Unilateral Hearing Loss in Children: Consensus Paper from Phonak International Conference Aims to Improve Standard of Care
AudiologyOnline: Thank you for your time, Dr. Tharpe. Last month, you served as Conference Chair for Phonak’s first international pediatric conference dedicated to the topic of unilateral hearing loss (UHL) in children. Why is the topic of UHL in children important?
Anne Marie Tharpe, PhD: I think it is important because these children are known to be at risk for a number of challenges. For example, in the original papers that came out of Vanderbilt back in 1984 and 1986, we recognized 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 unilateral hearing loss 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. So, we knew that children with UHL were having some problems and we dug into some of the reasons that we suspected might have been causing the problems. For example, 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.
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. So, we thought that it was time to pull together a conference again to examine what is going on currently with these children and what directions we might take.
AudiologyOnline: In what areas have we made gains over the years?
Dr. Tharpe: One area in which we have seen progress is in the area of technology. There is better technology available, for example modern CROS and remote microphone technology, which wasn’t around back then. These products assist children in listening in the presence of background noise, like in classroom settings. We know that classrooms tend to be complex and dynamic listening environments for children, and we are able to improve their listening in those situations. Another area where we've seen significant improvement has been in the early identification of unilateral hearing loss. Those early studies I mentioned were done 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 being identified earlier in many cases. Parents, teachers and other professionals are aware of the problem earlier in a child’s life and are hopefully able to implement measures to assist them in listening and with other issues they might be having.
AudiologyOnline: Where are some of the gaps in our management of children with UHL, and where are there opportunities to improve outcomes for these children?
Dr. Tharpe: I think one of the problems that we are seeing is that despite the improved identification and technology, children are still struggling academically and behaviorally. There are likely at least a couple of reasons for this. One reason is that despite the fact that 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 the kind of care that most audiologists are now recommending.
The second reason has to do with the fact that research into outcomes and management of UHL in children has been sparse. We have well documented the challenges that these children are having, but we are not doing the kind of research that will validate the effectiveness of our interventions.
And, the research that we are doing sometimes is not as clear as it could be.
AudiologyOnline: How so?
Dr. Tharpe: Many of the 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's 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 isolate those children with unilateral loss – perhaps even thinking of stratifying the degrees of unilateral hearing loss. Some studies suggest that children with severe- to- profound unilateral hearing loss have more difficulty than children who have lesser degrees of unilateral hearing 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.
Furthermore, we are left wondering whether we should treat all children with unilateral hearing loss the same because we just consider all of them at risk, when in fact we know that approximately 60-65% of these children will not have academic difficulties. That doesn’t mean those children do not need some level of intervention, but it might mean ‘different’ intervention for those at greatest risk. The notion of not personalizing our management is a difficult one to accept.
Additionally, a lot of our recommendations are based on really old data. For example, it is common to hear that CROS hearing aids are not useful in children with unilateral hearing loss in classroom settings, but that conclusion is largely based on two studies from the 1990s. Each of those studies had six subjects participating and, of course, technology has changed a lot since then. Yet, the recommendation persists today against using CROS hearing aids in classroom settings. Fortunately, Erin Picou presented some new data at the conference on current CROS technology that might change some of our thinking about its use in classrooms. It's things like that which came out of this conference that I think can impact our recommendations moving forward.
AudiologyOnline: So current best practices guidelines aren’t sufficient for assessment and management of unilateral hearing loss in children?
Dr. Tharpe: I would say no. One reason is that I'm not sure that we have thorough best practice guidelines specifically for the assessment and management of children with unilateral hearing loss. They are included, of course, in management guidelines for children with hearing loss in general, but not very specifically. I certainly do not blame anyone for not including more guidelines simply because, as we were just discussing, there's not a lot of good evidence on which to base such recommendations. This lack of evidence on what to do in terms of managing these children has led us, I think, to be somewhat stagnant in our approach. Audiologists might be hesitant to be very aggressive managing UHL because the supporting evidence is not there.
However, I do think it is reasonable for us to put together expert consensus guidelines at this time. In other words, even though we recognize the limitations in the current evidence base, we can pull together a group of individuals from around the world who have been considering these issues for a long time, and offer something to clinicians who are trying to do their best in working with these children and their families. At the conclusion of the Phonak pediatric conference, that’s what we did. We brought together researchers and clinicians and parents from around the globe and we spent considerable time discussing how to move forward with guidelines. We considered current literature and the presentations from the Phonak UHL Conference and I think we got off to a very good start. 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.
We would like to help clinicians think about and incorporate some of the newest research that came out of the conference, even if it's not complete at this time. For example, there's a lot of new research in the area of listening effort and fatigue in children. Some of that includes children with unilateral hearing loss, and some of it, as I mentioned earlier, is mixed in with children who have minimal or mild degrees of loss. This research suggests that children with hearing loss have to exert more listening effort that results in fatigue, and such effort can impact their performance on comprehension and other tasks. It's reasonable to assume that we should be able to apply these findings to children with unilateral hearing loss.
For example, there are listening fatigue scales being developed from some of the work by Fred Bess and Ben Hornsby. They have completed a fatigue scale for adults and they are working on a fatigue scale for children. I think encouraging practicing audiologists to look at those scales and see if they can be incorporated into assessment protocols for children with UHL is useful. There are other functional auditory assessments and language assessments that clinicians can also consider incorporating into their batteries if they see children with UHL.
AudiologyOnline: It is exciting to hear about these initiatives that can advance our care and hopefully improve outcomes for these children. Is there a plan to disseminate the consensus paper?
Dr. Tharpe: We are considering a couple of avenues. On the one hand, we want to be sure that we reach researchers as well as clinicians, and we also want to be able to reach people both in North America and globally. We're thinking that we will publish, if possible, in a peer-reviewed journal and we will also develop a white paper. The white paper can be disseminated by Phonak and offered as a download on their website so that it would be accessible to a global audience that might not have access to a journal version.
The attendance at the recent conference was quite surprising. This is a pretty narrow topic within the area of pediatric audiology, so initially we didn't know if we would have very many attendees. We were thrilled to have approximately 350 attendees at this conference, representing 16 different countries.
AudiologyOnline: Wow, that really speaks to the knowledge gap and need for more information in this area.
Dr. Tharpe: Absolutely. The Phonak conference truly was an international event, and I couldn't be more pleased that our colleagues around the globe are just as interested in this topic as we are in the U.S. There were also a number of parents who attended. We had a parent panel share their experiences with hearing professionals who influenced their ability to provide or obtain services that they needed for their children. That was an impactful part of the conference.
It’s time for us to make another leap forward in this area and I think the momentum from the conference will help us to do that.
AudiologyOnline: As always, it’s a pleasure speaking with you Anne Marie. Thank you for your time. I look forward to hearing more about the recommendations from the consensus group.