The following is a transcript from the Office of Naval Research‘s (ONR) online series, Tech Talk. On Sept. 15, ONR program manager Kurt Yankaskas answered questions from audiences on Facebook and Twitter. Yankaskas manages ONR’s Noise-Induced Hearing Loss Program.
Formerly with Naval Sea Systems Command, the engineer joined ONR in 2009 to lead the organization in its exploration of noise mitigation, training and education, protection and medical technologies to prevent and treat noise-induced hearing loss.
ONR: Welcome to our online dialogue with Kurt Yankaskas, program manager for ONR’s Noise-Induced Hearing Loss (NIHL) Program. We’re taking your questions now until 11:30 am, EST!
Shelley Hanes: For Mr. Yankaskas, for the noise-induced hearing loss program, do you do any of the hands on research of cochlear hair cell repair as well as minimizing environmental acoustic propagation there yourself at ONR? Or is the research primarily done at partnering labs, small business and universities? I actually proposed military-related hearing loss due to blasts last year as one of my bioengineering project focuses.
I learned that hearing loss is only one complication to such a related injury and repeated exposures. Mild and extreme vertigo as a complication of the exposures is problematic, too. Since sound wave propagation can often be on frequencies unheard in some military environments that penetrate through the entire body, along with the fact that the sensory area of the brain damaged is not only isolated to the cochlear region, such a project is very challenging.
Kurt: Shelley Hanes, thanks for your question. I do not do hands-on research, however, I follow very closely the projects in our NIHL portfolio as well as other research projects. You are correct in assuming about our partnership with academia, industry and government labs. These partnerships are vital to ONR’s ability to successfully deliver capability to the warfighter.
To address your point, I am familiar with whole-body noise propagation and you’re correct in that it’s a challenging project. The research trend is showing a strong connection between peripheral hearing (i.e., the cochlea) and central processing (i.e., the brain).
ONR: Rick Rogers, we can take your questions either way. In fact, here’s Kurt’s reply to your question, emailed from Harvard’s School of Public Health.
Kurt: Rick Rogers, you are correct in that NIHL is a national and international health concern that can use support beyond ONR. As the manager for ONR’s NIHL program, I am cognizant of that and strive to be a prudent steward of taxpayers’ dollars. As a part of the Executive Branch, we support the President’s budget. We do not lobby Congress.
Kurt: Kathy King, USA Today recently published an article on increased noise exposure in an increasingly noisy world. Concert noise levels are actually well known and those noise levels are very similar to many industrial settings, thus, you’re at risk for either a temporary hearing loss or eventually a permanent hearing loss.
To add, what concert-goers might expect to see in a few years is a type of hearing protection that will allow you to enjoy the music at safe levels for your ears while allowing you to talk to the person next to you. We are calling this talk-through circuitry, and ONR is developing this technology.
Tina Johnson-Marcel: I’ve always thought hearing loss was generally permanent, but I see that’s not always the case. How does this program help a sailor who has experienced work-related hearing loss and will continue to work in that loud environment?
Kurt: Tina, First, we have a much better understanding of hearing protection fit issues and how people should properly wear these devices if they’re going to continue working in loud environments. For Sailors, we’re using custom-molded hearing protection for high-noise environments. These devices only fit one way — the right way.
Tina, to add, the long-term objective is to develop the ability to regrow hair cells in the cochlea. Hair cells are the sensors of the ear. Current research is very promising, but I’d like to remind you that this is long-term research.
Jian Zuo: It is the deaf sailors who have inspired us to find ways to restore their hearing. As you may know, chickens have the capacity to regenerate sensory cells after acoustic injury while humans cannot. Our research focus is to find out why and how. It is our hope that in the not so distant future, we can provide some therapeutic ways to deaf patients to restore their sensory cells and enable them to hear again.
John Ohab: Kurt, are you going to be pursuing any neural repair work involving stem cells?
Kurt: John Ohab, we are currently working with the cellular structure within the ear. Specifically, we are trying to “trick” support cells into duplicating and differentiating into hair cells. Once that is accomplished, the challenge will then become to have these cells link to the auditory nerves that carry messages to the central hearing processing center.
John, to add, any knowledge gained through stem cell research will support basic science in restoring lost hearing.
Jian Zuo: John, you are right that now stem cell therapy is very promising, particularly in repairing auditory neural pathways. I refer you to a recent publication in the journal Cell from Dr. Heller’s laboratory in Stanford University who has made significant progress toward stem cell therapy. Again, this is a very first step toward that ultimate goal of stem cell therapy.
