Background. Our purpose was to identify infants with a bilateral, permanent, handicapping hearing loss and to provide them with amplification before age 6 months.
Methodology. The study population consisted of 10 372 infants born during a 5-year period. Universal hearing screening by automated auditory brainstem response was done in the nursery. Infants who failed the screening test were followed up diagnostically. Infants who were not tested in the nursery were followed up as outpatients. Hearing aids were recommended for those infants who had bilateral hearing loss.
Results. Successful screening in the nursery was achieved for 96% of infants. The failure rate was 4%. The incidence of bilateral loss requiring amplification was 1.4/1000. The false-positive rate was 3.5% after the initial screening and .2% when a two-stage screening procedure was used. The incidence of congenital bilateral hearing loss in the well population was 1/1000, and in the neonatal intensive care unit population, 5/1000. The cost of screening was $17 per infant, and the cost to identify each true bilateral hearing loss was $17 750. Amplification was recommended for 15 infants; well infants who used hearing aids before age 6 months achieved age-appropriate speech and language development.
Conclusions. Mild, moderate, and severe bilateral, persistent hearing loss can be identified in the nursery by automated auditory brainstem response measurement to provide amplification before age 6 months and thus optimize speech and language development.
- infant hearing screening
- newborn hearing screening
- neonatal hearing screening
- universal newborn hearing screening
- automated auditory brainstem response
- bilateral hearing loss
- congenital hearing loss
The Kaiser Permanente Medical Center in Honolulu, Hawaii, established a universal newborn hearing screening program in 1992 in response to state and national legislation. We chose automated auditory brainstem response (AABR) measurement performed in the nursery before discharge to optimize the identification of hearing-impaired infants. We report our 5-year experience in screening 10 372 newborn infants using AABR.
MATERIALS AND METHODS
Well infants, hospitalized from 24 to 36 hours, were screened at age 3 to 36 hours; neonatal intensive care unit (NICU) infants were screened before discharge (at age 2 days to 90 days or more). Specific statistics on the age of each infant at screening were not kept. All the NICU infants had risk factors1,2 for hearing loss; risk factors occurred in <2% of the well-infant population and included cleft palate, exposure to antibiotics, skin tags near the ears, and a family history of hearing loss.
The races of the population sampled included white, Asian, Pacific Islander, and mixed. Compared with the racial composition of the United States as a whole, Hispanic and black representation was minimal.
Less than 1% of our total population represented deaths or transfers to and from other facilities. The NICU is a level 2 facility, providing all services except cardiac surgery and extracorporeal membrane oxygenation.
The ALGO-1 Plus3 (Natus Medical Inc, San Carlos, CA) was used for all screenings. This automated hearing screener uses auditory brainstem response (ABR) measurement with a broad-band click stimulus [technical specifications for the click stimulus: duration = 100 microseconds; intensity = 35 dB nHL; polarity = alternating; acoustic frequency spectrum = 700 to 5000 Hz (±5 dB); filter settings: 0.05 to 1.5 kHz, 6 dB high pass, 24 dB low pass] which tests at frequencies greater than 1000 Hz.3 Built-in artifact rejection for myogenic, electrical, and environmental noise interference ensures that data collection is halted if testing conditions are unfavorable. The automated screener provides a pass-fail report; no test interpretation by an audiologist is required.
Screening in the Nursery
Infants born at Kaiser Permanente Medical Center, Honolulu, Hawaii, from March 1992 and through February 1997 were screened before discharge as part of an ongoing universal newborn hearing screening program. Screening was done 7 days per week, 365 days per year, by audiologists during the first 2 years of the program and subsequently by technicians. Successful screening requires infant comfort, a relatively quiet environment, proper application (electrode impedance <12 K ohms3) of surface electrodes in a noncephalic montage4 (electrode montage: noninverting = high forehead, inverting = nape, and common = mastoid), application of adhesive circumaural headphones, and presentation of the click stimulus. Well-infant screenings were performed at the mother's bedside with the infant resting in the mother's arms or in a quiet room adjoining the nursery with the infant in an open bassinet. NICU infants were screened in the nursery. Examinations took a mean 15 minutes (range, 1 to 60 minutes), depending on the infant's state and the infant's hearing status. Outpatient screening was conducted for infants who failed nursery screening and for those who were not screened in the nursery. Diagnostic ABR was done before age 1 month.
