20Q: Unilateral Hearing Loss in Children - Progress and Opportunities

From the Desk of Gus Mueller

It was not all that long ago that unilateral sensorineural hearing loss in children received little attention. The thought, more or less, was that one good ear is good enough.  Things began to change, however, in the early 1980s, spearheaded by research at Vanderbilt University.  Within a few years we started to see publications by lead researcher Fred Bess, and his colleague Anne Marie Tharpe.  Their pioneering work centered on 60 children (aged 6 to 18) who had been diagnosed with a unilateral loss of 45 dB or greater in the poorer ear, and thresholds no worse than 15 dB in the normally hearing ear.

Perhaps the most noteworthy of the findings from this early research was the revelation that only half of these children were performing satisfactorily in school. Moreover, 35% of the children had repeated at least one grade, and an additional 13% required resource assistance. This was especially concerning given that the failure rate in that metropolitan area for the general elementary school population was only 3.5%.

The findings from these Vandy studies, and supporting work from other sites, changed we way we thought about children with unilateral hearing loss. That was over 30 years ago. How are we doing today? Who better to fill us in on what progress we’ve made, and what still needs to be accomplished than Anne Marie Tharpe, PhD, this month’s 20Q guest author.

Dr. Tharpe is Professor and Chair of the Department of Hearing and Speech Science, and Associate Director of the Vanderbilt Bill Wilkerson Center. You are no doubt familiar with her many publications related to pediatric audiology, and her book Comprehensive Handbook of Pediatric Audiology, which has become the seminal text on hearing loss in children.  She also has been actively involved in the development of innovative approaches to teaching, as well as distance-learning programs, and comprehensive tele-audiology approaches.  She recently was honored with the Academy of Audiology’s Marion Downs Award for Excellence in Pediatric Audiology.

As you will see from Anne Marie’s excellent 20Q article, we’ve made a lot of progress in the area of unilateral hearing loss, but there is still more to do.

Gus Mueller, PhD
Contributing Editor
 

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

20Q: Unilateral Hearing Loss in Children - Progress and Opportunities

Learning Outcomes 

After this course, readers will be able to:

• Discuss challenges for children with unilateral hearing loss in the areas of academics, behavior, listening effort/fatigue based on longstanding and new research in these areas.
• Discuss technology considerations for children with unilateral hearing loss based on the latest research.
• Describe new initiatives to support professionals in the audiological management of children with unilateral hearing loss.

  Anne Marie Tharpe

1. Is there still more to learn about the topic of unilateral hearing loss in children?

Absolutely! Although we have made gains in some areas for children with unilateral hearing loss (UHL), much work remains to be done. These children continue to have many of the same difficulties today that we highlighted in our articles back in the 1980s (Bess & Tharpe, 1986; Bess, Tharpe, & Gibler, 1986; Culbertson & Gilbert, 1986). Specifically, in those papers, we reported that children were having academic difficulties to an extent that we were unaware prior to that time. In fact, we were quite surprised to see that children with UHL were having academic difficulties at a rate ten times that of their normal-hearing peers. When I say academic difficulties, I'm referring to grade repetition and the need for resource help. Those studies were then replicated throughout the United States as well as across Europe (e.g., Oyler, Oyler, & Matkin, 1988; Bovo et al., 1988; Jensen, Børre, & Johansen, 1989). So, we knew that some children with UHL were having problems (about 65% of them) and we dug into some of the reasons that we suspected might have been causing the problems.

2. What were some of the reasons?

We thought that the academic problems could have been the result of listening difficulties in the classroom, resulting in speech and language deficits, or perhaps attentional deficits. Even though we were able to identify peripheral hearing deficits, trouble with localization, and trouble with speech perception in the presence of background noise in these children, we were not able to pin down specific speech and language, or cognitive problems that would account for the extent of their academic challenges.

3. Was there any guidance provided to audiologists on how to manage these children with UHL back then?

To some degree, yes. In the summer of 2005, the Centers for Disease Control and Prevention Early Hearing Detection and Intervention Team joined with the Marion Downs Hearing Center to sponsor the National Workshop on Mild and Unilateral Hearing Loss. I was privileged to be a part of that meeting along with expert clinicians and researchers from around the country to discuss the latest findings in identification and management of children with mild and unilateral hearing loss. We also talked about research needs in the areas of screening, diagnostic evaluation, and management options for these children. The proceedings of that workshop along with summaries of the research articles discussed at that meeting are still available at www.cdc.gov, in the Hearing Loss in Children section.

