Audiologist and Chair, Department of Hearing and Speech Sciences, Vanderbilt University School of Medicine in Nashville Tennessee.
Dr. Tharpe's research interests are in the area of pediatric hearing loss. Specifically, she has explored the developmental impacts of minimal and mild hearing loss on children, children with hearing loss and additional disabilities, and more recently, the sleep patterns in those with hearing loss. Dr. Tharpe has published extensively in national and international professional journals, has published numerous books and book chapters, and has presented to over 250 audiences around the world on pediatric audiology issues.
I’ve known Professor Anne Marie Tharpe for many years and have been fortunate to work with her on a number of initiatives in pediatric audiology. We both share a strong passion for improving outcomes for children with unilateral hearing loss and I am so impressed with all the work she is doing in this area. It was my pleasure to interview her to discuss her recent collaborative efforts with experts in UHL and how their work will benefit HCPs around the world.
Here is our interview…
Anne Marie, thank you for joining me today. There are many terms which are being used to describe an asymmetrical hearing loss. I’ve heard the terms Single Sided Deafness, Unilateral Hearing and Limited Useable Hearing Unilaterally. What is the difference between these terms? And, is there are term you would recommend we use, moving forward?
I think the best way to think about this is that unilateral hearing loss is the umbrella term for all of these. So if there’s any degree of hearing loss in one ear with normal hearing in the opposite ear, it’s a unilateral hearing loss. It could be a mild hearing loss, it could be a high frequency hearing loss, or it could be a profound hearing loss.
More recently, people have been trying to define a term that would be more consistent with a description of the loss. That’s where ‘single-sided deafness’ originated. However, a problem with the term single-sided deafness is that it implies there is no hearing in that ear, which may or may not always be true in terms of the intent of the speaker. Sometimes the intent is to indicate there is limited usable hearing in the impaired ear. So, one could have, for example, a moderate hearing loss with very poor speech recognition ability. Under those circumstances, it wouldn’t be single- sided deafness because there is residual hearing, but there would be limited use of that hearing because of the very poor speech recognition ability. For that reason, the term ‘limited usable hearing unilaterally’ (LUHU) has been used by some.
I prefer describing unilateral losses in the terms that audiologists are already accustomed to using. For example, mild unilateral hearing loss, moderate unilateral hearing loss, and so on. When an ear is considered unaidable, it would be limited, usable hearing unilaterally.
As we become more and more aware of the potential difficulties a child with UHL can have, are we finding that the statistics around age of identification and prevalence are changing?
It’s a great question. I’m not sure that we are seeing a change in the overall prevalence, but we are gaining a better understanding of the prevalence relative to age. What I mean by that is, we know that approximately one per thousand children are born with unilateral hearing loss but at school age, it becomes about three to five per hundred, and in adolescence, the number gets closer to about 15 per hundred. Some of that increase over time is likely the result of progressive or late-onset hearing loss.
…we know that children who have unilateral hearing loss are at greater risk for academic difficulties than children who have normal hearing in both ears.”
Can you remind all of us hearing care professionals of the key concerns for children with UHL?
Of course. Imagine that if you didn’t have hearing in one ear it would be very difficult for you to be able to localize sound and to tell from what direction the sound is coming — that skill requires binaural cues that are so important for us in localizing sound sources. We also use those cues for speech perception, especially in noisy environments.
According to prior research, we know that children who have unilateral hearing loss are at greater risk for academic difficulties than children who have normal hearing in both ears. We assume that’s in part because they have difficulty with speech perception, although we aren’t able to directly make that link. We are also alarmed that about 50% of these children have difficulty in school. What I mean by that is that they either have to repeat a grade in school or they need tutoring, or special help in school with their academic challenges. Some of these children require speech and language therapy as well.
For audiologists, the most valuable clinical resource would be a guideline to help them manage these kids effectively. You were recently involved in creating a consensus paper to guide professionals. Can you tell us about it?
In Fall of 2017, Phonak sponsored an international conference specifically on unilateral hearing loss in children and it was a great event. We had many wonderful speakers and we learned all about the latest results in UHL research as well as clinical practice. Immediately following the conference, a group of experts came together to talk about what we know and what remains to be learned about unilateral hearing loss.
Out of that meeting, we produced a practice guideline for clinicians that summarized the best of clinical practice as we know it today. Recognizing that there are some limitations to what we know, this document can provide some guidance for clinicians who want to do the best for children with unilateral hearing loss.
Who was involved in its creation?
The group included Marlene Bagatto, Janet DesGeorge, Alison King, Padraig Kitterick, Diana Laurnagaray, Dawna Lewis, Pat Roush,, Douglas Sladen, and me.
That’s an impressive group. In your time working together on creating this paper, what did you find were your biggest learnings?
The document starts with some of the standard management approaches that audiologists have for children who have bilateral hearing loss. We wanted to emphasize that children with unilateral hearing loss also require accepted approaches to hearing healthcare similar to a child with bilateral hearing loss. Some literature and anecdotal reports suggest that sometimes healthcare professionals don’t take hearing loss in one ear as seriously as when there’s hearing loss in two ears. We started out by emphasizing that important point in the practice guideline.
In addition, it is common for hearing healthcare professionals to encourage audiologic monitoring because we know that a number of children with unilateral hearing loss will have progression of hearing loss to the opposite ear; thus, many of these children will end up with bilateral hearing loss. One explanation for this progression can be the etiology of the loss and, as a result, we recommend close medical management as well. Furthermore, inner ear malformations, like enlarged vestibular aqueduct, contribute to progressive loss. Reports note that even in children who have enlarged vestibular aquaduct in one ear, sometimes the opposite ear also demonstrates hearing loss.
We encourage talking with parents about how to ensure that their children remain safe during tasks that require localization ability, like crossing busy streets. Such tasks might require different training than that provided for children with normal binaural hearing.
We wanted to emphasize that children with unilateral hearing loss also require accepted approaches to hearing healthcare similar to a child with bilateral hearing loss.”
We know that the treatment methods available are: monitor with no intervention, traditional hearing aids, bone conduction hearing aids, CROS/BiCROS, cochlear implants and remote microphone systems. Were you able to provide further guidance on what technologies audiologists should be recommending?
Oh yes. We spent a lot of time talking about technology because there are so many different options and I think because we have so many options, it becomes confusing for professionals and for families. Which group of children with unilateral hearing loss should use which type of technology? As you noted, some professionals are recommending cochlear implants for children who have profound hearing loss. Others are recommending traditional hearing aids if the affected ear is aidable. The use of remote microphone systems is a popular recommendation to provide listening assistance in the presence of background noise. Those have traditionally been used in school settings for children with bilateral hearing loss. Evidence suggests that they’re also very effective for children with unilateral hearing loss.
As one way of trying to sort through all of those different options for the different types of unilateral hearing loss, we have suggested in this guideline that audiologists consider using functional auditory assessments to personalize or individualize their recommendations based on the problems reported by the child, by the child’s teacher, or by the child’s parents. By documenting what difficulties the child is having, we can personalize what type of technology might work best for that child in specific environments.
What would you say are the key takeaway messages from the consensus paper that will help ensure basic management for all children with UHL?
We should consider the components of management that we provide for ALL children with HL, including etiologic evaluation, speech and language assessments, functional auditory assessments, and vestibular assessments, when indicated. In addition, for children with unilateral hearing loss, we should assess localization ability either via questionnaires or direct measurements. Once we establish the skills and any deficits the child experiences, we can consider which technologies might be of assistance and counsel the family appropriately.
You also talk about the need for more research in the area of UHL. Can you share with us what immediate research topics were identified amongst the group?
That’s another good question. Thank you Angela. We spent a lot of time as a consensus group talking about research needs and also dove into limitations of prior research in order to inform tese current research needs.
We address the need for larger datasets or ‘big data’ approaches to answering some of the questions we have about children with unilateral hearing loss. Depending on the type of research we’re doing, this might require multi-site collaborations or pragmatic clinical trials. . Many of our past studies have had small cohorts and that has provided a good start. It helped us realize that there are problems that these children are experiencing, but I don’t think we’re going to make transformative progress until we look at much larger groups of children.
The other thing we need to do is start to stratify this research population. A lot of the studies in the past, including many of my own, have included children with minimal bilateral hearing loss along with children with unilateral losses and it’s just mixing apples and oranges. We need to look strictly at children who have unilateral hearing loss and stratify that group according to degree of hearing loss, aidable versus unaidable hearing in the affected ear, and laterality of the loss. I Additional work on individual interventions and technologies that might be most effective according to those stratifications is needed.
How can an audiologist get access to this consensus? Is it available publicly?
These guidelines were published in the International Journal of Audiology and it was an open-access publication, which means that anyone can go in and download a copy. Phonak is in the process of translating this document into Spanish, Portuguese, Polish, Hungarian and Japanese, so this knowledge is shared around the world.
Thanks so much Anne Marie for joining us today. It’s been a real pleasure to have you here with us to talk a little bit more about unilateral hearing loss.
|Summary of Dr. Anne Marie Tharpe’s key takeaways for clinicians:
1. Etiologic evaluation and audiologic monitoring are very important given UHL increases in prevalence over time and can progress to a bilateral loss.
2. During monitoring, it is important to assess for difficulties related to loss of binaural function (localization and speech perception), speech and language difficulties, possible balance concerns and functional challenges.
3. Hearing technology should be considered as part of intervention. A combination of solutions might be required to meet a child’s specific needs and these needs might change as they grow.
4. Effective communication between audiologists and parents is vital. Audiologists have an important role in providing support, information, and resources to parents throughout their journey.
To access recordings and pdf files of presentations from the Unilateral Hearing Loss in Children Conference, click here. To download a copy of the Consensus practice parameter: audiological assessment and management of unilateral hearing loss in children from the Phonak website, click here.
To watch Angela Pelosi and Dr. Anne Marie Tharpe discuss the UHL guidelines in more detail, we invite you to watch this short video.
Theory to Practice is a series of interviews with experts in the field of audiology and beyond. Interviewees share their knowledge and insights on relevant topics. The special focus of each interview is to translate theory into key take-aways which can be implemented into daily practice.