Cookie-bite hearing loss

Humans can normally hear a wide range of pitches, from low to mid to high. But if you have cookie-bite hearing loss, your ability to hear mid-range hearing frequencies will be affected. A lot of human speech and music is in the mid-range, between 500 Hz and 2,000 Hz.

This means you may find yourself raising the volume on the TV or radio, experiencing reduced clarity of speech, or having difficulty hearing in a crowd, explains Dr. Jordan Glicksman, an otolaryngologist and surgeon at Harvard Medical School. 

Mid-range hearing loss on an audiogram

If you have mid-range hearing loss, your audiogram will be shaped like a bell, or the letter U. This is why it's also known as "u-shaped" hearing loss.

“It got that name because when a patient with this pattern of hearing loss has an audiogram and the hearing thresholds are graphed, the pattern is a ‘U’ that looks as if someone took a bite out of it,” Glicksman says.

What you can hear clearly: Your high-frequency hearing may be normal or close to normal, so you’ll still be able to hear high-frequencies noises (i.e., higher pitch sounds like women and children’s voices and bird chirping). You’ll also still be able to hear low-frequency sounds (low-pitched sounds such as bass-heavy music or an engine rumbling).

Causes of cookie-bite hearing loss

This type of hearing loss is rare, according to experts. This can make it harder to diagnose, even though early detection can help a person maintain their auditory processing ability (the brain's ability to make sense of sound). 

Cookie-bite hearing loss is a type of sensorineural hearing loss. This means the sensory and nerve cells of the inner ear and auditory nerve are impaired for some reason. This is why it's sometimes referred to by its longer medical name, "mid-frequency sensorineural hearing loss," or MFSNHL. 

Typically, cookie-bite hearing loss is a genetic condition, Dr. Glicksman says. “A family history is a risk factor,” he says. Cookie-bite hearing loss can be congenital (aka, something you’re born with) or develop over time due to genetics, he says. 

There are some less common reasons cookie-bite hearing loss is developed beyond genetics. For instance, a rare benign tumor, known as vestibular schwannoma or acoustic neuroma, can lead to this mid-frequency hearing loss, Dr. Glicksman says. In some cases, mid-frequencing hearing loss is due to drug side effects, or certain viral infections.

More: I lost my hearing suddenly due to Ramsay Hunt syndrome. Here’s what I learned.

How mid-range hearing loss is diagnosed 

The diagnosis process for this form of hearing loss is simple: A hearing test. If mid-range hearing loss is present, the audiogram will show the distinctive pattern that points to cookie-bite hearing loss. 

Some cases are missed because the hearing loss may be mild

In fact, the biggest challenge for diagnosis may be requesting the test. “It’s commonly a mild form of hearing loss,” Dr. Glicksman says. People may be slow to realize that their hearing has worsened.  

It can also develop slowly

Plus, he notes, this mid-range frequency loss can occur over a long period of time, as opposed to a sudden hearing loss, which might be more noticeable. 

Treatment options

No cure exists for cookie-bite hearing loss. There’s no surgery or medication that will restore a person’s hearing abilities. However, there are treatment options available to help manage the condition. Per Dr. Glicksman, these include: 

• Hearing aids: Wearing hearing aids can help amplify the mid-frequency sounds. 
• Making adaptations: Simple changes, such as changing where you sit in restaurants and other social gatherings, as well as in classrooms, can be helpful, says Dr. Glicksman. Aim to move close to the person speaking, or make sure you can easily see their lips. If a person is speaking into a microphone, moving closer to the amplification device can be helpful, he notes. You can also improve your home's acoustics. 

Treatment options depend on how severe the hearing loss is, and how eager someone is to rehabilitate their hearing, Dr. Glicksman says. 

If you or a loved one suspect you have cookie-bite hearing loss, don't hesitate to visit a hearing aid center near you.