4. Have there been major conferences on unilateral hearing loss in children since the 2005 meeting?

Not until recently. Although we have made gains in some areas for children with UHL, much work remains to be done. These children continue to have many of the same difficulties today that we highlighted back in the 1980s. It was time for another conference to examine what was going on currently with these children and to determine if there are any new management approaches to consider. Phonak sponsored a conference in the fall of 2017 in Philadelphia exclusively on the topic of permanent UHL in children. It was an exciting conference with about 350 attendees from 16 countries all focused on learning more about the identification and management of children with UHL. 

5. What topics were covered?

We spent a day and a half listening to fascinating talks from clinicians and researchers addressing the topics of cortical neuroplasticity, effort and fatigue, language development, hearing technologies, and self-esteem in children with UHL. Of particular interest was hearing from a panel of parents who revealed their personal stories of either having unilateral hearing loss themselves, having children with unilateral hearing loss, or both. As we often say in health care, if you want to learn about a disorder – ask the patient! It was great to get their perspectives.

6. But was there really any new information presented at the conference?

Oh, yes, there was definitely new information! Although some things have not changed, one area where we've seen significant improvement has been in the early identification of UHL. Those early studies I mentioned previously were conducted prior to universal newborn hearing screening implementation. In the 1980s, children with unilateral hearing loss were being identified around five to six years of age, when they received hearing screenings upon entrance to kindergarten or first grade. Today, unilateral hearing loss is typically being identified much earlier. Parents, teachers, and other professionals are aware of the problem earlier in children’s lives.  There are more opportunities for early intervention but challenges remain. 

7. What kind of challenges do you mean? 

One of the problems that we are seeing is that despite the earlier identification and improved hearing technology, some children with UHL are still struggling academically and behaviorally. The reason for this difficulty is likely multifactorial. Although we have been discussing this problem for decades, there are still a lot of professionals who do not think that unilateral hearing loss is problematic for children. The notion that one good ear can get you by still is prominent in various circles – that might be pediatricians or otolaryngologists or educators, and perhaps a small segment of the audiology community as well. As a result, not every child is receiving optimum care. The parent panel at the conference highlighted the need for parents to be involved in the management decisions for their children. This might involve the trial use of hearing technologies by their children or other strategies. It also means that audiologists need to listen to and talk with parents about their concerns before deciding together on a management strategy.

8. What other possible factors might be contributing to the difficulties experienced by these children?

Another reason that children with UHL might be struggling academically is related to listening effort and fatigue. As you maybe have noticed, this has become a popular topic of research in our field in the last decade or so. 

9. What exactly is the difference between listening effort and fatigue?

Listening effort refers to the attentional requirements necessary to understand speech but fatigue is more difficult to define. Fatigue can be physical or mental, subjective or objective (Hornsby, Naylor, & Bess, 2016). At the conference, Ben Hornsby discussed subjective fatigue as an ongoing state of feeling tired, or having lack of energy. Dr. Hornsby presented a series of studies he and his colleagues have conducted in this area. Although most of the work so far has been with adults who have hearing loss, they are expanding their work in children, some of whom have UHL (e.g., Hornsby, Werfel, Camarata, & Bess, 2014).  A lot of work remains to be done before we can make a direct link between listening effort and fatigue and the academic difficulties experienced by some children with UHL, but this is a promising area of research.

10. What else was discussed about the difficulties children with UHL might have?

Work presented by Judith Lieu confirmed that school-age children with UHL today still have language, educational, and behavioral problems as were reported by the studies of the 1980s (Lieu, 2013). But, Judith Lieu, Christy Yoshinago-Itano, and Elizabeth Fitzpatrick all presented studies that extended findings of early communication deficits to infants and preschoolers (e.g., Fitzpatrick et al., 2017). Dr. Lieu also reported on current fMRI studies that suggest that some higher order cortical functions are affected by UHL (Rachakonda, Shimony, Coalson, & Lieu, 2014). She suggests that these findings might explain some of the educational and behavioral difficulties seen in some children with UHL.

11. Is classroom acoustics still an issue? 

Yes, we are still concerned about signal-to-noise ratio, speaker-listener distance, and reverberation times in classrooms. But, we are also considering that today’s classrooms tend to be complex and dynamic listening environments for children. That is, those acoustical factors could change throughout the day, even minute to minute! Dawna Lewis presented her work on the impact of UHL on children’s understanding in complex listening environments (Lewis, Smith, Spalding, & Valente, 2018). Children don’t only want to listen to their teachers; they want to hear their peers’ contributions to discussions as well. Today’s technology needs to accommodate all the listening needs of children in dynamic environments, not just traditional seating arrangements.

12. What should we consider when selecting and fitting hearing technology for children with UHL, to address listening in dynamic environments?