Diagnostic Follow-up Testing and Intervention
Infants referred for outpatient evaluation were tested by using diagnostic ABR (Compact Auditory 4; Nicolet Biomedical Inc, Madison, WI). Normal findings were defined as click thresholds of ≤35 dBnHL.5 Diagnostic testing also included high-frequency tympanometry and ipsilateral acoustic reflex testing (GSI-33; Lucas Grason-Stadler, Inc, Littleton, MA), behavioral observation audiometry using low-frequency stimuli and running speech (GSI-10, Lucas Grason-Stadler), and an evaluation by an otolaryngologist. Referrals were made outside our facility for distortion product otoacoustic emissions testing. Infants were discharged from the screening program if bilateral hearing loss was ruled out. Test results were communicated to the families and their primary care physicians.
Hearing aids and referrals to infant speech and language habilitation programs were provided when indicated. Well infants received aural habilitation therapy through private agencies. This therapy consisted of private one-to-one sessions conducted 2 to 3 times per week during the first 6 months and a home intervention curriculum provided at no charge via mail-order through a charitable private national agency. NICU infants received therapy as their health permitted.
Speech and language development was tested outside our facility, and information on test scores was retrieved from infants' medical records.
Of the 10 773 infants born during the 5-year study period, 10 372 (96.3%) were screened before discharge from the hospital (Table 1); 401 infants were not screened successfully in the nursery.
Infants Screened in the Nursery
Of the 10 372 infants screened in the nursery, 9957 passed screening, and 415 failed. Fifteen (3.6%) of the infants who failed had permanent bilateral loss >35 dB, a rate of .9/1000 of the study population (Table 2). The remaining 400 infants are described in Table3.
The 15 infants identified as having bilateral hearing impairment had losses ranging from mild to profound (Table4). At initial diagnostic testing, all the infants had moderate or greater ABR thresholds; their audiometric test results shifted as they grew older, and 3 were later found to have mild to moderate hearing impairment. Eleven of the hearing losses were sensorineural, 2 were mixed with a substantial sensorineural component, and 2 were permanent conductive (1 with craniofacial anomalies, 1 with bilateral atresia). Seven well infants and 6 NICU infants received hearing aids.
Infants Not Screened in the Nursery
We discharged 401 infants without successful screening; 250 screening examinations were unsuccessful because of myogenic interference, 143 infants were discharged before testing, and 8 parents refused screening. Attempts were made to recall all of these infants for outpatient screening. Only one half (n = 212) returned; the remaining infants' families moved (n = 101) or had parents who declined testing (n = 88). Of the 212 who returned, most (n = 200) had normal results of screening examinations. Abnormal results were found in 12 infants; 11 of these infants had transient losses or are still under evaluation. One infant had bilateral loss and received hearing aids.
Development of Newborn Hearing Screening Programs
Hearing loss in infants is a handicap which, if left unidentified and untreated, results in delayed speech and language development as well as emotional, social, and academic difficulty. Normal speech and language development depend on normal hearing, and even mild, persistent loss may result in delays.6-16 The average age of identification of hearing loss in the United States is 20 to 24 months,15,17 and mild and moderate losses are usually not identified until ≥48 months.18 Thus, intervention, which should ideally begin by age 6 months,19 has often been delayed.
