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BackTable / ENT / Article
Single-Sided Deafness in Children
Julia Casazza • Updated Jul 8, 2024 • 109 hits
As the name implies, patients with single-sided deafness (SSD) have normal hearing in one ear and deafness in the other. Since bilateral hearing is needed to easily access spoken conversation and localize sound, patients with SSD miss out on important auditory signals. For single-sided deafness in children, addressing hearing loss translates to better school and social outcomes. Interested in learning more? Join BackTable as we summarize the etiology, workup, and treatment of single-sided deafness.
This article features excerpts from the BackTable ENT Podcast. We’ve provided the highlight reel in this article, but you can listen to the full podcast below.
The BackTable ENT Brief
• Untreated single-sided deafness in children causes difficulties in school and social situations, as patients must “fill in the blanks” based on pieces of conversation missed.
• The most common cause of pediatric single-sided deafness is congenital cytomegalovirus (CMV). Less common causes include cochlear nerve hypoplasia/aplasia.
• Hearing options for children with single-sided deafness include contralateral routing of signals (CROS) hearing aids, bone-anchored hearing aids (BAHA), and cochlear implants (CI). CROS and BAHA systems can be accessed without surgery; CI always requires surgery.
• Single-sided deafness cochlear implants typically require 2-5 years of regular visits with their interdisciplinary treatment team. Auditory rehabilitation is a must to derive full benefit from the implant.
• Streaming audio directly to a patient’s cochlear implants allows them to benefit from hearing the content without the interference of background noise.
Table of Contents
(1) Challenges Associated with Single-Sided Deafness in Children
(2) Workup of Single-Sided Deafness in Children
(3) Helping Children with Single-Sided Deafness Hear
(4) Single-Sided Deafness Cochlear Implants: A Long-Term Commitment
Challenges Associated with Single-Sided Deafness in Children
Single-sided deafness in children causes difficulties at school and in social situations. Patients with one hearing ear must physically move their heads to hear a conversation on their deaf side. While “swiveling,” SSD patients often miss much of what is said. Practically, this means that a child with SSD sustains a greater cognitive load trying to interpret classroom instruction or conversation on the playground. Outside of academic settings, SSD poses safety concerns; since sound localization requires two ears, children with single-sided deafness can have difficulty interpreting environmental signals – for example, a car coming as they’re about to cross the street.
[Dr. Gopi Shah]
In terms of the impact of trouble in school, the single-sided hearing loss doesn't even have to be deafness. The impact is at the level of mild to moderate. You know what I mean? I think that as the ENT, it's important for us to take it very seriously and talk to the families, especially the school-age kids about FM system and preferential seating, and how do we help them even in those school environments?
[Dr. Anita Jeyakumar]
Absolutely. In adult world, they talk about the cocktail hour, right? If you have single-sided deafness as an adult and you're at a party or a gathering, something fun, you then lose half the room because your good ear is only pointing in one direction. Imagine a child in a playground, the most fun thing they can be. The kids are all milling around them and playing, but they lose half of the interaction of what's going on in that playground, which is a very fluid environment. A lot of these kids get labeled as being socially awkward or distant, or certainly as we know, kids, adults, people are not forgiving. The kids then get labeled as being unsuccessful people. It really is no fault of theirs. They just don't have access to 50% of the conversation and interaction that's happening, which makes them pariahs, is what ends up happening.
…
[Dr. Ashley Agan]
The other question would be the importance of sound localization. You need two hearing ears to be able to localize sound, right? I think that's another thing that gets overlooked, when we're like, "Oh, well, at least they've got one good hearing ear. They'll be fine." I think that's a pretty big deal when you're navigating the world.
[Dr. Anita Jeyakumar]
I completely agree. If a child can't safely cross a road, well, that's a safety issue, right? I think anyone would say it's a safety issue if a child can't safely cross a road. Yet, by having unbalanced hearing, they cannot safely cross a road. They look left, right, left, but something barrels through on the bad side or affected side, they don't know. It's a safety hazard. That goes into driving too.
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Workup of Single-Sided Deafness in Children
While audiometry assesses the extent of hearing loss, it cannot identify the cause of single-sided deafness. Nonetheless, magnetic resonance imaging (MRI) can provide hints. The most common cause of SSD is congenital cytomegalovirus (CMV); some (but not all) of these patients will have periventricular calcifications seen on MRI. Anatomic causes of single-sided deafness, including a hypoplastic and aplastic auditory nerve, must be ruled out using imaging, especially if the patient is considering a cochlear implant. These abnormalities can be missed on CT temporal bone imaging, which underscores the need for MRI.
