All About Newborn Hearing Screening – Episode 11
Welcome to the All About Audiology podcast. I’m your host Dr. Lilach Saperstein and in this episode we are going to be talking about the newborn hearing screening (NBHS) (as I have discussed in this article I wrote).
Now, one of the many hospital screenings that occur within the first day or two days of birth is the newborn hearing screening. The keyword is “screening” which means it’s a pass or fail kind of test. You either pass the screening or you don’t pass. It’s not a diagnostic test. A diagnostic test means that we are determining the specific type or degree or configuration of hearing loss and really getting a lot of information. The screening is just choosing a cutoff and saying anyone who passes this, we are calling it a “pass” and if they don’t we call it “fail”. They won’t tell you if there is a little bit of hearing loss, a lot of hearing loss, what kind of hearing loss… In other words just because the baby will fail the hearing screening, it doesn’t mean they have hearing loss. There can be other things going on and we will discuss it throughout this episode.
Also, even if the fail is accurate and there is a hearing loss, we still need to get more information about the type, degree and configuration. And if you have been listening to the podcast, we have discussed in previous episodes how important it is to understand the type, degree and configuration of a hearing loss in order to know which devices would be appropriate or what’s the best way to approach the rehabilitation process for the specific kind of hearing loss.
About the universal newborn hearing screening:
The universal newborn hearing screening is a means of identifying hearing loss as early as possible and it has been a very positive initiative throughout the world because early identification and intervention lead to better outcomes for deaf and hard-of-hearing children.
In the olden days before this universal newborn hearing screening was instituted, what would happen is that the first time a hearing loss or even deafness would be identified would be later on in the child’s life, maybe when they were two years old and weren’t speaking, or later on in their development when parents noticed they don’t always respond or hear softer sounds. So it would be identified through their behaviors and through noticing that a child wasn’t listening or wasn’t able to hear, but not at infancy. The reason that the universal newborn hearing screening is so valuable is because it can identify children who are deaf or hard-of-hearing much earlier on, right at the beginning of their life and get a full diagnosis and then implement interventions as early as possible to give the children language input.
Another thing that I have talked about on this show before, and it’s something that I’m very passionate about, is the problem of language deprivation. Now when I say language deprivation, I don’t necessarily mean spoken language, as speech, I am referring to other languages which can also include sign language.
One of the biggest detriments to deaf and hard-of-hearing children is language deprivation in the first 2-3 years of life which are the critical periods of language acquisition. If we identify a baby to have a hearing loss and that baby then gets a hearing aid or cochlear implant or other devices that will try to maximize their auditory potential, then they will get many months of auditory input in order to help them with their language development, with speech and language development in that case. Or if a baby is identified as deaf, and the primary mode of communication is sign language then that baby will receive sign language input from the start. This happens naturally if family members are deaf but it’s something that needs to be identified. And if parents want to pursue sign language as a mode of communication for their child then they can do so early on and the child will get language input from the start.
So we’ve talked about the value of the NBHS and how wonderful it is that it’s been implemented universally. That means every baby who is born will have the newborn hearing screening in the hospital. This is true in the US and many countries around the world. The newborn hearing screening in most hospitals consists of one or two tests, the OAE or the ABR. There are many medical abbreviations in audiology. I’ve briefly discussed these in a previous episode. But for right now I’ll be discussing the implications of the baby not passing the initial screening, be it with an OAE or an ABR.
If the baby doesn’t pass the screening in either ear then the screening is repeated once more before the baby is discharged home. Generally we try to do it so that the screening is done within 24-48 hours of the baby’s birth. And if they don’t pass or if there isn’t time to do the initial screening because the baby is sent home, they will be sent for a follow up screening at a community audiology practice or they will be asked to return to the hospital practice. There are protocols set in place for these babies and their families to be monitored to make sure they get the follow up screening. There are state wide databases that audiologists and other medical professionals can access to keep an eye on those babies who did not pass the screening.
