Farmers and Ranchers Among Those Who Suffer Hearing Loss

Dr. Richard Kopke, Ph.D.

Maybe 30 to 40 percent of my patients are farmers. Noise damage to the ear is almost epidemic ... The noise exposure of young people growing up on the farm stays with them even after they leave the farm for another career.
Dr. Richard Kopke, Ph.D.

Hear that? Maybe not, if you have been around farm tractors and other agriculture machinery your entire life.

According to the United States Department of Labor, twenty-two million workers are exposed to potentially damaging noise at work each year. Many of these workers are farmers and ranchers.

Exposure to tractors, forage harvesters, chain saws, combines, grain dryers, even squealing pigs and guns, can lead to significant hearing loss, says Dr. Richard Kopke, M.D., FACS, chief executive officer of the Hough Ear Institute in Oklahoma City. Kopke was in the military for 26 years and has conducted research on noise induced hearing loss since 1996.

“Maybe 30 to 40 percent of my patients are farmers,” Kopke said. “Noise damage to the ear is almost epidemic.”

“Most of the patients I see are in three main areas of occupation: the military, oil patch or farmers,” Kopke said.

The focus on hearing loss is especially important for family farmers with young children.

“The noise exposure of young people growing up on the farm stays with them even after they leave the farm for another career,” Kopke said.

The Oklahoma doctor is known worldwide for his work in the field of noise-induced hearing loss. He refers to the dilemma as the “silent hurt.”

“When you damage your ears with noise, you often don’t realize it because it’s not always painful,” Kopke said. “It’s not the shotgun blast from last weekend’s hunting trip as much as it is the everyday, constant exposure to machinery. It gradually sneaks up on you. You may not know until it’s too late.”

The most practical way to protect from hearing loss is with personal hearing protection, such as ear plugs in the ear canal or ear muffs. One of the leading manufacturers of hearing protection is Etymotic Research, Inc.

“Etymotic is one of the top companies in the country for protecting hearing,” Kopke said.

Dr. Wayne Staab, Ph.D. Dammeron Valley, UT, is an internationally recognized authority in hearing aids and consults on issues related to hearing protection. Staab has conducted research specific to agriculture (see sidebar accompanying this article).

Both Staab and Kopke agree hearing loss cannot be reversed today.

Damage is a function of the loudness of the noise and the duration or frequency of the noise.

Kopke says the damage can be life altering.

“Hearing loss can cause one to be socially isolated leading to depression,” Kopke said. He added other health areas such as loss of balance due to hearing damage, can impact one’s life.

Kopke said high quality foam ear plugs work well in most circumstances, but you must get them deep into the ear canal.

What Exactly is Too Much Noise?

Most of us probably think attending a rock concert or running a chain saw all day is the type of noise-induced hearing damage doctors are talking about. In actuality, it is much more diverse.

Anything you have to raise your voice above the sound of what you’re using, it’s probably a damaging noise. If the ringing lasts for more than 15 minutes, you’ve probably done some damage.
Dr. Richard Kopke, Ph.D.

Have you noticed ringing in the ears after shooting off fireworks or hitting a hammer on metal? The Oklahoma City doctor offers some guidelines on when to know if your hearing has been damaged.

Sound is measured in decibels (dB). Here is a quick reference to measure sound in everyday situations:

It is important to know that 85 to 90 dB is a relatively safe zone, 85 is about what you would experience in a modern, insulated tractor cab. The human voice is 60. Road traffic is about 80. Chopping silage is 90. Squealing sows is about 100. Chainsaw is about 115. Shotgun blast is 120.

It’s not just the sound level that contributes to hearing damage, but it’s also the duration of the exposure.

...during harvest, a farmer may be in that cab far longer for 8 hours, so in that case, the 85-dB exposure presents a risk to hearing because of the length of the exposure time.
Patty Johnson, AuD, Director of Audiology at Etymotic Research, Inc.

According to Patty Johnson, AuD, Director of Audiology at Etymotic Research, Inc., the National Institute for Occupational Safety (NIOSH), has established Recommended Exposure Limits (RELs) for noise, based on the best available science and practice.