Funding of early intervention programs for handicapped infants and toddlers was enacted in 1986 by the United States Congress. Public Law 99–457 reauthorized Public Law 94–142, The Education of the Handicapped Act, which included a provision for early intervention programs for handicapped persons from birth to age 3 years.20,21 In July 1990, the Hawaii State Legislature mandated development of a statewide program for early identification of hearing-impaired infants.22 In 1993, the National Institutes of Health recommended that all infants receive hearing screening within the first 3 months of life.23
Past efforts to evaluate newborn hearing have included various screening tools. The high-risk register24-26 reviewed birth certificates and hospital records to identify infants at risk for hearing loss. Parental noncompliance was a major problem with this method.27,28 Another screening tool monitored movement associated with a stimulus sound.29 This method proved unsatisfactory because false-positive rates ranged from 14%30 to 20%.29 Modifying the motion detection method by adding behavioral testing improved the sensitivity and specificity. However, precise identification of hearing loss remained elusive because these screening methods omitted the well-infant population,31-34 which accounts for one-half of all individuals afflicted with congenital hearing loss.35
More recently, two methods have been investigated for hearing screening: otoacoustic emissions (OAE) and ABR. Electrophysiologic measurement of responses to auditory stimuli eliminates the ambiguity of measuring body motion in response to auditory stimuli.
OAE, sounds theorized to be generated by the outer hair cells of the cochlea,36 may be measured microphonically in response to a click stimulus.37-43 The sensitivity of OAE screening in a typical hospital setting has been reported as 50% and the specificity, 53%.44 In addition, OAE requires interpretation by an audiologist for each of several (mean, 4) screening examinations performed on an infant.
ABR uses a click stimulus to elicit an electrical brainstem response measured by surface electrodes.11,45-47 The sensitivity of the ABR screener has been reported as 100% and the specificity, 97 to 98%.48-50 AABR screening does not require interpretation by an audiologist. Universal newborn hearing screening by OAE43,51,52 and screening of NICU populations by conventional ABR and AABR49,53-55 have been reported. We chose AABR because of its superior operating characteristics and because of the lower cost of professional services required to achieve accurate screening results.
Incidence of Bilateral Congenital Hearing Loss
We defined bilateral congenital hearing loss as the number of infants for whom amplification was recommended, regardless of etiology. This number included infants whose loss exceeded 35 dB and for whom the loss was permanent. Our incidence was 1.4/1000 for the universal population (Table 5). Another study using an alternate screening method reported a universal incidence of 3/100043; the difference between our incidence and theirs may be explained by the higher incidence for their NICU population, discussed in more detail below.
For the well-infant population, we reported an incidence of approximately 1/1000. This number represented a comparatively large group; only one other study focused on well infants as a separate population,50 and the size of that group was insufficient (n = 628) to identify any hearing loss. Others have reported data for a well population43 and found an incidence of 1.2/1000, which is not substantially different from ours.
The largest differences in incidence among studies may be seen in the NICU population. Our incidence of 5/1000 is markedly lower than that which others reported, and this difference may be explained by the inclusion in our NICU population of all infants who are not entirely normal (13% of our births), including minimally symptomatic infants. The higher incidence of hearing loss reported in other studies reflects populations of sicker infants. One study tested only infants whose gestation was <30 weeks,56 and 2 others tested only those requiring highly specialized intensive care;57,58these are regional tertiary facilities that receive infants who are at greater risk for death and disability. Poor compliance with follow-up examinations in the NICU population limited data in some studies.57-59
We noted that 38 infants (34 well, 4 in NICU) failed the initial hearing screening bilaterally and were unavailable at follow-up by our program (30 moved, 8 were noncompliant). Letters were sent to their families, and, when possible, referrals were made to other local newborn hearing screening programs. Because we found that 4% of infants who failed initial screening examination had true bilateral hearing loss, the 38 infants unavailable at follow-up may have included 1 infant who had bilateral congenital hearing impairment.
