Photo By Megan Mudersbach | Lt. Cmdr. N. Cody Schaal, Navy Industrial Hygiene Officer, is currently assigned to...... read more read more
By: LT. Cmdr. N. Cody Schaal, Industrial Hygiene Officer & NAMRU-Dayton Environmental Health Effects Laboratory Deputy Director
Tinnitus and hearing loss are the two most prevalent service-connected disabilities for separating and retiring service members, as reported by Veterans Affairs (VA, 2020). Hearing injury can result in poor speech intelligibility, poor warfighter performance, and is often irreversible. Naval Medical Research Unit Dayton (NAMRU-Dayton) has a research portfolio dedicated to understanding contributors to auditory disabilities and mitigations to enhance force health protection.
Hazardous noise is traditionally considered the primary risk factor for hearing injury. However, substances called ototoxicants, which affect auditory, vestibular, and connected neural pathway function, are reported to be linked to hearing injury, both alone and in combination with noise. Extended duration noise exposure may also present hearing injury challenges. Military personnel assigned to U.S. Navy operational platforms commonly work shifts that last longer than 12 hours per day. When at sea, they work and live in close proximity to sources of hazardous noise. Since most exposure limits represent shorter timeframes and assume a recovery (rest) period exists during non-occupational exposure periods, little is known regarding the increased risk of hearing injury for extended durations of hazardous noise exposure.
With support from the Defense Health Agency Research and Development Directorate and the Office of Naval Research, NAMRU-Dayton’s Environmental Health Effects Laboratory (EHEL) research team assessed if permanent hearing loss develops when a mildly elevated noise level is present during periods when auditory recovery would normally occur. Researchers tested whether permanent hearing loss would be exacerbated by exposure to steady noise levels during a representative occupational time period, followed by an elevated but non-damaging noise level during a daily 16 hour “auditory recovery” period, and an occasional impulse noise exposure. This noise profile was selected to mirror noise exposure characteristics commonly found on U.S. Navy vessels at-sea for Sailors that work and live in environments where hazardous noise areas and hearing recovery spaces such as sleeping areas are in close proximity to one another. Researchers are also investigating if the combined effects of ototoxicants and noise worsen hearing injury when found together. Using in-house custom-built unique noise and chemical exposure systems, NAMRU-Dayton’s talented scientists are attempting to model scenarios that would better encompass the entirety of operational hearing injury-related exposures by determining if combined exposure to JP-5 jet fuel and “extended duration” steady and impulse noise exposures intensify permanent hearing loss.
EHEL scientists are also collaborating with researchers from the U.S. Air Force Research Laboratory’s 711th Human Performance Wing (AFRL/711 HPW) to investigate occupational and non-occupational noise exposure during 24 hour durations for Sailors, Airmen, and Soldiers. This study will develop an exposure framework for future DoD wide studies, evaluate the efficacy of widely used noise sensors such as an Apple Watch™ as a substitute for noise dosimeters typically used in workplace environments, and assess service member attitude changes in the use of hearing protection during high noise activities on and off duty.
| Date Taken: | 01.15.2021 |
| Date Posted: | 01.15.2021 15:25 |
| Story ID: | 387050 |
| Location: | DAYTON, OH, US |
| Web Views: | 127 |
| Downloads: | 0 |
This work, NAMRU-Dayton’s Hearing Health Program, by Megan Mudersbach, identified by DVIDS, must comply with the restrictions shown on https://www.dvidshub.net/about/copyright.
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