Good Vibrations

When it came to treating single-sided deafness, Ear Technology Corporation’s Dan Schumaier built a solution from scratch that keeps getting better.

Dan Schumaier, PhD

In a conversation with Ear Technology Corporation President Dan Schumaier, PhD, he discusses single-sided deafness, its perception among treatment professionals, and the evolution of TransEar, the revolutionary instrument he invented to treat it.

Will Campbell  Let’s start off with your background and involvement in the hearing health care industry?

Dan Schumaier Well, it’s interesting. I had planned all of my educational career to teach on the university level, and when I graduated, I certainly did. I taught for 2 years at East Tennessee State University and started their graduate program in audiology, which I enjoyed very much. But one of the problems with teaching in an institution is the bureaucracy—it kind of got to me.

At that time back in the early 1970s, there weren’t many people in private practice in the country, so in 1973 I left the university and went into private practice where I set out to do three things, one of which was diagnostics. I also decided I was going to dispense hearing aids, so I went out and got my hearing aid dispensing license and started dispensing hearing aids that year. The other thing I went into was industrial hearing conservation—and this was before we had all the regulations where companies had to actually do testing.

But that’s how I started my practice and it’s since grown to three offices [in Johnson City, Greeneville, and Kingsport, Tenn] for dispensing and doing diagnostic work. We also now have Industrial Hearing Conservation Services Inc, a large industrial practice that tests over 300 companies with five trailers that are on the road all the time.

WC  How did you become involved in treating single-sided deafness?

DS I saw a need. The only hearing aids we had that helped people with single-sided deafness were the CROS [Contralateral Routing of Signal] hearing aids, whether they’d be wired or wireless. Unfortunately, most of these weren’t accepted by the patients that we would see. As a matter of fact, I think only about one out of 10 or 12 would actually keep the hearing aid because they’d say, “You know, I can hear better with it in quiet, but when there’s any noise, it really occludes my good ear.”

With the old CROS hearing aids, we had to put the signal into the ear that didn’t have single-sided deafness and that would occlude the hearing and people would say they heard better when they took it out.

There were also problems with cords, wires, and breakage, so it wasn’t a very viable option. As a matter of fact, a lot of dispensers wouldn’t even try it because they knew it was going to come back.

WC  Explain a bit about the surgical methods available.

DS There were some surgical options over in Europe. A company there had an instrument out that was bone-anchored, and that product was eventually sold to Cochlear, and then it came into the United States sometime in 2000 and was accepted for treatment of single-sided deafness.

But bone-anchored hearing aids and TransEar were the only things that were really new compared to the CROS hearing aids. We had some people who have tried to do CROS aids with power instruments in the dead ear, and those are called Trans-Cranial Air Conduction CROS instruments. Basically, you fit a person with a tight-fitting earmold and crank the gain up as far as you could go without feedback. The idea would be that the acoustic energy would set up sound waves that would actually vibrate the ear canal, and those vibrations would be transferred from the ear canal to the skull to the good cochlea,

These instruments do work sometimes. But the problem is you have to have such a tight fit. And the other problem is feedback. It’s not very comfortable and not very successful.

We’ve also had some instruments that use bone conduction, especially the eyeglass hearing aids, where you could put a bone vibrator eyeglass instrument on an individual. Unfortunately, patients had to wear glasses all the time and you had to wear a type that generally had pretty thick frames, which you don’t see much anymore. And if you didn’t have your glasses on, you didn’t hear.

So with such a large incidence of single-sided deafness in the United States, I simply decided there was a better way to do this.

WC  How prevalent is it?

DS There are somewhere between 40,000 and 60,000 individuals per year in the United States and they’re equally distributed by sex. The average onset is somewhere between the age of 30 and 60. In addition, we have somewhere between 2% and 3% per thousand children who also have single-sided deafness, and very often these children don’t get diagnosed until they’re 6 or 7 years old.

The standard definition for single-sided deafness is a significant sensorineural hearing loss in one ear and essentially normal hearing in the opposite ear. The ear with the single-sided deafness may have a profound sensorineural hearing loss. It may be an ear with some hearing, however, very poor or no word recognition ability—or it could be an ear with recruitment. These are people you just can’t fit regular hearing aids to.

So we’ve got a large population. And if you consider 40,000-60,000 adults in the United States every year, you spread that out over a 5-year period, that’s a lot of people. Worldwide, it’s probably about 120,000 per year.

WC  What causes single-sided deafness?

DS There can be all kinds of causes. You can have measles, mumps, otitis media, trauma to the head, acoustic neuromas. There are a lot of things that can cause single-sided deafness. But sudden deafness is probably the leading cause. We’ve all run into these people. They generally have a rapid sensorineural hearing loss. It occurs immediately or over a number of days. The loss can be mild or total. Generally, we don’t know what causes these sudden hearing losses. About half can return to normal, but the rest don’t. And of those that don’t, about 90% end up with the classic single-sided deafness definition.

In the past there has been an underestimation of the negative effect single-sided deafness has on a person’s quality of life. Unfortunately, too often I hear patients say they’ve been told, “Well, you’ve got another ear, you can get by.”

But this is not really what the patients tell us—and we’ve known that for a long time. If we look back at some of the earlier studies, the chief complaint was understanding speech in noisy environments. These people reported confusion, embarrassment, selflessness, annoyance—a lot of problems. But the biggest thing they felt is that professionals were not concerned with their single-sided deafness.

WC  Tell me about how TransEar came to be.

