Screening the newborn for hearing loss

INTRODUCTION — Hearing loss in infancy can lead to delayed language development, difficulties with behavior and psychosocial interactions, and poor academic achievement. Early detection of hearing loss facilitates early intervention, which is associated with improved language, cognitive, behavioral, and academic outcomes.

Screening for hearing loss in the newborn will be reviewed here. The etiology, evaluation, and management of hearing impairment in children are discussed separately. (See "Hearing loss in children: Etiology" and "Hearing loss in children: Screening and evaluation" and "Hearing loss in children: Treatment".)

DEFINITIONS

Types of hearing loss — Neonatal hearing loss can result from transient or permanent conductive, permanent sensorineural, auditory neuropathy, and mixed defects (table 1) (see "Hearing loss in children: Etiology"):

●Conductive loss is caused by abnormalities of the outer or middle ear, which limits the amount of external sound that gains access to the inner ear (cochlea and vestibular apparatus). Cochlear function remains normal because the inner ear develops separately from the external and middle ears. Conductive hearing loss may be either transient (middle ear fluid) or permanent (anatomical). Transient conductive hearing loss is a frequent cause of a false-positive neonatal screen [1].

●Sensorineural hearing loss (SNHL) results from malfunction of inner ear structures, including the outer and inner hair cells of the cochlea and the eighth cranial nerve components of the auditory neural pathway.

●Auditory neuropathy (AN) is a hearing disorder that affects the neural processing of auditory stimuli and may involve the eighth cranial nerve, auditory brain stem, or cerebral cortex. Sound enters the inner ear (cochlea and outer hair cells) normally, but the transmission of signals from the inner hair cells of the cochlea to the auditory nerve/pathway is either absent or severely distorted. Screening for hearing loss using otoacoustic emissions will not detect patients with AN, as their outer hair cells function normally. (See 'Comparison of AABR and OAE' below.)

●Mixed hearing loss occurs when there is a conductive component in combination with SNHL or AN. There is impairment in the middle ear and inner ear or auditory nerve.

Severity of hearing loss — The extent of hearing loss is defined by measuring the hearing threshold in decibels (dB) at various frequencies. Normal hearing has a threshold of -10 to 15 dB.

Hearing loss ranges from slight to profound. In individuals with bilateral hearing loss, the severity of loss is based on the better-functioning ear.

Severity of hearing loss defined by the American Speech-Language Hearing Association as follows [2-4]:

●No hearing loss – -10 to 15 dB

●Slight – 16 to 25 dB

●Mild – 26 to 40 dB

●Moderate – 41 to 55 dB

●Moderately severe – 56 to 70 dB

●Severe – 71 to 90 dB, or 61 to 80 dB based on the World Health Organization (WHO) definition [3]

●Profound – >91 dB, or >80 dB based on WHO definition

EPIDEMIOLOGY

General newborn population — Clinically significant bilateral hearing loss occurs in 1 to 3 per 1000 live births [5-7]. In the United States, data from the Centers for Disease Control and Prevention (CDC) reported a rate of permanent hearing loss of 1.7 per 1000 infants screened for hearing loss, with an overall screening rate of 98.4 percent for all newborns, excluding infant deaths and parental refusal [7]. There was no documented diagnosis reported in 38.0 percent of infants who failed the newborn hearing screening.

The prevalence of moderate, severe, and profound bilateral permanent hearing loss is estimated at 1 in 900 to 2500 newborns [6,8]. The prevalence of unilateral hearing impairment above 30 decibels (dB) has been reported as 6 out of 1000 newborns [3].

Congenital hearing loss may be due to genetic/hereditary disorders or acquired conditions due to perinatal problems (eg, congenital infections) [5]. Permanent hearing loss is often associated with other congenital abnormalities, and there are >400 syndromes reported to be associated with permanent hearing loss (table 2).In approximately one-quarter to one-half of infants and children with permanent hearing loss, the cause is not identified [9,10]. (See "Hearing loss in children: Etiology".)

NICU setting — Infants cared for in a neonatal intensive care unit (NICU), which includes neonatal level II, III, and IV care units, are at greater risk of hearing loss compared with healthy term infants [11-13]. In particular, sensorineural hearing loss (SNHL) and auditory neuropathy (AN) are much more common with reported rates of 16.7 and 5.6 per 1000 infants, respectively among infants cared for in a NICU compared with an estimated incidence of 0.06 per 1000 infants among a healthy newborn population [11,12]. If infants with hyperbilirubinemia are included in the healthy newborn population, the incidence of SNHL rises to 0.3 per 1000 infants, still one-tenth of the rate seen in infants cared for in the NICU.

Risk factors associated with acquired SNHL and AN include very low birth weight (<1500 g), congenital infections, severe hyperbilirubinemia, perinatal asphyxia, and exposure to ototoxic medications (eg, aminoglycosides, diuretics) (table 3) [8]. (See "Hearing loss in children: Etiology", section on 'Acquired sensorineural hearing loss'.)

RATIONALE FOR SCREENING — Screening newborns for hearing loss leads to earlier detection and intervention in patients with congenital hearing impairment. Early intervention can significantly improve language acquisition and educational achievement in affected patients [2,14-19].

