hypernatremia/dehydration, and hypoglycemia - accounting for most U.S. neonatal readmissions. These and other consequences of neonatal starvation and deprivation may substantially contribute to fully preventable morbidity and mortality in previously healthy neonates worldwide. Previous advanced civilizations recognized this problem of breastfeeding insufficiencies and had an infrastructure to solve it: Wetnursing, shared nursing, and prelacteal feeding traditions used to be well-organized and widespread. Modern societies accidentally destroyed that infrastructure. Then, modern reformers missing a few generations of direct knowledge transmission about safe breastfeeding invented a new, historically anomalous conception of breastfeeding defined in terms of exclusivity. As that new intervention has become increasingly widespread, so too have researchers widely reported associated possible harms of the longer neonatal starvation/deprivation and later infant under-nutrition periods that it creates when breastfeeding is insufficient. Early insufficient nutrition/hydration has possible long-term effects including neurodevelopmental consequences such as attention deficit hyperactivity disorder, autism, cerebral palsy, cognitive and developmental delay, epilepsy, hearing impairment, kernicterus, language disorder, mood disorders, lower IQ, and specific learning disorder. Current early infant feeding guidelines conflict with the available evidence. Recent reform efforts have tended to focus on using more technology and measurement to harm fewer neonates instead of proposing the indicated paradigm shift in early infant feeding to prevent more harm. The scientific evidence is already sufficient to mandate application of the precautionary principle to feed neonates early, adequate, and often milk before mothers' milk comes in and whenever signs of hunger persist, mitigating possible risks including death or disability. In most contexts, the formula is the best supplementary milk for infants at risk from breastfeeding insufficiencies. National-level reviews of scientific evidence, health policy, and research methods and ethics are needed to initiate the early infant feeding paradigm shift that the data already support. Policy experiments and related legislative initiatives might also contribute to the shift, as insurers might decline or be required by law to decline reimbursing hospitals for costs of this type of preventable hospitalization, which otherwise generates profit.

Hearing screening in neonates with hyperbilirubinemia

BACKGROUND

Hyperbilirubinemia is toxic to the auditory pathways and to the central nervous system, leaving sequelae such as hearing loss and encephalopathy. The damage to the auditory system occurs primarily within the brainstem and cranial nerve VIII, and manifests clinically as auditory neuropathy spectrum disorder.

AIM

to establish the relationship that exists between hyperbilirubinemia at birth as a risk factor of neonatal hearing loss in children born in ABOU-EL-REISH hospital.

MATERIALS AND METHODS

we carried out of 60 neonates categorized into two groups: Group (A n = 30), neonates with hyperbilirubinemia; Group (B n = 30), neonates without hyperbilirubinemia.

RESULTS

Ten neonates were boys and twenty were girls from group A and eleven boys and nigh-teen girls from group B.There was significant statistical difference between group A and group B regarding ABR (P-value = 0.001) and a statistical difference regarding OAE (P-value = 0.103 in the right ear and 0.028 in the left ear). Also, our study shows the area under the curve and the diagnostic accuracy of total serum bilirubin (TSB) level for detection of hearing screening results (ABR) at a cut-off point 21 mg/dl (P-value = 0.008 and 0.009 in the right and left ears respectively.) CONCLUSIONS: Our study showed a relevant association between bilirubin levels and abnormal hearing screening results and the importance of combined screening with OAE and ABR tests.

Predicting hearing loss from 10 years of universal newborn hearing screening results and risk factors

OBJECTIVE

This study investigated whether demographic variables, risk factor presence or absence and universal newborn hearing screening (UNHS) results can be used to predict permanent childhood hearing loss (PCHL) in infants referred from screening.

DESIGN

Retrospective analysis of a UNHS database.

STUDY SAMPLE

Data were extracted from the state-wide UNHS database storing details of the 613,027 infants who were born in Queensland, Australia between 1 January 2007 and 31 December 2016 and participated in UNHS. This study included the 6735 children who were referred from the UNHS program for diagnostic audiology due to failing the screen in one or both ears or bypassing screening.

RESULTS

Factors with a significant positive association with PCHL that were incorporated into a logistic regression model were: female gender, non-indigenous status, family history of PCHL, craniofacial anomalies and syndromes associated with PCHL, and a bilateral refer result on screening.

CONCLUSIONS

Odds of PCHL vary among infants referred for diagnostic assessment from UNHS programs. When an infant refers on the newborn hearing screen, information about their gender, indigenous status, identified risk factors and specific screening outcome can be used to predict the likelihood of a congenital PCHL diagnosis.

Results of the Universal Neonatal Hearing Screening in a Tertiary Care Hospital in Mexico city

INTRODUCTION

Universal Neonatal Hearing Screening (UNHS) includes as its main objective, that all Newborns (NB) receive an audiological evaluation during their first month of life.

OBJECTIVE

To determine the prevalence of hearing loss in a population of healthy NB in a tertiary care hospital in Mexico City.

MATERIAL AND METHODS

A prospective cross-sectional study was designed. The period was from October 1, 2011 to May 15, 2019. UNHS was performed with a flowchart in three phases using Transient Evoked Otoacoustic Emissions and Brainstem auditory evoked potentials. Data were analyzed using descriptive statistics.

RESULTS

14,000 NB were evaluated, 28,000 ears. Gender was distributed in n = 7038 (50.3%) males and n = 6962 (49.7%) females. The mean age at the time of the first UNHS study was 48.3 ± 22.2 days. Hearing loss was confirmed in n = 31 (0.22%) NB, in 20 (64%) of the cases with hearing loss there were no documented audiological risk factors.

CONCLUSIONS

The prevalence of hearing loss was 2.2 per 1000 NB in a tertiary care hospital in Mexico City. Diagnosis and early habilitation of hearing loss in NB constitute quality indicators in health care and guarantee the best prognosis for NB with hearing loss.

Hyperbilirubinemia impact on newborn hearing: a literature review

The increase in bilirubin levels in newborns can cause toxic effects on the auditory system, which can lead to hearing loss. This review aimed to verify the impact of hyperbilirubinemia in the hearing of newborns, relating audiological findings to serum levels of bilirubin. A literature review was conducted during October 2017, using the terms "hyperbilirubinemia", "jaundice", "infant", "newborn" and "hearing loss", on databases CAPES journals, MEDLINE and BIREME (SciELO, BBO). 827 studies were identified and 59 were selected for full-text reading, resulting in the selection of seven articles that met the inclusion criteria and were considered relevant to the sample of this study. All the reviewed studies performed brainstem auditory evoked potential as the main test for audiological evaluation. Changes in the audiological findings of neonates with hyperbilirubinemia were observed in all studies. There was no consensus on the serum bilirubin levels that may cause auditory changes; however, the relationship between hearing disorders and blood levels of bilirubin was positive. We identify the need to establish reference values for bilirubin levels considered critical for the occurrence of hearing disorders as well as the audiological follow-up of neonates with hyperbilirubinemia.

Long-term Effects of Indirect Hyperbilirubinemia on Auditory and Neurological Functions in Term Newborns

Objective:

The aim of this study was to investigate the long-term effects of hyperbilirubinemia on neurological and hearing function in otherwise healthy term newborns with neonatal indirect hyperbilirubinemia.

Method:

This study was performed prospectively in 41 term newborns hospitalized for indirect hyperbilirubinemia. Patients with no signs of hemolysis were categorized in 3 groups based on stabil levels as sTB <20 mg/dl, 20-24.9 mg/dl, and =>25 mg/dl. Patients with total bilirubin level =>20 mg/dl and hemolytic disease were classified as the fourth group. The relationship between maximum sTB level, duration of exposure to sTB levels >20 mg/dl and etiology of jaundice with neurological and auditory functions was investigated. Detailed neurological examination, Denver II developmental screening test and hearing tests (otoacoustic emissions, OAE and auditory brainstem responses, ABR) were performed to all patients between 18-24 months of age.

Results:

Neurodevelopmental disorder was found in 5 (12.2%) patients. Hemolytic disease was detected in two of these patients. Hearing loss was found in 4 (9.8%) of the patients. Two of these patients had auditory neuropathy spectrum disorder and the other two had cochlear hearing loss. The sTB levels of all these patients were above 25 mg/dl. No neurological disorder or hearing loss was found in the patients who had stabil of <25 mg/dl. Exposure time to sTB levels above 20 mg/dl was significantly longer in patients with neurological dysfunction and pathologic ABR results (p:0.007, p:0.007; p<0.05).

Conclusion:

This study demonstrates that kernicterus may develop in term newborns with severe hyperbilirubinemia (sTB>25 mg/dl) without any finding of significant hemolysis. Not only the bilirubin level but also the duration of exposure to high bilirubin levels may be effective in the development of bilirubin neurotoxicity. The high rate of hearing loss in our patients emphasizes the importance of screening for infants with severe hyperbilirubinemia using comprehensive auditory evaluation for early diagnosis of possible hearing loss.

Effect of Hyperbilirubinemia on Medial Olivocochlear System in Newborns

OBJECTIVES

To evaluate medial olivocochlear efferent system of babies with hyperbilirubinemia with normal auditory brain stem responses.

MATERIALS AND METHODS

This was a prospective study in a tertiary referral hospital. The study involved 40 hyperbilirubinemic and 44 healthy newborns. Cochlear and auditory activity of participants was evaluated by transient otoacoustic emissions (TOAEs) and brainstem auditory evoked response components (BAER). Medial olivocochlear (MOC) reflex was evoked with contralateral acoustic stimulation and recorded with TOAEs.

RESULTS

A comparison of the MOC reflex activity between two groups with Mann Whitney U test revealed that MOC reflex activity were significantly decreased in the hyberbilirubinemic group for both ears (p<.05). This difference was significant for all frequencies in both ears. There was no significant relation between total serum bilirubin level and MOC reflex activity.

CONCLUSION

Hyperbilirubinemic newborns had decreased MOC reflex activity. This may be indicative of future problems in speech discrimination and effective hearing in noisy background. Additional long cohort studies are needed to evaluate the clinical importance of MOC reflex measurements in this group. MOC reflex measurement has the potential to form part of the audiologic evaluation of newborns with hyperbilirubinemia in the future.

Updates on an At-Risk Population: Late-Preterm and Early-Term Infants

The American Academy of Pediatrics published a clinical report on late-preterm (LPT) infants in 2007 that was largely based on a summary of a 2005 workshop convened by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, at which a change in terminology from "near term" to "late preterm" was proposed. This paradigm-shifting recommendation had a remarkable impact: federal agencies (the Centers for Disease Control and Prevention), professional societies (the American Academy of Pediatrics and American College of Obstetricians and Gynecologists), and organizations (March of Dimes) initiated nationwide monitoring and educational plans that had a significant effect on decreasing the rates of iatrogenic LPT deliveries. However, there is now an evolving concern. After nearly a decade of steady decreases in the LPT birth rate that largely contributed to the decline in total US preterm birth rates, the birth rate in LPT infants has been inching upward since 2015. In addition, evidence revealed by strong population health research demonstrates that being born as an early-term infant poses a significant risk to an infant's survival, growth, and development. In this report, we summarize the initial progress and discuss the potential reasons for the current trends in LPT and early-term birth rates and propose research recommendations.

Early Amplitude-Integrated Electroencephalography Predicts Long-Term Outcomes in Term and Near-Term Newborns With Severe Hyperbilirubinemia

BACKGROUND

We aimed to determine the predictive neurological prognostic value of early amplitude-integrated electroencephalography (aEEG) in term and near-term neonates with severe hyperbilirubinemia compared with cranial magnetic resonance imaging (MRI) and auditory brainstem response (ABR).

METHODS

Infants of ≥35 weeks of gestation with severe hyperbilirubinemia (total serum bilirubin [TSB] ≥340 μmol/L) or with hyperbilirubinemia (TSB ≥257 μmol/L) in association with bilirubin-induced neurological dysfunction were recruited. All the subjects had an aEEG after being admitted to the neonatal intensive care unit, whereas cranial MRI and ABR were performed when TSB had come down to the normal range. All the infants were followed up to 12 months.

RESULTS

During the study period, 77 of 83 infants were eligible, of which 71 had severe hyperbilirubinemia and six had hyperbilirubinemia in association with bilirubin-induced neurological dysfunction. Thirty-three infants were diagnosed with acute bilirubin encephalopathy (ABE), two of whom died of ABE, and 62 completed the follow-up, of which 12 infants had adverse outcomes. Sixty-four infants underwent aEEG, 40 infants had cranial MRI, and 39 infants had ABR. Logistic regression and the receiver-operator characteristic curve analysis showed that the ability of severely abnormal aEEG to predict adverse neurological outcomes in severe hyperbilirubinemia was no better than abnormal ABR, with a sensitivity of 35.7% versus 83.3%, a specificity of 92.0% versus 74.1%, a positive predictive value of 55.6% versus 58.8%, and a negative predictive value of 83.6% versus 90.9%.

CONCLUSIONS

Early aEEG could predict adverse neurodevelopmental outcomes in neonates with severe hyperbilirubinemia, although the sensitivity was lower than ABR.

Relationship research between auditory neuropathy spectrum disorder and exchange transfusion in neonates with severe hyperbilirubinemia

OBJECTIVE

To explore the effects of exchange transfusion on auditory neuropathy spectrum disorder (ANSD) in neonates with severe hyperbilirubinemia (SH).

