I often call myself a giant lab rat in jest, but I do so proudly. Since getting my first cochlear implant in 2006, and my second in 2008, I have been a volunteer for numerous research studies at the newly renamed House Research Institute in Los Angeles. I have worked with more than a dozen researchers and keep going back; I kid that I should bring a sleeping bag.
Dr. David Landsberger is the first researcher I ever worked with. David is brilliant and a rugged individualist, and I consider him a good friend — a friend not just to me, but to everyone with hearing loss.
I wanted an expert to discuss what is happening with research at House and to comment on the bright future of implants in general, and I couldn’t think of anyone better qualified.
Alicia Fernandez: First some questions about you: How did you get started in research?
David Landsberger: My father, who was researching influenza virus when I was a kid, probably influenced me. After school, instead of going home to an empty apartment, I hung out in his laboratory.
I personally stumbled upon research as a psychology major. Part of the psychology major was studying sensory perception. In a visual perception seminar I had to report on a published research paper. While I was presenting the paper, I realized that there was a huge mistake in the experimental design that caused unintended results and a incorrect conclusion about the experiment. I spent the rest of the semester reproducing the experiment and ended up successfully demonstrating that I had been correct all along. That project got me excited about research and started me on the path towards being a scientist.
What led you to start researching cochlear implants? Kind of a narrow field, isn’t it?
I suppose cochlear implant research seems like a narrow field, but while in the depths of it, it seems very broad. I actually did my Ph.D. in color vision. But while I was working on my Ph.D., I found that I was much more interested in issues related to sound than vision. So when I finished my degree, I spent a few months knocking on the doors of various auditory researchers in the Boston area asking each of them what they did and what other people in the field did that might be of interest to me. Eventually, I ended up in the office of Don Eddington at MIT, who is one of the pioneers of cochlear implants. Don told me about the device and I was amazed at the technology. Additionally, I was excited by the prospect of doing something that was not only intellectually challenging but also made a difference in people’s lives. I decided in his office that cochlear implant research was what I wanted to do with my life.
Where else have you worked, in addition to House Research Institute? I understand you’ve been a lot of places around the world?
About a month after meeting with Eddington, I found a job in Otolaryngology at the University of Melbourne in Australia doing cochlear implant research. The University of Melbourne department is responsible for the original development of what became the Nucleus cochlear implant and still maintains close ties. While in Melbourne, I had the honor to get to know Rod Saunders, the very first person to receive a prototype Nucleus implant. After Australia, I worked for two years at Aston University in Birmingham, England. Four years ago, I moved to Los Angeles to take a job at the House Research Institute.
Tell us about the research you’re doing at House.
My research investigates new ways of improving both speech in noise and music perception with a cochlear implant.
In a cochlear implant there are typically 12 to 22 electrodes implanted in the cochlea where each electrode is used to provide different pitch information. Unfortunately, when electrical current is applied on a given electrode, the current spreads broadly such that multiple electrodes stimulate the same neural population.
As a result, even though a cochlear implant is designed to provide different pitches and information with each electrode, the auditory system perceptually fuses the independent information from adjacent electrodes. The resulting sound from adjacent electrodes is “smeared together,” which limits speech in noise performance and ability to here melodic information. Regardless of how many electrodes a cochlear implant user has, the rule of thumb is that they perform as if they only have 8 electrodes.
My research investigates different ways of changing the shapes of the electrical fields to allow more precise electrical stimulation. We change the shape of electrical stimulation by simultaneously using multiple electrodes to control how the electrical fields interact. Our current work suggests that indeed reshaping the electrical fields can improve the independence of each electrode as well as provide a cleaner sound than the standard techniques. We will soon be investigating whether or not these stimulation optimizations can be used clinically to improve speech in noise and music perception.
What other kinds of research are being done at House — especially concerning cochlear implants or hearing aids?
There’s a lot of interesting and exciting research being conducted at the House Research Institute:
- Elizabeth Eskridge and John Galvin are researching methods of improving music perception for cochlear implant users.
- Sandy Oba, John Galvin and Qian-Jie Fu are studying how training can improve speech comprehension in noise and music perception with cochlear implants. Commercial versions of their research software have been released by major manufacturers so that CI users can train at home and at their convenience.
- Justin Aronoff and Yang-Soo Yoon are each working on projects looking at the advantages and limitations of bilateral cochlear implantation.
- Paddy Boyle is examining modifying the automatic gain control of a cochlear implant so that it works differently across different frequencies. Hopefully the result of his work is that uninteresting sounds (i.e. background noise) are reduced while important information (i.e. speech) is emphasized.
- Caili Ji has been working on the effect of synthesized speech (i.e. “computer voice”) with cochlear implant users.
- Eric Wilkinson is working on a pediatric auditory brainstem implant project for children with cochlear nerve deficiency, absence of cochlea, or severe ossification. Additionally, he is spearheading a project where we will be giving implants to patients who have deafness in only one ear.
- Sig Soli develops assessment tools to measure performance with cochlear implants, hearing aids, and other devices.
Are there any breakthroughs on the horizon in terms of hearing loss that you can tell us about?
Actually, it is a very exciting time in implant research. Good progress has been made in hair-cell regeneration and it is possible that at some point hair cells will be grown towards the electrodes of a cochlear implant to improve performance.
The Institute is starting to get involved with a new implant design pioneered by John Middlebrooks and Russ Snyder that actually penetrates the auditory nerve instead of being inserted into the cochlea. This has the potential of providing much more accurate stimulation as the electrodes are placed inside the nerve it wants to stimulate. Potential benefits include better speech in noise and music performance as well as greatly improved battery life.
Clinical trials in Europe (and hopefully soon at House) are being conducted on implanting patients who are deaf only in one ear who suffer grea tly from tinnitus. Early results suggest that implanting single sided deaf patients greatly reduces tinnitus and provides improved localization and spatial hearing.
And new work with Auditory Brainstem Implants (ABIs) has demonstrated that with new surgical techniques, patients can perform as well as cochlear implant patients. This is excellent news for patients who cannot use cochlear implants because of damage to the cochlea or the auditory nerve.
What do you see as the next big change coming in the area of hearing loss — either a new type of cochlear implant, bone implants, implantable devices, or so on?
I expect the use of the Auditory Brainstem Implant (ABI) will become more frequently used and performance will continue to improve quickly. Penetrating electrodes may replace electrodes in the cochlea allowing much cleaner and more direct electrode to neural interface. This should lead to sounds being perceived as “less smooshed together” and provide better music perception and speech comprehension in noise.
I also believe that the acquisition of Advanced Bionics by Sonova (the parent company of Phonak) will be excellent for the entire implant industry as it will accelerate the incorporation of all of the cool bells and whistles that are implemented in hearing aids into cochlear implant speech processors.
How do you define success in cochlear implant research?
Simply, success is learning something new and hopefully useful. The best outcome is that the discoveries will actually improve hearing for patients. However, a discovery that explains how the auditory system works or shows why a specific idea doesn’t work is also successful.
Where do you find subjects for your research?
I find subjects sometimes with help from the clinic, but I have found that word of mouth has been the best recruitment tool.
If our members are interested in volunteering, how would they go about it? How can someone find out what research panels are open? Unfortunately, there is no central location or contact person to find out about research. If a member is interested in participating, please let one of the researchers know. Personally, I am looking to recruit users of the Advanced Bionics or Med-El implants. However, we also do research with Cochlear Americas users and all manufacturers of hearing aids, and even with normally hearing individuals.
If someone is interested in participating in any of these projects, please feel free to send me an email at firstname.lastname@example.org and I would be happy to help figure out who might be appropriate for that individual to work with.
Can you ever have too many volunteers for research projects?
I suppose it’s possible… We should all have such problems.
Notes from Alicia
Giving Back: How We Can Advance the State of the Art
Why do I keep going back to help out with research, even though I live more than 50 miles away from House?
First, researchers are interesting people doing amazing work to help all of us. Second, while some of the tests are a bit boring, the researchers make them enjoyable and pleasant. Third, I owe it to people: I lead a life I could not dream of living when I started going deaf.
I am particularly grateful to the first implant users who spent years plugged into wall-sized machines listening to weird sounds. I owe it to scientists and engineers who spend their lives doing work which may or may not pan out. Their studies pave the way for breakthroughs; nobody makes discoveries alone. I owe it to those whose implants don’t work as well so they can receive better technology.
Most importantly, I owe it to the next generation with hearing loss. I hope one day they will wear improved devices because of what many of us do at House and many other clinics and institutes around the world.
I encourage all of you who are able and who have time to give to contact David and his colleagues. Where would we be without them? Where would they be without us? Let’s help each other — and ourselves — to make this a better world for those with hearing loss.