Earlier detection — The available evidence demonstrates that screening newborns detects hearing loss at an earlier age than relying solely on identifying clinical signs of hearing loss [20-25]. This is because caregivers and clinicians are often not able to detect hearing loss in infants until there are signs of delayed speech and language development.

This point was best illustrated by a clinical trial carried out in the 1990s at four hospitals in England [20,25]. Over a three-year period, the hospitals alternated between six-month periods of screening all newborns and periods of no screening. Among the 25,609 infants born during screening periods, 27 were found to have bilateral permanent hearing loss (incidence 105 per 100,000 live born infants) and among the 28,172 infants born during periods without screening, 26 were found to have bilateral permanent hearing loss (incidence 92 per 100,000 live born infants). Compared with infants with hearing loss who were born during periods without screening, those born during screening periods were more likely to have the hearing loss confirmed before age 10 months (59 versus 38 percent) and to start intervention before age 10 months (56 versus 27 percent; odds ratio 2.4, 95% CI 1.0-6.0).

Language and developmental outcomes — Earlier diagnosis and intervention for permanent hearing loss in infants appears to improve language and developmental outcomes [2,15-19,26]. Earlier diagnosis allows for earlier introduction of hearing aids.

In a study of 120 children with bilateral permanent hearing loss identified from a large birth cohort in England, children whose hearing loss was confirmed by nine months of age had better receptive and general language abilities compared with those confirmed after nine months of age [15,16,20,25]. In subsequent follow-up reports, patients from this cohort who were identified before nine months had better reading and communication skills than those diagnosed after nine months of age through adolescence [15,17].

SCREENING TESTS FOR HEARING — An effective neonatal hearing screening test is one that is reliable in infants ≤3 months of age and that detects hearing loss of ≥35 decibels (dB) in the better ear [27].

Two electrophysiologic techniques meet these criteria:

●Automated auditory brainstem responses (AABR)

●Otoacoustic emissions (OAE)

Both AABR and OAE techniques are inexpensive, portable, reproducible, and automated. They evaluate the peripheral auditory system and the cochlea, but cannot assess activity in the highest levels of the central auditory system. These tests alone are not sufficient to diagnose hearing loss; thus, any child who fails one of these screening tests requires further audiologic evaluation. In addition, both methods will miss mild hearing loss. (See 'Infants who fail two-stage screening' below and "Hearing loss in children: Screening and evaluation".)

Automated auditory brainstem response

●What the test measures – AABR measures the summation of action potentials from the eighth cranial nerve (cochlear nerve) to the inferior colliculus of the midbrain in response to a click stimulus. It can detect both sensorineural hearing loss (SNHL) and auditory neuropathy (AN). Other names for this test include the screening ABR (SABR), and screening brainstem auditory evoked response (BAER). Approximately 4 percent of infants screened with AABR are referred for further audiologic evaluation, which uses a diagnostic ABR including an evaluation by an audiologist skilled in assessing infants and young children [27].

●Technique – The AABR utilizes click or chirp stimuli presented at 35 dB. Three surface electrodes placed on the forehead, nape, and mastoid or shoulder detect waveform recordings generated by the ABR to the stimuli. In the screening AABR, the morphology and latency of the waveforms are compared with normal neonatal templates, and a pass or fail reading is generated, and the examiner does not need to interpret the waveforms if visibly accessible. AABR screening typically requires 4 to 15 minutes for testing, although newer AABR screening equipment can complete testing in an infant in 4 to 8 minutes in ideal conditions.

●AABR versus ABR – It is important to note that an automated ABR (AABR) is not the same as a diagnostic ABR. AABR is a screening tool with an automated pass/fail response. By contrast, diagnostic ABR provides quantitative data (eg, waveforms) that must be interpreted by a trained audiologist, thereby determining the degree and the site of the hearing loss. As an example, delayed or absent waves suggest a neurologic or cochlear deficit. Many neonatal intensive care units (NICUs) now complete the diagnostic ABR prior to discharge for infants who fail the screening AABR. Additional detail regarding ABR are provided separately. (See "Hearing loss in children: Screening and evaluation", section on 'Brainstem response'.)

Otoacoustic emissions

●What the test measures – OAE testing measures the presence or absence of sound waves (ie, OAEs) generated by the cochlear outer hair cells of the inner ear in response to sound stimuli. A microphone at the external ear canal detects these low-intensity OAEs. Since OAE evaluates hearing from the middle ear to the outer hair cells of the inner ear, it is used to screen for SNHL but cannot detect AN.

●Technique – The apparatus for OAE screening consists of a miniature microphone placed into the infant's outer ear canal. The microphone produces a stimulus (clicks or tones) and detects sound waves as they arise from the cochlea. The device also measures the signal-to-noise ratio to ensure accuracy. OAE screening generally requires approximately one to two minutes per ear in ideal testing conditions.

OAEs are classified by the stimuli used to produce the cochlear basal membrane vibrations. The tests most commonly used for clinical purposes are transient OAEs (TOAEs) and distortion product OAEs (DPOAEs).

Comparison of AABR and OAE — The following is a comparison between the automated auditory brainstem response (AABR) and otoacoustic emissions (OAE) screening methods:

●Test time – OAE tends to require less patient preparation time and a shorter test time than AABR [28]. AABR may also present time constraints because infants need to be asleep or quiet awake when tested. In contrast, OAE can be performed when the infant is awake, feeding, or sucking on a pacifier [29]. Response time, however, is much quicker for OAE if the infant is sleeping or quiet awake.

●Interference – OAE is sensitive to background noise, and physiological noise generated by the infant [30]. It may be difficult to obtain OAE responses at low frequencies due to physiological noise, myogenic noise, or poor acoustics. This noise interference is greater when the recorded frequency is below 1500 Hertz (Hz). Thus, screening with OAE can be improved by programming protocol parameters to include select high frequencies, which are more important for understanding speech [30-32]. These protocol changes should be implemented by an audiologist with a specialized skill set in pediatrics. OAE, unlike AABR, is not subject to muscle artifact [29,33]. AABR can also be complicated by electrical artifacts [29].

●False-positive results – During the first three days of life, there is an increased false-positive rate with OAE compared with AABR, most commonly due to transient conductive hearing loss caused by vernix occluding the external ear canal or middle ear fluid (due to amniotic fluid). [33-36]. In several reports, 19 to 25 percent of newborns with abnormal OAE screening during the first three days after birth had subsequent normal hearing in follow-up testing [35-38]. In one study, cleaning of vernix increased the pass rates from 59 to 69 percent [36].

It is important to recognize that the pass threshold is higher for OAE than for AABR, resulting in a higher fail rate. Both methods will miss minimal and mild hearing loss.

●Tympanic membrane mobility – OAE requires normal middle ear function. Thus, decreased tympanic membrane mobility can reduce screening pass rates with this technique [29]. The magnitude of this problem was illustrated in a series of 200 infants, in which the pass rate in the 23 percent of infants with decreased tympanic membrane mobility was lower with OAE than AABR (33 versus 95 percent, respectively) [36]. This issue is not currently assessed in screening programs in the United States.

●Auditory neuropathy – Infants at risk for developing AN include those with severe hyperbilirubinemia, prematurity, perinatal asphyxia, craniofacial abnormalities, and others who are admitted to neonatal intensive care units (NICUs). AABR will detect the hearing loss in infants with AN, but OAE will not. Therefore screening for AN with OAE may lead to a false-negative result [29,39]. Thus, AABR should always be used to screen hearing in infants who are at risk for AN (eg, infants with hypoxia, prematurity, hyperbilirubinemia, neurologic impairment and all infants who require ≥5 days of NICU care).

●Relative costs – Although the actual screening cost is lower for OAE compared with AABR, the overall cost of screening and audiologic evaluation may be lower with AABR because of the lower referral rate for diagnostic audiologic assessment, although this varies by location. One study evaluated screening programs initiated at two sites, one using automated ABR administered by neonatal nurses and the other using OAE performed by master's level audiologists [40]. Less time was needed for testing with OAE than with AABR (5 versus 13 minutes), but the rate of referral for further testing was higher with OAE (15 versus 4 percent). Although the costs before discharge were similar for the two programs, the increased referral rate with OAE increased the overall cost per infant screened.

RISK FACTORS FOR HEARING LOSS — Major risk factors for neonatal hearing loss include the following (table 3) [6,41]:

●Neonatal intensive care unit (NICU) admission for ≥5 days, especially if the neonate required mechanical ventilation or extracorporeal membrane oxygenation (ECMO) support (see 'Neonatal intensive care unit' below)

●Syndromes associated with hearing loss (table 2) (see "Hearing loss in children: Etiology", section on 'Genetic')

●Family history of permanent childhood hearing loss

●Craniofacial and ear abnormalities (eg, cleft lip and/or palate, temporal bone abnormalities, anomalies of the pinna or ear canal) (see "Syndromes with craniofacial abnormalities" and "Congenital anomalies of the ear")

●Congenital infection (particularly cytomegalovirus but also other TORCH infections such as Zika virus, toxoplasmosis, rubella, syphilis, herpes simplex virus [HSV]) (see "Congenital cytomegalovirus infection: Clinical features and diagnosis", section on 'Isolated hearing loss' and "Overview of TORCH infections")

●Postnatal central nervous system infection (eg, bacterial meningitis, HSV encephalitis) (See "Bacterial meningitis in the neonate: Neurologic complications", section on 'Long-term complications' and "Neonatal herpes simplex virus infection: Management and prevention", section on 'Outcome'.)