METHODS

The clinical data of 2216 SH neonates who met the standard of exchange transfusion and 732 non severe-hyperbilirubinemia (NSH) neonates in the same period who did not require exchange transfusion in the neonatology department of Childrens' Hospital of Chongqing Medical University between January 2010 and December 2015 were retrospectively analyzed. In addition, the SH neonates were further divided into the exchange transfusion group and photography group. Hearing screening was conducted on all neonates using transiently evoked otoacoustic emission (TEOAE) and auto auditory brainstem response (AABR), and neonates who failed the above screening were performed diagnostic hearing test. And then neonates diagnosed with hearing disorder were followed up for 2-5 years.

RESULTS

The pass rates of hearing screening were 80.58%, 79.71% and 87.84% in the phototherapy group, exchange transfusion group and NSH group respectively, with a significant difference(P < 0.05). Hearing loss was diagnosed in 10.15%, 12.39% and 8.54% of neonates in the phototherapy group, exchange transfusion group and NSH group. After follow-up, ultimate incidence rates of ANSD were 11.96%, 11.57% and 2.4% respectively in the 3 groups, with a significant difference (P < 0.05).

CONCLUSIONS

SH is one of risk factors for ANSD. SH neonates have a lower incidence of ANSD in the exchange transfusion group than in the phototherapy group. Neonates who meet the standards of exchange transfusion adopt this therapy in early stage, which can quickly decrease bilirubin level and ultimately reduce incidence of ANSD.

High unbound bilirubin for age: a neurotoxin with major effects on the developing brain

Neonatal hyperbilirubinemia is one of the most frequent diagnoses made in neonates. A high level of unconjugated bilirubin that is unbound to albumin is neurotoxic when the level exceeds age-specific thresholds or at lower levels in neonates with neurotoxic risk factors. Lower range of unbound bilirubin results in apoptosis, while moderate-to-high levels result in neuronal necrosis. Basal ganglia and various brain stem nuclei are more susceptible to bilirubin toxicity. Proposed mechanisms of bilirubin-induced neurotoxicity include excessive release of glutamate, mitochondrial energy failure, release of proinflammatory cytokines, and increased intracellular calcium concentration. These mechanisms are similar to the events that occur following hypoxic-ischemic insult in neonates. Severe hyperbilirubinemia in term neonates has been shown to be associated with increased risk for autism spectrum disorders. The neuropathological finding of bilirubin-induced neurotoxicity also includes cerebellar injury with a decreased number of Purkinje cells, and disruption of multisensory feedback loop between cerebellum and cortical neurons which may explain the clinical characteristics of autism spectrum disorders. Severe hyperbilirubinemia occurs more frequently in infants from low- and middle-income countries (LMIC). Simple devices to measure bilirubin, and timely treatment are essential to reduce neurotoxicity, and improve outcomes for thousands of neonates around the world.

Developmental influence of unconjugated hyperbilirubinemia and neurobehavioral disorders

Bilirubin-induced brain injury in the neonatal period has detrimental effects on neurodevelopment that persist into childhood and adulthood, contributing to childhood developmental disorders. Unconjugated bilirubin is a potent antioxidant that may be useful for protecting against oxidative injuries, but it becomes a potent neurotoxin once it crosses the blood brain barrier. Because bilirubin toxicity involves a myriad of pathological mechanisms, can damage most types of brain cells, and affects brain circuits or loops that influence cognition, learning, behavior, sensory, and language, the clinical effects of bilirubin-induced neurotoxicity are likely to be manifold. One possible effect that several experts have identified is bilirubin-induced neurological dysfunction (subtle kernicterus). However, the underlying biological mechanisms or pathways by which subtle kernicterus could lead to developmental disorders has not been elucidated previously. Our aim in this review is to describe a spectrum of developmental disorders that may reflect subtle kernicterus and outline plausible biological mechanisms for this possible association. We review existing evidence that support or refute the association between unconjugated hyperbilirubinemia and developmental disorders, and limitations associated with these studies.

Bilirubin-induced neurotoxic and ototoxic effects in rat cochlear and vestibular organotypic cultures

Exposure to high levels of bilirubin in hyperbilirubinemia patients and animal models can result in sensorineural deafness. However, the mechanisms underlying bilirubin-induced damage to the inner ear, including the cochlear and vestibular organs, remain unknown. The present analyses of cochlear and vestibular organotypic cultures obtained from postnatal day 3 rats exposed to bilirubin at varying concentrations (0, 10, 50, 100, or 250 μM) for 24 h revealed that auditory nerve fibers (ANFs) and vestibular nerve endings were destroyed even at low doses (10 and 50 μM). Additionally, as the bilirubin dose increased, spiral ganglion neurons (SGNs) and vestibular ganglion neurons (VGNs) exhibited gradual shrinkage in conjunction with nuclei condensation or fragmentation in a dose-dependent manner. The loss of cochlear and vestibular hair cells (HCs) was only evident in explants treated with the highest concentration of bilirubin (250 μM), and bilirubin-induced major apoptosis most likely occurred via the extrinsic apoptotic pathway. Thus, the present results indicate that inner ear neurons and fibers were more sensitive to, and exhibited more severe damage following, bilirubin-induced neurotoxicity than sensory HCs, which illustrates the underlying causes of auditory neuropathy and vestibulopathy in hyperbilirubinemia patients.

Hyperbilirubinemia and Follow-up Auditory Brainstem Responses in Preterm Infants

Objectives.

Neonatal hyperbilirubinemia is considered one of the most common causative factors of hearing loss. Preterm infants are more vulnerable to neuronal damage caused by hyperbilirubinemia. This study aimed to evaluate the effect of hyperbilirubinemia on hearing threshold and auditory pathway in preterm infants by serial auditory brainstem response (ABR). In addition, we evaluate the usefulness of the unconjugated bilirubin (UCB) level compared with total serum bilirubin (TSB) on bilirubin-induced hearing loss.

Methods.

This study was conducted on 70 preterm infants with hyperbilirubinemia who failed universal newborn hearing screening by automated ABR. The diagnostic ABR was performed within 3 months after birth. Follow-up ABR was conducted in patients with abnormal results (30 cases). TSB and UCB concentration were compared according to hearing threshold by ABR.

Results.

The initial and maximal measured UCB concentration for the preterm infants of diagnostic ABR ≥40 dB nHL group (n=30) were statistically higher compared with ABR ≤35 dB nHL group (n=40) (P=0.031 and P=0.003, respectively). In follow-up ABR examination, 13 of the ABR ≥40 dB nHL group showed complete recovery, but 17 had no change or worsened. There was no difference in bilirubin level between the recovery group and non-recovery group.

Conclusion.

UCB is a better predictor of bilirubin-induced hearing loss than TSB in preterm infants as evaluated by serial ABR. Serial ABR testing can be a useful, noninvasive methods to evaluate early reversible bilirubin-induced hearing loss in preterm infants.

Characterization of Detailed Audiological Features of Cytomegalovirus Infection: A Composite Cohort Study from Groups with Distinct Demographics

Congenital cytomegalovirus (cCMV) infection is a common congenital infection that causes sensorineural hearing loss (SNHL). Despite its substantial impact on public health and cost burden, epidemiology and clinical features of CMV-related SNHL have never been reported in the Korean populations. This study investigated the detailed audiologic phenotypes of cCMV infection to see if a specific SNHL pattern is associated with a particular clinical setting. A total of 38 patients with cCMV infection were studied retrospectively. Patients were classified into three groups with distinct demographics: clinically driven diagnosis (n=17), routine newborn CMV screening according to the NICU protocols (n=10), or referral to ENT for cochlear implant (CI) (n=11). The incidence of cCMV infection was 3.6%, showing 33.3% of SNHL among cCMV patients, 38% of asymmetric hearing loss, 29% of late-onset hearing loss, and diverse severity spectrum in patients with CMV-related SNHL. CI recipients with CMV-related SNHL showed a significantly improved speech perception. Surprisingly, in 36.4 % of CI implantees, initial audiological manifestation was significant asymmetry of hearing thresholds between both ears, with better ear retaining significant residual hearing up to 50dB. CMV turns out to be a significant etiology of SNHL, first to date reported in the Korean pediatric population. Analysis of audiologic phenotypes showed a very wide spectrum of SNHL and favorable CI outcomes in case of profound deafness. Especially for the patients with asymmetric hearing loss, close surveillance of hearing should be warranted and CI could be considered on the worse side first, based on the observation of rapid progression to profound deafness of better side.

Patterns of acute bilirubin encephalopathy in Nigeria: a multicenter pre-intervention study

BACKGROUND

Acute bilirubin encephalopathy (ABE) is an important cause of neonatal morbidity in Nigeria, accounting for 5-14% of neonatal deaths. Most newborns with severe ABE have irreversible damage before receiving treatment emphasizing the need for timely pre-admission monitoring and referral. There is limited evidence that educational interventions targeting mothers and health care providers will reduce delayed care.

OBJECTIVE

To provide baseline data on the incidence of ABE and associated pre-admission risk factors in five centers of Nigeria in order to evaluate the effect of subsequent educational interventions on outcome.

STUDY DESIGN

The incidence of ABE among newborns treated for hyperbilirubinemia was documented prospectively. Bivariate analysis and multivariate logistic regression were used to evaluate risk factors for acute bilirubin encephalopathy and reasons for regional differences in its occurrence.

RESULTS

Of 1040 infants, 159 treated for hyperbilirubinemia (15.3%) had mild to severe bilirubin encephalopathy (including 35 deaths), but the incidence ranged from 7 to 22% between centers. Logistic regression identified four common predictors: total serum bilirubin (odds ratio 1.007 per mg/dl rise), out-of-hospital births (OR 2.6), non-alloimmune hemolytic anemia (OR 2.8), and delayed care seeking (OR 4.3).

CONCLUSION

The high occurrence of bilirubin encephalopathy in Nigeria is due in large part to a delay in seeking care. A planned intervention strategy will target conditions leading to severe hyperbilirubinemia and delay.

Chronic Auditory Toxicity in Late Preterm and Term Infants With Significant Hyperbilirubinemia

BACKGROUND AND OBJECTIVES

Significant hyperbilirubinemia (SHB) may cause chronic auditory toxicity (auditory neuropathy spectrum disorder and/or sensorineural hearing loss); however, total serum bilirubin (TSB) does not discriminate neonates at risk for auditory toxicity. Our objective was to compare TSB, bilirubin albumin molar ratio (BAMR), and unbound bilirubin (UB) for their association with chronic auditory toxicity in neonates with SHB (TSB ≥20 mg/dL or TSB that met criteria for exchange transfusion).

METHODS

Infants ≥34 weeks' gestational age (GA) with SHB during the first 2 postnatal weeks were eligible for a prospective longitudinal study in India. Comprehensive auditory evaluations were performed at 2 to 3 months of age by using auditory brainstem response, tympanometry, and an otoacoustic emission test and at 9 to 12 months of age by using audiometry. The evaluations were performed by an audiologist unaware of the degree of jaundice.

RESULTS

A total of 93 out of 100 infants (mean GA of 37.4 weeks; 55 boys, 38 girls) who were enrolled with SHB were evaluated for auditory toxicity. Of those, 12 infants (13%) had auditory toxicity. On regression analysis controlling for covariates, peak UB (but not peak TSB or peak BAMR), was associated with auditory toxicity (odds ratio 2.41; 95% confidence interval: 1.43-4.07; P = .001). There was significant difference in the area under the receiver operating characteristic curves between UB (0.866), TSB (0.775), and BAMR (0.724) for auditory toxicity (P = .03) after controlling for covariates.

CONCLUSIONS

Unconjugated hyperbilirubinemia indexed by UB (but not TSB or BAMR) is associated with chronic auditory toxicity in infants ≥34 weeks' GA with SHB.

Changes in tonal audiometry in children with progressive sensorineural hearing loss and history of Neonatal Intensive Care Unit discharge. A 20 year long-term follow-up

OBJECTIVE

Newborns from Neonatal intensive care units (NICU) are at high-risk for sensorineural hearing loss (SNHL) a follow-up is needed for early diagnosis and intervention. Our objective here was to describe the features and changes of SNHL at different periods during a follow-up of almost 20 years.

METHODS

Risk factors for SNHL during development were analyzed. The audiological examination included: Brainstem auditory evoked potentials (BAEP), and Transient evoked otoacoustic emissions (TEOAE). At birth; tonal audiometry (between 125 and 8000 Hz), and tympanometry were performed at 5, 10, 15, and 20 years of age.

RESULTS

Sixty-five percent of cases presented bilateral absence of BAEP. At 5 years of age, the most frequent SNHL level was severe (42.5%), followed by moderate (22.5%), and profound level (20%), in all cases, the SNHL was symmetrical with a predominance of lesion for the high frequencies. Exchange transfusion was associated with a higher degree of SNHL (OR = 6.00, CI = 1.11-32.28, p < 0.02). In 55%, SNHL remained stable, but in 40% of the cases it was progressive. At the end of the study six cases with moderate loss progressed to the severe level and seven cases with severe level progressed to profound.

CONCLUSIONS

Forty percent of infants with SNHL discharged from NICU may present a progression in the hearing loss. Exchange transfusion was associated with a higher degree of SNHL. NICU graduates with SNHL merit a long-term audiological follow-up throughout their lifespan.

Report about term infants with severe hyperbilirubinemia undergoing exchange transfusion in Southwestern China during an 11-year period, from 2001 to 2011

OBJECTIVES

This study was intended to explore the etiology and risk factors of severe neonatal hyperbilirubinemia and to analyze the adverse events associated with ECT (Exchange Transfusion), as well as to identify the factors related to the poor prognosis.

METHODS

All of the full-term neonates who had undergone ECT for hyperbilirubinemia at Children's Hospital of Chongqing Medical University from January 2001 to December 2011 were enrolled in this study. General demographic characteristics, comorbidities, pre- and post-exchange TSB(Total Serum Bilirubin) levels, duration and frequency of ECT, and clinical outcomes were recorded and analyzed anonymously.

