The ongoing conflict in Southwest Asia has brought new understanding – and treatments – to a number of age-old military medical issues. One that has received less public attention than most, but has become a top concern among both military commanders and health care providers, is hearing impairment.
Concerns about hearing damage sustained in combat and affecting returning veterans for the rest of their lives grew during the period from World War I to World War II, ultimately leading to the 1946 creation of the Army Audiology and Speech Center (AASC) at Walter Reed Army Medical Center. AASC’s primary focus was on rehabilitation – assisting soldiers with hearing impairments to return to duty, if possible, or to help them function in civilian life.
“Today it is the flagship center for audiology and speech pathology missions within the Army and probably unique within DoD [the Department of Defense],” according to AASC Director Col. Kathy Gates, who also serves as audiology consultant for the Army Surgeon General. “We have the clinical mission, in both audiology and speech, but also our research mission. That makes us different from other medical centers dealing with hearing impairment.
“Our research center allows us to do clinical studies and, from those results, develop policy and establish guidelines that can be used within the Army. However, we see AASC evolving into a DoD-wide audiology and speech center once we merge under the new Military Medical Center at Bethesda [Md.].”
As part of the Base Realignment and Closure (BRAC) process, the current Army Medical Center and the Naval Medical Center at Bethesda, are being merged into a new Walter Reed National Military Medical Center. Gates also functions as integrated service chief for the National Audiology and Speech Center being created as part of that new facility.
“The Army has been very proactive in looking at our hearing conservation program and really determined we needed to transform it to meet the needs of the 21st century,” Gates said. “The result is the Army Hearing Program, which consists of four major areas:
• “Hearing readiness, which allows us to annually monitor our routinely exposed population for early identification of those who may have changes in their hearing; that also includes education and fitting of hearing protection;
• “Clinical hearing services, providing follow-up for those identified with hearing loss, where the audiologist determines the severity of the loss and makes sure their records are up to date;
• “Operational hearing services, the newest element, is which soldiers who deploy continue to receive hearing services – both hearing injury treatment as well as prevention;
• “Our traditional hearing conservation program, which we discovered is really designed for our industrial workforce, and our military operations force really didn’t fit into that model.”
In addition to treatment and rehabilitation efforts, AASC works with – and provides some grant funding to support – outside organizations conducting hearing research. One such study is looking at the hearing profile criteria currently used to determine fitness for duty. Another is looking at a functional speech and noise test.
“Warriors in combat are around lots of noise, both nuisance and hazardous. Hearing impairment makes it very difficult for them to communicate in that environment, so we are looking for a functional speech and noise test that will provide commanders with useful information on when they can deploy someone with hearing loss or when they might not want to deploy that individual,” Gates said.
The Army has three primary categories of hearing impairment:
• H1 is essentially normal capability, with some high-frequency loss;
• H2 falls within a mild to moderate category – such as normal hearing through 3,000 hertz (Hz) and 55 decibels (db) in both ears, compared to up to 45 db at 4,000 Hz for H1 – but also looks at specific criteria for missed frequency thresholds; and
• H3 is moderate to severe hearing loss, with thresholds of 60 db or greater at 4,000 hz, although someone also could fall into H3 if they have low-frequency problems.
“I’ve never seen our profile criteria updated in the more than 20 years I’ve been in the Army, so the center will revalidate those to assure we are using the appropriate criteria to determine who is H1, H2, or H3,” Gates said. “The goal is not only to benefit the Army but perhaps allow the creation of a DoD hearing retention standard. Currently within DoD, we have an entry standard for all recruits within all the services, but the services do not have a common retention standard.”
The Department of Veterans Affairs (VA) also has an interest in those efforts, as do the Army, Navy, and Air Force departments with respect to their civilian workforce. Some of those, from Army Corps of Engineers civilians to security personnel, also are exposed to high noise levels, often in a combat environment.
“The audiology profession, as a group, is very good about working together and collaborating. For example, the Institute of Medicine publication on noise and military service looked at hearing loss in our active-duty and veteran populations and made recommendations to improve the services we provide to hearing impaired service members and veterans. As a result of that study, the Army has implemented 100 percent baseline testing on recruits at each training center before they begin basic training and are exposed to hazardous noise,” Gates said.
“Another recommendation from that study was to conduct termination audiograms. In addition, DoD is working on giving the VA access to our hearing data and the VA is working on providing us access to their electronic audiology software, in particular the ROES [remote order entry system] for hearing aids. That will allow us to use VA software to document a service member’s hearing threshold, so when they transition out of DoD, the VA will have access to that information.”