●Severe hyperbilirubinemia requiring exchange transfusion [42] (see "Unconjugated hyperbilirubinemia in neonates: Risk factors, clinical manifestations, and neurologic complications", section on 'Consequences of severe hyperbilirubinemia')

●Perinatal asphyxia or neonatal encephalopathy (see "Perinatal asphyxia in term and late preterm infants" and "Clinical features, diagnosis, and treatment of neonatal encephalopathy")

●Ototoxic mediation (eg, aminoglycosides, diuretics) (see "Hearing loss in children: Etiology", section on 'Ototoxic drugs')

The risk of permanent hearing loss rises as the number of risk factors increases [41]. Of note, many of the same risk factors (congenital infection, hyperbilirubinemia, perinatal asphyxia) are associated with both sensorineural hearing loss (SNHL) and auditory neuropathy (AN). In contrast, craniofacial abnormalities, are most often associated with permanent conductive loss due to abnormalities of the pinna, including microtia and atresia of the ear canal. As a result, a comprehensive diagnostic audiology assessment by an audiologist skilled in assessing young infants and children is required to guarantee the most optimal evaluation and treatment including amplification for the infant. (See 'Infants with risk factors for hearing loss' below.)

UNIVERSAL SCREENING — Universal newborn hearing screening (NHS) is the preferred method to screen newborns for hearing loss [14,27,43,44].

The approach outlined in the following sections is generally consistent with guidelines of the United States Preventive Services Task Force (USPSTF) and the Joint Committee on Infant Hearing (JCIH) [14,27,43]. Links to these and other guidelines are provided separately. (See 'Society guideline links' below.)

Practitioners should familiarize themselves with local mandates in their practice area. In the United States, information for each state is available at the National Center for Hearing Assessment and Management.

Universal versus selective screening — Prior to universal NHS, the main approach to identifying infants with a permanent hearing loss was to selectively test newborns with risk factors for hearing loss (table 3). (See 'Risk Factors for Hearing Loss' above.)

Selective screening is no longer recommended because the available evidence suggests that this approach misses or delays detection of hearing loss in a significant number of patients. Thus, universal NHS is the preferred approach. (See 'Rationale for screening' above.)

A targeted screening program using the risk factors discussed above (table 3) can identify only 50 to 75 percent of infants with moderate to profound bilateral hearing loss [6,45], and the time of diagnosis may be delayed [46]. In particular, infants with congenital hearing loss may not have any identifiable risk factors and selective screening will fail to identify these individuals [6,21,34,47-51].

Goals of newborn screening — The goal of NHS is early recognition and treatment of hearing loss, thereby maximizing language development in children who are deaf or hard of hearing [27,52].

Specific goals of universal NHS as summarized in the Early Hearing Detection and Intervention (EHDI) guidelines include [14,27]:

●Perform screening in all newborns before the age of one month. (See 'Protocols' below.)

●For infants who fail their screening test, perform audiologic assessment by three months of age. (See 'Infants who fail two-stage screening' below and "Hearing loss in children: Screening and evaluation".)

●For infants found to have significant hearing loss, start intervention by six months of age. The intervention should be individualized to meet the needs of the infant and family/caregiver [53,54]. (See "Hearing loss in children: Treatment".)

Impact of screening — With the widespread adoption of universal NHS, the age at identification of hearing loss has decreased from a range of 24 to 30 months to 2 to 3 months of age [55].

The impact of NHS in the United States has been shown by the Centers for Disease Control and Prevention (CDC) EHDI programs [56]:

●Data from the 2019 CDC EHDI report from 47 states and 7 territories showed 98 percent of births (3.5 million infants, excluding refusals) were screened, of which 1.7 percent infants (n = 61,475) did not pass the final newborn screen [56].

●Among infants who did not pass the NHS, approximately 10 percent (n = 5934) were ultimately diagnosed with permanent hearing loss. The prevalence of permanent hearing loss was 1.7 per 1000 live births.

●Almost 85 percent of newborns diagnosed with permanent hearing loss were referred to early intervention and 67 percent enrolled in early intervention, of whom nearly all were enrolled before six months of age.

A separate 10-year quality assurance review of the two-stage screening program for Dutch neonatal intensive care unit (NICU) graduates demonstrated 96 percent of NICU patients were screened before one month corrected gestational age, and 82 percent were tested before six weeks of age [57]. Two-thirds of the patients with hearing loss were diagnosed before three months of age.

Attributes of effective screening programs — Each birth hospital should establish a screening program. Attributes of an effective screening program include [27,58]:

●The program should have a medical director and staff with adequate training.

●A minimum of 95 percent of infants should be screened before discharge from the birth hospitalization. Either OAE or AABR can be used for healthy term infants. AABR should be used for infants at risk for auditory neuropathy (AN) (eg, infants admitted to the neonatal intensive care unit [NICU]). (See 'Neonatal intensive care unit' below and 'Comparison of AABR and OAE' above.)

●An effective communication system that ensures results of screening are conveyed to the family/caregiver and the primary care provider.

●A system to ensure that all infants who fail the screening test are referred for audiologic assessment.

●A high follow-up rate (at least 95 percent), including follow-up of infants referred for audiologic assessment and infants who were not screened during the birth hospitalization (unless parents/caregivers declined screening).

●A process for rescreening infants who are readmitted within the first month after birth for conditions associated with risk of hearing loss (eg, hyperbilirubinemia, meningitis).

Protocols — The two types of universal screening protocols routinely used are single- or two-stage.

Single stage — A single-stage NHS utilizes one screening test, either OAE or AABR, which detects 80 to 95 percent of ears with hearing impairment. With either single test, there is a high false-positive rate resulting in a substantial number of infants with normal hearing referred for audiologic assessment, thereby increasing the overall cost of universal NHS. Referral for audiologic evaluation is generally required for 4 percent of infants screened with AABR [59,60] and between 5 to 21 percent of infants screened with OAE [23,47]. The prevalence of moderate to severe hearing loss is estimated to be one case for every 900 to 2500 newborn infants. Thus, for one case of significant hearing loss, the number of infants with normal hearing referred for audiologic evaluation after a single-stage screen would range from 40 to 500 patients. As a result, most birthing hospitals in the United States use two-stage protocols.

Two stage — In a two-stage screening protocol, a second screen is given to patients who fail the initial study, and only patients who fail both screens are referred for audiologic assessment (algorithm 1 and algorithm 2) [61]. The two-stage protocol is preferred as it reduces the rate of false-positive tests and reduces the referral rate for audiologic assessment [62,63].

Data from studies utilizing a two-stage NHS reported that approximately 900 to 1400 infants would need to be screened to identify one case of bilateral hearing loss [20,64]. It is estimated that one of every 45 infants from the newborn nursery referred for audiologic evaluation by a two-stage NHS would have moderate to profound bilateral permanent hearing loss [6].

However, the two-stage screening may miss infants with hearing loss, because it inaccurately assumes that all infants who fail the initial screen but pass the second have normal hearing [61,65,66]. In addition, the screening devices currently available have thresholds of approximately 35 decibels (dB) and will miss mild hearing loss, which will delay diagnosis of hearing loss. Because of this finding, continued surveillance of hearing skills and language development as described in the AAP periodicity schedule is recommended by the JCIH and AAP.

APPROACH TO SCREENING DURING BIRTH HOSPITALIZATION

Newborn nursery — In the newborn nursery setting (neonatal level of care 1), we suggest performing a two-stage rather than one-stage newborn hearing screen (NHS) primarily to reduce the number of infants with normal hearing who would be referred for further audiologic assessment (algorithm 1) (see 'Two stage' above). Infants are screened initially with otoacoustic emissions (OAE), and those who fail the OAE are then screened a second time using either OAE or automated auditory brainstem responses (AABR).

OAE is the preferred over AABR for initial test for the following reasons [67]:

●OAE takes less time to administer.

●OAE is less costly to administer.

●OAE can be performed in an awake infant; by contrast AABR is optimally performed during sleep or in a quiet awake state.

●While OAE does not detect auditory neuropathy (AN), the incidence of AN is low in infants admitted to the newborn nursery.

For hospitals using a one-stage NHS, we suggest screening with AABR since it results in a lower false-positive rate and lower referral rate for audiologic assessment compared with OAE, and it can identify infants with AN [39,68]. (See 'Comparison of AABR and OAE' above.)

For infants who do not pass the NHS, we suggest referral for formal audiology be made prior to discharge to home. If evaluation by a skilled pediatric audiologist is not possible, the infant can be rescreened after they are discharged, but follow-up should be no later than three months of age. (See 'Infants who fail two-stage screening' below.)

Infants in the newborn nursery who pass the hearing screen but have a risk factor for hearing loss should be closely monitored and referred for further audiology assessment depending on the nature of the risk factor and parent or provider concerns. At-risk infants should have at least one reassessment by 9 months of age [27]. (See 'Infants with risk factors for hearing loss' below.)

Information for parents should be provided on the importance of screening the newborn for hearing loss and the need for follow-up for infants who fail screening. (See 'Information for patients' below.)

Neonatal intensive care unit — Infants cared for in a neonatal intensive care unit (NICU) for >5 days are at increased risk for hearing loss, primarily due to sensorineural hearing loss (SNHL) and AN. Thus, infants admitted to the NICU should be screened using AABR rather than OAE since the latter does not detect AN (algorithm 2). This approach is consistent with the guidelines of the Joint Committee on Infant Hearing (JCIH) [27,39].

The risk of permanent hearing loss among infants admitted to the NICU is approximately 2 percent [11,69]. Preterm infants, especially very low birth weight (VLBW) infants, (BW <1500 g) are at increased risk for SNHL and AN. The risk of hearing loss increases with decreasing gestational age and BW. For VLBW infants, the risk is six times higher than for those with normal BW [69]. (See "Hearing loss in children: Etiology", section on 'Prematurity'.)

FOLLOW-UP — All infants, regardless of the results of the newborn hearing screen (NHS), should have continued surveillance by the primary care provider to identify hearing problems. This includes assessment of developmental milestones, speech, auditory skills, parental concerns, and middle ear status during routine well-child visits [27,70]. Additional recommendations for follow-up are based on the clinical setting. Rescreening for hearing loss can be performed in the outpatient setting or in the medical home [43,71].

Infants who pass initial screening

Newborns without risk factors — Follow-up for healthy newborns who pass the NHS includes continued routine monitoring of language acquisition, auditory skills, middle ear status, and attention to any parental/caregiver concerns that arise. (See "Hearing loss in children: Screening and evaluation", section on 'Screening for hearing loss in children'.)

