CONCEALMENT 12 Sound Advice: The Psychology and Physiology of Saving Your Hearing Dr. Neal Olshan Join the Conversation During the filming of the movie Die Hard, Bruce Willis fires over 15 full-flash blank rounds from his Beretta 92F. Two rounds were fired directly on the terrorist first entering the room, and the rest were fired through the table. According to the movie’s director, the proximity of the gun to Willis’ ear during this scene caused permanent hearing loss for Willis. He’s also visibly hit in the face by spent casings as he blasts away. What Makes the Sound? Muzzle blast: The sound of escaping gases produced by the gunpowder after a bullet leaves the barrel, which causes the “report” of a gunshot. Bullet crack: The sound associated with the collation of the shockwaves created by an object traveling through the air faster than the speed of sound. Rolling the Hearing Loss Dice Exposure to noise greater than 140 dB can permanently damage hearing. Almost all firearms create noise that exceeds this threshold. A small .22-caliber rifle can produce a report around 140 dB, while big-bore rifles and pistols can produce sounds over 175 dB. Firing guns in a place where sounds can reverberate, or bounce off walls and other structures, can make noises louder and increase the risk of hearing loss. Also, adding muzzle brakes or other modifications can make the firearm louder. People who don’t wear hearing protection while shooting will suffer a severe hearing loss with as little as one shot if the conditions are right. Audiologists see this often, especially during hunting season when hunters and bystanders may be exposed to fire from big-bore rifles, shotguns, or pistols. It’s not uncommon for people with hearing loss to deny the deficit and instead fill in the blanks. They use guesses or approximations of what they think was said, therefore creating the potential for accidents. What’s the NRR? All hearing protectors supplied in the USA should be provided with an NRR (noise reduction rating). It can be used to estimate the sound level at the ear when wearing the protectors, with figure derived through a series of complex formulas. Enough said. The NRR describes the average sound level reduction (attenuation) provided by a hearing protection device (HPD) in a laboratory test. Since the NRR is based on laboratory testing, it doesn’t take into account the loss of protection that occurs when hearing protectors aren’t fitted or worn properly or when they’re not worn for the entire time that the wearer is exposed to noise For most wearers, the NRR identified on the EPA label significantly overestimates the protection of the hearing protector in actual usage. This rating is based on an “experimenter fit” method of measuring HPD attenuation. The Anatomy of Hearing and Balance The process of hearing is a series of events modifying sound waves that move through the air into electrical signals. Our auditory nerve then carries these signals to the brain through a complex series of steps. The ear has three major parts: external ear, middle ear, and inner ear. They all have different but important features that facilitate hearing and balance. The external ear, also called the auricle or pinna, is the loop of cartilage and skin attached to outside of the head. It works much like an old-time megaphone. Sound is funneled through the external ear and piped into the external auditory canal or ear hole. The sound waves pass through the auditory canal and reach the tympanic membrane, or eardrum. The thin sheet of connective tissue lets the vibrations enter the middle ear, also called the tympanic cavity, which is lined with mucosa and filled with air and the auditory ossicles, three tiny bones called the malleus (hammer), incus (anvil), and stapes (stirrup). The nerve impulses are sent to be processed by the auditory cortex, situated in the temporal lobe of the brain, beneath the temples. Additionally, the impulses give certain parts of the brain information on the orientation of your body to the environment (balance), allowing the muscles to process the brain’s signals. Your ears are not the same! Your left ear is better at music, and your right ear is better at understanding language; this is due to where those processing centers reside in your brain. The sense of hearing is a response to mechanical stimuli, vibrations that are converted into nerve impulses that the brain receives and interprets. Hearing Facts 1. The inner ear is the circumference of a pencil eraser. 2. Your sense of hearing depends on tiny hairs deep inside your ear. If you lose these hairs, you lose your hearing. 3. The number one cause of hearing loss is exposure to excessively loud sounds (85 decibels or higher). 4. Your hearing can be damaged permanently even after a single exposure to extremely loud noise (shotgun blast, explosion, and so on). 5. Your ears never stop hearing. When you sleep, your brain just ignores incoming sounds unless they relate to your personal safety or that of a loved one. 6. Ears are more than just necessary for hearing, they also help you keep your balance, essential in any situation that you’re utilizing a firearm. How We Measure Sound Simply put, the decibel is considered the unit to measure and describe the intensity of a sound. The basic decibel scale is most often used since the human ear can be incredibly sensitive. Your ears, depending on general health, age, and noise exposure, can be capable of hearing everything from your fingertip brushing lightly over your skin to a loud jet engine. Two Types of Hearing Loss 1. Exposure to even a single incident of high intensity sound that causes immediate and unrepairable hearing damage/loss. 2. Repeated exposure to sounds that can cause chronic hearing loss. Some sources estimate that 80 to 100 percent of sport shooting and hunting may result in some degree of hearing impairment. These figures should be viewed with a certain degree of skepticism since people have a tendency to lie about their hearing loss. Incidence of law enforcement and military hearing loss could be as high as 100 percent. Firearm users tend to have permanent high-frequency hearing loss, which means that