20Q: Preschool Hearing Screening is Essential for Early Identification of Childhood Hearing Loss

From the Desk of Gus Mueller

Hearing screening programs are recommended across all pediatric age ranges to detect potential hearing loss.  Hearing screenings are designed to provide a quick and cost-effective method of identifying individuals at risk.  While we hear a lot about newborn screenings, and rightfully so, screening programs for the pre-school years also are important. We know that even mild hearing loss can prevent normal language development, impede cognitive growth and potentially delay socialization skills.

The audiologist’s role in the pre-school hearing screening programs might include selecting the screening protocol, training screening personnel, monitoring key indicators, documentation of findings, medical referrals, and maybe even conducting the testing.  A lot of responsibility. To catch us up on current thinking in this important area, our guest author for this month’s 20Q is James W. “Jay” Hall, PhD.

Dr. Hall’s website is www.audiologyworld.net.  While you might think that the “audiology world” thing is just a snazzy moniker that he made up, his University appointments suggest that he lives up to the billing. Dr. Hall holds academic appointments as Professor (part-time) at the University of Hawaii and Salus University in the USA, and Extraordinary Professor at the University of Pretoria in South Africa. He’s also president of James W. Hall III Audiology Consulting LLC (with offices in both Florida and Maine).

There are few clinical audiologists who have not read an article or heard a talk by Dr. Hall on topics such as diagnostic audiology, clinical electrophysiology, auditory processing disorders, tinnitus, hyperacusis, and tele-audiology. For the past 40 years, he has traveled internationally conducting seminars and workshops.  At last count, he has authored nine textbooks, the two most recent being the 2014 Introduction to Audiology Today and the 2015 eHandbook of Auditory Evoked Responses.  Who knows, maybe the classic Audiologists’ Desk Reference will have a new life in the next few years!

As always, you’ll find Jay’s 20Q an informative, yet easy to read review of the topic of pre-school hearing screening.  And, then we have to ask, do we have the most efficient protocols in place?

Gus Mueller, PhD
Contributing Editor
April 2017

Browse the complete collection of 20Q with Gus Mueller CEU articles at www.audiologyonline.com/20Q

20Q: Preschool Hearing Screening is Essential for Early Identification of Childhood Hearing Loss 

        James W. Hall, III

1. Why is preschool hearing screening so important for identifying hearing loss in children? Isn’t that why we have universal newborn hearing screening?

We are talking about two different things. In the United States, universal newborn hearing screening (UNHS) has been a reality for almost two decades. The emergence of UNHS can be traced back to a convergence in the 1980s of multiple distinct developments. Advances in hearing screening technology were one of the obvious requirements for UNHS. Automated auditory brainstem response (ABR) and otoacoustic emission (OAE) devices permitted relatively cost-effective hearing screening of large numbers of infants with reliance on non-audiology personnel. Subsequent clinical trials with the two new types of technology confirmed acceptable performance, including sensitivity, specificity, failure rates, and false positive rates. Research began to confirm the benefits of early intervention for permanent hearing loss. In combination, these developments plus legislative efforts contributed in the late 1990s to the all-important American Academy of Pediatrics endorsement of UNHS and establishment of benchmarks for UNHS programs (American Academy of Pediatrics, 1999).

2. That’s what I thought. I figured all children with hearing loss were detected soon after birth?

Unfortunately, the era of UNHS in the United States has not yet led to universal identification of and early intervention for childhood hearing loss. In other words, early intervention does not occur for some young children with hearing loss. This breakdown in the EHDI (Early Hearing Detection and Intervention) process from newborn hearing screening to the delivery of subsequent required services is often referred to as a problem with “loss to follow-up.”  Put another way, the first step in the 1-3-6 EHDI approach usually takes place but the other two steps don’t always occur on schedule or even at all, as there are many factors that can influence a delay in the process.

3. The 1-3-6 EHDI approach?  You lost me.

Per the Centers for Disease Control, all babies should be screened for hearing loss before 1 month of age, but best if before leaving the hospital. If a baby does not pass a hearing screening, a full hearing evaluation should be completed before 3 months of age. If a child is identified as deaf or hard of hearing, they should be enrolled in appropriate early intervention before 6 months of age. 

4.  That sounds like a good plan, which brings me back to my original question…why then is preschool hearing screening so important?

The quick answer to that good question is that hearing screening at or soon after birth doesn’t identify all young children with hearing loss. Even today a small proportion of infants are not screened at birth. The actual proportion of newborn infants who do not undergo hearing screening varies from state-to-state, but it’s usually less than 5%. Prominent reasons for missed hearing screenings include parent refusal for newborn hearing screening and hospital discharge or transfer to another facility before screening is completed. A very common reason for babies not having a newborn hearing screening is because they are born at home, and the number of home births is rising.  Although the percentage of babies who miss the birth screening is small, the actual number of babies could be substantial, particularly in larger states. That is one of a number of reasons why preschool hearing screening is important.