Practical application of screening requires identification of remediable loss at an appropriate developmental stage and on early intervention. However, initiation of amplification may be delayed for ≥6 months after hearing loss is identified.17,60-62Recent research has shown the benefits of early identification and amplification. Yoshinaga-Itano, et al19 reported that children in whom bilateral hearing loss was identified at birth or before age 6 months had statistically significantly larger lexicons and higher expressive language scores than children in which bilateral hearing loss was identified at age ≥6 months. At age 4 years, no differences in language development were found between the group in whom bilateral hearing loss was not identified until age 6 months and the group in whom bilateral hearing loss was not identified until age 2 years. This finding shows that hearing loss must be identified and amplification initiated before age 6 months.
No profound hearing losses were identified in our well-infant population. In addition, none of our hearing-impaired well infants had a risk factor for hearing loss. All hearing loss in well infants was remediable by amplification, and well infants who complied with hearing aid use and who regularly attended aural habilitation sessions showed speech and language development at and greater than age equivalency (Table 4). Well infants are the population for whom screening programs hold the greatest value, and because these infants gain the most by early identification and aural habilitation, society at large is spared the expense of remedial education.
The NICU population showed a notable lack of speech and language acquisition despite early identification of hearing loss. Pervasive medical problems and additional handicaps limited the use of hearing aids and reduced attendance at infant aural habilitation sessions. Neurologic cognitive impairments in this population limited speech and language development independent of auditory system function. Identification and amplification efforts in this population yielded less success.
Treatment of Unilateral Loss
Currently, no accepted standard interventions exist for infants who have unilateral impairment. To conserve resources, our program focused on infants who had persistent bilateral hearing loss because appropriate remediation is available for this population. Other programs have structured their efforts similarly.35,49,58,59,63,64 Although infants with unilateral hearing loss were not tracked in our program, the AABR screening methodology may provide a mechanism to identify and to clarify the natural history of unilateral hearing loss.
Identification of unilateral hearing loss was not part of this hearing screening program. When individual treatment of unilateral loss is requested, the parents are counseled and the infant is monitored every 6 months to ensure that the status of the normal-hearing ear has not changed; referral to an otolaryngologist is made as needed. When the child reaches school age, unilateral amplification or a contralateral routing of signal instrument is considered. Teachers are informed of the student's unilateral hearing loss. Parents and the student are counseled regarding the hazards of noise exposure and contact sports.
Satisfactory testing requires a quiet neuromuscular state. The test was unsuccessful for infants who were active or crying; these infants were recalled for outpatient testing. In 250 infants (2.3%), testing was unsuccessful because of myogenic interference; 237 were well infants and 13 were NICU infants. Myogenic interference resulted in exclusion of infants from the program in the beginning years. We now extend the test time in the nursery for these infants, which saves the larger expense of aggressive efforts made to track them by phone, by letter, and by coordinating appointments with pediatricians. The increased skill and perseverance of our technicians led to the steadily declining number of infants not tested in the nursery because of myogenic interference, from 6% in year 1 to 0.05% in year 5.
The 5-year capture rate of our screening program (98%) compares favorably with rates (71% to 97%) previously reported.50,51,65-67 Despite the trend toward shorter duration between birth and discharge, we were able to screen infants by using a single daily evaluation time. In the early years of our program, 2.6% of our infants were not screened. Successfully integrating our screening program into the regular nursery protocol led to a .1% rate of infants left unscreened during year 5, and all of the unscreened infants were successfully recalled for outpatient screening within 2 days of discharge from the hospital, producing a capture rate of 100%.
We recommend that other screening programs take steps to maximize the number of infants who receive nursery screening by extending the test time (ie, so that active infants may be soothed) and by recalling excluded infants for outpatient screening as soon as possible after discharge from the hospital.
The false-positive rate merits further discussion. Of the 376 infants who returned for repeated testing as outpatients, 96% had normal hearing in at least one ear (Table 3). We believe that they were correctly identified at initial screening and had a transient conductive loss,68 possibly caused by incomplete clearance of normal fetal middle ear fluid. Normal responses established within 1 month relieved concern regarding development of speech and language in this group.
Another subset of infants had bilateral transient or fluctuating loss at initial diagnostic examination (Table 3) but with serial testing showed slowly progressive improvement in hearing. Because of concerns related to acquisition of cognitive skills in the first year of life, we suggest that these might not be false-positive results and that these infants might benefit from amplification during the first year of life, even though the hearing losses might resolve later. Investigation related to the natural history and benefit of amplification in this subpopulation is suggested.
In 1995, 3 years into our program, we purchased a second automated screener and began rescreening all infants who failed initial screening. Rescreening took place at age 4 weeks; 14 infants failed the second-stage screening, and 4 had confirmed bilateral hearing losses. Using this two-stage protocol, the false-positive rate dropped to .3% (Table 6), yielding a positive predictive value69 of 27%. We recognize that a false-positive result may cause emotional stress for families until more definitive diagnostic testing is completed. The benefits of a two-stage screening process are that it reduces stress for families and reduces the number of time-consuming and costly diagnostic evaluations.
The cost of screening may be important to groups who are considering establishing hospital-based neonatal hearing screening programs. Cost varies regionally, and confusion may arise when comparing the cost to do a test, the cost to the person who pays for the test, and the cost to the community if the test is not done. Because our program is a prepaid health care plan, members are not charged; nonmembers are charged $30. We report a per infant screening cost of $17 (Table 7). This cost may be compared with the charges for existing state programs that screen newborns. Current charges for phenylketonuria screening examinations range from $17 to $50 each, and for hypothyroid screening examinations, charges range from $28 to $50 each. The estimated incidence of phenylketonuria in the United States is 1/6000 to 1/25 000,70 and the estimated incidence of congenital hypothyroidism is 1/5000.71
This screening program was inspired by legislation that recognized the benefits and cost savings obtainable (from speech and language acquisition, avoidance of special educational programs, and improved quality of life) when infants' hearing loss is detected and treated with amplification. The cost of not identifying hearing impairment in one person may reach 1 million dollars.72 Considering the cost of screening and the incidence of hearing loss we identified, we conclude that the cost effectiveness of our program compares favorably with that of other state screening programs.
Beyond immediate financial consideration is the evaluation of hearing loss caused by trauma, infection, or heredity (in cases in which the latter causes progressive hearing loss). Our data differentiated only between acquired and congenital hearing impairment.
AABR was used to screen a large newborn population for bilateral hearing loss. The incidence of congenital bilateral loss in a large population of well infants has not previously been reported. Hearing loss identified in the well-infant population was remediable by amplification. The cost of identifying infants' hearing loss at birth was a fraction of the anticipated cost of providing educational and community services to people whose hearing loss is found later. We recommend a two-stage universal newborn screening protocol, amplification before age 6 months, and regular attendance of infants at aural habilitation sessions. We feel that further research is warranted for infants who have transient and fluctuating hearing losses because this group may benefit from temporary amplification.73-84
Christine Jiminez, MA, provided program design and data collection; June Uyehara-Isono, MS, managed infant amplification and aural habilitation; Georgiana Yap, RN, provided guidance for the program; and Yi Ching, MD, reviewed the manuscript.
The Medical Editing Department, Kaiser Foundation Research Institute, provided editorial assistance.
- Received January 28, 1997.
- Accepted June 18, 1997.
Reprint requests to (J.A.M.) Department of Audiology Services, Kaiser Permanente Medical Center, 3288 Moanalua Rd, Honolulu, HI 96819.
Related material was presented at the American Academy of Audiology Annual Conference, Richmond, Virginia, April 26, 1994, and at the American Academy of Audiology Annual Conference, Dallas, Texas, April 1, 1995.
