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Don't Forget Hearing Protection in the Field

August 30, 2012

By DAVID RAINER
Alabama Department of Conservation and Natural Resources
 
 
It was about 10 years ago at the annual Buckmasters Classic hunt when I learned a valuable, somewhat-costly lesson.

Sitting in a deer stand that was open on three sides and had a low roof, I had to pull my rainsuit hood up to counter the rain blowing in from the west. With the hood blossomed out around my ears instead of pulled tight, I spotted a nine-point buck slipping down the edge of the field where I was sitting.

At the time, I was shooting a .264 Winchester Magnum with a muzzle brake. The .264 is loud anyway, and the muzzle brake amplified the noise even more. At about 150 yards, the buck turned toward a pine plantation. I placed the crosshairs on his shoulder and squeezed the trigger. The buck dropped and at the same instant, it felt like someone had dropped a Black Cat firecracker inside my hood. My ears were ringing like crazy, and my hearing was significantly diminished.

When the folks at Southern Sportsman Lodge came to pick me up, the guide’s voice crackled like I was listening to a distant AM radio station with static. It took several days for the crackling to go away, but I had permanently damaged my hearing.

Dr. Tim Holston, Audiology Clinic Coordinator at the University of South Alabama Speech and Hearing Center, said what I had experienced is called acoustic trauma.

“That’s a sudden, very loud stimulus that basically causes immediate – and most of the time – irreparable damage to the hair cells in your inner ear,” Holston said. “It tends to affect the high pitches first, possibly because the part of the inner ear responsible for the high-pitch range is right at the beginning where sound goes in. It takes the brunt of the blow, if you will. Usually, it initially causes a hearing loss in one particular area of the high frequencies. You often see that at 4,000 Hertz (Hz). What you often see with acoustic trauma is what is called a ‘noise notch.’ In other words, your hearing is pretty good to that point, and then it drops down sharply at say 4,000 or 6,000 Hertz. It actually comes back up at 8,000, so it affects that particular area.

“If you continue to be exposed to that noise over a period of time and continually shoot without hearing protection, it will eventually start affecting those frequencies around 4,000 Hertz, and it’s going to start lowering all the high pitches. When it works its way back toward 2,000 Hertz, that’s when people really start noticing the loss a lot more.”

Holston said the damage risk criteria that is used in the U.S. is that an individual can be technically exposed to 90 dB (weighted average) of sound for about 8 hours without being at risk for hearing loss. The actual action level that the industry uses to start a hearing conservation program is 85 dB.

“The criteria is that for every 5 dB above 90, you have half the time you can be exposed without hearing loss,” he said. “So if you had a level of 95 dB, you would have four hours. If it was 110 dB, you would have about 30 minutes.”

Holston said the other type of common hearing damage is called noise-induced hearing loss, which occurs over a long period of time. An example would be a carpenter cutting wood with a circular saw without hearing protection.

Holston said that, in an industrial setting, a person may suffer temporary hearing loss from exposure to noise, but that loss may be recovered unless the exposure continues for a longer period of time.

“When you’re shooting a firearm, that may not be the case at all,” he said. “In a noise trauma, like shooting a gun, it can cause immediate damage to the inner ear. Hair cells are broken or sheared in that region. It’s there and it’s not going to get better. When that happens, one of symptoms is you get tinnitus, ringing in the ears. With tinnitus, suddenly the inner ear is not sending the same signal to the brain. The theory is that the brain interprets that as ‘we’re missing something here,’ and that’s where we think the ringing comes from.”

After my acoustic trauma, I started wearing hearing protection. In my left ear, which is exposed to the most noise when shooting because I’m right-handed, I use a hearing aid that shuts down the device at a certain dB level with a custom-molded ear plug. In my right ear, I wear a foam ear plug.

“I have people ask me all the time, ‘I wear a hearing aid; is it going to put me at risk for further damage?’” Holston said. “I tell people that the maximum output for the hearing aid is 110 to 115 dB. I can tell you that a shotgun blast is a lot higher (140-150 dB) than that. A hearing aid might even act as a buffer to loud noises. The hearing aid has a ceiling where it’s not going to get any louder.”

Holston said the typical level where acoustic trauma causes hearing damage is somewhere in the 120-130 dB range, although different people have different susceptibility.

“Some people can take more than others, but it’s not worth the gamble,” he said. “Once it happens, there’s no, ‘Oh I shouldn’t have done that. I’ll never do that again.’ If you have a trauma, it’s more than likely not coming back.”

Holston said when communication is not essential, like shooting skeet, he recommends using professionally made ear molds or ear muffs or both. When shooting a high-powered rifle or shotgun, Holston recommends using hearing protection with the highest noise reduction rating (NRR) possible. There are also electronic ear devices designed to clip the sound before it reaches damaging levels.

“There are plenty of products out there that do that,” Holston said. “It’s just a matter of getting people to use them.”

For those who use foam ear plugs, Holston said it’s comes down to how well the product is applied.

“The foam plugs work, but you have to get them inserted in your ear properly,” he said. “It’s only as good as how well you get it inserted in your ear. They’re not always the most comfortable, but when you consider what you’re risking if you don’t use them, it’s worth it.”

Holston does believe there is better awareness now in the general public about hearing loss, although he does still have concern about the younger generation that listens to digital music at high levels with ear plugs.

“I do think people are a little more cognizant of the effect of noise now,” he said. “On the shows you see on television, the hunters are almost always protected. They’re providing good education in that they’re always wearing plugs or muffs.

“The thing is you can’t go to your doctor and tell him, ‘Fix me, Doc.’ There’s nothing he can do. You can go to an ENT (Ear, Nose and Throat) doctor and he’s going to say all you can do is get a hearing aid. Once that cochlea is damaged, there’s no surgery or medication that will fix that.”

Don’t be like me and end up with a constant ringing in your ears.

What’d you say?

PHOTOS: (By David Rainer) At an outdoor writers' conference in Huntsville, Charles Bridwell (seated) and Bill Booth follow Dr. Tim Holston recommendation of using ear muffs or properly inserted foam ear plugs (or both) at the rifle or shotgun range. Hearing protection is also important in the field, which is why the author relies on a custom-made ear plug and commercial hearing device that electronically limits the volume of loud noises that could cause acoustic trauma.

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