5. But if almost all babies undergo hearing screening soon after birth, then why not track down the relatively small proportion of them who slipped through the cracks?

I’ll begin with one part of the answer. In addition to babies who don’t undergo hearing screening, an equally serious problem is the number of infants who fail hearing screening at birth but do not receive a follow-up diagnostic assessment by age 3 months, or at all.

6. Where’s the breakdown in the process?

There is a long list of reasons for why infants are lost to follow-up after a refer outcome on newborn hearing screening.  We probably don’t have the time here to discuss all of the reasons. I suggest you read an article I published recently (Hall, 2016a) if you’re interested in a detailed review of the topic.  It's available here.

Some of the reasons are related to screening, such as infants who are screened in one state who live in another state, or an excessively high failure rate that requires follow-up testing on many more infants. A major factor involves socioeconomic issues which relate to maternal age, maternal education, race, ethnicity and whether the family is on Medicaid versus those with private insurance, etc. Other reasons that involve parents include transportation problems or inadequate information about the importance of follow up. Physician misunderstanding about the screening and diagnostic process also plays a role in the loss to follow up. And, the inadequate number and geographical distribution of audiologist with the skills and experience to conduct diagnostic infant hearing assessment is certainly a factor.

I should point out that there is another smaller group of infants who undergo a diagnostic assessment to confirm a hearing loss who are then lost to further follow-up. Again, there are multiple explanations for these follow-up problems. In any event, an unknown number of children with hearing loss do not receive timely intervention services.

7. That’s complicated. Do you have any suggestions for solving these problems?

That question also deserves a long and rather detailed answer, which also is included in the article I mentioned. The solution to the loss to follow-up problem requires a multi-faceted and multi-disciplinary approach at the regional and state level that must include hospitals, physicians, audiologists, EHDI personnel in each state, and of course parents.

A concerted effort is necessary because the problem is quite serious. Using existing calculation methods, Centers for Disease Control and Prevention (CDC) estimates for national data are 36% for loss to follow up before diagnostic assessment and 25% for loss to follow up for early intervention.  These percentages may not accurately reflect the true status of the problem given concerns about the methods used to calculate lost to follow-up statistics.  Also, it’s important to keep in mind that reported loss to follow-up rates vary widely from year-to-year and also from state-to-state. In some years in some states, including states with very large numbers of birth, follow-up rates are far above 50%.

8. Let’s say all babies who fail newborn hearing screening actually do undergo diagnostic assessment, would that solve the problem?

Unfortunately, the answer is no. I’ve already mentioned that some children who complete the diagnostic audiological assessment do not, for various reasons, enroll in timely intervention before the age of 6 months.

We also need to consider another reason for late diagnosis of and intervention for childhood hearing loss. A surprisingly high proportion of children who pass newborn hearing screening later acquire hearing loss during the preschool years. For example, Fortnum and colleagues (2001) describe a significant increase in prevalence of hearing loss from birth to school age. Up to 50% of children with hearing loss at age 9 years passed newborn hearing screening. Bamford and colleagues (Bamford et al., 2007) and White (2007) also note greater prevalence of hearing loss in the range of 6 to 10 per 1000 for school-age children versus infants (3/1000). And, according to Grote (2000), UNHS programs do not detect from 10 to 20% of children with permanent hearing loss.

Clearly, hearing loss for a some children would be missed even if all infants underwent UNHS and all infants failing screening received appropriate diagnostic and intervention services. 

9. Are there any risk factors that would help to find these children with hearing loss?

There are a number of risk indicators for acquired permanent sensorineural hearing loss in the preschool years, as delineated in the 2007 Joint Committee on Infant Hearing (JCIH) statement (JCIH, 2007). Hearing loss acquired in early childhood is often categorized as either progressive or delayed/late onset hearing loss. Risk factors include caregiver concern regarding hearing, family history of hearing loss, an intensive care nursery stay of > 5 days, in utero and post-natal infections, craniofacial anomalies, neurodegenerative disorders, head trauma, potentially ototoxic medications, and a variety of syndromes associated with hearing loss (JCIH, 2007). Documentation of these risk factors is essential for prompt identification of hearing loss in early childhood, even in the era of UNHS. There are also a number of genetic causes of progressive and delayed-onset hearing loss. Unfortunately, risk factors for hearing loss are not consistently tracked in every state.

10. Can you help me understand the distinction between progressive and delayed onset hearing loss?

Gladly! The phrase progressive hearing loss assumes normal auditory function at birth or at the time of newborn hearing screening with the subsequent development of hearing loss over time. Depending on the etiology, progressive hearing loss may begin in one ear or both ears. And, hearing loss may first affect the high frequency region or the low frequency region. Hearing loss often gradually progresses from slight to more serious during early childhood, and sometimes even into school age years.

The term delayed or late onset hearing loss implies normal auditory function at birth with the rather abrupt onset of auditory dysfunction and associated hearing loss sometime during infancy or early childhood. Delayed or late onset hearing loss may also be unilateral or bilateral.

11. So I’m ready to hear about how preschool school children should be tested. I assume pure-tone screening is the best approach?

General recommendations for hearing screening of preschool children date back to the 1980s, and pure-tone hearing screening was typically suggested as the best available technique. The American Speech-Language-Hearing Association (ASHA) in 1997 published in a 64-page document that until recently was the most comprehensive and the most widely used set of guidelines for childhood hearing screening. Consistent with earlier ASHA recommendations, the 1997 guidelines call for pure tone hearing screening with conditioned play audiometry at 20 dB HL for test frequencies of 1000, 2000, and 4000 Hz. Rather detailed instructions are offered in the guidelines for performing conditioned play audiometry. Criteria for a “refer” outcome are the absence of a reliable response for at least 2 out of 3 signal presentations at 20 dB HL for any frequency in either ear, or inability to condition the child to the task.

12. Are there any problems with this good old technique?

There are a number of serious potential problems associated with the pure tone hearing screening of preschool children. Even the 1997 ASHA guidelines unequivocally state at the outset that the hearing screening of infants and children requires considerable professional expertise and technological sophistication. The guidelines emphasize repeatedly, and in my opinion unrealistically, that it is “appropriate and necessary” for certified audiologists only to conduct preschool hearing screening, particularly for younger children.

The most recent recommendations relevant to preschool hearing screening are within the 2011 American Academy of Audiology (AAA) Clinical Practice Guidelines on Childhood Hearing Screening (AAA, 2011). The 2011 AAA guidelines provide a very detailed section on pure tone hearing screening that begins with the statement: “Historically, the most widely preferred hearing screening procedure and the one that has been considered the gold standard is the pure tone audiometric sweep test."

It’s important to note here that many published studies of preschool hearing screening highlight challenges in the application of existing guidelines that rely exclusively on pure tone screening techniques, even under ideal test conditions with well-trained and qualified personnel. And, there is general acknowledgment in the guidelines that hearing screening of children younger than 3 years is simply not feasible with behavioral techniques.

13. Do you have any other concerns about relying on pure tone hearing screening of preschool children?

Halloran and pediatrician colleagues (Halloran, Wall, Evans, Hardin, & Woolley, 2005) describe one of the most real-world experiences with hearing screening of preschool children. These authors reported only a 45% hearing screening completion rate for children younger than 3 years of age, plus a discouragingly low pass rate of 67% for 21 developmentally delayed children. As Halloran and colleagues (2005) note: “The findings from this study are worrisome because physicians took no further action in more than 50% of the children who failed the hearing screening and more than 70% of the children who could not be tested" (p. 934). In other words, pediatricians have little confidence in pure tone hearing screening of preschool children.

Challenges associated with pure tone hearing screening of preschool children are serious. Audiologists are rarely available at sites where screening is conducted. Adequately low ambient sound levels are rarely achieved. Screening times for each child are unacceptably long, usually at least 4 or 5 minutes. That’s a serious problem when one person is faced with the task of screening a large number of children. Age, cognitive level, and language skills of young children are also major factors affecting pure tone hearing outcome. And, pure tone hearing screening doesn’t consistently identify middle ear dysfunction commonly-encountered in the preschool population.

In a follow-up article, Halloran, Hardin & Wall (2009) raised serious questions about the value of pure tone hearing screening during well-child visits because of poor sensitivity (50%) and only fair specificity (78%), plus a high no-show rate for children referred for complete hearing evaluation by their primary care physician.

14. What are your suggestions for how the younger group should be screened?

I’ll come right back to the studies by Donna Halloran and her fellow pediatricians. They conclude: “Given the poor validity of pure tone audiometry, other methods of hearing screening should be considered for the primary care setting. One such option that practices and school are increasingly using is otoacoustic emissions” (Halloran et al., 2009, p. 161).