A lot of our recommendations are based on really old data. Earlier studies demonstrated that FM systems were the hearing technology of choice for children with UHL in classroom settings (Kenworthy, Klee, & Tharpe, 1990; Updike, 1994). Several professional guidelines have cited those studies as evidence that CROS amplification might not be effective in educational settings. But, those studies used a fixed microphone placed near the ‘teacher’ position, which ignores the other talkers in a classroom setting who the listener would want to hear. Erin Picou reported on some work that she and her colleagues are doing at Vanderbilt.  They evaluated re-routing amplification systems (CROS and remote microphone systems or RMS) in a simulated, dynamic classroom. And, they not only assessed sentence recognition ability but also story comprehension as the children listened in both monaural direct and monaural indirect conditions. The bottom line is that benefits were seen with both RMS and CROS use depending on the listening configuration. There is more work to be done in this area, but this is great information.

13. What other technology was discussed for children with UHL?

In addition to RMS and CROS, Doug Sladen presented recent outcome data from the use of cochlear implants (Sladen et al., 2016a; Sladen et al., 2016b) and bone-anchored devices (Snapp, Holt, Xuezhong, & Rajguru, 2017).  These technologies were rarely thought of during the CDC conference 18 years ago. Yet, today, clinicians are faced with considering these technologies as options for children with profound UHL. Cochlear implantation has been shown to improve localization and speech understanding in noise among adults and children with profound UHL. Hillary Snapp made clear to us that we are in the nascent stage of understanding the impact of bone-conduction devices on speech perception. She outlined when such devices should be considered for use with young children. And, we had an excellent expert clinical panel discussion on how to approach making technology decisions with families.

14. Fitting today’s bone-conduction devices on children seems challenging. Were any updates on the actual fittings provided?

Marlene Bagatto provided an excellent review of surgical and non-surgical indications for bone-conduction devices. Some early work is being done on prescriptive targets and clinical verification of bone conduction devices, including work by The Pediatric Bone Conduction Working Group and others (Hodgetts & Scollie, 2017; Scollie, Hodgetts, & Pumford, 2018). 

15. A lot of good information was presented at this conference. Is there a way to access all these presentations?

Yes. Videos and pdfs of the presentations can be accessed at www.phonakpro.com in the Training & Events section.

16. What's next? Is the plan to wait 15 more years and have another conference?

Ha! No, no. Immediately following the conference, an international panel of parents and experts on screening, assessment, management, and monitoring of children with UHL met for a day to discuss the next steps. We agreed to create a practice parameter that could assist clinicians with management decisions and outline research needs moving forward. So far, we have created a Quick Practice Guideline: Tools and Considerations for Assessing and Managing Unilateral Hearing Loss in Children. This guideline is available free of charge on the Phonak website. We wanted to create this guideline as a way to reach practicing audiologists across the globe with current information on children with UHL.

17. A “Quick Practice Guideline” doesn’t sound very thorough for such a complicated topic. Is a more comprehensive guideline in the works?

Yes. We are currently working on a longer, more detailed consensus document. This document will provide much more background information, including information presented at the conference and a review of the literature. We would like to help clinicians think about and incorporate some of the newest research that came out of the conference. I am hopeful that in the coming months we will have an expert consensus paper that can help guide decision-making and care-planning for clinicians to support children with UHL and their families.

18. What about the research needs that you mentioned?

Research into outcomes of UHL has been ongoing. But, intervention research has been sparse. Many studies examine cohorts that include children with minimal bilateral hearing loss along with children with unilateral hearing loss, so they are grouped together as children with “minimal degrees of hearing loss.” There is some evidence to suggest that children with minimal bilateral losses have different listening concerns than children with unilateral loss and their outcomes can be different as well. We need to improve the way that we are examining this population and separate the cohort of children with UHL. We need to perhaps even stratify those with varying degrees of UHL when possible as some studies suggest that children with severe-to-profound UHL have more difficulty than children who have lesser degrees of loss. Because we oftentimes lump all of those children into one cohort, it's difficult for us to learn if that's the case or not.

19. Why haven’t researchers separated these cohorts of children before?

It isn’t always easy to find sufficient numbers of children with UHL to ensure significant and strong effects when present. That’s why researchers need to consider partnering with clinical audiologists at multiple sites and work together to identify important research questions. A big-data approach to identifying risk factors for UHL is needed but requires large data sets with wide-ranging information such as genetics, imaging, audiometric evaluations, etcetera. 

20. Any other important questions that need to be answered?

There are many! But one that has bothered me for years is whether we should treat all children with UHL the same. We consider all of these children at risk but, in fact, we know that approximately 60% to 65% of these children will have difficulties. That doesn’t mean that the other 30% to 35% of children with UHL do not also need some level of intervention, but it might mean ‘different’ intervention for those at greatest risk. Audiologists need the tools and information to assist them to be better able to determine the risk level of individual children.