RESULTS

Of 614 total infants, 368 patients (59.9%) with ABO incompatibility were identified, of whom 197 (53.5%) developed acute bilirubin encephalopathy (ABE) and 16 (4.3%) suffered a poor prognosis. The etiology was unidentified in 103 patients (16.8%), of whom 62 (60.1%) developed ABE and 9 (8.7%) had a poor prognosis. Identified adverse events secondary to ECT included thrombocytopenia (54.6%), hyperglycemia (42.8%), apnea (3.3%) and necrotizing enterocolitis (NEC) (1.3%). No ECT-related mortality was documented in this study.

CONCLUSIONS

The etiology, peak TSB level before ECT, and time of ECT had a significant impact on the outcome of severe neonatal hyperbilirubinemia. ABO incompatibility was the most common cause of extreme neonatal hyperbilirubinemia. Pathological weight loss could be involved in the development of extreme hyperbilirubinemia with an unidentified cause.

AUNA2: A Novel Type of Non-Syndromic Slowly Progressive Auditory Synaptopathy/Auditory Neuropathy with Autosomal-Dominant Inheritance

BACKGROUND

Auditory synaptopathy/neuropathy (AS/AN) is a heterogeneous disorder, which may be caused by environmental factors like postnatal hyperbilirubinemia or by genetic factors. The genetic forms are subdivided into syndromic and non-syndromic types, and show different inheritance patterns with a strong preponderance of autosomal-recessive forms. To date, only a single locus for non-syndromic autosomal-dominant AS/AN (AUNA1) has been reported in a single family, in which a non-coding DIAPH3 mutation was subsequently described as causative.

MATERIALS AND METHODS

Here, we report detailed clinical data on a large German AS/AN family with slowly progressive postlingual hearing loss. Affected family members developed their first symptoms in their second decade. Moderate hearing loss in the fourth decade then progressed to profound hearing impairment in older family members. Comprehensive audiological and neurological tests were performed in the affected family members. Genetic testing comprised linkage analyses with polymorphic markers and a genome-wide linkage analysis using the Affymetrix GeneChip® Human Mapping 250K.

RESULTS AND CONCLUSION

We identified a large family with autosomal-dominant AS/AN. By means of linkage analyses, the AUNA1 locus was excluded, and putatively linked regions on chromosomal bands 12q24 and 13q34 were identified as likely carrying the second locus for autosomal-dominant AS/AN (AUNA2). AUNA2 is associated with a slowly progressive postlingual hearing loss without any evidence for additional symptoms in other organ systems.

Modiolar ossification in paediatric patients with auditory neuropathy

Objective:

To describe our finding of increased ossification of the modiolus in paediatric patients with auditory neuropathy who met criteria for cochlear implantation.

Methods:

A retrospective case series with a comparison group at a tertiary referral centre is described. Seven paediatric patients with auditory neuropathy who met criteria for and underwent cochlear implantation were identified. Fifteen paediatric implantees with bilateral profound sensorineural hearing loss were included as the comparison group. All patients underwent pre-operative computed tomography. Attenuation at the modiolus was measured in all subjects by a neuroradiologist blinded to clinical information.

Results:

Attenuation values in the modiolus in the auditory neuropathy patients (mean ± standard deviation = 796.2 ± 53.0 HU) was statistically significantly higher than in the comparison sensorineural hearing loss patients (267.1 ± 45.6 HU; p < 0.05, t-test).

Conclusion:

Patients with auditory neuropathy who meet criteria for cochlear implantation demonstrate significantly higher modiolar attenuation on computed tomography imaging, consistent with increased ossification at the modiolus.

Prediction of 3- to 5-Month Outcomes from Signs of Acute Bilirubin Toxicity in Newborn Infants

OBJECTIVE

To evaluate the ability of the bilirubin-induced neurologic dysfunction (BIND) score to predict residual neurologic and auditory disability and to document the relationship of BIND score to total serum bilirubin (TSB) concentration.

STUDY DESIGN

The BIND score (assessing mental status, muscle tone, and cry patterns) was obtained serially at 6- to 8-hour intervals in 220 near-term and full-term infants with severe hyperbilirubinemia. Neurologic and/or auditory outcomes at 3-5 months of age were correlated with the highest calculated BIND score. The BIND score was also correlated with TSB.

RESULTS

Follow-up neurologic and auditory examinations were performed for 145/202 (72%) surviving infants. All infants with severe acute bilirubin encephalopathy (BIND scores 7-9) either died or suffered residual neurologic and auditory impairment. Of 24 cases with moderate encephalopathy (BIND 4-6), 15 (62.5%) resolved following aggressive intervention and were normal at follow-up. Three of 73 infants with mild encephalopathy (BIND scores 1-3) but severe jaundice (TSB ranging 33.5-38 mg/dL; 573-650 µmol/L) had residual neurologic and/or auditory impairment. A BIND score ≥4 had a specificity of 87.3% and a sensitivity of 97.4% for predicting poor neurologic outcomes (receiver operating characteristic analysis). BIND scores trended higher with severe hyperbilirubinemia (r² = 0.54, P < .005), but 5/39 (13%) infants with TSB ≥36.5 mg/dL (624 µmol/L) had BIND scores ≤3, and normal outcomes at 3-5 months.

CONCLUSIONS

The BIND score can be used to evaluate the severity of acute bilirubin encephalopathy and predict residual neurologic and hearing dysfunction.

Auditory toxicity in late preterm and term neonates with severe jaundice

AIM

Jaundice may cause auditory toxicity (auditory neuropathy and hearing loss). However, total serum bilirubin (TSB) does not discriminate neonates at risk for auditory toxicity. We compared TSB, bilirubin:albumin molar ratio (BAMR), and unbound bilirubin for their association with auditory toxicity in neonates with severe jaundice (TSB ≥342μmol/L, or that met exchange transfusion).

METHOD

Neonates greater or equal to 34 weeks gestational age with severe jaundice during the first 2 postnatal weeks were eligible for prospective cohort study, unless they had craniofacial malformations, chromosomal disorders, toxoplasmosis, other infections, rubella, cytomegalovirus, herpes simplex infections, surgery, or family history of congenital deafness.

RESULTS

Twenty-eight out of 100 neonates (mean gestational age 37.4wks; 59 males, 41 females) had auditory toxicity. Peak unbound bilirubin, but not peak TSB and BAMR, was associated with auditory toxicity (p<0.05) in neonates with severe (TSB <427.5μmol/L) and extreme hyperbilirubinemia (TSB ≥427.5μmol/L). Area under the receiver operating characteristic curve for unbound bilirubin (0.78) was significantly greater (p=0.03) than TSB (0.54) among neonates with severe but not extreme hyperbilirubinemia.