John Ohab: Thanks, I appreciate it!
Gigi Gorospe Lovell: My parents are getting older and seem to have a harder time hearing. Is it hereditary or just old age?
Kurt: Gigi, I personally question whether we lose hearing as a result of age moreso than cumulative noise exposure over the years. We have numerous electronic devices against our ears for long periods of time. We commute long distances, either in public transportation or private conveyances, none of which are necessarily quiet. I can’t give you specifics about your parents, but I can encourage you to take the proper precautions in noisy environments.
Jian Zuo: Dear Gigi Gorospe Lovell, it is possible that both aging and hereditary processes contribute to your parents’ difficulty in hearing. If no one else in your family suffers hearing loss, then aging process is the main factor. In the general population, more than half of people over the age of 65 suffer age-related hearing loss. Most of them first lost their hearing to high pitch sounds.
ONR: We’ll take one last question from Chris Harding submitted this morning.
Chris Harding: When considering the effect of noise on the middle and inner ear, is it possible that the following factors exacerbate the hearing loss:
- Chronic reduction of water consumption combined with continuous sound energy and variable atmospheric …conditions reduces the “elastic” properties of membranes. I realize this may seem to contradict the “action” of the tensor tympani muscle when considering “tension” induction upon high sound pressure. As we know, loss of water is a main factor in affecting other structures composed of collagen-spinal column and older people.
- Since low energy EMF induces collagen production, can high sound pressures cause collagen production as well? If so, would the area of malleus attachment be affected differently than the flaccid area? The area of malleus attachment has collagen fibers arranged in two directions-could one direction be affected more than the other area creating an imbalance? Although we normally consider “symmetry” and “average”, some people may be more susceptible than others if they have a slightly different density in one direction,
- Also, is it possible to use electromagnetic energy to excite nerve innervation and artificially tighten the membrane or affect muscle contraction during a “brief” moment of communication. If combined with a material thats designed to allow certain sound propagation, like a specially designed ear plug, the device may allow one to hear a frequency that isn’t normally heard! As such, this could be quite beneficial!
- I also realize the “hair cells” may be permanently damaged. How does this affect the polarization? Chronic reduction of depolarization?
- According to my anatomy book, “high tone deafness” is caused by changes to the spiral organ, but is it possible that the thermodynamics caused by sound could affect other structures?
Kurt: Chris, you bring up some interesting points. ONR’s primary focus at this time is the regeneration of hair cells which amphibians and birds can naturally perform. We’re also looking at the role of antioxidants, such as n-acetylcysteine, in taking a prophylactic approach to hair cell protection.
Jian Zuo: These are great points that are worth investigating further. Thank you for these insightful thoughts. Totally agree with Kurt that cumulative noise exposure over the years would accelerate the aging related hearing loss.
Chris Harding: Thanks for your answers. I have never researched the area but I have two degrees: Chemical Engineering and Biological Sciences! I’m not sure my thoughts are accurate but I “wondered.” Thanks for the insight-science! I did a search: A good a…nd free article related to reduction of ROS by using melatonin with some nice photomicrographs: Jeong-Beom Kim, MD; Jae Yun Jung, MD, PhD; Jin-Chul Ahn, PhS, Chung Ku Rhee, MD, PhD; Hee-Jun Hwang, PhD. Antioxidant and Anti-Apoptotic Effect of Melatonin on Vestibular Hair Cells of Rat Utricles. Clinical and Experimental Otorhinolaryngology [online]. 2009. Vol. 2(1). pp. 6-12, The Life Sciences Search Engine. doi: 10.3342/ceo.2009.2.1.6. PMCID: PMC2671833
ONR: Final words from Kurt?
Kurt: Through continued collaboration with the scientific community, we are making progress on NIHL and tinnitus, a chronic ringing in the ears. These conditions are national and international health issues that impact warfighter performance. We’re open to good ideas and collaboration. I encourage you to visit the NIHL page on ONR’s public web site.
ONR: Great! Thanks to everyone for participating in this inaugural “Tech Talk” with ONR. Join us next at 11 a.m., EST, Wednesday, Sept. 22, for a conversation with Keith Hammack on sensor technologies on autonomous vehicles.
Editor’s note: Dr. Jian Zuo, of the St. Jude Children’s Research Hospital, joined the conversation. Zuo leads medical research in part funded by ONR in the area of hearing restoration.
For more information on ONR’s Noise-Induced Hearing Loss Program: