Automated auditory brainstem response in neonatal hearing screening

Severe congenital hearing impairment is an important handicap affecting 0.1% of apparently healthy liveborn infants and 1-2% of graduates of neonatal intensive care units. The prognosis for intellectual, emotional, language and speech development in the hearing-impaired child is improved when the diagnosis is made early and intervention is begun before the age of 6 mo. Universal screening is preferable, since about 50% of infants with hearing loss are not discovered if neonatal hearing screening is restricted to high-risk groups. The automated auditory brainstem response (AABR) screener is a dedicated hearing screening device which provides information not only about the outer/middle ear and cochlea but also about the auditory pathway up to the brainstem. AABR has an agreement with conventional auditory brainstem response up to 98%. It uses a 35 dB near hearing level click. No operator interpretation is needed and it can be used on the ward and during oxygen therapy without disturbance from ambient noise. Reported referral rates in a hospital-based screening programme at the time of discharge vary, with an average of 4%. AABR has also been used in a home-based setting, with the same results. The time necessary for screening varies with the setting, but ranges from 4 to 15min. Initial costs range from $15 to $25 per test, which is similar to neonatal screening for metabolic diseases. In addition to individual healthcare savings, early diagnosis may lead to savings on costs of intensive speech-language intervention and educational facilities.     

Ligurian experience on neonatal hearing screening: clinical and epidemiological aspects

AIM: Early identification and rehabilitation of newborns with congenital hearing impairment (HI) by Universal Neonatal Hearing Screening (UNHS). METHODS: The neonatal population was divided into two groups: babies with No Audiological Risk (NAR), and babies With Audiological Risk (WAR). NAR neonates underwent OAE testing, and in case of a doubtful (Refer) result, ABR testing was carried out. All WAR newborns underwent ABR testing within the third month of life. RESULTS: Between February 1, 2002 and December 31, 2004, UNHS was carried out on 32 502 newborns at the 13 regional birth centres, representing 98.7% of the whole regional neonatal population. The prevalence of HI in the population we tested was estimated at about 1 per thousand, while Bilateral Hearing Impairment (BHI) was estimated at 0.65 per thousand. A 3.7% prevalence of HI and a 2.8% prevalence of BHI was observed among the WAR population. Median age at the end of the diagnostic procedures was 6.7 months in the WAR population and 6.9 months in the NAR population. CONCLUSIONS: Our project is based on two levels of testing, which resulted in a 0.28% false-positive rate with 100% sensitivity and 99% specificity. Our screening is the first Italian experience that has been extended to a whole region and the results prove that regional neonatal hearing screening is feasible.     

Neonatal hearing screening with an automated auditory brainstem response screener in the infant's home

Universal neonatal hearing screening is essential if all infants with congenital or perinatally acquired hearing impairment are to begin treatment before the age of 6 months to facilitate development of speech, language, communication and academic skills. Screening cannot always take place in hospital because of the increase in very short-stay deliveries. Therefore screening in the home may be necessary to achieve a high level of screening. We describe a feasibility study with an automated auditory brainstem response (AABR) screener in the infant's home as part of the service offered by the Well Baby Clinics in the Netherlands. Of the 277 infants who completed the screening 266 had the result "pass", 7 "refer" and 4 had inconclusive results. The mean time needed per screening was 18 min. This study shows that neonatal hearing screening by nurses using an AABR infant screener in the home is feasible.     

Universal hearing screening

Objective To determine the weighted incidence of hearing impairment in a standardized population of at risk and not at risk neonates seeking care at a tertiary level hospital in India. Methods A prospective study of a nonrandomized cohort of 1769 neonates (1490: Not at risk; 279: At risk) from a total of 8192 neonates (6509: Not at risk; 1683: At risk) who sought care at St John’s medical College hospital from 1^st September 2002 to 31^st March 2006 were screened for hearing impairment using transient evoked otoacoustic emissions. Weighting was performed using the expected value of 10 % at risk and 90 % not at risk infants in a typical tertiary care level center in India derived from the National Neonatology and Perinatology database 2002–2003. Z test and 95 % confidence interval was used to determine the external validity of the results. P less than 0.05 was considered as statistically significant. The power of the study is 90 %. Results The incidence of hearing impairment in infants screened was 10 per 1769 infants screened (1490: Not at risk; 279: At risk) which is 5.65 per 1000 screened. 279 at risk infants were screened and 3 were detected to have hearing impairment which is an incidence of approximately 10.75 per 1000 screened. Of the 1490 not at risk infants screened 7 had hearing impairment that is 4.70 per 1000 screened. If this was extrapolated to a standardized population consisting of 10 % at risk and 90 % not at risk then the incidence would be 5.60 per 1000 screened with a 95 % confidence interval of 4.13–7.06. This narrow 95 % confidence interval with a p equal to 0.001 indicates that this value may be close to the caseload in a typical tertiary care center. Conclusion In this study the incidence of hearing impairment is 3 per 279 in at risk infants screened and 7 per 1490 in not at risk infants screened. The weighted incidence in a standardized population of neonates seeking care at tertiary level center in India is 5.60 per 1000 as per this study. This high incidence calls for all pediatricians to consider incorporating a basic hearing screen for all the neonates using cost effective and appropriate technology. Initial screening may be performed using behavioral observation techniques and confirmation by otoacoustic emissions.     

婴儿听力筛查及听力损伤干预效果评估

目的了解我院新生儿听力障碍发生率和听力障碍干预效果,促进听力障碍婴儿言语智能发育。方法应用耳声发射分析仪和听觉脑干诱发电位对2007—2010年无锡市妇幼保健院出生的婴儿进行听力筛查和听力障碍诊断,对确诊听力障碍婴幼儿根据家长对干预的依从性分为干预组和非干预组,同时选择同期出生听力正常儿童为对照组,采用Gesell发育量表进行言语能发育商测定,评估干预效果。结果研究期间总共筛查11 697名婴儿,初筛未通过930例(79.5‰),复筛未通过183例(15.6‰),确诊听力障碍24例(2.1‰),听力障碍确诊率由2007年的3.9‰逐年下降至2010年的1.4‰。听力障碍婴幼儿干预组和非干预组言语能发育商均低于对照组[(82.5±10.3)、(67.0±14.4)比(94.5±5.7)],且非干预组低于干预组,差异均有统计学意义(P<0.05)。结论我院婴儿听力障碍的确诊率呈逐年下降趋势,佩戴助听器和语言训练综合干预有助于提高听力障碍婴幼儿的言语智能发育。     

Infant hearing screening with an automated auditory brainstem response screener and the auditory brainstem response

From 1653 babies hospitalized in the Veterans General Hospital—Taipei from 1993 to 1995, 260 infants at risk of hearing impairment were selected. The risk criteria of hearing impairment for neonates were based on the recommendation of the US Joint Committee on Infant Hearing, 1990 Position Statement. All these infants were screened with the Algo-1 Plus, an automated auditory brainstem response (ABR) screener at a mean postconceptional age of 40.7 ± 4.5 weeks. Thirty-nine cases (39/260, 15%) involving 57 ears (57/520, 11%), failed the screening. Except for one infant who died, the babies had an ABR test for both air- and bone-conducted stimuli and an otological examination. The case-specific incidence of conductive hearing deficit at the initial ABR test was 5.4%. The prevalence of sensorineural hearing deficits was between 2.3% confirmed and 3.1% including infants who did not have follow-up tests. The n-value that indicated agreement between the Algo-1 and ABR results was 0.64, and the overall efficiency of using Algo-1 to correctly identify pass or failure of the ABR was 83%.     