So if a baby did not pass the screening it can be due to a number of things. It doesn’t necessarily mean that the baby has a hearing loss. We know that there is a concept of a false positive which means the test result shows that this patient should be flagged and that this baby “failed” and that they are having a problem, when they actually don’t have the problem that’s being tested for. They are failing for other reasons.
Possible reasons for a false positive:
Here are some of the reasons why a baby would have had a false positive, meaning it seems that they failed the screening but they actually have normal hearing. The first one would be malfunctioning equipment, and even though equipment is calibrated every day or regularly and it’s tested to ensure that it’s working properly, sometimes equipment does malfunction. And the people who are doing the screenings in the hospital, whether it’s a nurse or technician or audiologist are looking out for signs that the equipment isn’t working. For example, if they get a few babies not passing in a row, they take a moment and think that although it’s possible that a few babies don’t pass in a row, maybe there is something wrong with equipment so they check and make sure that this isn’t the case. Oftentimes the screen-er can test their own ears if they know that they have normal hearing to make sure it isn’t malfunctioning equipment. There’s also equipment made to test the screening equipment, called calibration equipment.
Another reason would be fluid or debris in the ear remaining from the birth. We have to remember that a baby was living in amniotic fluid for nine months and when they are born it can take a couple of hours for the ears to clear out the fluid or other things. Sometimes it can take up to two weeks for this to happen and for the ear canals to actually be clear and for the test to be valid and be able to test the hearing. The size and shape of the ear canal also comes into play even though the equipment is designed for infants and for tiny little ears. The probe, the little ear piece that’s put into the ear, needs to fit in snugly withing the ear. Some babies have extremely small ears or have curvy ear canals, especially premature babies that have very small structures and are just too small for the equipment and you can’t get a good seal, although we do have different sizes to try and fit. That might be why the hearing screening won’t be able to be performed.
There is also human error and when people are performing and recording the screenings, everyone is after all human and mistakes do happen. Even mistakes in keystroke in the medical record, can trigger the system to label the test as a “fail” and request a follow up screening even if they actually did get a “pass”, but it was recorded incorrectly. Any time that there is a follow up we always repeat the screening first to rule out if this was the case. Whenever there is a re-screening scheduled and it lists that they passed in the right ear but not in the left ear, no matter what we will always re-screen both ears to make sure we are covering all of our bases.
In the case that the second screening also results in a “fail”, that’s when we are going to say that we need to do a full diagnostic workup. This workup is performed by an audiologist. The full workup consists of an “ABR”, the Auditory Brainstem Response and that’s done while the baby is sleeping with electrodes stickers on their forehead and behind their ears. These are used to monitor the auditory nerve and brainstem activity in response to sounds, where the sounds are placed with the little earphone into their ear. This evaluation can take between 45 minutes to an hour, depending on the sleep state of the baby. It’s not uncommon for several appointments to be needed in order to obtain complete results, especially if the baby is fussy or keeps waking up so we might have to see them a few times.
In some rare cases where we can’t do it in a natural sleep state, then an ABR can be performed in the hospital under sedation to get the results. With the results of an ABR, we are able to see if the child has a hearing loss, what degree of hearing loss (mild, moderate, moderately-severe, severe, and profound) and we can get a sense of the configuration of the hearing loss (high frequency, flat- meaning the same kind of hearing loss across all the frequencies that are tested), and we also get information about each ear individually. Like I said before, the earlier the identification the better it will be for that child because we can implement early interventions.
When a hearing loss is identified, it’s sometimes recommended that the entire ABR is repeated in another clinic with different equipment and different clinicians to confirm the diagnosis because even though we are getting results that are coming from the equipment, and they are objective, and the baby doesn’t have to do anything to get the results, but it’s sometimes a good idea to get a second opinion on the interpretation of those results. Once a hearing loss is identified the process of deciding which communication modes will be introduced, which includes sign language or the auditory oral method. We’ll start to take a look at what are the intervention options for this child, which devices are going to be considered (hearing aids), and will they be interested in pursuing a cochlear implant evaluation. Of course there will be scheduling monitoring and further evaluations. This is all an effort to set this child up for success.
