Noise Damage and Traumatic Brain Injury: Emerging Therapies and Evidence-Based Practices: Proceedings from the National Center for Rehabilitative Auditory Research (NCRAR) Conference: Hearing Therapies for the Future

This issue of Seminars in Hearing arises from the proceedings of a conference held by the National Center for Rehabilitative Auditory Research (NCRAR) located at the Portland Veterans Affairs (VA) Medical Center in Portland, Oregon. The 2007 International Biennial NCRAR Conference, entitled “Hearing Therapies for the Future,” took place on September 27 and 28. The conference was attended by 162 students, clinicians, and scientists from the United States and abroad. We brought together internationally acclaimed speakers to provide theoretical and practical information relevant to the diagnosis and treatment of noise-induced hearing loss and tinnitus and of traumatic brain injury (TBI). These content experts were scientists and clinicians from the VA, Department of Defense (DoD), National Institute for Occupational Safety and Health (NIOSH), House Ear Institute, Oregon Hearing Research Center (OHRC), prominent universities, and the pharmaceutical industry. Talks were broadcast nationally by the VA Employee Education System. These published proceedings comprise a subset of the talks, with a focus on those deemed most clinical in nature.

The conference was structured thematically across four half-day sessions. Within each session were basic- and clinical-research treatments of each topic. After each session, a round-table discussion panel of selected speakers and conference attendees with experience in the area under discussion answered pertinent questions from the audience. This structure promoted interaction between speakers and audience members so that attendees gained insight and learned new information that they could apply in their work. There was a particular focus on promoting the use of evidence-based procedures to refine existing best-practice procedures for hearing conservation and to help create best-practice procedures for the audiologic treatment of individuals with TBI.

Paula Myers from the James A. Haley Veterans' Hospital/Polytrauma Rehabilitation Center in Tampa, Florida, and Debra Wilmington, Frederick Gallun, James Henry, and Stephen Fausti from the NCRAR in Portland, Oregon, begin these proceedings with an account of audiologic and nonaudiologic sequelae of soldiers exposed to explosive blasts. These authors have compiled data from numerous VA centers of TBI treatment and, based on these data, describe emerging strategies to diagnose and treat noise-induced hearing loss and TBI. A rare epidemiologic study linking noise-induced hearing injuries of various sorts to (in-theater) deployment of armed service personnel is provided by Nikki Jordan, Robyn Lee, and Thomas Helfer from the U.S. Army Center for Health Promotion and Preventive Medicine Aberdeen Proving Ground in Maryland. This study suggests an association between improvements in noise-related health outcomes and use of modern hearing conservation procedures for Army personnel. Peter Steyger provides a summary of recent evidence that chemical toxicity is heavily influenced by exposure to noise. This finding has important implications for individuals routinely exposed to noise, including impacts for industrial workers and deployed soldiers. Dr. Steyger's laboratory is located at the OHRC at Oregon Health and Science University in Portland.

Exciting information is coming out of the many studies of otoprotective drugs and supplements that may prevent or reduce hearing loss associated with exposure to noise and ototoxic medications. Eric Lynch and Jonathan Kil from Sound Pharmaceuticals, Inc. in Seattle, Washington, provide one example of a drug that might prevent hearing loss from noise and toxins through a mechanism that boosts antioxidant protection of auditory structures. Mark Stephenson from NIOSH at the Centers for Disease Control and Prevention concludes the proceedings with a discussion of modern hearing protection devices and health promotion techniques that will undoubtedly prevent suffering in very real terms by preventing hearing loss in individuals routinely exposed to noise.

The topics presented in these conference proceedings are important because many Americans (roughly 10% of those aged 20 to 69 years, or 22 million) suffer from noise-induced hearing loss, even though it is a preventable disorder.[1] Such losses cause immediate difficulties and are now thought to have long-term effects on the aging auditory system.[2] [3] This is particularly troubling because it is becoming increasingly common for children and young adults to incur hearing loss related to noise exposure from recreational activities.[4] [5] Understanding the interaction of noise-induced hearing loss and TBI, disorders common to Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) soldiers exposed to explosive blasts (see Myers et al[6] and Jordan et al[7], this issue), is vital to DoD and VA, especially during this time of ongoing deployment of military personnel in Iraq and Afghanistan.

We thank the speakers who generously shared the content of their talks in this special issue of Seminars in Hearing. We are grateful to the NCRAR Center director, Stephen A. Fausti, for his vision to conduct Biennial International Conferences to promote the translation of research to clinical practice. The 2007 NCRAR Conference was funded by the NCRAR, VA Rehabilitation Research and Development (RR&D) Service (C4844C), and the National Institute for Deafness and Other Communication Disorders (NIDCD) of the National Institutes of Health (NIH) (R13DC009193–01). On behalf of the many individuals who have contributed to the 2007 NCRAR Conference and these proceedings, we hope this work provides a basis for developing hearing therapies and best practices for the diagnosis, treatment, and prevention of noise damage and TBI. These are vitally important areas of study and clinical practice in our time.

The next NCRAR conference will be held on October 8 to 10, 2009, in Portland, Oregon. Conference speakers will address auditory rehabilitation from multidisciplinary perspectives, including cognition, vision, computer science, engineering, and neuroscience.

REFERENCES

• 1 National Institute on Deafness and Other Communication Disorders .Noise-Induced Hearing Loss: Who Is Affected by NIHL?. Available at: http://www.nidcd.nih.gov/health/hearing/noise.asp Accessed April 17, 2008
• 2 Gates G, Schmid P, Kujawa S G, Nam B, D'Agostino R. Longitudinal threshold changes in older men with audiometric notches.  Hear Res. 2000;  141 220-228
• 3 Kujawa S G, Liberman M C. Acceleration of age-related hearing loss by early noise exposure: evidence of a misspent youth.  J Neurosci. 2006;  26 2115-2123
• 4 Montgomery J K, Fujikawa S. Hearing thresholds of students in the second, eighth and twelfth grades.  Lang Speech Hear Serv Sch. 1992;  23 61-63
• 5 Mostafapour S P, Lhargoue K, Gates G A. Noise-induced hearing loss in young adults: the role of personal listening devices and other sources of leisure noise.  Laryngoscope. 1998;  108 1832-1839
• 6 Myers P J, Wilmington D J, Gallun F J, Henry J A. Hearing impairment and traumatic brain injury among soldiers: special considerations for the audiologist.  Semin Hear. 2009;  30 5-27
• 7 Jordan N N, Lee R B, Helfer T M. Noise-induced hearing injury among Army active duty soldiers deployed to the Central Command area of operations.  Semin Hear. 2009;  30 28-37