Implementation of a nation-wide automated auditory brainstem response hearing screening programme in neonatal intensive care units

AIM: As part of a future national neonatal hearing screening programme in The Netherlands, automated auditory brainstem response (AABR) hearing screening was implemented in seven neonatal intensive care units (NICUs). The objective was to evaluate key outcomes of this programme: participation rate, first stage success rate, pass/referral rates, rescreening compliance, diagnostic referral rates, age of first diagnostic evaluation and prevalence of congenital hearing loss (CHL). METHODS: This prospective cohort study collected data on 2513 survivors. NICU graduates with one or more risk factors according to the Joint Committee on Infant Hearing were included in a two-stage AABR hearing screening programme. Conventional ABR was used to establish a diagnosis of CHL. RESULTS: A total of 2513 newborns enrolled in the programme with a median gestational age of 31.6 (range 24-43) wk and a median birthweight of 1450 (range 510-4820) g. In 25 (1%) cases parents refused screening. Four out of 2513 newborns were initially lost; 2484 newborns have been tested initially. A final 98% participation rate (2465/2513) was obtained for the whole programme. After a median postmenstrual age at the first test of 33.7 (range 27-54) wk, a pass rate of 2284/2484 (92%) resulted at the first stage. The rescreening compliance after the first test was 92% (184/200). A referral rate for diagnostic ABR of 3.1% (77/2484) resulted. Of the 77 referrals 14 (18.2%) had normal screening thresholds, 15 (19.5%) had unilateral CHL and 48 (62.3%) had bilateral CHL. The prevalence of unilateral CHL was 0.6% (15/2484) and of bilateral CHL 1.9% (48/2484). CONCLUSION: A financially supported two-stage AABR hearing screening programme can be successfully incorporated in NICU centres and detects a high prevalence of CHL in NICU graduates. Neonatal hearing screening should be part of standard clinical practice in all NICU infants.     

听觉脑干反应和耳声发射在高危儿听力筛查中的应用

目的：耳声发射(OAE)和听觉脑干反应(ABR) 是新生儿听力筛查的常用方法。该研究旨在探讨畸变产物耳声发射(DPOAE) 和ABR应用于重症监护病房(NICU)高危新生儿听力筛查的差异和意义。方法：分别应用Smart-EP型听觉脑干诱发电位仪和Smart-OAE畸变产物耳声发射检查仪对600例(1 200耳)不同病因所致的高危儿同时进行DPOAE和ABR检查,将两种方法取得的检测结果进行比较。结果：在600例(1 200耳)高危新生儿中,ABR的异常率(78.6%,943/1 200耳)远高于DPOAE的未通过率(22.3%,268/1 200耳);二种检查的共同阴/阳性率分别为20.8%(241/1 200耳)和21%(252/1 200耳)。1 200耳中有493耳DPOAE和ABR的测试结果一致,占41.1%;707耳的测试结果不一致,占58.9%。DPOAE测试的假阳性率为6.0%(16/268耳),假阴性率为74.1%(691/932耳)。结论： DPOAE仅反映耳蜗功能,单独用于高危新生儿听功能筛查的价值有限。ABR检查果相对可靠,NICU高危新生儿听力筛查应先做ABR检查,ABR异常者再做OAE检查。ABR和OAE二种检测方法相互结合,方能提高高危新生儿听力筛查的准确性。     

Implementation and results of bedside hearing screening with automated auditory brainstem response in the neonatal intensive care unit

Aim: To evaluate implementation and results of neonatal hearing screening with automated auditory brainstem response (AABR) by bedside nurses in a single‐centre neonatal intensive care unit (NICU). Methods: Retrospective review of charts of 2074 newborns admitted over a 4‐year period. Results: One thousand eight hundred and 24 newborns (88%) were screened. A ‘pass’ result was obtained in 1761 patients (96.5%). From 63 infants with ‘refer’, 40 were tested with auditory brainstem response: in 28 hearing loss was confirmed. Three hundred and nine neonates were screened before postmenstrual age (PMA) of 34 weeks: 78% successfully passed the first test. Sixty‐seven infants with ‘refer’ at the first test before PMA of 34 weeks were re‐evaluated: 48 had normal hearing tests, 24 of whom still younger than 34 weeks. For 12 of 19 infants with ‘refer’ before 34 weeks, follow‐up was available: in 7 hearing loss was confirmed. Conclusion: Neonatal hearing screening with AABR can be easily performed by the bedside nurse in the NICU even in premature babies before 34 weeks PMA. A ‘pass’ result can be obtained in almost 80% of them; a ‘refer’ result at that age, however, must be interpreted cautiously, as false ‘refer’ occurred in 5/12 of these infants.     

