Until 10 years ago, audiologists insisted that anyone who could pass a hearing test had normal hearing. In a typical hearing test, the audiologist looks for damage to the hair cells inside of the ears that detects vibration and transfers it to sound. During a test called an audiogram, the audiologist plays sounds at various frequencies. They then measure the response of the inner-ear hair cells. In most cases, those diagnosed with a hearing loss have difficulty hearing low-volume sounds played at specific frequencies.
The image below shows a cross section through the cochlea of the ear with detail of the organ of Corti, showing the tectorial membrane and cells responsible for hearing.
Hidden Hearing Loss is Hard to Detect
Unfortunately, a person can have damaged hearing and still pass a typical audiogram. Before hearing loss affects the hair cells of the ears, it first impacts fibers located in the auditory nerves. These nerves typically connect to hair cells to allow people to hear in a noisy environment. When working together properly, the auditory nerves and hair cells help people to block out background noise and hear the conversation of the people sitting closest to them.
Hidden hearing loss doesn’t appear on an audiogram due to the way an audiologist typically performs the test. Besides taking place in a quiet room, the low-volume frequencies played by the audiologist don’t cause any response in the auditory nerve fibers. The person passes the test and likely continues to struggle with hearing loss for many years.
Recently, Juan Bagnell of SomeGadgetGuy.com opened up about his troubles with hidden hearing loss on his YouTube Channel with Dr. Alison Grimes of UCLA. Here is how Dr. Grimes explained hidden hearing loss:
“The classic patient with hidden hearing loss comes into the clinic and says, ‘I feel like I have hearing loss.’ We do a hearing test and we tell the patient that their hearing test is normal. And they come back and say, ‘But I have difficulty hearing… I have difficulty hearing in noise… I’m missing conversations.’ And then if you sort of scratch the surface a little bit you come to find out this is person who’s maybe had quite a bit of noise exposure.
So we know it’s happening. It’s happening probably at the junction of the hair cell and the inner ear to the primary auditory neuron of the eighth cranial nerve. So, when people have hearing tests, our hearing tests are very gross. Hidden hearing loss is very fine. We’re just not picking it up. But these are people who have difficulty hearing speech and noise. That’s one of the primary complaints.”
Watch the full video below:
Causes and Symptoms of Hidden Hearing Loss
As alluded to by Dr. Grimes, repeated exposure to loud noise is the most common reason that people develop hidden hearing loss. It is most prevalent in younger people who may go on to develop more serious damage to their hearing as time goes on. Researchers believe the popularity of attending concerts and listening to music through headphones among younger people is one of the causes of this new epidemic.
When a person continually hears loud noise, it damages the nerve cells in the brain that connect the inner ear’s cochlea to the brain. The brain eventually starts to receive less auditory feedback from the ear. It also struggles to make sense of the information it does receive.
A hidden hearing loss isn’t always obvious, even to the person who suffers from it. That is because he or she can usually hear normally in quieter environments. It becomes much more apparent when the person must compete with loud background noises to hear the conversation right in front of him or her.
Ever-Increasing Noise Levels in Restaurants
Restaurants are notoriously loud and only seem to be getting louder. Consequently, people hidden hearing loss often can’t enjoy dining out with their friends or family without specific accommodations. This could include anything from turning the overhead music down or off or requesting seating in a quieter section.
Between the playing of overhead music, the whirring of kitchen equipment, the conversation of other guests, and the seating and departure of other guests, visiting a popular restaurant can be as loud as sitting near a diesel truck. At this level, even those with normal hearing can’t make out what others are trying to say.
Restaurant and other business owners are just starting to understand the impact of repeated loud noises on their customers. Some have deliberately reduced the noise level to make things more comfortable while others cater to crowds who enjoy and feel energized by the noise. Fortunately, people do have options when choosing where to eat or enjoy other leisure activities. Two recent smartphone applications, Soundprint and iHEARu allow users to look up places to visit based on decibel level and other factors that can affect their hearing and comfort level.
Additionally, devices such as IQbuds BOOST offer an alternative solution to managing restaurant noise and the symptoms of hidden hearing loss. This devices amplifies speech in noisy environments at a fraction of the cost of a traditional hearing aid. As a result, IQbuds BOOST are a more affordable and more accessible option.
What to Do About Hidden Hearing Loss
Because this type of hearing loss doesn’t impact the ears in a typical way, hearing aids are rarely helpful. People who suspect or know they have this problem should limit their exposure to noisy environments as much as possible. Additionally, new medications may eventually reverse hidden hearing loss by repairing the damaged auditory nerve fibers. Finally, advocate for quieter environments in public spaces. This cause will not only assist those currently suffering from hidden hearing loss but future generations as well.