Intentional Stress Challenge: Noise Exposure

Progressive challenge series to train resilience with the use of sound.

As a military audiologist, one of my primary jobs is to prevent the most common injury in the armed forces, noise-induced hearing damage. Loud sounds can chronically and/or instantaneously cause hearing loss. Damaged hearing can have detrimental effects on a person’s performance, especially in regard to communication capability and situational awareness. 

Another consequence of injury to the inner ear is tinnitus or a persistent ringing sensation. Like the phantom-limb, where someone has lost an arm or leg but still feels pain, itching, burning, or other sensations where the limb used to be, tinnitus is a brain-derived phenomenon. The damage is in the peripheral nervous system but the bothersome sensation comes from the central nervous system, specifically the mind. These sensations occur because the body is full of nerves continuously communicating back and forth with our brains. The inner ear is lined with hair cells, all coded for different frequencies or pitches, that are constantly sending complex messages down our auditory nerve to our brains that then get decoded into speech, music, or sounds. When the system is disrupted, the brain still has regions coded for the damaged area and attempts to send it signals which can be seen on functional MRIs. If this produces unwanted symptoms like tinnitus, we unfortunately only reinforce that cycle by focusing on it. We often hear high-pitched ringing in response to hearing loss because it is the high frequency hair cell region that is most susceptible to damage. While there are other causes of tinnitus that can be ruled out, there is unfortunately no “cure” for this sensation when caused by permanent hearing loss. Due to its prevalence, however, there are many treatments on the market aimed at reducing or eliminating this phenomenon. Similar to many other medical symptoms and disorders, placebos have been shown to be as effective as any of the pharmaceutical treatments marketed for tinnitus. The most successful treatment for tinnitus has been shown to be habituation training which refers to conditioning of the mind to remove perceived significance from the sensation.

If you had never heard the sound of your refrigerator running before, you’d most likely be at least curious about what that noise was the first time hearing it. If everyone around you said they didn’t hear anything while you continued to be unsure of the sound’s source, it’s likely you’d attach a negative meaning to that sound. Is something broken? Is it a some sort of creature? Has someone secretly planted a device in my house to spy on me?! As you can imagine, a misunderstood sensation can produce significant concern causing that stimulus to become progressively more bothersome over time.

I’ve had patients understandably worried that their tinnitus was a symptom of a brain tumor or other life-threatening medical disorder. In rare cases, this actually is possible but there are many tests that can be done to rule out these scary pathologies. I’ve had other patients believe that their tinnitus was feedback from a medically-implanted device placed by the government, warnings from god for being a sinner, or signals from demons trying to drive them crazy. As you can imagine, it would be pretty difficult to live a normal life having such strong beliefs about the cause of ringing in your ears. 

Once I’m able to rule out the possibly concerning causes of tinnitus and then counsel someone on the most common reason persistent tinnitus exists (phantom limb phenomenon), the challenge then becomes making this permanent consequence of hearing damage less bothersome. 

We are always in the presence of noise. I love teaching this concept to people when they tour the current lab I manage that contains an anechoic chamber - a completely soundproof room made for research. Being in the absence of any external noise is eerie. When inside the chamber with the sealed doors, someone with normal hearing can hear the electricity if the lights are on. Turn the lights off and any tinnitus you may have will become very apparent even if it’s not bothersome. Aside from tinnitus, it only takes a few moments until you can start hearing the blood pumping through your head, your stomach digesting food, and many other sounds in your body. 

Our brain is very good at ignoring noise that we understand and don’t find contextually significant. Introduce sounds we aren’t familiar with, believe to be important, or find distracting and the mind has a hard time filtering them out regardless of loudness level. This is useful for threat identification, speech detection, and other signals that support situational awareness. It becomes detrimental when nonthreatening sounds consistently interfere with functioning relating to concentration, sleep, and stress. 

Misophonia and hyperacusis are two other conditions I occasionally work with as an audiologist. Misophonia is aversion to specific types of sounds whereas hyperacusis is sensitivity to louder sounds. As I already described, loud sounds can damage hearing, however, moderate level sounds that are louder but not hazardous shouldn’t cause an emotional reaction. The main component in a diagnosable case of bothersome tinnitus, misophonia or hyperacusis is consistent functional impairment.

The key to successful habituation is modifying the perception of the bothersome sensation. This is best done through progressive exposure therapy. Exposure therapy, in this case, isn’t aimed at having the person focus on the bothersome stimulus, rather, have a task, distracter, and/or different stressor present while the stimulus can be perceived. 

What you focus on, you get more of.

Stop bitchin’ and start habitchin’.

The goal is to shift focus from what is considered annoying or threatening in an initially subtle way and then build upon any small wins. Think sitting in the presence of the bothersome sound at a soft level while adding in a perceptually pleasant sound and focusing on breathing techniques. Assuming this task decreases perceived severity of the sensation, we then progressively add in stressors while attempting to maintain or improve upon that new level of perception. Changing the task, distracter, and/or stressor is always an option when an attempt to decrease perceived severity is unsuccessful or when ready to progressively train our mind to habituate further.

While diagnosing pathologic tinnitus, misophonia and hyperacusis all require consistent functional impairment, we are all prone to non-clinical variations of these conditions. 

Some sounds are almost universally disturbing such as babies crying or nails on a chalkboard. Others produce unique responses based on the person. Many people can’t stand the sound of chewing, snoring, heavy breathing, construction tools, or car alarms. Every form of music will have differing amounts of supporters and haters. One person’s favorite song could be torturous for another. 

Contemplate the sounds in your life that cause you stress or impact your performance in some way. What forms of music do you stay away from? Are there any types of noise that you can’t stand? 

All of these answers provide opportunity for habituation training. 

Basic Challenge: Listen to sounds you don’t enjoy for five minutes a day for one week.