Newborn hearing screening in a single private Japanese obstetric hospital

BACKGROUND: Hearing loss is one of the most common abnormalities present at birth. The authors examined the frequency of newborn hearing disturbance at a single obstetric hospital to exclude technical varieties or varieties of subjects which are inevitable in multiple institutional cooperative studies. METHODS: The newborns were examined with an automated auditory brainstem response screener, the ALGO 2e, on day 4 post-partum. This Screener uses 35 dB near hearing level click stimuli and provides a PASS/REFER result that requires no interpretation. The PASS result is accepted as adequate evidence of hearing and REFER result as required further diagnostic testing to determine hearing status. Screenings of REFER outcomes were repeated at 1 month of age. Comparisons were made of the results and the Japanese multiple institutional trials by Mann-Whitney U-test. RESULTS: The authors screened 8979 out of 13 494 neonates born from July 1999 to October 2004. The neonates with unilateral or bilateral REFER outcomes were 37 cases (0.41% of the total examined) on day 4, and 31 cases (0.35%) at 1 month of age. Five of the 31 neonates had PASS outcomes at 6 months of age. Among the 31 REFER neonates, eight (25.8%) had otolaryngeal complications. CONCLUSION: In the present study, screening results at 1 month of age resembled the final diagnosis obtained at 6 months of age; out of 31 REFER cases, 26 cases were diagnosed with hearing loss. In contrast, in the multiple institutional study, both unilateral and bilateral REFER rates were much higher than the rates of final hearing loss. Concerning the final diagnoses of bilateral hearing loss, the authors' results (0.10%) and the multiple institutional studies' results (0.05% in low-risk and 2.19% in high-risk neonates) were comparable to the results reported in the USA. To expand the newborn hearing screening program, it is crucial that authority and institutions concerned promote the development of a national or prefecture-based early hearing loss identification and intervention network.     

高胆红素血症新生大鼠耳蜗核NMDAR活性变化与听力损伤的实验研

目的：探讨高胆红素血症时听力损伤的机制及NMDAR活性变化在此损伤中的作用。方法：7 d龄 Sprague-Dawley大鼠60只,随机分为对照组和实验组,实验组又根据腹腔注射胆红素的剂量（100 μg/g和200 μg/g）分为M1、M2组,对照组以生理盐水取代胆红素溶液。测试各组动物脑干听觉诱发电位（ABR）,检测血清胆红素浓度和脑组织胆红素含量,免疫组化SABC法测试大鼠耳蜗核NMDAR的活性变化。结果：M1组和M2组ABR反应阈明显升高,I、II、III波潜伏期及I～Ⅱ、Ⅱ～III、I～III波间期明显延长。M1组、M2组耳蜗核NMDAR免疫组化平均灰度值明显低于对照组,与脑组织胆红素含量呈显著负相关,与ABR反应阈亦呈显著负相关。结论：NMDAR活性升高在高胆红素血症听力损伤过程中发挥重要作用。［中国当代儿科杂志,2010,12（3）：201-204］     

Post-natal hearing loss in universal neonatal hearing screening communities: current limitations and future directions

Abstract:   Universal hearing screening has dramatically improved outcomes for babies born with detectable hearing abnormalities; yet there are some infants who develop significant hearing problems after passing a neonatal screen. There is much conjecture as to the number and the characteristics of infants with post-natal hearing losses; yet evidence suggests that many children may be affected, and that a large proportion have no discoverable cause. Currently, screening programmes use lists of risk factors to enrol babies into surveillance programmes. This practice is problematic because audiological follow-ups are expensive and under-utilised, and parental disclosure is often inaccurate. The large databases from universal neonatal programmes could inform the development of effective, evidence-based practice and policy for the detection and intervention of children who develop post-natal hearing losses.     