they may have trouble hearing speech sounds like “s,” “th,” or “v” and other high-pitched sounds. The left ear (in right-handed shooters) often suffers more damage than the right ear because it’s closer to, and directly in line with, the muzzle of the firearm. Also, the right ear is partially protected by head shadow. People with high-frequency hearing loss may say that they can hear what is said, but that it’s not clear, and they may accuse others of mumbling. They may also have ringing in their ears, called tinnitus. The ringing, like the hearing loss, can be permanent. Listen Up Recent studies have shown that only about half of shooters wear hearing protection devices all the time when target practicing because they say they can’t hear instructors or other shooters. Hunters are even less likely to wear hearing protection because they say they can’t hear approaching game. While some HPDs do limit what a person can hear, there are many products that allow shooters to hear softer sounds while still protecting them from the discharge of firearms. The Two Types of HPDs Nonlinear HPDs aren’t electronic and are designed to allow soft and moderate sounds to pass through while still reducing loud sounds. Nonlinear HPDs can be either earplugs that are inserted into the ear or custom-made ear molds. Nonlinear HPDs that have filters are the best choice. They’re better than those that use mechanical valves because the valves may not close fast enough to protect your hearing from loud noises. Insert plug-type nonlinear HPDs cost about $10 to $20, while custom-made nonlinear devices cost about $100 to $150 per pair. Electronic HPDs make softer sounds louder, but shut off when there’s a loud noise. The device then becomes hearing protection. Electronic HPD styles include earmuffs, custom-made in-the-ear devices, one-size-fits-all plugs, and behind-the-ear devices. Electronic HPDs range in price from $100 for earmuffs to over $1,000 for high-tech, custom-made devices. Military/Law Enforcement Prior to 1940, there was very little information regarding hearing protection for soldiers. Pilots were luckier. Even the early leather flight caps had built-in earphones that allowed the pilot or crew to communicate in the excessive noise of the poorly insulated aircraft. Any hearing protection was more by accident than design. Occasionally, paintings of soldiers from the Civil War depict a soldier with cloth material in his ears, but this was almost solely soldiers firing or reloading cannon. Sailors on ships in World War II had hearing protection in the gun turrets. Today, the U.S. military uses both electronic and nonlinear HPDs to protect soldiers’ hearing during combat and weapons training. Suppressor No article on hearing protection would be complete without a mention of the suppressor, also referred to as a can or silencer. This is a device attached to the end of the barrel, with a series of baffles that contain and redirect the expanding gases exiting the end of the firearm’s barrel. The concept is similar to a car’s muffler. The suppressor and the car muffler were developed in parallel by the same inventor, Hiram Maxim, in the early 1900s. Suppressors allow for more effective training since students can hear each other, and they assist in compliance with safety regulations. Suppressors are now regulated through the National Firearms Act of 1934 (NFA). Prior to the NFA, suppressors could be purchased straight from a catalog. Suppressors also reduce felt recoil and help to lessen the shooter’s “flinch.” When using a suppressor, there’s typically a reduction in anticipation of the gun’s report/recoil, reduction in sleight-of-hand tremors, and a reduction in the blink response prior to firing, which also leads to a reduction in muzzle flip. Many European countries are less restrictive regarding the purchase and ownership of suppressors (though the guns themselves are highly regulated) and actually encourage their usage, especially in practice, training, and hunting. In the United States, suppressors can be used in 40 states for hunting and are allowed to be owned in 42 states. Very rarely are suppressors used in committing a crime that involves a rifle or a handgun. Shooter’s Ear Many audiologists refer to the asymmetry in hearing loss as “shooter’s ear,” with the ear nearest the muzzle blast showing significantly more hearing loss than the “shadowed” ear. In law enforcement and the military, it’s not uncommon to receive a medical retirement or discharge due to Noise Induced Hearing Loss — it only takes one incident. Shooting Inside Versus Outside In the past, shooting inside an enclosed area would potentially put yourself at greater risk for hearing damage. Today’s science of sound dynamics allows specialized designers and architects to create facilities with greater sound dampening and acoustical baffling. Shooting ranges that aren’t enclosed may allow for greater dissipation of the sound, but on the flip side, at an outdoor range, there’s a greater chance that you may encounter higher-caliber guns. The Absolutes Are Worth Repeating – Always use some type of hearing protection anytime you fire a gun or are near guns being fired. – Always have disposable HPDs handy — make them part of your gear. – Double-protect your ears, such as putting muffs over plugs, when shooting big-bore firearms. – Choose smaller-caliber firearms for target practice. – Avoid shooting in groups or in reverberant environments. – Use electronic or nonlinear HPDs for hunting. About the Author Dr. Neal H. Olshan is the developer of Evolution of Mindset Training Program and is a consulting psychologist in the areas of forensics and performance enhancement. He is also a glider pilot and an award-winning photographer. He is the author of seven nonfiction books. With his wife, Mary, they have written the Kindle novel The Panama Escape. He is the chief combat psychologist for LMS Defense. He lives in Scottsdale, Arizona. Send your thoughts, ideas or suggestions on hearing protection or thoughts for future articles at [email protected]. Explore RECOILweb:Scrutinizing the Dead BirdSkinning KnivesNightforce Introduces the Wedge PrismTrump Lowers - Would You?