Infants with risk factors for hearing loss — Infants with ≥1 of the risk factors listed in the table (table 3) should undergo formal audiologic assessment by 9 months adjusted age even if they passed the NHS [27,72]. In addition, referral for formal audiology is generally warranted if parental/caregiver concerns arise. (See 'Formal audiologic assessment' below.)

Formal audiologic testing is recommended for these infants because NHS does not detected all cases of newborn hearing loss (ie, false-negatives) and since hearing loss can be acquired after the newborn period (eg, meningitis, ototoxic medications) [73-76]. In addition, hearing loss associated with some genetic disorders and congenital infections (cytomegalovirus [CMV] and Zika virus) may have a delayed onset [77].

Earlier and repeated assessments may be indicated for infants with congenital CMV infection, genetic conditions associated with progressive hearing loss, some neurodegenerative disorders, meningitis, or when concerns are raised regarding hearing skills or speech development by the parent or primary care provider [27].

Many centers have follow-up programs for at-risk neonatal intensive care (NICU) graduates. For example, at the author’s institution, NICU graduates are followed by the Rhode Island Early Hearing Detection and Intervention (EHDI) program, in which assessment is performed at an earlier age (between 7 and 12 months of post-menstrual age). This ensures that intervention can be provided as early as possible for infants with identified hearing loss.

Infants who fail initial screen but pass the second — The primary care provider should provide increased oversight for term infants who fail the initial screen but pass the second screening test, as they are still at risk for hearing loss. If any clinical suspicion arises regarding the patient's hearing, the infant should be referred for formal audiologic assessment [3]. (See "Hearing loss in children: Screening and evaluation".)

Infants who fail two-stage screening

Audiologic assessment and management

●Newborn nursery ‒ If an infant has failed the two-stage newborn hearing screening test, audiologic assessment should be performed preferably before birth hospitalization discharge (algorithm 1 and algorithm 2). If audiologic assessment is not available before discharge, referral to an audiologist skilled in evaluating infants for hearing loss should be done as soon as possible and no later than three months of age [14,27].

●NICU ‒ For infants cared for in the neonatal intensive care unit (NICU), audiology testing should be performed for infants who failed screening prior to discharge as they are at high risk for hearing loss [14,27]. (See "Care of the neonatal intensive care unit graduate", section on 'Hearing'.)

Subsequent management of infants with hearing loss should be provided by a multidisciplinary team skilled in caring for infants and children with hearing loss. This includes audiologists, otolaryngologists, speech pathologists, geneticists, and educational specialists. (See "Hearing loss in children: Treatment".)

Additional details regarding formal audiology and other aspects of the evaluation for infants with hearing loss are provided in a separate topic review. (See "Hearing loss in children: Screening and evaluation", section on 'Formal audiology' and "Hearing loss in children: Screening and evaluation", section on 'Evaluation of the child with hearing loss'.)

Screening for cytomegalovirus (CMV) — Targeted screening for CMV in newborns who fail the NHS has been proposed as a strategy to identify and potentially treat infants with CMV-related hearing loss. This approach is based on the rationale that CMV is the most common infectious cause of congenital or early-onset hearing loss and there is a potential treatment. However, data are limited and it is unclear if the benefits of screening for CMV in this setting outweigh the burdens, costs, and potential adverse effects of follow-up and therapy [78].

●Our approach – In our practice, until further evidence is available, we perform targeted testing for CMV in infants who fail the hearing test only in infants who [79]:

•Require NICU care, and/or

•Have other signs or symptoms consistent with congenital CMV infection (see "Congenital cytomegalovirus infection: Clinical features and diagnosis", section on 'Symptomatic neonate')

However, practice varies and other centers perform targeted CMV screening in all infants who fail the NHS [80]. (See "Congenital cytomegalovirus infection: Clinical features and diagnosis", section on 'Targeted newborn screening'.)

If CMV testing is performed, we prefer polymerase chain reaction (PCR) testing of urine samples rather than saliva, as the former is more accurate [81,82]. If CMV is detected, additional diagnostic testing may be required to confirm CMV infection, as discussed separately. (See "Congenital cytomegalovirus infection: Clinical features and diagnosis", section on 'Approach to testing'.)

For infants with CMV-related hearing loss who are identified through newborn screening and who are otherwise asymptomatic, expert opinion varies as to whether the benefits of antiviral therapy outweigh the risks. These decisions should be individualized based on the values and preferences of the parents or caregivers. This is discussed separately. (See "Congenital cytomegalovirus infection: Management and outcome", section on 'Who to treat'.)

●Limitations of targeted CMV screening – Important limitations of targeted screening for congenital CMV in this setting include:

•This strategy will miss a considerable subset of infants with CMV-related hearing loss because hearing loss caused by congenital CMV infection often has delayed onset (ie, the newborn may pass the newborn hearing screen and then develop hearing loss later in infancy or childhood) [83-85]. (See "Congenital cytomegalovirus infection: Clinical features and diagnosis", section on 'Isolated hearing loss'.)