INTERPRETATION

Unbound bilirubin is more strongly associated with auditory toxicity than TSB and/or BAMR in greater or equal to 34 weeks gestational age neonates with severe jaundice. Unbound bilirubin is a better predictor than TSB in neonates with severe hyperbilirubinemia.

Newborn hearing screening in Queensland 2009-2011: Comparison of hearing screening and diagnostic audiological assessment between term and preterm infants

AIM

This study compares rates and timing of newborn hearing screening outcomes, audiological assessment and hearing loss diagnosis between infants of different gestational age groups. Early identification and management of sensorineural hearing loss (SNHL), ideally by 3-6 months of age, facilitates speech and language optimisation. Literature stratifying hearing screening and diagnostic audiology assessment by gestational age groups is lacking.

METHODS

Subjects were infants with recorded gestational ages receiving newborn hearing screening in Queensland between 2009 and 2011. Data were provided through the Queensland Healthy Hearing database. Infants were analysed in <34 weeks, 34-36⁺⁶ weeks, 37-38⁺⁶ weeks and ≥39 weeks gestational age groups.

RESULTS

Infants (175 911) were eligible for analysis, 7.9% being preterm. Per 1000 infants analysed, bilateral SNHL of >40 dB occurred in 2.4 for <34, 1.4 for 34-36⁺⁶ , 0.7 for 37-38⁺⁶ and 0.7 for ≥39 weeks gestation. Diagnoses attributable to newborn hearing screening direct referral were 93.1% for bilateral >40 dB SNHL and 88.2% for other hearing loss. Relative to term, preterm infants had a higher incidence of direct and targeted surveillance referrals, audiology assessment and hearing loss diagnosis. Preterm infants were screened later after birth.

CONCLUSIONS

Specific hearing screening and diagnosis characteristics differed between preterm infants <34 and 34-36⁺⁶ weeks gestation, and term infants. Consideration of unique gestational age strata characteristics supports care individualisation. Preterm infants represent a diagnostic challenge, with higher rates of bilateral >40 dB SNHL than term but correspondingly higher false positive results on screening, justifying vigilant monitoring. Focused research into specific risk factors in preterm infants is warranted.

Auditory neuropathy spectrum disorder (ANSD) in referrals from neonatal hearing screening at a well-baby clinic

Auditory neuropathy spectrum disorder (ANSD) is a particular kind of hearing disorder characterised by normal outer hair cell function and abnormal or absent auditory brain stem responses. Little data are available regarding the prevalence of this condition in healthy newborns. We performed a retrospective medical records review of 791 referrals from universal neonatal hearing screening (UNHS) at a well-baby clinic to investigate the prevalence of ANSD. Hearing screening was performed by automated auditory brain stem response (ABR) testing. A diagnosis of ANSD was established when ABR tracings were absent in the presence of otoacoustic emissions and/or a cochlear microphonic. Amongst 201 infants with confirmed congenital hearing loss, 13 infants were diagnosed with ANSD. The condition was unilateral in six and bilateral in seven infants. A risk factor for hearing loss could be identified in three infants. Abnormalities on magnetic resonance imaging were found in six infants; five of them had cochlear nerve deficiency.

CONCLUSION

The prevalence of ANSD was 6.5 % amongst well babies with confirmed congenital hearing loss identified through UNHS. The estimated incidence of ANSD in our population of newborns at the well-baby clinic was 0.09/1000 live births. Magnetic resonance revealed an underlying anatomical abnormality in about half of the patients.

WHAT IS KNOWN

• Auditory neuropathy dyssynchrony spectrum disorder (ANSD) is a particular form of hearing loss, mostly encountered in neonatal intensive care unit (NICU) graduates. • Little data are available on the prevalence and risk factors for ANSD in healthy newborns. What is new: • The estimated prevalence of ANSD in healthy newborns is 0.09/1000 live births. • In about half of the healthy newborns with ANSD, a structural abnormality was detected on magnetic resonance imaging of the posterior fossa/brain.

Bilirubin Binding Capacity in the Preterm Neonate

Total serum/plasma bilirubin (TB), the biochemical measure currently used to evaluate and manage hyperbilirubinemia, is not a useful predictor of bilirubin-induced neurotoxicity in premature infants. Altered bilirubin-albumin binding in premature infants limits the usefulness of TB in premature infants. In this article, bilirubin-albumin binding, a modifying factor for bilirubin-induced neurotoxicity, in premature infants is reviewed.

Unbound Bilirubin and Auditory Neuropathy Spectrum Disorder in Late Preterm and Term Infants with Severe Jaundice

OBJECTIVE

This study evaluates whether unbound bilirubin is a better predictor of auditory neuropathy spectrum disorder (ANSD) than total serum bilirubin (TSB) or the bilirubin:albumin molar ratio (BAMR) in late preterm and term neonates with severe jaundice (TSB ≥20 mg/dL or TSB that met exchange transfusion criteria).

STUDY DESIGN

Infants ≥34 weeks' gestation with severe jaundice during the first 2 weeks of life were eligible for the prospective observational study. A comprehensive auditory evaluation was performed within 72 hours of peak TSB. ANSD was defined as absent or abnormal auditory brainstem evoked response waveform morphology at 80-decibel click intensity in the presence of normal outer hair cell function. TSB, serum albumin, and unbound bilirubin were measured using the colorimetric, bromocresol green, and modified peroxidase method, respectively.

RESULTS

Five of 44 infants developed ANSD. By logistic regression, peak unbound bilirubin but not peak TSB or peak BAMR was associated with ANSD (OR, 4.6; 95% CI, 1.6-13.5; P = .002). On comparing receiver operating characteristic curves, the area under the curve for unbound bilirubin (0.92) was significantly greater (P = .04) compared with the area under the curve for TSB (0.50) or BAMR (0.62).

CONCLUSIONS

Unbound bilirubin is a more sensitive and specific predictor of ANSD than TSB or BAMR in late preterm and term infants with severe jaundice.

Bilirubin-Induced Audiologic Injury in Preterm Infants

Although hyperbilirubinemia is extremely common among neonates and is usually mild and transient, it sometimes leads to bilirubin-induced neurologic damage (BIND). The auditory pathway is highly sensitive to the effects of elevated total serum/plasma bilirubin (TB) levels, with damage manifesting clinically as auditory neuropathy spectrum disorder. Compared to full-term neonates, preterm neonates are more susceptible to BIND and suffer adverse effects at lower TB levels with worse long-term outcomes. Furthermore, although standardized guidelines for management of hyperbilirubinemia exist for term and late preterm neonates, similar guidelines for neonates less than 35 weeks gestational age are limited.

Acquired Hearing Loss in Children

Hearing loss is the most common congenital sensory impairment. According to National Health and Nutrition Examination Survey data from 2001 to 2008, 20.3% of subjects aged greater than or equal to 12 had unilateral or bilateral hearing loss. The World Health Organization notes that, worldwide, there are 360 million people with disabling hearing loss, with 50% preventable. Although many hearing losses are acquired, many others are manifestations of preexisting conditions. The purpose of a pediatric hearing evaluation is to identify the degree and type of hearing loss and etiology and to outline a comprehensive strategy that supports language and social development and communication.