DS I figured I could build a better mousetrap, so to speak. And I thought we really need to put the hearing aid in the dead ear. If we could do that and actually put a vibrator in the ear canal, we could put a processor behind the ear, change acoustical energy through the wire to electrical [energy], and then vibrate the ear canal.

TransEar

WC  Did anyone ever tell you that strategy wouldn’t work?

DS Sometimes [laughter]. There are always people who doubt. But part of the problem is that for years we’ve been taught really wrong about the anatomy of the ear canal. Ask almost anyone how much of the ear canal is cartilaginous and how much is bone, and they’ll say the ear canal is two-thirds cartilaginous and a third bone. But because of the imaging we’ve got now, we know that’s really not true; the ear canal is really about half and half.

When I first started developing TransEar, I decided the best way to do this would be with piezoelectricity, and I spent about $65,000 with a company that guaranteed me they could come up with a piezo that was going to work fine in the ear canal.

Piezos are crystals that will convert energy from one form to another. So if you take a piezo crystal and put an electric charge to it, it’ll vibrate. In the same way, if you bend a crystal, it will give off a charge. They’ve been around for years.

Well, we tried to get it to work and we couldn’t. Then we said, let’s take bone vibrators and see how we can mount them either in the concha of the ear or in the canal. And I worked with Knowles Corporation to develop a very small bone vibrator. I also had one made overseas that was a little larger. Then we had to figure out ways to mount these things in the ear canal, and we also had to have a cord that could carry the electrical energy from the processor behind the ear to the shell with the vibrator in the ear canal.

That cord was pretty critical. When we first came out, we had a pretty stiff wire. Unfortunately, that wire limited the ability to get as much sound as we want because the vibration would come back to the instrument through that stiff wire. So that led to another invention of a wire that is very flexible, and to support it we’ve got certain connectors that connect the faceplate in the processor that goes behind the ear. There was quite a bit of money involved to develop that, but we needed it. And it made a big difference in how well TransEar worked.

The same was true for the faceplate where after we mount the vibrators in the ear canal, we had to have a certain faceplate that wire would click into. So all these things have been developed over time, and the product has just gotten better and better.

And now we’re even looking at piezos again. There are some new ones out that may be able to do what we wanted to initially. We’re also looking at better vibrators and a new processor—as a matter of fact, it is being worked on right now.

WC  How would you compare the original TransEar with the current version?

DS I think it’s 200% to 300% better.

WC  How accepted is TransEar?

DS Well, as with any product, it actually depends on the person. If someone loses their hearing right away, then they’re going to miss it right away and we can put a TransEar on and they’ll say, “That’s fine.” Now if you take someone who has had single-sided deafness and they’re 70 years old, then the acceptance is not going to be there. So it depends on the enthusiasm of the individual and how long they’ve had the hearing loss.

I will tell you, when you fit a person with a TransEar who’s been told they’ll never hear again, it’s a pretty moving experience. It’s one of the few times in my practice that people literally cry, whether they’re an adult or younger person. Often when we’re adjusting it, we tell them simply to take the phone and put it up to their dead ear. All of a sudden they can hear the dial tone. That’s a pretty amazing thing.

WC  On top of that, you are providing a far less invasive alternative.

DS There need to be options for people. A lot of people who’ve just gone through surgery for an acoustic neuroma don’t want to face another surgery and go with a bone-anchored system. TransEar is something people can try, and if they don’t like it, they can take it off.

By the same token, TransEar is not appropriate for everybody. If they’ve got a draining ear, it can’t be used. You have to find the appropriate fit for the patient.

WC  What was the FDA approval process for TransEar like?

DS TransEar is considered a Class II hearing instrument, same as a bone-anchored hearing aid. Cochlear implants are Class III, and then a regular hearing aid is Class I. For a Class I, you don’t have to go through the more specific FDA applications. When you get into the Class II and IIIs, it gets pretty significant in terms of showing how it works, doing trial tests, etc.

So there’s a lot of paperwork. It doesn’t make a whole lot of sense to me why a bone conduction hearing aid should be considered Class II, but it is.

WC  Any consideration about taking TransEar wireless?

DS Not at this time. Our big goals right now are improving the processor and the vibrator. TransEar’s pretty much down into a canal size, so it looks pretty good. When we first started out, TransEar was ITE-sized with a BTE. We’ve been able to get it down to a real small size and we hope to keep it in that canal size. Eventually, we may be able to go to an all ITE and do away with the BTE processor.

I think the good news is that technology advances pretty quickly, and with new transducers on the horizon now, I think you’re going to see some tremendous improvements in the TransEar product.

We’re also going to see changes in the way we do the fitting.

WC  What’s involved in the fitting process?

DS Right now, the fitting is done with software and a plug-in using a Hi-Pro. Probably in the future it’s going to go more toward the Clik philosophy, where everything for fitting will be built in to the processor. Then it’s simply a matter of clicking through different parameters to get it set where you want it. That’ll come with the new BTE processor we’re working on.

WC  Is there an ETA for the new processor?

DS I wish it could be 6 months, but every time I predict for something to happen, it always takes twice as long. It’s still fast but I wish it could be faster—especially at my age! You’ve got to get it done in a hurry [laughter].

But those are the changes that are going to take place. I think what we’ve got now as far as the bone-anchored systems and TransEar are some great viable options for people with single-sided deafness, and I think audiologists and dispensers need to be aware of these options so when they see someone in their office who has single-sided deafness, they can say, “I think I can help you.”