Solving the Noise Induced Hearing Loss Problem by Asking the Right Questions: Part Two of a Two Part Series

Last issue we explored the problem of noise induced hearing loss (NIHL). We discovered that labelling the potential protective capability of a hearing protector on the packaging did not aid in reducing NIHL. We also discussed how the industry had fixated on the fitting of the protector to the ear only to discover situations where attempting to maximize the fit didn’t solve the problem. In fact, we’re no closer to a solution even though we have 30-plus years of developing a better understanding of the problem. Certainly discovering how to reduce or eliminate NIHL is a real conundrum.

Where Hearing Stands Apart

In trying to puzzle this out, I recalled a speech given by Dr. Barry Blesser to the NHCA in 2011 on the reasons people play their music at the volumes they do. Dr. Blesser cited the primacy of hearing in the ordering of our senses. As Dr. Blesser pointed out:

• Hearing is the only fully formed sense with which we are born.
• Hearing operates 24/7/365 — we have no “ear lids.”
• Hearing acts to warn us of danger before any other sense because it works around blind corners in 360 degrees.

Is it possible that what prevents us from using hearing protection devices (HPDs) correctly is the protection itself? Unlike any other PPE, HPDs typically work by partially disabling the sense they seek to protect.

It is true that the human ear hears more definitively when the sound pressure is limited to the ears’ normal operating range. Just like a speaker that is “overdriven” garbles the sound, so when the ear is overdriven intelligibility suffers. Reducing the sound pressure level can improve intelligibility in the laboratory. It does not, however, seem to have the desired effect in the noisy workplace.

If improving intelligibility were valued sufficiently by the worker they would leave a well-fitted earplug in place. But they don’t. By disconnecting us from our surroundings, reducing or eliminating the effectiveness of our hearing in a noisy, dangerous, environment, a situation is created the human may be “hard wired” to perceive as unsafe.

“Deaf Is Better Than Dead”

The deck of an aircraft carrier during flight operations is one of the noisiest places on earth. Sound levels can reach 150 decibels. Flight crews exposed to those levels are mandated to wear earplugs, inside an earmuff, inside a helmet (the helmet is not impact protection. It reduces “bone conduction,” the tendency of the bones of the skull to conduct sound to the ears). It is well known that workers in high noise environment are easier to protect than workers in moderate noise; they seem to take noise more seriously. But, given this dangerously noisy environment, why do airmen sometimes leave out their earplugs? Anecdotally, the expression used by flight crews to explain their actions “deaf is better than dead” implies that a sense of life-threatening danger outweighs the sense to protect one’s hearing. Could this be more prevalent than we have ever imagined?

Is it possible we have undervalued our need to hear when safety is at issue? Let’s presume, for a moment, that we have. What would hearing protection that allowed us to hear safely be?

We know that most industrial noise is in certain frequency ranges. If these are not the same frequencies humans’ use for speech, then we should be able to create hearing protection that passes “speech frequencies” and blocks noise. In this way we could control the loudness with which our ear perceives our environment and set a separate level for interpersonal communication. In addition, we could facilitate other forms of communication through use of radios, such as 2-way or cellphones, while still keeping industrial noise at a safe level. Would this make a difference as to how users wore their hearing protection?

Sir Arthur Conan Doyle’s protagonist Dr. Watson, from the Sherlock Holmes novels, was fond of saying “When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.”

We take intelligent individuals, teach them to operate sophisticated machinery, and they create precision parts repeatedly to exacting tolerances. Why would these same individuals not be able to master the process of inserting and earplug or wearing an earmuff correctly?

What Hearing Protection Really Feels Like

There’s one thing we know for certain about workers wearing hearing protection in the workplace. They have a clear understanding of what it sounds like and what it feels like to wear their favorite hearing protector. And in many cases, those senses are wrong if they’re going to be protected. They have learned to value the feeling, which may be contributing to them losing their hearing. To be effective, the hearing loss prevention program (a term I prefer to “hearing conservation program;” it is more proactive) must teach them to change their sense of what effective hearing protection sounds and feels like.

In an article in the Journal of Applied Psychology in 2002, Dov Zohar of the Technion – Israel Institute of Technology reported on how a study on interventions by supervisors, managers and even executives did modify workers behavior to improve hearing protection use (and thereby Hearing Loss Prevention Program outcomes)(1).

We can improve hearing loss prevention program outcomes. It requires hearing protection that works like other PPE enabling protection without disabling the function. It requires the commitment of the organization to change behavior. It starts with using engineering to remove as much of the noise as possible and protecting against the rest. It requires facilitating functional hearing protection options. And it requires persistence and perseverance but it can be done.

I know. I’ve seen it work.

Written by Jeffrey Goldberg | Chairman of Protect Ear