Risk of Sensorineural Hearing Loss and Bilirubin Exchange Transfusion Thresholds

BACKGROUND AND OBJECTIVES

High bilirubin levels are associated with sensorineural hearing loss (SNHL). However, few large studies of relative and excess risk exist. We sought to quantify the risk of SNHL in newborns who had bilirubin levels at or above American Academy of Pediatrics exchange transfusion thresholds (ETT).

METHODS

Infants born at ≥35 weeks gestation in 15 Kaiser Permanente Northern California hospitals from 1995-2011 were eligible (N = 525 409). We used a nested double cohort design. The exposed cohort included subjects with ≥1 bilirubin level at or above ETT. The unexposed cohort was a 3.6% random sample of subjects with all bilirubin levels below ETT (10 unexposed per exposed). An audiologist, blinded to bilirubin levels, reviewed the charts of children in whom SNHL had been diagnosed before age 8 years to confirm the diagnosis. We calculated Cox proportional hazard ratios for time to diagnosis of SNHL.

RESULTS

SNHL was confirmed in 11 (0.60%) of the 1834 exposed subjects and in 43 (0.23%) of the 19 004 unexposed. Only bilirubin levels ≥10 mg/dL above ETT were associated with a statistically significant increased risk of SNHL (hazard ratio: 36 [95% confidence interval (CI): 13 to 101]). Likewise, only bilirubin levels ≥35 mg/dL were associated with a statistically significant increased risk of SNHL (hazard ratio: 91 [95% CI: 32 to 255]). For subjects with total serum bilirubin levels 0 to 4.9 mg/dL above ETT, the upper limit of the 95% CI for excess risk was 0.5%.

CONCLUSIONS

Only bilirubin levels well above ETT were associated with SNHL. At lower bilirubin levels, the excess risk of SNHL was low.

Central auditory processing disorder profile in premature and term infants

OBJECTIVE

The aim of this study is to compare central auditory processing disorder (CAPD) profile between children born prematurely and at term.

METHODS

A retrospective study involving children 7 to 13 years of age who were referred for CAPD evaluation over the past 3 years. Parental reports and medical records were used to collect information. Children with a score ≥ two standard deviations below the mean for at least one ear on at least two different CAPD tests were considered to have CAPD.

RESULTS

A total of 82 children were evaluated for CAPD of which 22 met exclusion criteria, resulting in 60 children with CAPD (15 premature and 45 term). Premature children had higher prevalence of cesarean section delivery and neonatal jaundice compared with term children. Premature children had a higher total number of failed CAPD tests compared with the term children. Among CAPD tests, there was an increased frequency of abnormal Phonemic Synthesis test (PST) and decreased frequency of abnormal Staggered Spondaic Word test (SSW) among premature children compared with term children.

CONCLUSION

Premature children differ in CAPD profile compared with term children. Findings suggest possible etiological differences for CAPD such as jaundice or differential susceptibility of premature children for altered PST and SSW performance when compared with the term children.

Evaluation of auditory brain stems evoked response in newborns with pathologic hyperbilirubinemia in mashhad, iran

Background:

Neonatal jaundice is a common cause of sensorneural hearing loss in children.

Objectives:

We aimed to detect the neurotoxic effects of pathologic hyperbilirubinemia on brain stem and auditory tract by auditory brain stem evoked response (ABR) which could predict early effects of hyperbilirubinemia.

Patients and Methods:

This case-control study was performed on newborns with pathologic hyperbilirubinemia. The inclusion criteria were healthy term and near term (35 - 37 weeks) newborns with pathologic hyperbilirubinemia with serum bilirubin values of ≥ 7 mg/dL, ≥ 10 mg/dL and ≥14 mg/dL at the first, second and third-day of life, respectively, and with bilirubin concentration ≥ 18 mg/dL at over 72 hours of life. The exclusion criteria included family history and diseases causing sensorineural hearing loss, use of auto-toxic medications within the preceding five days, convulsion, congenital craniofacial anomalies, birth trauma, preterm newborns < 35 weeks old, birth weight < 1500 g, asphyxia, and mechanical ventilations for five days or more. A total of 48 newborns with hyperbilirubinemia met the enrolment criteria as the case group and 49 healthy newborns as the control group, who were hospitalized in a university educational hospital (22 Bahaman), in a north-eastern city of Iran, Mashhad. ABR was performed on both groups. The evaluated variable factors were latency time, inter peak intervals time, and loss of waves.

Results:

The mean latencies of waves I, III and V of ABR were significantly higher in the pathologic hyperbilirubinemia group compared with the controls (P < 0.001). In addition, the mean interpeak intervals (IPI) of waves I-III, I-V and III-V of ABR were significantly higher in the pathologic hyperbilirubinemia group compared with the controls (P < 0.001). For example, the mean latencies time of wave I was significantly higher in right ear of the case group than in controls (2.16 ± 0.26 vs. 1.77 ± 0.15 milliseconds, respectively) (P < 0.001).

Conclusions:

Pathologic hyperbilirubinemia causes acute disorder on brain stem function; therefore, early diagnosis of neonatal jaundice for prevention of bilirubin neurotoxic effects is essential. As national neonatal hearing screening in not yet established in Iran, we recommend performing ABR for screening of bilirubin neurotoxicity in all cases with hyperbilirubinemia.

Audiologic impairment associated with bilirubin-induced neurologic damage

Hyperbilirubinemia occurs commonly in neonates and is usually mild and transient, with no long-lasting sequelae. However, bilirubin-induced neurologic damage may occur in some infants. The auditory pathway is the most sensitive part of the central nervous system to bilirubin-induced toxicity, and permanent sequelae may result from only moderately elevated total serum/plasma bilirubin levels. The damage to the auditory system occurs primarily within the brainstem and cranial nerve VIII, and manifests clinically as auditory neuropathy spectrum disorder.

Societal impact of bilirubin-induced hearing impairment in resource-limited nations

Infants with bilirubin-induced neurologic dysfunction (BIND) are characterized by several developmental disabilities including auditory impairments. This paper explores the societal impact of bilirubin-induced auditory impairments, inclusive of hearing impairments and auditory neuropathy spectrum disorders, on these infants, their families, and on the community in resource-limited countries (per capita income of US$6,000 or less). Auditory impairments have substantial emotional, social, and economic impact on the affected infants, their families and communities. The burden is exacerbated by widespread poverty, unfavorable community attitudes towards disabilities, and lack of requisite health, educational, and social services. Curtailing the incidence of avoidable severe hyperbilirubinemia through proactive and effective management of infants at risk or with severe hyperbilirubinemia is necessary at all levels of healthcare delivery. Early detection and intervention for unavoidable auditory impairments should be widely promoted to provide improved developmental trajectories for the affected infants.

