NIHL, ANSD, and Tinnitus: Interview with Kelly Tremblay, PhD
NIHL, ANSD, and Tinnitus: Interview with Kelly Tremblay, PhD
Douglas L. Beck, AuD, spoke with Dr. Tremblay about noise-induced hearing loss (NIHL), auditory neuropathy spectrum disorder (ANSD), tinnitus, and her new book, Translational Perspectives in Auditory Neuroscience.
Academy: Good morning, Kelly. Thanks for taking the time to chat with me.
Tremblay: Hi, Doug. Thank you, too. I appreciate your interest in my work.
Academy: Kelly, I have to say right from the start, I've read the 2012 series of books you just published (with co-editor/co-author Robert Burkard, PhD) and I think they're fascinating and brilliant! The series is titled Translational Perspectives in Auditory Neuroscience.
Tremblay: Thanks, I appreciate that!
Academy: So let's start with the basic question—what is "translational research"?
Tremblay: Different people use different definitions but for me, as an audiologist, translational research means conducting research that could be translated into something meaningful to patients and clinicians. Doug, as you know, despite a common mission to improve hearing health care, basic and clinical scientists ask very different questions, use very different approaches, and they belong to different cultures. Further, they attend different conferences, publish in different journals, and are often driven by different passions.
Academy: Absolutely. There are a number of differences between the folks in the trenches and the folks in the ivory towers! So how is it that you and Bob decided to tackle this project and how did you approach it?
Tremblay: Bob has been doing translational research for years, before the term "translational" became so well used. So we speak the same language and have similar backgrounds. He's been a great mentor to me, so I approached him about this idea that I had about making information about science and its application more accessible to the next generation.
To do this, we approached colleagues who work in different situations and in each step along the scientific continuum, from basic to applied, and asked them to provide information that was theoretically deep, but contextually broad. In some instances, this meant pairing authors (e.g., clinician with a basic scientist) who wouldn't ordinarily work together so both perspectives could be unified in writing. We also included a diverse group of students, postdoctoral researchers, and scientists to interact with the authors by asking questions and infusing comments during the review process. This process ensured that both basic and applied material would be integrated.
Academy: Very good. Okay, let's talk about a few specific chapters in the book titled Special Topics. For example, in the chapter, Current Issues in Noise-Induced Hearing Loss" (by Kevin K. Ohlemiller), I was delighted to see Ohlemiller address important and updated facets of noise-induced hearing loss (NIHL). Some of the points he made included that although NIHL is the most common and most preventable type of hearing loss, it's also a relatively new phenomena. That is, prior to the industrial revolution, there really wasn't much noise except the occasional volcanic eruption of thunder storm. Further, he reports industrial and military noise previously held the distinction of being the primary causes of NIHL, but now, recreational noise is the more common cause.
Tremblay: Yes, and it makes you realize that there are likely more ways audiologists can teach prevention. Further, in that same chapter, Ohlemiller talks about how and why cells die biologically and chemically, so it goes quite a bit deeper than simply addressing what the audiometric profile looks like that best correlates with NIHL.
Academy: One of my other favorite notes from that chapter is that I recall learning decades ago, that a damaged ear (i.e., an ear with NIHL) was more susceptible to additional damage from noise, than is an ear without NIHL. Ohlemiller tackles that question directly and states there's no evidence to support that supposition.
Tremblay: Yes, and he relates this to the issue of fitting hearing aids to an ear with NIHL, with a question that perhaps hearing aid amplification will increase the opportunity for additional hearing loss. This is a question patients often ask so I was pleased to read his answer, that there is no evidence that a damaged ear is more vulnerable. As long as the hearing aid has been well fitted with due attention to UCLs and real-ear measures and best practices, the ear will not develop additional hearing loss secondary to an appropriate hearing aid fitting.
Academy: Another fascinating discussion in that chapter is the idea of "programmed hair cell death."
Tremblay: Absolutely. Another fascinating aspect of hair cell vitality is the concept of "pre-conditioning" such that, a little bit ("mild stress") of noise exposure may better prepare those hair cells to not experience as significant of a traumatic event when they eventually do experience noise exposure. Of course, there's a lot left to learn on this topic, too.
Academy: Although I'd love to get more into NIHL, due to time constraints, let's address a few more chapters, and leave "programmed hair cell death" for the readers to learn about directly from the book. Another fascinating chapter is the one by Linda Hood and Thierry Morlet, titled Current Issues in Auditory Neuropathy Spectrum Disorder.
Tremblay: Yes, this is a thought-provoking chapter. Of course the authors start with the audiological definition and clinical description of auditory neuropathy spectrum disorder (ANSD) and they dig deeply into the issues, such as when to consider hearing aid amplification and when to consider cochlear implantation. These are very difficult challenges and although we've learned so much in the last 25 years about ANSD, there's much more to know! This chapter offers insight and tackles the current discussion and debate.
Academy: And to just highlight one issue, Hood and Morlet note multiple cases in the literature of ANSD "normalizing/outgrowing." This is absolutely stunning clinically, and speaks to the issue of there's much more to know and understand with regard to research on ANSD—but perhaps most importantly, it calls into question the issue of the child who does not do well with hearing aid amplification, is not showing progress with regard to speech and language milestones, and so the child receives a cochlear implant….How do we know this child would not have "normalized" in a year or two? Further, if we wait to see if the child does "normalize," we're potentially losing substantial ground with regard to brain plasticity and speech and language development!
Tremblay: Absolutely right—the issue of ANSD is far from solved. Fortunately, we're learning more all the time. And I agree with the interview you did with Chuck Berlin for the Academy in which Dr. Berlin essentially says deciding when to progress to cochlear implant is a decision reached with the audiologist, the parents, and the speech-language pathologist—and should be based on a global analysis of the child's speech and language progress and milestones.
Academy: Exactly…I totally agree. And as usual, the more we learn about ANSD (and audiology in general) the more questions we formulate!
Tremblay: And again, that gets us back to the need and value of translational research and the very important ability to directly apply research to real time clinical decision making.
Academy: And although we're totally out of time and you have so many relevant and important chapters in this book, let's spend a few moments on Jos J. Eggermont's chapter, Current Issues in Tinnitus.
Tremblay: Sure. Eggermont did a fantastic job reviewing the literature and getting all of us up to speed. He notes some fascinating data which many clinicians are not aware of. For example, I enjoyed learning about tinnitus maskers from a biological perspective, what they are intended to do and why they may or may not work for individuals. Further, Eggermont addresses the neural mechanisms of tinnitus and that there really are no quick fixes to treating tinnitus and he stresses that the best management techniques appear to involve a sound generator or masker plus counseling, such as cognitive behavioral therapy, when needed.
Academy: Kelly, thank you so much! You've been very generous with your time and I'll absolutely look forward to two more interviews with you (over the next few months) to provide an overview of the other two texts in the series. In the meantime, I have to say that this series of books would serve as an excellent text for doctoral students taking research or research methods, and by the way – there's an awful lot here for the practicing professional, too!
Tremblay: Thanks, Doug. I appreciate your time, too, and I'm appreciative of your interest in these topics!
Kelly Tremblay, PhD, is a professor, Department of Speech and Hearing Sciences, and an affiliate of the Virginia Merrill Bloedel Hearing Research Center at the University of Washington. She is also co-editor and author of the new three-part book series titled Translational Perspectives in Auditory Neuroscience (Normal Aspects of Hearing, Hearing Across the Life Span—Assessment and Disorders, and Special Topics).
Douglas L. Beck, AuD, Board Certified in Audiology, is the Web content editor for the American Academy of Audiology.