Shooters are at Risk

Noise is all Around and YourEars Can't Tell the Difference

For more information, contact:Med Compass7841 Wayata Boulevard #214Minneapolis, MN 55426800-205-8729(V), 952-542-0095(F)sales@medcompass.net (E-mail)www.medcompass.net

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NHCA thanks Dr. Michael Stewart of Central Michigan University, Mt. Pleasant,Michigan and Barbara Garrett of St. Luke's Hospital, Cedar Rapids, Iowa,for their contributions to this pamphlet.

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Hearing loss, in most cases, is the result of a lifetimeof accumulation of exposure to noise from varioussources. Although the damage caused by exposure togunfire may be different from that caused by expo-sure to continuous noise (see “What Makes FirearmNoise So Dangerous”, inside), the end result is thesame — loss of your ability to hear. The total of allexposure to all hazardous noise adds up to the resultin your ability — or lack of ability — to hear.

Exposure to continuous noise for long periods oftime, like in a factory or on the farm, can damagehearing, too. Here are a couple of ways to determinewhether the noise you are in, be it in your car,on the job, from using power tools at home, or in anightclub, could result in damage to your hearing.

■ If you have to raise your voice to be heard at adistance of three feet or so, sound levels areprobably approaching 85 decibels or dB. That’sabout the level where regular long-term exposurecan result in permanent damage.

■ Tinnitus or ringing in the ears is a sign of potentialdamage. If you hear a ringing or rushing sound inyour ears after leaving a noisy environment, it wasprobably too loud.

■ Temporary Threshold Shift or TTS is atemporary loss of hearing. After exposure to loudnoise, you may lose some hearing, then recoverafter a “rest period” in quiet. If conversationsounds muffled or unclear after leaving a noisyarea, or if you have to turn up the radio in yourcar to make it sound the same as before, it’s likelythat you overloaded your hearing system.

Recreational shooting for hunting or sport purposes hasbecome an increasingly popular leisure-time activity. Inthe US, as many as 60 million people engage in shootingactivities, with firearm use ranging from a few shots peryear for the casual hunter to 10,000 or more shots peryear for avid competition shooters.

Although most serious shooters will use appropriatehearing protection devices (HPDs) during extendedsessions on the firing range, many do not protect theirhearing during shorter sessions. In addition, since theability to hear all environmental sounds is paramount inhunting activities, few individuals are willing to use HPDsin the field.

Too often, exposure to firearm noise results in serious,irreversible harm to the shooter’s hearing. This PracticalGuide is intended to provide information to shooters andthe hearing health professionals who help them so thatthey will understand the hazards of firearm noise and theactions they can take to protect their hearing.

Permission is granted for individuals to print and copy this document.However, the document cannot be used commercially without permissionfrom the NHCA office.

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Unlike loud continuous noise that causes gradual hearingloss over a long period of time, firearm noise can causesevere instantaneous hearing loss with as little as oneexposure.

Gunfire is an intensely loud impulse noise that shattersthe acoustic environment with incredible concussion,generating a rapid change in pressure and extremely highsound levels.

Although impulse type noise only lasts for a few thou-sandths of a second, the extreme force it generates hasthe potential to destroy the delicate tissue in the innerear if the sound level reaches a critical level.

This critical level varies from person to person, withsome people more susceptible than others to noise-induced hearing loss (NIHL), whether it comes fromsteady industrial types of sound or the impulse noisesassociated with gunfire.

Why Can’t I Understand My Family?Because NIHL generally involves more hearing loss inhigh frequencies than in lower, bass ranges, a person withNIHL can usually hear louder, low frequency vowelsbetter than softer, high frequency consonant sounds. Thismeans that although they may be able to hear speech,they may not be able to understand it clearly. Forexample, the difference between “mine”, “kind”, and“time” is very hard for someone with NIHL to pick out.

Often, people with NIHL think that others mumble.People with NIHL sometimes give the impression thatthey are not listening, when in fact, they just don’tunderstand. Many times people with NIHL also have aringing or roaring in the ears called tinnitus that can beextremely annoying.

Although there are no clearly defined allowable noiseexposure limits for gunfire like those enforced inindustrial settings, the Environmental Protection Agency(EPA) has estimated that exposure to one impulse noiseper day over about 150 dB has the potential to damagehearing over time. Most shotguns, high power rifles, andpistols can produce sound levels that high or higher.

Large caliber, short-barreled guns that can be rapidlyfired are the most dangerous to your hearing.

Modifying the barrel of a gun by drilling holes to reducerecoil (like a muzzle brake) increases sound exposure bysending the shock wave back toward the shooter insteadof out of the front of the gun through the barrel. Inaddition, shooting from an enclosed structure like a duckor deer blind can significantly increase the noise levelsreaching to the ear of the shooter.

During Target PracticeMost hearing protection devices (HPD) with a labelednoise reduction rating (NRR) on the package will beadequate for shooting situations when consistently andcorrectly utilized where hearing verbal communicationor environmental sound is not critical. Choose an HPDthat attenuates sound adequately and is comfortable towear for long periods of time. For the ultimate inprotection, wear insert type plugs under earmuffs. UsingHPD can actually help improve your aim because you willflinch less in anticipation of the “big boom” of your gun.

While HuntingBecause most hunting involves listening for approach-ing game, wearing conventional HPDs is not practicalin the field. However, there are two solutions to thisproblem.

Use a specially designed level-dependent HPDwith a filter or valve mechanism to let more low levelsounds pass and yet provide increasing protectionwith increasing sound level.

A more costly option is to use electronic hearingprotective devices (EHPDs). The basic EHPD consistsof a microphone, amplifier, volume control, andbattery, housed either in a headset, a behind-the-ear(BTE) device, or an in-the-ear (ITE) configuration.The amplifier increases low and moderate levelsounds that can improve hearing ability, but is alsoequipped with a special circuit which prevents loudsounds from reaching damaging levels in the ear. Eachtype has advantages and disadvantages, as listed below.

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Ask your audiologist or hearing healthprofessional for more information

EHPDEHPDEHPDEHPDEHPDTypeTypeTypeTypeType AdvantagesAdvantagesAdvantagesAdvantagesAdvantages DisadvantagesDisadvantagesDisadvantagesDisadvantagesDisadvantagesHeadset Least expensive, Bulky, uncomfortable

high amplification, for long periods of use,good protection excessive wind noise,

poor localization ofsounds

BTE Moderate ampli- More expensive thanfication, good local- headset, some typesization of sounds may be uncomfort

able, some wind noise

ITE Moderate ampli- Most expensivefication, good pro-tection, good comfort,best localization ofsounds, leastwind noise