One-third of term babies after perinatal hypoxia-ischaemia have transient hearing impairment: dynamic change in hearing threshold during the neonatal period

AIM: To examine the process of change in hearing threshold during the neonatal period after perinatal hypoxia-ischaemia. METHODS: The threshold of brainstem auditory evoked responses (BAER) was measured serially during the first month after birth in 92 term babies who suffered hypoxia-ischaemia. RESULTS: The mean BAER threshold in these babies was significantly increased on day 1 (ANOVA p < 0.001). The elevated threshold decreased progressively on days 3 and 5, but was still significantly higher than that in normal controls (p < 0.01). The elevation continuously decreased more slowly on days 10 and 15, and to a near normal level on day 30. Threshold elevation was seen in 31.7% of the babies on day 1, and 34.5% during the first three days. The rate of elevation decreased progressively thereafter. On day 30, 10.6% of the subjects still had increased thresholds. Moderate to severe elevation occurred mainly during the first week and severe elevation occurred predominately on day 1. Threshold elevation starting after days 3-5 is likely to be due to middle-ear disorders. As a whole, during the first month, 44.6% (41/92) of the babies studied had threshold elevation. BAER threshold was correlated weakly with the stage of hypoxic-ischaemic encephalopathy on days 1 and 3. The threshold was significantly higher in babies with severe encephalopathy than in those with mild or moderate encephalopathy during the first 3 d of life. CONCLUSION: Hearing threshold is elevated in about one-third of term babies after hypoxia-ischaemia. The elevated threshold decreases progressively after birth, and returns to normal by one month in most babies. The threshold correlates weakly with the severity of encephalopathy.     

Universal newborn hearing screening

The present statement reviews the evidence for universal newborn hearing screening (UNHS). A systematic review of the literature was conducted using Medline and using search dates from 1996 to the third week of August 2009. The following search terms were used: neonatal screening AND hearing loss AND hearing disorders. The key phrase "universal newborn hearing screening" was also searched. The Cochrane Central Register of Controlled Trials and systematic reviews was searched. Three systematic reviews, one controlled non-randomized trial and multiple cohort studies were found. It was determined that there was satisfactory evidence to support UNHS. The results of the available literature are consistent and indicate clear evidence that without UNHS, delayed diagnosis leads to significant harm for children and their families; with UNHS, diagnosis and intervention occur earlier; earlier intervention translates to improved language outcomes; and in well-run programs, there is negligible harm from screening.     

Prediction of permanent hearing loss in high-risk preterm infants at term age

The aim of this series was to assess hearing screenings; auditory brainstem responses (ABR), transient evoked otoacoustic emissions (TEOAE) and free field auditory responses (FF) for the prediction of permanent bilateral hearing loss in high-risk preterm infants at term post-conceptional age. A total of 51 preterm infants (gestational age <34 weeks, birth weight <1500 g) underwent examinations at term and hearing, speech and neurological development were followed up until a corrected age of 18 months. Significant hearing defects were verified by broader ABR examinations under sedation and by clinical ward observation including responsiveness to sounds and enhancement of hearing using an amplification device. Seven bilateral fails in ABR were found, together with nine bilateral fails in TEOAE and four fails in FF screening at term age. Six preterm infants were later confirmed to have a significant permanent bilateral hearing loss, four of whom had also cerebral palsy. Bilateral failure in ABR screening predicted hearing loss with a sensitivity of 100% and a specificity of 98%, TEOAE with a sensitivity of 50% and a specificity of 84% and in the FF examination at the levels of 50% and 98%, respectively. Conclusion Transient evoked otoacoustic emissions alone seem not to be so applicable to the neonatal screening of hearing in high-risk preterm infants as shown earlier in full-term infants, possibly because a hearing defect may be due to retrocochlear damage. Consequently, auditory brainstem response screening seems to be more suitable for very low birth weight preterm infants. Received: 21 September 1999 / Accepted: 5 January 2000     

