Both children and adults may suffer from hearing loss, but the same hearing device an adult uses may not be right for a child. Ruth Bentler, PhD, professor in the Department of Communications Sciences and Disorders at the university, talks about her research in hearing loss and current treatment for children and adults:
What causes hearing loss in children and adults?
There are many causes of hearing loss.
For children, the most common cause is probably ear infection, which is typically temporary and treatable. About half of all permanent loss in children, however, is genetic or hereditary. That’s the case, even if no one in the family appears to have a hearing loss, because the parents could be carriers of this hearing loss.
The other half, in children, is due to:
- Environmental factors such as prematurity, which will increase the risk of hearing loss
- Infections during pregnancy. We used to worry, 10 to 20 or 30 years ago, about German measles or rubella during the first trimester or pregnancy. That seemed to result in a number of different and negative outcomes at birth, and one of those was hearing loss—sometimes very significant hearing loss—at birth. But due to successful immunizations, public health efforts over the years, that’s much less likely to occur now. Today the main infection that we are concerned about is CMV or Cytomegalovirus. That again can lead to a variety of negative outcomes and one of those is hearing loss, so we see that frequently enough to be concerned about it.
For adults, that’s a different story. For adults, hearing loss can be a result of a number of experiences in life that includes:
- Noise exposure. Work related, social, or environmental—motorcycle riders or boat operators who have spent much of their life listening to loud sounds,and so on.
- Ototoxic drugs.
- Hereditary factors.
- Aging. It probably gets most of the blame for causing hearing loss in adults. But the aging process is a culmination of a lifetime of diet, work style, noise environment, stress, and so on.
When we put all of those things together and we attribute it to age, we call that particular hearing loss presbycusis.
Can a person with hearing loss that occurs gradually always recognize they have a hearing loss?
Not necessarily. Often in our own clinic and in my laboratory setting, it’s apparent that the first report of hearing loss comes from the significant other. This is especially true when we see older adults who come into the lab or into the clinic with their children or a spouse, for example, it’s typically that the significant other person who notes or pointsout the difficulty in hearing, even before the person (him or herself) acknowledges it.
How would a parent recognize that their child may have a hearing loss?
There are a number of milestones that we want to pay attention to with the children. Fortunately, in the state of Iowa and many states, we have newborn hearing screening mandate. That means children are screened for hearing within the first 24 hours of their life. If that is a successful screening, we pick up or recognize the possibility of potential of hearing loss and the child will be monitored closely to continue any services that would be appropriate.
Sometimes, because of milder hearing loss, newborns are not identified as having hearing loss, and it’s up to the parents to watch for signs or symptoms of hearing loss. There are several things that I suggest:
- Behavioral compliance. That’s one of the predictors of hearing loss in children. If the milder hearing impaired child is not adhering to behavioral rules or mandates in preschool or school, we want to rule out hearing loss as a possibility there.
- Distractibility. I think children are often more distractible because they are not getting the full message from their communication partner.
- Poor speech or language development. While not always recognizable as a hearing loss indicator, children may not be talking at the age they should, or maybe not putting the words together in the manner they should for a given age.
Once someone loses their hearing, is there a possibility it will return?
It depends on the cause of the hearing loss or the source of the hearing loss. For most hearing loss, served in most clinics and hospitals these days, hearing loss is a permanent thing.
If the cause of hearing loss is wax in the ear canal, or an ear infection, or something such as that, that’s treatable or manageable. Most hearing loss we see is a permanent, non-treatable or non-returnable level of hearing. We have to manage that hearing loss in different ways and those different ways include hearing aids, assistive listening devices, or perhaps some (we call them) communication strategy training classes, and so on.
Has technology with regard to hearing aid devices changed over the past decade?
Oh, absolutely! While hearing aids still cannot restore hearing and I think that’s still a misperception and misconception amongst many out there. Some of the earlier problems with hearing aids like high distortion, excessive loudness, or even unacceptable style, have been eliminated, so hearing aids are pretty good. And having done research on those hearing aids for more than 20 years, I’m pretty optimistic about them being effective to the degree we can expect them to be effective in managing hearing loss.
How do hearing aids work to improve hearing?
A hearing aid is basically a small amplifier that we put in or on the side of the ear. It’s got some current programming capabilities that will allow us to make the loudness of the hearing aid appropriate for a variety of degrees and configurations of hearing loss.
There are also features in those hearing aids, again that we can turn on or turn off that will help the listening ease or listening comfort or so on in backgrounds of noise. Now, I said help with the listening ease or comfort, I didn’t say remove the background noise, because that is still not possible, regardless of what some marketing suggests.
Another really good feature in some of the current hearing aids is that we no longer have to deal with that squealy sound; that feedback that comes from a hearing aid for a variety of reasons that is not always manageable. Those are some of the new things in hearing aids that are being studied and are being presented in hearing aids that make them more useful and more helpful than before.
Another thing that I might point out—hearing aids can be about any size or any color and you can wear them in or out of the ear. So that makes the whole concept of having to use this hearing aid more agreeable or more tolerable for some of our listeners with hearing loss.
What is your research looking at with regard to hearing loss?
We’ve been looking at efficacy and effectiveness for various hearing aid features.
Let me explain efficacy and effectiveness first. There are features in hearing aids that have been highly touted, highly marketed over the last couple of years, such as the directional microphone and the noise reduction within the hearing aid.
Now, when we study the efficacy of these features, we’re looking to see if in fact they work at all. Do they work in the laboratory, can we make them work to be successful parts of a hearing aid processor. Now, effectiveness has more to do with how effective they are in the real world on a real person’s ear, and that’s a whole other area of research.
So while we take many, many measurements in the lab and in our anechoic space, which is a large space in the subbasement of my building, we’re really more interested in whether or not these features (such as noise reduction or directional microphones) provide any benefit in real world settings.
We have been looking at that both in the adult populations and now looking at it in the pediatric population. There’s at least some concern in the research community that some of these features could hamper the speech and language learning of the pediatric client or pediatric hearing aid use. So we’re looking at that as a possibility.
We’ve had a couple of research projects over the last two years that suggest neither of those features is negative. I mean that’s an interesting way to do research, isn’t it, but the features are new and they’re high technology, but we need to be sure that they’re not somehow going to hamper or reduce the input to the younger child. That younger child needs to have that speech and language input in order to develop good speech and language ability.
When do you hope to finish this phase of the research?
I’m not sure that’s ever going to happen. I’ve said this for about five years in a row. I think we’ve answered every question we want to answer, for example, about the directional microphone and now we have several research proposals out for funding possibilities, so we always have one more thing we want to look at within the realm of higher technology and whether higher technology results in higher benefit to these hearing aid users.
I’m not sure that will ever end, because there’s always something new that’s being proposed or marketed and so we’re just trying to keep tabs on those innovations to indeed be sure they are promoting hearing as opposed to denying hearing to certain age groups. |