Although audiologists are aware that children with UHL are at risk for communication, behavioral, and educational difficulties, awareness isn’t enough. We need to work together as clinicians, researchers, and families to develop systematic approaches for the management of children with UHL. We have great momentum coming out of this conference – now it’s time to get to work!

References

Bess, F.H., & Tharpe, A.M. (1986). Case history data on unilaterally hearing-impaired children. Ear Hear, 7, 14-19.

Bess, F.H., Tharpe, A.M., & Gibler, A.M. (1986). Auditory performance of children with unilateral hearing loss. Ear Hear, 7, 20-26.

Bovo, R., Martini, A., Agnoletto, M., Beghi, A., Carmignoto, D., Milani, M., & Zangaglia, A.M. (1988). Auditory and academic performance of children with unilateral hearing loss. Scand Audiol Suppl, 30, 71-74.

Culbertsonn J.L., & Gilbert, L.E. (1986). Children with unilateral sensorineural hearing loss. Ear Hear, 7(1), 38-42.

Fitzpatrick, E.M., Al-Essa, R.S., Whittingham, J., & Fitzpatrick, J. (2017) Characteristics of children with unilateral hearing loss. Int J Audiol, 56(11), 819-828.

Hodgetts, W.E., & Scollie, S.D. (2017). DSL prescriptive targets for bone conduction devices: Adaptation and comparison to clinical fittings. Int J Audiol, 56(7), 521-530. doi: 10.1080/14992027

Hornsby, B.W., Naylor, G., & Bess, F.H. (2016). A taxonomy of fatigue concepts and their relation to hearing loss. Ear Hear, 37 Suppl 1, 136S-44S. doi:10.1097/AUD.0000000000000289

Hornsby, B.W., Werfel, K., Camarata, S., & Bess, F.H. (2014). Subjective fatigue in children with hearing loss: Some preliminary findings. American Journal of Audiology, 23, 129–134. doi:10.1044/1059-0889(2013/13-0017)

Jensen, J.H., Børre, S., & Johansen, P.A. (1989). Unilateral sensorineural hearing loss in children: Cognitive abilities with respect to right/left differences. Brit Jour Aud, 23, 215-220.

Kenworthy, O.T., Klee, T., & Tharpe, A.M. (1990). Speech recognition ability of children with unilateral sensorineural hearing loss as a function of amplification, speech stimuli and listening condition, Ear Hear, 11(4), 264-270.

Lewis, D., Smith, N., Spalding, J., & Valente, D.L. (2018). Looking behavior and audiovisual speech understanding in children with normal hearing and children with mild bilateral or unilateral hearing Loss. Ear Hear, 39(4), 783-794. https://doi.org/10.1097/AUD.0000000000000534  

Lieu, J.E. (2013). Unilateral hearing loss in children: speech-language and school performance. B-ENT Suppl. 21, 107-115.

Oyler, R.F., Oyler, A.L., & Matkin, N.D. (1988). Unilateral hearing loss: Demographics and educational impact. Lang Sp Hear Serv Schools, 19, 201-210.

Rachakonda, T.,  Shimony, J.S., Coalson, R.S., & Lieu, J.E.C. (2014). Diffusion tensor imaging in children with unilateral hearing loss: A pilot study. Front Syst Neurosci, 8, 87.

Scollie, S., Hodgetts, W.E, & Pumford, J. (2018, June). DSL for bone anchored hearing devices: Prescriptive targets and verification solutions. AudiologyOnline, Article 22962.  Retrieved from www.audiologyonline.com

Snapp, H.A., Holt, F.D.,  Liu, X., & Rajguru, S.M. (2017). Comparison of speech in noise and localization benefits in unilateral hearing loss subjects using contralateral routing of signal hearing aids or bone anchored implants. Otol Neurotol, 38(1), 11-18. doi:  10.1097/MAO.0000000000001269

Sladen, D.P., Carlson, M.L., Dowling, B.P., Olund, A.P., Teece, K., Dejong, M.D., . . . Driscoll, C.L. (2016a). Early outcomes after cochlear implantation for adults and children with unilateral hearing loss. Laryngoscope, 127(7), 1683-1688.

Sladen, D.P., Frisch, C.D., Carlson, M.L., Driscoll, C.L., Torres, J.H., & Zeitler, D.M. (2016b). Cochlear implantation for single-sided deafness: A multicenter study. Laryngoscope, 127(1), 223-228.

Updike, C.D. (1994). Comparison of FM auditory trainers, CROS aids, and personal amplification in unilaterally hearing impaired children. Journal of the American Academy of Audiology, 5, 204-209.