- AABR =
- automated auditory brainstem response •
- NICU =
- neonatal intensive care unit •
- ABR =
- auditory brainstem response •
- OAE =
- otoacoustic emissions
- ↵Guidelines for the identification of hearing impairment in at risk infants age birth to 6 months. ASHA. 1988(Apr);30(4):61–64
- ↵Audiologic screening of newborn infants who are at risk for hearing impairment. ASHA. 1989(Mar);31(2):89–92
- ↵Natus Medical, Inc. ALGO-1 Plus Infant Hearing Screener. User Manual. Foster City, CA: Natus Medical, Inc; 1990:23
- ↵Hall JW III. Newborn auditory screening. In: Hall JW III, ed. Handbook of Auditory Evoked Responses. Boston, MA: Allyn and Bacon; 1992:475–509
- ↵Hall JW III. Calibration and normative data. In: Hall JW III, ed. Handbook of Auditory Evoked Responses. Boston, MA: Allyn and Bacon; 1992:267
- Ross M
- Brackett D,
- Maxon AB,
- Blackwell PM
- ↵Haggard M. Screening children's hearing. Br J Audiol. 1992;26:209–215. Editorial
- Hasenstab MS
- ↵Hayes D. Auditory brainstem response (ABR) in infants: screening and diagnostic applications. In: Bess FH, Hall JW III, eds. Screening Children for Auditory Function. Nashville, TN: Bill Wilkerson Center Press; 1992:127–143. (International Symposium on Screening Children for Auditory Function; June 27–29, 1991; Nashville, TN)
- ↵Northern JL, Downs MP. Hearing in Children. 3rd ed. Baltimore, MD: Williams & Wilkins; 1984:1–21
- ↵United States Maternal and Child Health Bureau. Healthy Children 2000: National Health Promotion and Disease Prevention Objectives Related to Mothers, Infants, Children, Adolescents, and Youth. Washington, DC: DHHS; 1990:177. US Department of Health and Human Services publication HRSA-M-CH-91–2
- ↵Mahon WJ. Hearing care for infants and children: issues in identification and management. Hear J. 1987(Sep);40(9):7–11
- Coplan J
- ↵Yoshinaga-Itano C, Sedey A, Apuzzo M, Carey A, Day D, Coulter D. The Effect of Early Identification on the Development of Deaf and Hard-of-hearing Infants and Toddlers. Presented at the American Academy of Audiology Annual Conference; April 1996; Salt Lake City, UT
- ↵Bailey DB Jr. Current issues in early intervention. In: Bess FH, Hall JW III, eds. Screening Children for Auditory Function. Nashville, TN: Bill Wilkerson Center Press; 1992:385–398. (International Symposium on Screening Children for Auditory Function; June 27–29, 1991; Nashville, TN)
- ↵State of Hawaii. A bill for an act relating to a newborn hearing screening program for the early identification of hearing loss. Senate Bill No. 2587 ed. 1990:Act 85
- ↵Early identification of hearing impairment in infants and young children. NIH Consens Statement. 1993;(Mar 1–3);11(1):1–24
- Feinmesser M,
- Tell L,
- Levi H
- ↵Hall JW III, Prentice CH. Newborn hearing screening with auditory brainstem response (ABR): experience with 1982 versus 1990 Joint Committee Risk Criteria. In: Bess FH, Hall JW III, eds. Screening Children for Auditory Function. Nashville, TN: Bill Wilkerson Center Press; 1992:145–161. (International Symposium on Screening Children for Auditory Function; June 27–29, 1991; Nashville, TN)
- Salamy A,
- Amochaev A
- ↵Marcellino GR. The Crib-o-gram in neonatal hearing screening. In: Swigart ET, ed. Neonatal Hearing Screening. San Diego, CA: College-Hill Press; 1986:47–66
- ↵Swigart ET. Model program IV: a high-risk register, Crib-o-gram, and auditory brainstem response. In: Swigart ET, ed. Neonatal Hearing Screening. San Diego, CA: College-Hill Press; 1986:183–222
- ↵McClatchie AC, Mikulich DM. Model program I: the Crib-o-gram. In: Swigart ET, ed. Neonatal Hearing Screening. San Diego, CA: College-Hill Press; 1986:145–155
- ↵Watkin PM, Baldwin M, McEnery G. Neonatal at risk screening and the identification of deafness. Arch Dis Child. 1991;66(10 Spec No):1130–1135
- White KR,
- Vohr BR,
- Behrens TR
- ↵Jacobson JT, Hyde ML. The auditory brainstem response in neonatal hearing screening. In: Swigart ET, ed. Neonatal Hearing Screening. San Diego, CA: College-Hill Press; 1986:67–98
- ↵Hall J, Kileny P, Ruth R, Kripal J. Newborn auditory screening with ALGO-1 vs. conventional ABR. Presented at the American Speech and Hearing Association Annual Convention; November 15, 1987; New Orleans, LA
- Herrmann BS,
- Thornton AR,
- Joseph JM
- ↵Joseph JM, Herrmann BS, Thornton AR, Pye RK. Well-baby Hearing Screening Using Automated ABR. Presented at the American Speech-Language-Hearing Association Annual Convention; November 1993; Anaheim, CA
- Stewart DL,
- Bibb KW,
- Pearlman A
- ↵Jacobson JT, Jacobson CA, Spahr RC. Automated and conventional ABR screening techniques in high-risk infants. J Am Acad Audiol. 1990(Oct);1(4):187–195
- ↵Stroble MF, Thelin JW. Hearing Screening in the Well-baby Nursery. Presented at the American Academy of Pediatric Otolaryngology; May 20, 1989; San Diego, CA
- Bradford BC,
- Baudin J,
- Conway MJ,
- Hazell JWP,
- Stewart AL,
- Reynolds EOR
- ↵Berrick JM, Thornton AR, Herrmann BS. ABR Hearing Screening of Intensive Care Nursery Graduates. Poster Session presented at the American Speech-Language-Hearing Association Annual Convention; November 1985; Washington, DC
- ↵Elssmann SF, Matkin ND, Sabo MP. Early identification of congenital sensorineural hearing impairment. Hear J. 1987(Sep);40(9):13–17
- ↵Weber B. Screening of high-risk infants using auditory brainstem response audiometry. In: Bess F, ed. Hearing Impairment in Children. Parkton, MD: York Press; 1988:112–132
- ↵Weber B, Jacobson C. Newborn hearing screening. In: Jacobson JT, ed. Principles and Applications in Auditory Evoked Potentials. Boston, MA: Allyn and Bacon; 1994:357–383
- ↵Mahoney T. Early identification of hearing loss in the USA. Audiol Today. 1993(May–June);5(3):27–30
- Marlowe JA
- Stein LK
- ↵Fria T. Screening principles and test selection. In: Swigart ET, ed. Neonatal Hearing Screening. San Diego, CA: College-Hill Press; 1986:21–29
- ↵Avery ME, First LR, eds. Pediatric Medicine. Baltimore, MD: Williams & Wilkins; 1989:925
- ↵Northern JL, Downs MP. Hearing in Children. 4th ed. Baltimore, MD: Williams & Wilkins; 1991:1–31
- ↵Frankenburg WK, Dodds JB, Fandal AW. The Denver Developmental Screening Test. Denver, CO: University of Colorado Press; 1975
- ↵Zimmerman I, Steiner V, Pond R. The Preschool Language Scale-3. San Antonio, TX: The Psychological Corporation; 1992
- ↵Bzoch K, League R. Receptive-expressive Emergent Language Scale. Austin, TX: Pro-Ed; 1970
- ↵Dunn L, Dunn L. The Peabody Picture Vocabulary Test—Revised. Circle Pines, MN: American Guidance Service; 1981
- ↵Tonelson S, Watkins S. SKI*HI Language Development Scale. Logan, UT: Project SKI*HI; 1979
- Joint Committee on Infant Hearing
- Schulman-Galambos C,
- Galambos R
- McClelland RJ,
- Watson DR,
- Lawless V,
- Houston HG,
- Adams D
- Cevette M
- Copyright © 1998 American Academy of Pediatrics