Evaluation of an automated auditory brainstem response infant hearing screening method in at risk neonates

An automated auditory brainstem response (ABR) methodthe ALGO-1 Plus-has been developed for hearing screening in healthy neonates. The aim of this study was to test the validity of this automated ABR screening method in at-risk neonates in a neonatal intensive care unit. Two hundred and fifty at-risk neonates were selected for screening according to the criteria of the American Joint Committee on Infant Hearing. All 250 neonates were screened with the ALGO-1 Plus for bilateral hearing loss. When two consecutive screenings pointed to bilateral hearing loss (refer) further audiological investigations were performed and where necessary therapeutic measures were taken. All children who passed the screening unilateral or bilateral enrolled in a nationwide behavioural screening programme at the age of 9 months as well as in a 6-monthly follow up programme documenting speech and language development. A total of 245 (98%) neonates passed the ALGO-1 screening, 230 (92%) at the first attempt and 15 (6%) at the second attempt. Five (2%) were referred with bilateral hearing loss. One of these died of congenital rubella shortly after screening and bilateral congenital hearing loss of >35 dB was confirmed in the other 4. None of the infants who passed the screening were discovered to have moderate to severe bilateral hearing loss (> 40 dB) with behavioural screening (n=183/233) or at follow up (n=233/233). In this study, all at-risk neonates with bilateral congenital hearing loss were detected with ALGO-1 Plus screening. No falsenegatives were discovered.     

Low prevalence of hearing impairment among very low birthweight infants as detected by universal neonatal hearing screening

OBJECTIVES: To (a) study the prevalence of hearing impairment in a cohort of very low birthweight (VLBW) infants and (b) evaluate the effectiveness of transient evoked otoacoustic emissions (TEOAE) as a first stage in-hospital hearing screening tool in this population. STUDY DESIGN: The study group was a cohort of 346 VLBW infants born in 1998-2000 at The Sheba Medical Center. The prevalence of hearing impairment in the study group was compared with that of all other newborn infants participating in a universal newborn hearing screening programme during the same period. To evaluate the effectiveness of TEOAE, a control group of 1205 healthy newborns who had no known risk factors for hearing impairment was selected. The results and follow up of hearing screening for these infants were examined retrospectively. RESULTS: Only one VLBW infant (0.3%) was diagnosed with bilateral sensory-neural hearing loss. In addition, nine infants (2.7%) were diagnosed with conductive hearing loss. Bronchopulmonary dysplasia and low Apgar score were the most significant factors for predicting the occurrence of conductive hearing loss. The percentage of VLBW infants who successfully passed the in-hospital TEOAE screening was 87.2, compared with 92.2% in the full term control group. No false negative cases were detected on follow up. CONCLUSIONS: The study shows a low incidence of sensory-neural hearing loss in a cohort of VLBW infants and a relatively high incidence of conductive hearing loss. TEOAE screening was found to be an effective first stage in-hospital hearing screening tool in this population.     

先天性巨细胞病毒感染对婴幼儿听力及智力影响的研究

目的　探讨先天性巨细胞病毒 (CMV)感染对婴幼儿生长发育、听力及智力的影响。方法　对 65例先天性CMV感染儿及 82例非感染儿于新生儿期进行生长发育及听力的检测 ,并于生后 6个月至 4岁进行随访。随访内容包括 :体格检查、发育商测试及听力测试。结果　两组生长发育状况无显著性差异。感染组发育商落后8例 ,对照组仅 1例 ,二者有显著性差异。感染组新生儿期、随访时分别有 7例 9耳、9例 11耳未通过TEOAE听力测试 ,对照组均为 1例 1耳未通过 ,未通过率感染组明显高于对照组。新生儿期、随访时双耳反应能量感染组明显低于对照组。 14例进行了ABR检测 (感染组 12例 ,对照组 2例 ) ,其中感染组 9例 17耳听力异常 ,对照组 1例 1耳听力异常。结论　先天性CMV感染对婴幼儿生长发育可能无明显影响 ,但对听力、智力的损害却不容忽视