[Dr. Gopi Shah]
Then when do you get imaging, and do you prefer a CT or an MRI? What's your workup?
[Dr. Anita Jeyakumar]
Great question. I think if they're older and I'm just identifying them, I probably get imaging right away. I tend to prefer an MRI. There's a fair amount of robust data coming in the literature beyond the radiation issue that in an MRI, you're going to identify more issues that are pertinent to people with single-sided deafness. There's a high degree of hypoplastic auditory nerve, aplastic auditory nerve, and then other cochlear anomalies, which you really should be able to identify on a CT or an MRI. Now, the cell, of course, as otolaryngologist, I'm the same as everyone else. I trained mostly on CTs. I love my CTs. It was a shift.
I'm not a neurotologist by training. I had to teach myself how to look at MRIs and not freak out that I didn't have all my bony windows and cuts and things like that. Then you have to often sedate them. If they're under double digits in age, you do have to weigh that risk of sedation. The problem is there's a fair amount of data out there showing that if they have a normal CT with normal IACs, they still can have an aplastic or hypoplastic nerve. Getting a CT temporal bone on someone with single-sided deafness, while it might appear normal to us, it may not necessarily be normal.
That definitely feeds into some of the options we might want to give them, is that if they have a hypoplastic or aplastic nerve and you don't know that, and let's say you move forward, jumping right ahead into one of the potential treatments, cochlear implantation, then you probably haven't done your due diligence in counseling the patients about their outcome with implantation because you don't know that they have an aplastic or hypoplastic nerve. Not to say it's the wrong option, but the counseling needs to be different.
…
[Dr. Anita Jeyakumar]
Oh gosh, I could go on forever. Wrapping up, I will say, I think the only thing that we didn't really touch on is etiology. If a baby is coming with a new diagnosis of single-sided deafness, a couple of things that we need to talk about beyond the nerve hyperplasia is that there is a strong association with congenital CMV. Now, congenital CMV, it's its own beast in and of itself, and most places in the country don't screen for congenital CMV. The only ones that are caught are about the 10% of kids who have symptomatic congenital CMV as defined by a neonatologist. Unfortunately, congenital CMV, even in asymptomatic kids, has a pretty high degree of hearing loss.
Up to 15% to 20% of adolescents with asymptomatic congenital CMV will develop sensorineural hearing loss. Just something to keep in mind, another plug to get imaging, because most of the times you can't get access to their blood spots by the time they come to see us as otolaryngologists. You can usually find some of those periventricular calcifications on an MRI when you do imaging for workup for single-sided deafness. Another reason. Is that definitive? No, it's not, unfortunately. It gives you a pretty good idea when you put all the pieces together. Intervention is important, whatever that intervention is. I know I dogged on BAHA a little bit, but the key is intervention is important. Someone needs to be paying attention to these children, and helping their parents help them is really key.
Helping Children with Single-Sided Deafness Hear
Social and technological support helps children with hearing loss engage with the world. Children with milder hearing loss might have their needs met with an individualized education plan (IEP) that includes preferential seating and the use of a frequency modulation (FM) system that amplifies what their teacher says, but children with single-sided deafness require more support.
Hearing options for children with single-sided deafness include contralateral routing of systems (CROS) hearing aids, bone-anchored hearing aid (BAHA) technology, and cochlear implants (CI). Single-sided deafness hearing aids (CROS) require users to wear aids in both ears; signals are wirelessly transmitted from the deaf ear to the hearing ear. BAHA technology uses bone conduction to route signals from the patient’s deaf side to the patient’s hearing side. Patients can benefit from BAHA either through surgical implantation of the aid or by wearing a soft headband that incorporates BAHA technology. Single-sided deafness cochlear implants are surgically implanted electrodes (connected to a sound processor worn on the head) that directly stimulate the cochlear nerve.
[Dr. Ashley Agan]
Can I stop you for a second and just have you elaborate on some of those terms for maybe our non-physician listeners? When you say CROS, can you go into what that means for the patient? Questions that frequently come up is, so am I wearing one hearing aid or two hearing aids? What does that look like from a patient standpoint, what your patients feel?
[Dr. Anita Jeyakumar]
Thanks, Ashley. I know we get excited and we forget ourselves with our acronyms. A CROS is basically hearing aid technology. Technically, they're wearing two hearing aids. There's one in the affected ear and one in the unaffected ear. They're both designed a bit differently because you don't want to mess up the sound in the good ear, so to speak. Usually, the hearing aid in the good ear doesn't have a full seal that's blocking off the ear canal and things like that to mess up the good hearing that they have. Essentially, the hearing aid in the affected ear is sending the signal to the hearing aid in the good ear. The child learns to understand that that signal is coming from the affected side.
If it sounds complicated, it is, because children don't necessarily understand that right away. It's called CROS because it's crossing over to the good side, essentially. There's also something called BiCROS, but that's for people who have hearing issues on both ears. That's not the situation we're talking about right now.
[Dr. Ashley Agan]
The big thing with CROS is that you're not actually aiding the deaf ear. You're just taking any sound that's coming from that side of the body and routing it over to the good hearing ear…
[Dr. Anita Jeyakumar]
BAHA technically is a generic term that encompasses a whole bunch of stuff. It traditionally means a bone conduction device. It's some technology that's either worn or surgically placed on the affected side that's, again, routing the signal through bone to the unaffected ear, to the unaffected hearing ear. You don't need to have an intact auditory nerve or anything like that on the affected side for you to have a BAHA. If you're super young, meaning that you're too young as a patient to meet the criteria to get the surgery, you can wear it on a soft band.
The nice thing I will say about the BAHA is that you can truly try it non-surgically and get some sense of whether it will help the patient or not, which I really do love because you can't do that with a cochlear implant. A cochlear implant is like you're all in or all out, but you can wear it on a soft band. Now, I will say also that my teens, males, and boys in general, are not enamored by wearing anything on a headband. If you stick a bow on it, they're even more ticked off. There are ways that our audiologists have come up with like rigging baseball caps and things like that that you can put it on and get that band-like sensation.
They can really have a real-time attempt to see if they like it before they go for the surgery. I tend to encourage my patients to do that because, one, we have the capability. Two, from a billing standpoint, if you can get approval for BAHA surgery, they can get the device and you don't have to jump right to the surgery. They can truly try it for a several-month period without burning any bridges for them. Again, they're not hearing on that affected side, which, gosh, it's really hard for us to conceptually understand that. That I'm doing a surgery on, let's say it's a right single-sided deaf ear, but I'm really not accessing the right side except anatomically. I'm really using your left side.
Single-Sided Deafness Cochlear Implants: A Long-Term Commitment
Initially approved for children with Single-Sided Deafness in 2019, cochlear implants restore hearing with the help of an appropriate rehabilitation protocol following surgery. To qualify for a cochlear implant, patients must have a normal cochlear nerve. Following surgery, completion of a hearing rehabilitation program – such as auditory-verbal therapy – can help achieve positive hearing outcomes. Families should be advised that committing to a cochlear implant means committing to 2 to 5 years of frequent office visits. Streaming audio directly to the implant’s sound processor allows children to benefit from content without competing with background noise.
[Dr. Anita Jeyakumar]
Technically, the FDA approval for single-sided deafness is only for one of the companies, but all the companies do what's called streaming. Just like we can stream into our headphones, like we're streaming now on this podcast, you can stream into a cochlear implant and you need to have all those pieces in place that the child has to have some daily time on top of working with a speech therapist for an unclear period of time where they're going to be streaming into the affected ear and going to periods where they're going to hear things that sound awful to them, with the idea that between time and audiologic programming and speech therapy, that it'll get to a place that they'll have a balance of sound on both sides.
That's what the parental commitment needs to be in. If the parent is not going to do that, if they are going to presume that it's like a light switch, or God forbid, even worse, if we presume that it's like a light switch, the child is not going to do well. Then it's not the right answer for them. That was a very long answer to your question…
[Dr. Ashley Agan]
Do you give people an estimate of like, weeks? months, a year, don't commit to a time, it just depends.
[Dr. Gopi Shah]
This is like allergy shots, two to five years.
Podcast Contributors
Dr. Anita Jeyakumar
Dr. Anita Jeyakumar is a practicing Pediatric Otolaryngologist in Ohio that specailzes in ear surgery.
Dr. Gopi Shah
Dr. Gopi Shah is a pediatric otolaryngologist and the co-host of BackTable ENT.
Dr. Ashley Agan
Dr. Ashley Agan is an otolaryngologist in Dallas, TX.
Cite This Podcast
BackTable, LLC (Producer). (2021, October 12). Ep. 33 – Single Sided Deafness in Children [Audio podcast]. Retrieved from https://www.backtable.com
Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
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