•Confirming the diagnosis of congenital CMV infection requires performing viral testing by 21 days of age. Detection of CMV after this age in an infant with confirmed hearing loss suggests congenital CMV infection, but it may also reflect postnatal acquisition of CMV infection. (See "Congenital cytomegalovirus infection: Clinical features and diagnosis", section on 'Approach to testing'.)

•Limited data are available as to whether antiviral therapy improves hearing outcomes in infants with congenital CMV and isolated hearing loss. These data are discussed separately. (See "Congenital cytomegalovirus infection: Management and outcome", section on 'Antiviral treatment'.)

The author of this topic believes additional prospective studies are needed to study the long-term efficacy of targeted screening for CMV, the benefits and burdens of antiviral therapy in this setting, and the overall cost effectiveness of this strategy. However, other experts support the strategy of targeted newborn CMV screening, as discussed separately. (See "Congenital cytomegalovirus infection: Clinical features and diagnosis", section on 'Targeted newborn screening'.)

●Supporting evidence – Studies evaluating the efficacy of targeted screening for congenital CMV in this setting have reached different conclusions.

In a multicenter study of 99,945 newborns who underwent both hearing and CMV screening, the overall rate of failing the hearing screen was 1 percent [84]. The rate of failing the hearing screen was higher in the CMV-positive group compared with those who were CMV-negative (7 versus 0.9 percent). Of the 31 CMV-positive infants who did not pass the newborn hearing screen, 20 (65 percent) had confirmed SNHL on formal audiology. An additional 15 CMV-positive infants who passed newborn hearing screen had SNHL confirmed by age two months. Thus, newborn screening identified only 57 percent of infants with CMV-related hearing loss.

In a state-wide study that utilized data from the Utah Department of Health, of the 509 infants who failed newborn hearing screening, 234 were screened for congenital CMV (screened within 21 days of age) [79]. Fourteen of these infants were diagnosed with congenital CMV, and six had confirmed hearing loss. An additional 80 patients were screened for CMV after 21 days of age, and of the seven who were CMV-positive, three had confirmed hearing loss. However, an accompanying editorial points out there were an estimated 400 to 700 infants with congenital CMV during the same study period, most of whom were not detected by these data [83].

In a report of a single institution's experience with targeted screening, the rate of CMV testing in infants who did not pass the NHS increased from 14 to 88 percent after implementation of targeted screening program [80]. Of the six CMV-positive infants with confirmed hearing loss identified through the program, all were treated with oral valganciclovir. Hearing improved in one patient, remained stable in three, and progressed in two patients.

●Implementation – In the United States, as of 2023, 11 states (Connecticut, Florida, Illinois, Iowa, Kentucky, Louisiana, Maine, New York, Utah, Pennsylvania, and Virginia) have passed legislation requiring that targeted CMV testing be performed or offered to all newborns who fail the hearing screen; one state (Minnesota) mandates CMV testing in all newborns regardless of hearing screen results [86]. Several other states have proposed legislation for targeted or universal newborn CMV screening.

Formal audiologic assessment — When an infant is referred for formal audiologic assessment, the test performed depends upon the infant’s age and developmental stage. Visual reinforcement audiometry (VRA) is the gold standard for hearing assessment for nonverbal children [87]. However, VRA cannot be performed reliably before the infant is six to nine months of developmental age [88]. Until VRA can be performed, infants who fail a screening test should have a diagnostic ABR performed, which includes testing with click stimuli, tone burst stimuli, or chirp stimuli from loud (80 to 90 decibels [dB]) to soft (0 to 20 dB). The audiological evaluation of infants is discussed in greater detail separately. (See "Hearing loss in children: Screening and evaluation", section on 'Tests for young and/or uncooperative children'.)

Management of confirmed hearing loss — For children with documented hearing loss, hearing amplification can be provided with hearing aids, cochlear implants, and other assistive listening devices, which are discussed separately. (See "Hearing loss in children: Treatment".)

In addition, educational and psychological support should be provided to all children with hearing loss and their families/caregivers. Information about support for families/caregivers can be found on the Hands and Voices website, a parent-driven, nonprofit organization dedicated to providing unbiased support to families/caregivers with children who are deaf or hard of hearing.

Minimizing loss to follow-up — For a screening program to be successful, it is imperative that all infants who fail the initial screening undergo formal audiologic evaluation by three months of age [27]. Infants with significant hearing loss can be missed if they cannot be located due to inadequate tracking procedures [40].

In the United States, despite high rates of initial NHS, losses to follow-up and failure to document audiologic outcomes have remained problematic. Approximately 25 to 30 percent of infants who fail the NHS are lost to follow-up [56,89-92]. Reasons for failure of follow-up cited in the available reports were family/caregivers unresponsiveness, inability to contact, or unknown. In addition, new challenges for screening and follow-up occurred with the onset of the COVID pandemic.

●Barriers to follow-up – Barriers to adequate follow-up include [93]:

•Insufficient support system to track patients with a positive screening test

•Primary care provider lack of knowledge regarding screening test results

•Challenges to families/caregivers in obtaining services

•Insufficient number of audiologists to perform further evaluation

•Low socioeconomic status [94-96]

Targeting these challenges, especially for at-risk groups, may improve return rates for further audiologic evaluation. For example, in Massachusetts and Colorado, NHS programs actively follow-up with families/caregivers and providers, resulting in rates of loss to follow-up that are fairly low (approximately 6 percent). Participation of other programs or services can also be used to effectively target follow-up [97].