Subtle bilirubin-induced neurodevelopmental dysfunction (BIND) in the term and late preterm infant: does it exist?

Subtle bilirubin-induced neurological dysfunction (BIND) is defined as disturbances in sensory and sensorimotor integration, central auditory processing, coordination, and muscle tone in the absence of the classical findings of kernicterus. This review is restricted to the (sensori)motor signs of BIND associated with unconjugated hyperbilirubinemia in term and late preterm neonates. The diagnosis of BIND at follow-up requires validated, age-specific techniques that are designed to identify these disturbances in infancy and later childhood. The (sensori)motor signs of BIND are compatible with the pathological substrate of unconjugated hyperbilirubinemia and its known effects on the brain.

Serum bilirubin and bilirubin/albumin ratio as predictors of bilirubin encephalopathy

BACKGROUND AND OBJECTIVE

Bilirubin/albumin ratio (B/A) may provide a better estimate of free bilirubin than total serum bilirubin (TSB), thus improving identification of newborns at risk for bilirubin encephalopathy. The objective of the study was to identify thresholds and compare specificities of TSB and B/A in detecting patients with acute and posttreatment auditory and neurologic impairment.

METHODS

A total of 193 term/near-term infants, admitted for severe jaundice to Cairo University Children's Hospital, were evaluated for neurologic status and auditory impairment (automated auditory brainstem response), both at admission and posttreatment by investigators blinded to laboratory results. The relationships of TSB and B/A to advancing stages of neurotoxicity were compared by using receiver operating characteristic curves.

RESULTS

TSB and B/A ranged from 17 to 61 mg/dL and 5.4 to 21.0 mg/g, respectively; 58 (30%) of 193 subjects developed acute bilirubin encephalopathy, leading to kernicterus in 35 infants (13 lethal). Auditory impairment was identified in 86 (49%) of 173 infants at admission and in 22 of 128 at follow-up. In the absence of clinical risk factors, no residual neurologic or hearing impairment occurred unless TSB exceeded 31 mg/dl. However, transient auditory impairment occurred at lower TSB and B/A (22.9 mg/dL and 5.7 mg/g, respectively). Intervention values of TSB and B/A set at high sensitivity to detect different stages of neurotoxicity had nearly the same specificity.

CONCLUSIONS

Both TSB and B/A are strong predictors of neurotoxicity, but B/A does not improve prediction over TSB alone. Threshold values detecting all affected patients (100% sensitivity) increase with advancing severity of neurotoxicity.

Auditory neuropathy in late preterm infants treated with phototherapy for hyperbilirubinemia

OBJECTIVE

To evaluate the prevalence of auditory neuropathy (AN) in late preterms treated with phototherapy for hyperbilirubinemia.

DESIGN

Prospective observational study comprising late preterms treated with phototherapy for hyperbilirubinemia. Newborns were screened with combined transient-evoked otoacoustic emissions (TEOAEs) / automated auditory brainstem responses (AABR). Infants who failed screening underwent diagnostic (ABR). Infants were all re-evaluated with AABR at one year.

STUDY SAMPLE

Eighty-five infants with a mean serum total bilirubin concentration of 22.3 ± 1.76 mg/dl; severe-hyperbilirubinemia (SH), and 102 infants with a mean serum total bilirubin concentration of 18.6 ± 1.26 mg/dl; non-severe hyperbilirubinemia (NSH) were included.

RESULTS

From 85 late preterms with SH, six (7.1%) failed screening and underwent diagnostic ABR for six weeks. AN was diagnosed in two (2%) infants with SH. Four (3.9%) of the 102 controls with NSH demonstrated failure at TEOAE/AABR. No AN was diagnosed in the control group at the diagnostic ABR. No statistically significant difference was found between infants treated with phototherapy for SH and NSH with regard to AN/AD either in the postnatal period or at one year. No correlation was found between serum bilirubin levels and ABR latencies or thresholds.

CONCLUSIONS

AN (2%) in late preterms treated with phototherapy for severe-hyperbilirubinemia was not higher than in those with non-severe hyperbilirubinemia.

Hearing and neurological impairment in children with history of exchange transfusion for neonatal hyperbilirubinemia

The objective was to determine frequency of sensorineural hearing loss (SNHL), identified by abnormal threshold in evoked potentials, absence of otoacoustic emissions and behavioral responses, auditory neuropathy (AN) (absence of evoked potentials, with preservation of otoacoustic emissions), and neurological comorbidity in infants with hyperbilirubinemia (HB) treated with exchange-transfusion (ET). From a total of 7,219 infants, ET was performed on 336 (4.6%). Inclusion criteria were fulfilled in 102; 234 children did not meet criteria (182 outside of the study period, 34 did not have complete audiological evaluation, and 18 rejected the followup). Thirty-five children (34%) were born at-term and 67 (66%) were preterm. Children had a mean age of 5.5 ± 3.9 years. Main causes of ET were Rh isoimmunization in 48 (47%), ABO incompatibility in 28 (27.5%), and multifactorial causes in 26 (25.5%). Fifteen (15%) children presented with SNHL. Preterm newborns presented more often with SNHL. Indirect bilirubin level was higher in children with SNHL (22.2 versus 18.7 mg/dL, P = 0.02). No cases of AN were documented. An increased risk of neurologic sequelae was observed in children with SNHL. In conclusion, we disclosed a high frequency of SNHL in children with neonatal HB and ET and neurological alterations. No cases of AN were observed.

Auditory dyssynchrony or auditory neuropathy: understanding the pathophysiology and exploring methods of treatment

OBJECTIVE

To review the literature on auditory dyssynchrony (AD) or neuropathy which is characterized by absent auditory brainstem responses, normal otoacoustic emissions, and word discrimination disproportional to the pure tone audiogram.

RESULTS

Several papers attempt to estimate the prevalence of AD that seems to range between 0.23 and 2% in infants "at risk" for hearing impairment and it is considered to be responsible for approximately 8% of newly diagnosed cases of hearing loss in children per year. The prevalence gets even higher, reaching 10% in children with permanent hearing loss. It seems that AD is not a single disease but a spectrum of pathologies that affect the auditory pathway at the level of the inner hair cells, the synapses, or the auditory nerve. Many predisposing or contribution factors have been reported, including prematurity, hyperbilirubinemia, hypoxia, low-birth weight, immunological conditions, infectious diseases, etc. Before proposing any method of management, parents should be informed about the variation among patients and the changes that may appear in some children's audition over time. Sigh language, speech and language therapy, hearing-aids, and cochlear implantation have been used in the treatment of AD. In general, AD is rather refractory to conventional amplification and cochlear implantation has been found an effective method of management in young implanted children with severe/profound deafness and AD. However, the situation is more complicated and challenging in milder hearing losses.

CONCLUSION

The selected and proposed 30 related articles published in the International Journal of Pediatric Otorhinolaryngology aim to stimulate the related research in order to further explore the etiology, pathophysiology, and management of AD.