AASC also works closely with hearing aid manufacturers, including providing research grants to help them advance work on devices to meet some of the military’s unique requirements. Similar relationships exist with other DoD research labs.
For example, the Army Aeromedical Research Lab is examining blast effects on Marine breachers – warfighters whose job is to force their way into buildings or through barricades, typically involving heavy machinery and explosives. The Air Force Research Lab is looking at integrated hearing protection devices, continuing a long history of assessing commercial products that may give service members enhanced hearing capability while at the same time protecting their hearing. The Army Research Laboratory is working with AASC on studies into how an individual locates sound from different directions and, if a soldier has a hearing loss in one ear, how that affects the ability to localize sound.
“We also are in early discussions with the House Ear Institute in Los Angeles, which does a lot of research in many different areas of audiology, on some of the newer areas of interest, such as hearing loss associated with mild TBI [traumatic brain injury] and what treatment strategies should be used in assessing those,” Gates added.
TBI, caused by both direct impact and concussive forces, is considered the signature health issue of the war in Southwest Asia and has been linked to a variety of other health issues, including hearing impairment. It, too, is largely a byproduct of the enemy’s weapon of choice in Southwest Asia – improvised explosive devices (IEDs) – which expose warfighters to blast noise and concussive forces that can result in ringing in the ears (tinnitus), changes in hearing capability, middle ear damage, and balance problems.
“We also are seeing an increase in central auditory processing problems, where someone may have normal hearing but cannot understand speech or hear certain noises,” Gates said. “Overall, the move within DoD is to make sure we have effective treatment strategies in place for individuals who may have TBI or TBI-related problems and taking a more holistic approach to providing services to wounded warriors.
“Within AASC, we’ve been very proactive as part of interdisciplinary teams assessing TBI. Another area we’re looking at involves cognitive aspects associated with TBI and mild TBI and the best approach to providing rehabilitative services.”
As with warfighters who return to duty – including combat – with prosthetic feet or legs, many with hearing problems also want to continue serving rather than accept medical discharges.
“You can’t expect an infantryman to communicate effectively on the battlefield without a hearing aid, but you don’t want them wearing a hearing aid because the amplification of noise could cause more hearing loss,” Gates explained. “So we’re really looking at tactical communications and protection systems [TCPS] – what can we give these warriors that will allow them to accomplish their missions, communicate effectively, and still protect their hearing?
“If the hearing injury is limited to the middle ear, that can be surgically repaired and hearing may be restored to normal. But for those with nerve damage – permanent hearing loss – we can’t restore that at this point in time.”
One device already in limited use is the QuietPro Combat Headset, which soldiers with hearing loss often prefer to the Combat Arms Earplug, a device that allows warfighters to maintain hearing with regard to soft combat sounds but still protect their hearing from IED explosions, weapons fire, and so on. Developed by the Norwegian company NACRE, the QuietPro combines hearing protection, voice-activation radio transmission (VOX), and programmable control for tactical radio sets.
In the end, however, whether a soldier is allowed to deploy is based on his or her hearing history and recent test results. While requiring a hearing aid does not automatically disqualify an individual from deployment, neither does using a device such as QuietPro automatically qualify the user for duty.
For the most part, the hearing aids, treatments, and rehabilitative efforts used to counter hearing loss caused by combat-related noise are similar to those used for non-combat active duty and age-related hearing problems among veterans. For both, researchers are working on hair cell regeneration – regrowing hair cells within the cochlea to restore hearing; on the prevention side, development is under way on prophylactic pills to reduce or prevent hearing loss due to noise exposure.
By sharing knowledge and collaborating on both prevention and treatment, the DoD/VA goal is to provide the highest quality of hearing care for all current and past military personnel, both uniformed and civilian.
“In the near term, I would like to see a minimum standard of hearing care, so all soldiers in the active component, Guard, and Reserve are provided the services they need throughout their careers. Mid-term goals would be continuing to move forward with changing our mindset that hearing loss is an acceptable byproduct of military service,” Gates concluded.
“That continues to be a challenge, but we must get our leadership to understand we don’t have to accept hearing loss as a natural result of military service and really stress the importance of hearing as a critical sense for the soldier that increases both lethality and survivability. Long-term would be seeing a reversed trend in our veteran population – fewer noise-induced hearing loss disabilities within the VA. That will be years away, but I think the measures we put in place now eventually will see that, and hearing loss and tinnitus will no longer be the top two disabilities among veterans.”
This article was first published in The Year in Veterans Affairs and Military Medicine: 2009-2010 Edition.