15. Do you agree with this recommendation?

Most certainly.  There are multiple advantages of OAEs in preschool hearing screening that are supported by recent studies (e.g., Foust, Eiserman, Shisler, & Geroso, 2013; Kreisman, Bevilacqua, Day, Kreisman, & Hall, 2013). As an objective technique, OAE findings are not influenced by the many listener variables like developmental age, cognitive level, and language that confound hearing screening with a behavioral technique such as pure tone measurement. A quiet test setting is not a requirement for OAE screening (although is preferred). OAE devices are easily portable and often hand-held. Also, OAE test outcome is documented with a display that can be stored electronically, interfaced with data management systems, and printed immediately.

Also, abnormal OAE findings are very likely in children with middle ear dysfunction and/or with cochlear hearing loss involving outer hair cell dysfunction (Dhar & Hall, 2012). Obviously, recording OAEs in young children is feasible and technically rather simple as evidenced by widespread application of OAEs in newborns undergoing hearing screening.

16. When used for this purpose, are OAEs applied the same way as they are with newborn hearing screening?

The screening technique is the same for both pediatric populations, but analysis of OAE findings is distinctly different. The goal in newborn hearing screening with OAEs should be the same as it is for pure tone hearing screening … detecting hearing loss 20 dB or greater. The problem with “false-negative” screening errors should be avoided, that is, a pass outcome in children with some degree of sensory hearing loss. That type of error is usually associated with reliance only on a pass/fail criterion that is based on the relative difference between OAE amplitude versus noise floor levels without regard to the absolute OAE amplitude value. Most published studies in neonatal and preschool hearing screening have employed a pass criterion limited to an OAE-to-noise floor difference of > 3 or > 6 dB SPL.

A simple strategy for increasing sensitivity to varying degrees of sensory hearing loss is the addition of a second criterion involving the absolute amplitude of OAEs (Dhar & Hall, 2012). Sensitivity of OAE screening to even mild sensory or conductive hearing loss is achieved with criteria for a pass outcome of an OAE amplitude minus noise floor difference of 6 dB SPL plus the requirement for an absolute OAE amplitude of > 0 dB SPL.  It’s possible with some OAE screening devices to incorporate this requirement into the pass/fail criteria. That is, an audiologist can create a specific protocol for preschool hearing screening. 

Long-standing research on the relation between OAE amplitude and hearing threshold levels supports the application of these two criteria in combination for identification of persons with any degree of sensory hearing loss involving the outer hair cells (Gorga, Neely, Ohlrich, Hoover, & Redner, 1997).

17. Are there any other differences in the protocol for preschool hearing screening versus newborn hearing screening?

Yes, in my opinion there are at least three differences. First, tympanometry is performed for all preschool children who do not pass the initial OAE screening in order to identify those with middle ear dysfunction that is often transient or successfully treated medically. Second, the immediate follow-up screening technique for younger preschool children, under the age of 4 years, is acoustic reflex measurement. Acoustic reflex screening is conducted with a broadband noise (BBN) stimulus. BBN-evoked acoustic reflexes offer a quick and objective method for detection of likely sensory hearing loss in children with normal middle ear function as inferred from tympanometry (Hall, Berry & Olson,1982). Finally, pure tone hearing screening is the follow-up screening technique of choice for children of 4 years or older who do not pass OAE screening but who have normal tympanograms. Obviously, pure tone testing is not possible in the newborn population.

18. Is there published research in support of your recommendation for OAEs in preschool hearing screening?

I already hinted at the research in support of OAEs in preschool hearing screening. Actually, there are dozens of articles describing the application of OAEs in preschool hearing screening dating back to the early 1990s (see Hall 2016a for review). Collectively, these papers confirm the feasibility and usefulness of OAEs, and particularly DPOAEs, for hearing screening in the preschool population. Also, the well-known crosscheck principle is essentially applied even in the screening process in children who do not pass the OAE screening (Jerger & Hayes, 1976; Hall, 2016b).

19. You’ve convinced me that objective tests are the way to go for hearing screening of preschool children. Is there still a role for traditional pure tone hearing techniques in this population?

Absolutely. As I mentioned already, pure tone hearing screening can immediately be conducted for older preschool children who fail OAE screening and who have normal middle ear function as evidenced by normal tympanograms.  Technological advances in pure tone hearing screening instrumentation (Wenjin et al., 2014) offer an opportunity to avoid some of the well-appreciated drawbacks associated with conventional pure tone hearing screening of preschool children detailed earlier in this paper.

20. This has been an eye-opening conversation. How would you sum it up?

Here’s the bottom line: An unacceptable number of infants failing newborn hearing screening do not receive necessary follow-up services in a timely fashion as a result of loss to follow-up problems. In addition, some children who pass newborn hearing screening later acquire hearing loss during the preschool years. Tracking infants and consistent reporting of test results is important for any screening program. In addition, systematic pre-school hearing screening offers a logical strategy for detection of hearing loss among these children. OAEs offer the most promising option for systematic hearing screening of the preschool population.

References

American Academy of Audiology (AAA). (2011). Childhood Hearing Screening Clinical Practice Guidelines. Retrieved from www.audiology.org

American Academy of Audiology (AAA). (2013). Clinical Practice Guidelines on Pediatric Amplification. Retrieved from www.audiology.org

American Academy of Pediatrics, Task Force on Newborn and Infant Hearing. (1999). Newborn and infant hearing loss: detection and intervention. Pediatrics,103, 527–530.

American Speech-Language-Hearing Association (ASHA). 1997. Guidelines for Audiological Screening. Rockville MD: ASHA.

Bamford, J., Fortnum, H., Bristow, K., Smith, J., Vamvakas, G., Davies, L.,...Hind, S. (2007). Current practice, accuracy, effectiveness, and cost-effectiveness of the school-entry hearing screen. Health Technology Assessment, 11, 1-168.

Dhar, S., & Hall, J.W. III. (2012). Otoacoustic emissions: Principles, procedures & protocols. San Diego: Plural Publishing.

Fortnum, H.M., Summerfield, A.Q., Marshall, D.H., Davis, A.C., & Bamford, J.M. (2001). Prevalence of permanent childhood hearing impairment in the United Kingdom and implications for universal neonatal hearing screening: questionnaire based ascertainment study. British Medical Journal, 323, 536-554.

Foust, T., Eiserman, W., Shisler, L., & Geroso, A. (2013). Using otoacoustic emissions to screen young children for hearing loss in primary care settings. Pediatrics, 132(1), 118-23. doi: 10.1542/peds.2012-3868. 

Gorga, M. P., Neely, S. T., Ohlrich, B., Hoover, B., & Redner, J. (1997). From laboratory to clinic: A large scale study of distortion product otoacoustic emissions in ears with normal hearing and ears with hearing loss. Ear & Hearing, 18, 440-455.

Grote, J. (2000). Neonatal screening for hearing impairment. Lancet, 355, 513-514.

Hall, J.W. III. (2014) Introduction to Audiology Today. Boston: Pearson Educational.

Hall, J.W. III. (2016a). Effective and efficient preschool hearing screening: Essential for successful early hearing detection and intervention (EHDI). Journal of Early Hearing Detection and Intervention, 1, 1-12. doi: 10.15142/T3XW2F. Retrieved from: https://digitalcommons.usu.edu/jehdi/vol1/iss1/3/

Hall, J.W. III. (2016b). The crosscheck principle in pediatric audiology: A 40-year perspective. Journal of Audiology and Otology, 20(2), 1-9.

Hall, J.W. III., Berry, G.A., & Olson, K. (1982).  Identification of serious hearing loss with acoustic reflex data:  Clinical experience with some new guidelines. Scandinavian Audiology, 11, 251-255.

Halloran, D.R., Wall, T.C., Evans, H.H., Hardin, M., & Woolley, A.L. (2005). Hearing screening at well-child visits. Archives of Pediatrics and Adolescent Medicine, 159(10),949-955. doi:10.1001/archpedi.159.10.949

Halloran, D.R., Hardin, M.D., & Wall, T.C. (2009). Validity of pure-tone hearing screening at well-child visits. Archives of Pediatrics and Adolescent Medicine, 163(2), 158-163. doi:10.1001/archpediatrics.2008.526

Joint Committee on Infant Hearing (JCIH). (2007). Joint Committee on Infant Hearing Year 2007 position statement: Principles and guidelines for early hearing detection and intervention programs. Pediatrics, 120, 898-921.

Jerger, J.F., & Hayes, D. (1976).  The cross-check principle in pediatric audiometry. Archives of Otolaryngology, 102, 614-420.

Kreisman, B.M., Bevilacqua, E., Day, K., Kreisman, N.V., & Hall, J.W. III, (2013). Preschool hearing screenings:  A comparison of distortion product otoacoustic emission and pure tone protocols. Journal of Educational Audiology, 19, 49-57.

Wenjin, W., Jingrong, L., Yun, L., Kam, A.C.S., Tong, M.C.F., Zhiwu, H., & Hao, W. (2014). A new hearing screening system for preschool children. International Journal of Pediatric Otorhinolaryngology, 78, 290-295.

White, K.R. (2007). Early Intervention for children with permanent hearing loss: Finishing the EHDI revolution. Volta Review, 106(3), 237-258.