“The REL for noise is 85 dB as an 8 hour, time-weighted average; exposures at or above this level are considered hazardous to hearing,” Johnson said. “This standard uses a 3-dB exchange rate: for every 3-dB increase in noise level, the recommended exposure limit is halved. This means that 85 dB is allowed for 8 hours; 88 dB is allowed for 4 hours, 91 dB is allowed for 2 hours, 94 dB for one hour, and so on. This is why it’s important to consider not only the sound level, but also the duration of the exposure. If a modern insulated tractor cab has a typical sound level of 85 dB, short exposures don’t pose much of a hazard. However, during harvest, a farmer may be in that cab far longer for 8 hours, so in that case, the 85-dB exposure presents a risk to hearing because of the length of the exposure time. The simplest solution to protecting hearing is to use hearing protection any time an exposure is 85 dB or greater, since exposures are cumulative over our lifetime. If a sound is loud enough that you have to raise your voice to be heard at a distance of three feet, it’s loud enough that you should be using hearing protection.”

Q+A ON HEARING LOSS WITH DR. WAYNE STAAB, PH.D.

Editor’s note: We recently interviewed Dr. Wayne Staab, Ph.D. internationally recognized authority in hearing aids, and has done extensive work on hearing loss in the agriculture industry.

What is the best way to protect their hearing?

Avoid loud noises, both impulse and continuous, when and if possible.
Use enclosed cabs that are sound treated. Some farm equipment, especially cab-related, often provides the noise level in the cab during operation. For example, one farm tractor the family farm uses alot provides the following information in the User’s Manual: John Deere 8310R pulling a J&M 875-bushel grain cart. The tractor cab level was rated at 73 dB(A). Dosimeter measurements con rmed this level over a full day (about 10 hours of operation). Link
Augers (not usually enclosed, especially when lling granaries from a grain truck) are best managed with hearing protection
Start hearing protection early in life. If you wait until a problem exists, the damage has been done.
Utilize an inexpensive dosimeter to measure your sound exposures (a product that Etymotic Research sells, and which I have used during wheat harvesting). This provides a good estimate of noise dose and alerts the user to the risk of over-exposure, essentially indicating when hearing protection should be used. It does not measure impulse noise. But, it can be positioned in the farm/ranch vehicle and turned on whenever noise exposure occurs.
Make certain that all tractor door and window seals are intact.
If driving a tractor with the rear window open, close it.

Can hearing loss be reversed?

For the most part, no. Most noise exposure results in a sensorineural hearing loss, meaning that damage has occurred at least to cochlear hair cells.
If anything, continued exposure to loud noise is progressive with respect to hearing.

Does a using hearing protection device actually work?

Yes.
There are different kinds of noise protection devices. Some are noise reduction earphones that fit over the ears, while others take the appearance of ear plugs.
A difficulty with most ear plugs and even with many hearing protection earphones is that when they are in use, they reduce the overall level of incoming signals, including speech. This can be a dangerous situation. The Etymotic noise plugs employ two safety features. 1) When the incoming sound reaches a pre-determined level, the ear plug actively reduces the incoming sound to an acceptable level. In other words, it compresses the incoming speech based on the noise protection algorithm designed into the device. The amplified noise signal cannot be made louder than the output limit of the device. If the noise is reduced, even if for short periods of time, the Etymotic noise plug provides amplification so that the wearer can communicate. This does not occur with passive ear protection, such as most ear plugs. This is a great feature for individuals engaging in sport shooting activities. The loud noise is not allowed to be amplified because the ear plug circuitry prevents this from happening. 2) Then, following the cessation of the gun blast, the unit provides appropriate amplification for communication, even though the plug remains in the ear.

Isn’t it a lot of trouble to use these devices?

It should not be. Either keep them in a case in the pocket (not really a good idea for farmers and ranchers), or leave them in the truck, tractor, combine, feed trucks, hay grinders, and other places where they are readily available, along with a supply of batteries, in the case of Etymotic’s, to power the noise reduction/amplification device.
But, it is not the most convenient for some individuals. Many farming and ranching activities occur on the spur of the moment, and sometimes unexpectedly. It is for this reason I suggest that hearing protection devices by kept in farm equipment where they are most likely to be needed.

Image courtesy Etymōtic

Is There a Miracle Cure for Hearing Loss?

The best thing is to protect the ears, but within five years we could have something to reverse the loss.

Kopke said recent research indicates the nerve endings on the inner hair cell in the cochlea are much more sensitive than the hair cells themselves. If those nerve endings can be repaired, perhaps hearing loss can be restored.

“One drug that we’re working on is a pill that may regrow the nerve endings between the hearing nerve and the inner hair cells,” Kopke said. “This could restore some hearing and reduce the ringing sound. The second approach involves regenerating sensory cells in the inner ear. We have another treatment that would be injected through the ear drum that would regenerate these cells.”

These “hairs” are more like glass rods than the wispy hairs we have on our heads. These cells are very deep inside the inner ear.

Kopke emphasizes they are still in the research stage so his best advice today is to wear hearing protection.