We talked about the false positive and what would happen if a child doesn’t pass the screening but has normal hearing. I also want to mention that the opposite can also be true to a degree, which is that even if a child passes the screening it doesn’t rule out that they might have a mild hearing loss. A mild hearing loss sounds mild, and not such a big deal. But actually for the language and speech development for children, a mild hearing loss will affect their speech and language development. There is also progressive hearing loss which means at the time of birth, they passed and there wasn’t a hearing loss present. But it could be that over time throughout their life span, children can develop hearing loss, or that their hearing loss which was mild at the time of birth progresses to more severe hearing loss. So any babies that are risk for hearing loss should continue to be monitored. Risk factors include family hearing loss, any time spent in the NICU, any deformities of the ear or face or identified syndromes. And if there are any of these other things going on, even though the child passed the initial hearing screening, we are going to want to check up on them when they turn one, and turn two to evaluate their hearing at that time and monitor their hearing ability.
This episode was about the newborn hearing screening and although I mentioned many benefits of the newborn screening, we also have to recognize that it’s a very difficult time for any parents, especially new parents who have just had a baby and they learn that their baby has failed the hearing screening, they leave the hospital with questions and don’t have answers. Their baby has failed the hearing screening and they don’t know what that means. And maybe at a follow up appointment they do learn of their child’s diagnosis of hearing loss or deafness, this is still very difficult news to receive. On top of all the stressors of the postpartum period, this information in addition can be really difficult to receive and be hard for parents. There is a grief cycle; grief is natural and necessary when the news is unexpected. Most children with hearing loss are actually born to hearing parents. So I’ll just say a word to anyone out there, it’s important to give yourself permission to experience any emotions and any of the feelings that you have about this, they are all valid. I recommend that you seek support from other parents and from professionals who can provide you with guidance and information. It’s one of the reasons that I make this podcast. There is a lot of support out there for children with hearing loss and although it’s a very difficult diagnosis, I believe that having a lot of information will give you power and when you become empowered with information and knowledge and you have the proper guidance and support, you can become the best advocate that your child deserves.
Additional referrals can also be made as they pertain to your child and these might include genetic testing, counseling, vision testing, a workup of the heart and lungs or the kidneys depending on what the genetic tests show. There’s a lot of information and it can be extremely overwhelming but having that information can help you understand your child’s situation and address their needs better.
If you are listening to this because you googled, “my baby didn’t pass the newborn hearing screening”, I want to tell you, don’t jump to conclusions. Be prepared for the screening to be repeated and for the baby to undergo diagnostic testing over the next couple of weeks and whatever the results will be, you are your child’s best advocate and know that knowledge is power and you are going to do what’s best for your child. By the way, congratulations on your new baby!
Thank you for joining me for today’s episode on the All About Audiology podcast where we talked about the newborn hearing screening. On the next episode we are going to be talking about ear infections, middle ear fusion and we will talk about ear tubes that are sometimes put in by an ENT to drain the fluid and keep it from building up. These are also called PE tubes, pressure equalizing tubes that are also known as grommets in the UK and we will talk about that in the next episode. Before that we are going to have our All About You episode and I’m really looking forward to hearing what you guys have to say about today’s episode and about newborn hearing screenings. I’d love to hear your experience about it or anything else you’d like to share or ask me about or any feedback you have about the show. You can reach me in lots of different ways. On my website allaboutaudiology.com, there is a contact page where you can leave comments on any of the posts. You can find me on Instagram @allabooutaudiology podcast and we have a listening group on Facebook which you can join. I look forward to hearing from you and I’m so glad you are listening to the podcast. I’m Dr. Lilach Saperstein and this is the All About Audiology podcast.