Nevertheless, in the United States overall, the rate of loss to follow-up for NHS in 2019 was 27.5 percent, a rate that is unacceptably high [56]. Improved state early hearing detection and identification program tracking procedures and follow-up with families/caregivers by their primary care providers are needed as discussed below.

●Tracking – Establishment of a statewide data management system is critical for tracking and ongoing surveillance of infants who fail the newborn screen or have a risk factor for hearing loss, and facilitating communication with providers. In the United States, all states have an Early Hearing Detection and Intervention (EHDI) coordinator who is available to assist providers. Another resource available to providers in the United States is the EHDI-PALS website, which provides information on audiology facilities that provide pediatric services.

In Rhode Island, which is where the author practices, NHS results are provided to the family/caregivers prior to discharge, a letter is sent to the primary care provider, and the data are entered into a state database, KIDSNET (located in the state's Department of Health). This data system links births, birth defects, and information from the Rhode Island Hearing Assessment Program (RIHAP) from birthing hospitals, audiologists, and pediatricians. RIHAP provides primary care physicians with regular lists of patients needing audiology follow-up (figure 1). The RIHAP working group also includes a parent of a child with deafness, who plays a key role for liaison and support for parents/caregivers with a newly diagnosed deaf or hard of hearing child. In addition, the parent member reviews all the resources and opportunities including referral to early intervention programs for children who are deaf and hard of hearing.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Hearing impairment in infants and children".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topic (see "Patient education: Screening for hearing loss in newborns (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Prevalence of neonatal hearing loss ‒ Clinically significant hearing loss occurs in 1 to 3 newborns per 1000 live births. Infants cared for in neonatal intensive care units (NICUs) are at increased risk for hearing loss, primarily due to sensorineural hearing loss (SNHL) and auditory neuropathy (AN). (See 'Epidemiology' above.)

●Universal screening ‒ We recommend universal hearing screening in all newborns rather than targeted or selective testing (ie, testing only at-risk infants or those with clinical concerns for hearing loss) (Grade 1B). Universal newborn screening results in earlier identification of infants with hearing loss, earlier intervention, and possibly better language and developmental outcomes by school age compared with selective testing. (See 'Universal screening' above and 'Rationale for screening' above.)

●Screening tests ‒ Two electrophysiologic techniques, automated auditory brainstem responses (AABR) and otoacoustic emissions (OAE), are routinely used as screening tests. Both tests are portable, automated, and inexpensive, making them well suited to newborn screening. However, OAE does not detect AN, and therefor AABR is used for screening in infants who are at risk for AN (eg, preterm neonates). (See 'Screening tests for hearing' above and 'Neonatal intensive care unit' above.)

●One- versus two-stage protocol ‒ Protocols used for newborn hearing screening may be one-stage (ie, utilizing a single screening test [AABR or OAE]) or two-stage (ie, utilizing two screening tests or repeating the same test). In the two-stage approach, only patients who fail the initial test receive a second screening test, and only patients who fail both tests are referred for audiologic assessment (algorithm 1 and algorithm 2). We suggest a two-stage rather than one-stage protocol (Grade 2C). At many birthing centers, OAE is the initial test in healthy term infants because of lower cost and ease of administration. This is followed by AABR if the OAE is abnormal. Infants admitted to the NICU are screened using AABR because they are at risk for AN, which is not detected by OAE. (See 'Protocols' above and 'Approach to screening during birth hospitalization' above.)

●Follow-up

•Follow-up for healthy newborns who pass the hearing screen includes continued routine monitoring of language acquisition, auditory skills, middle ear status, and attention to any parental/caregiver concerns that arise. (See "Hearing loss in children: Screening and evaluation", section on 'Screening for hearing loss in children'.)

•Infants who pass the newborn hearing screen but have risk factors for hearing loss (table 3) should be monitored for late-onset hearing loss. Follow-up for these at-risk infants includes (see 'Infants with risk factors for hearing loss' above):

-Audiologic reassessment by 9 months of age

-Regular assessment of auditory skills and language acquisition

-Monitoring middle ear status

-Attention to parental/caregiver concerns

•Term infants who fail the initial screen but pass the second screen of a two-stage screening protocol should be monitored by their primary care providers for any clinical signs of hearing loss. This includes assessment of developmental milestones, speech, auditory skills, parental concerns, and middle ear status during routine well-child visits. (See "Hearing loss in children: Screening and evaluation", section on 'Screening for hearing loss in children'.)

•Newborns who fail the hearing screen require formal audiologic evaluation, which preferably is performed before birth hospitalization discharge, but not later than three months of age. (See 'Infants who fail two-stage screening' above.)

ACKNOWLEDGMENTS — The UpToDate editorial staff acknowledges Lisa M Adcock, MD, and Drifa Freysdottir, MD, who contributed to an earlier version of this topic review.