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Auditory Brainstem Implants in Children

Laurie Eisenberg

DOI: 10.1044/cred-int-bts-004

What are you working on?

Right now I’d say my career is focused less on specific research questions, hypothesis-driven questions, and more into clinical trials with devices.

So we have one NIH grant that’s looking specifically at the development of children how are hard of hearing who are hearing aid recipients. Another project is a long-term project working with Dr. Niparko on how children develop with cochlear implants, this is a national study and a multi-center study, we’re now in our eleventh or twelfth year.

But our most recent project, and the one we’re very enthusiastic about is about pediatric auditory brainstem implants in children. This is not a new project by any means. Dr. William House and Dr. William Hitselberger from the House — at that time it was called the House Ear Institute, actually probably the Ear Research Institute — came up with this concept for their patients who had neurofibromatosis 2, or NF2. These are patients who have a terrible neurological disease where they have tumors growing on their nervous system and usually both auditory nerves or vestibular nerves and end up, just for life-saving reasons, having to have the tumors removed, and it renders them deaf. The two Drs. William House and Hitselberger came up with this implant that bypasses the cochlea, rests on the auditory brainstem, or the cochlear nucleus. So, that developed into a project, one of the implant companies started building the device and manufacturing, it went through FDA clinical trials, and now it’s standard clinical procedure in the United States, but it’s only approved for individuals 12 years and older who have this NF2.

So, over ten years ago a doctor in Italy, named Dr. Vittorio Colletti, started conducting surgery using this device in patients who are non-NF2, for other reasons that caused their deafness, and they were not recipients of a cochlear implant — such as a temporal bone fracture where the nerve was severed, or meningitis where the cochlea was completely filled with bone — and started having quite improved results with this device than what you typically saw with individuals with NF2 who are recipients of the device. He then went to children who are not considered cochlear implant candidates, and started showing some nice success with a segment of that population, not all of his children.

About seven or eight years ago, our team worked with the manufacturer who produces the device that’s used in this country for this application about going to FDA to try this procedure in children, or to start a clinical trial. They were not receptive.

We sort of gave it up, then families from the United States started traveling to Verona, Italy, at great personal expense, to have the surgery done there. Then these families came back and started looking for centers that could clinically manage their child. We became that center. So we’ve been following — I don’t know, maybe five, six, almost seven children who had surgery in Italy. Based on this, we decided about two years ago to again approach the FDA. This time, they were receptive to the idea, and it’s been a long, long, long journey, but a little over a year ago, we did receive FDA approval, and then we went and applied for a clinical trials grant with the National Institutes of Health and have recently received that grant. So, we’re set to go, and we’re having families contact us, audiologists contact us, neurotologists contact us, saying I have a patient, they’re not candidates for an implant, their anatomy doesn’t support an implant. So we are just about set to go.

What is this clinical trial designed to accomplish?

It’s a five-year, it’s called a Phase I safety feasibility study. We’ve asked for support from the NIH for five years. The FDA would not approve any more than ten surgeries as a first look as a safety trial. We will enroll the first five, conduct surgery and follow these children for one year to look at medical-surgical safety and programming safety — by that I mean electrical stimulation, programming the device, activation of the device. So, after one year, essentially the safety component is over and we will continue to follow these children for efficacy for two more years. That’s the clinical trial.

The first five children, we have to send all data to the FDA. FDA will review it and tell us whether or not we can continue with the next five subjects.

Our trial is a little different from some other trials going on in the United States in that we require in most cases children to have a cochlear implant first. Some parents don’t want to have their child go through that surgery. They’ll either go straight to Italy or find one of the two or three other centers in the US that don’t have NIH funding for the project. The National Institutes of Health essentially insisted that that be a condition of the trial. So the children we’re seeing, so far, have all had cochlear implants and have not progressed in their auditory skill development.

But I’d say the families are really on top of things. They have every service set up, they are very knowledgeable, they read the literature. In a sense, these families are going to be part of our team and be our teachers as well.

This will be the first time that we conduct the surgery. Dr. Colletti will fly in from Italy for our first two surgeries. Our surgeons have been to Italy a number of times to observe surgery. But I think our first programming of these children will be a new experience for us, and we’re excited about it.

What has surprised you most about this project?

I think before we started seeing the data come out of Europe — and the data from Europe involves children from a number of different countries that had surgery from Dr. Colletti. And they don’t do a very formal follow-up, so it wasn’t clear how well these children were performing with the device. I’d say we had very low expectations, based on what we knew from adults with NF2, that maybe they would get, probably closed-set word identification– in other words, they’d pick a word from a choice of words — but not a very good chance of understanding speech in an open set or, you know, telephone communication.

The children that we started working with that came back from Europe that were very young, typically developing, and very strong family commitment, and then all the habilitative programs in place. Some of these children started progressing very rapidly, and are starting to show similar development to, I would say, average performance or a little below average performance to children with a cochlear implant.

I think that really surprised me, and really was pretty amazing actually, to see these children developing spoken language. Now these children are a little different than children with implants. One, they are heavily reliant on lip reading, even if they do have some open-set word recognition. They also have all come to us with sign language as their mode of communication. We think that’s very important for all of these children to have a language foundation. We can’t predict what the ABI or auditory brainstem implant will provide them.

But these top performers, we’re watching them dropping signs and starting to communicate with spoken language. We can’t say their speech is as intelligible as children with cochlear implants, and this is something we hope to study as well.

What impact do you hope this line of research will have?

It’s really a very small population of patients that are eligible for this procedure. Most children with severe to profound hearing loss easily fall into the cochlear implant category. That’s now standard clinical procedure. But there’s a small subset of children that one, have not succeeded with a cochlear implant — we’re also investigating this, why are there some children with implants that fail to progress in auditory skill development. One reason is their anatomy just doesn’t support a cochlear implant. So for this small group of children — and adults, as a matter of fact — this is one thing that can help them. And, it’s probably the last group that — this now makes, essentially, all children eligible for some sort of sensory device technology. There’s going to be some reasons some children won’t succeed with this device, as with the cochlear implant — additional disabilities, cognitive delays, other factors — but at least, now, this small subset of children will have an opportunity to hear, and if they’re implanted young enough, they have some possibility of developing spoken language skills. Not all children will, but they certainly will have contact with an auditory environment.

Further Reading

Fisher, L. M., Eisenberg, L. S., Krieger, M., Wilkinson, E. P. & Shannon, R. V. (2015). Regulatory and funding strategies to develop a safety study of an auditory brainstem implant in young children who are deaf. Therapeutic Innovation & Regulatory Science49(5), 659–665 [Article] [PubMed]
Wilkinson, E. P., Eisenberg, L. S., Schwartz, M. S., Krieger, M. D., Fisher, L. K. & Shannon, R. V. (2015). NIH pediatric auditory brainstem implant clinical trial: Initial surgical and audiological results. Brain Stimulation8(2), 363 [Article]