Could You Have Hidden Hearing Loss?

According to the National Council on Aging (NCOA), hearing loss affects about 60.7 million American adults. However, that statistic may not include millions of people affected by hidden hearing loss, a type of hearing impairment that's undetected by standard hearing tests.

You could have hidden hearing loss if standard hearing tests come back normal but you struggle to hear conversations in places with background noise.

It's possible to manage hidden hearing loss using assistive devices such as hearing aids fitted by an audiologist or purchased over the counter from a company such as Eargo.

Read on to learn more about hidden hearing loss, its potential causes and signs that you could be affected by it.

Table of contents

• What is hidden hearing loss?
• What causes hidden hearing loss?
• Signs you could have hidden hearing loss
• How is hidden hearing loss diagnosed?
• How is hidden hearing loss managed?
• Tips to prevent hidden hearing loss

What is hidden hearing loss?

Anish V. Thakkar, Au.D., director of audiology at the Los Angeles Center for Ear, Nose, Throat and Allergy defines hidden hearing loss (HHL) as "a deficiency in hearing that may not show up in a traditional audiogram or hearing test."

"A comprehensive hearing test includes air conduction thresholds, speech testing, bone conduction thresholds, tympanometry and acoustic reflexes. While someone with hearing loss may present with normal hearing thresholds, they still may experience difficulty hearing."

Hearing care specialists have observed this issue for years, but researchers are just recently gathering statistics on how many people are affected by it.

"It is hard to find reliable statistics on hidden hearing loss, especially since it is often confused with other issues like ADHD or CAPD (Central Auditory Processing Disorder)," remarks Dr. Thakkar. "But if I had to estimate, I would say [it affects] about 5 to 8% of the U.S. population."

Hidden hearing loss can affect anyone, but the Ear Science Institute of Australia reports that populations exposed to recurrent and loud noises are at a higher risk. This includes occupations such as military members, tradespeople, farmers and air traffic controllers.

What causes hidden hearing loss?

The cause of hidden hearing loss is subject to continuous research. According to a review of hidden hearing loss published in Current Opinion in Otolaryngology & Head and Neck Surgery, hidden hearing loss is often called cochlear synaptopathy.

Cochlear synaptopathy implies a type of hearing loss that's caused by damage to the synapses between the auditory receptor cells (known as hair cells) and cranial nerve fibers, unlike other types of deafness which are caused by damage to the hair cells.

Like other types of sensorineural hearing loss, cochlear synaptopathy can develop due to normal aging as well as exposure to loud sounds, according to an evaluation of diagnostic tools for hidden hearing loss published by the International Brain Research Organization (IBRO).

Signs you could have hidden hearing loss

"Some signs [of hidden hearing loss] include a strong preference toward quieter places to chat, feeling easily distracted by background noise and often mishearing [or] misinterpreting people." says Dr. Thakkar.

Tinnitus could also be a symptom of hidden hearing loss. Investigators at Massachusetts Eye and Ear, a teaching hospital of Harvard Medical School, showed that individuals affected by tinnitus — a humming, ringing, buzzing or roaring noise in the ear — also experienced auditory nerve damage that was undetected by standard tests.

How is hidden hearing loss diagnosed?

Unfortunately, there aren't standard testing guidelines for your doctor to successfully diagnose hidden hearing loss. This type of hearing impairment is subject to ongoing research, and finding accurate diagnostic tools is one of the challenges.

Hearing care professionals may start by taking a detailed history of the patient's hearing troubles and administering a normal audiogram. They may also evaluate the auditory brainstem response (ABR), the middle-ear muscle reflex and perform other tests.

"Sometimes, in addition to traditional audiometry, further testing such as a speech-in-noise (SIN) test may help in diagnosing hidden hearing loss. This is because, during SIN testing, patients need to repeat segments of speech in an increasingly noisy setting instead of hearing in silence for the majority of traditional audiometry," says Dr. Thakkar

Some studies suggest high-frequency audiometry as an effective diagnostic tool. This test is used to evaluate loss of subtle speech recognition like the ability to pick up high-pitched "s" sounds. These high-pitched sounds correspond to high-frequency soundwaves that may be outside the range of a traditional audiogram. High-frequency audiograms evaluate frequencies in a range from 8,000 to 20,000 Hertz (compared to the range of 250 to 8,000 Hertz of a traditional audiogram).

How is hidden hearing loss managed?

Individuals can manage hidden hearing loss with assistive technology and by implementing new communication strategies in social situations.

Dr. Thakkar suggests improving speech-in-noise (speech recognition in noisy environments), "through the usage of low-gain hearing aids with directional microphone technology, possibly in conjunction with a remote microphone accessory. [This feature] helps the intended speaker's voice go directly into the hearing aids (or Bluetooth-paired headphones) of the listener."

Many self-fitting hearing aids feature speech recognition technology as well as directional microphones. These devices are available without a prescription and may help if you have mild to moderate hearing loss.

Dr. Thakkar also recommends meeting or hanging out in quieter environments, choosing restaurants with carpeting and soft or no music, or using free apps like HearCoach to help hone listening skills.

Tips to prevent hidden hearing loss

Earlier this year, the World Health Organization published a sobering forecast — over 1 billion young adults are at risk of irreversible hearing loss. This risk is mainly due to personal audio devices like smartphones and harmful sound levels at public venues like concerts and movie theaters.

Modern smartphones with high-fidelity audio and long battery life have made it easy to listen to sounds at high volumes for longer periods of time, regardless of the damage it may cause.

Here's what hearing professionals recommend so you can protect your hearing well into old age:

• Wear hearing protection in environments where you can't control the volume, such as the movie theater or a concert.
• Avoid or minimize the use of headphones, as these amplify sound closer to the eardrum.
• Listen to music at no louder than 50% of your phone's maximum volume.
• Use noise-canceling headphones to eliminate the temptation to increase the volume if you're in a noisy area.
• Get regular hearing checkups with a professional every couple of years.

Summary of Money’s Could You Have Hidden Hearing Loss?

You may have hidden hearing loss (also known as cochlear synaptopathy) if your hearing tests come back normal but you still have trouble understanding normal conversations in certain environments.

Cochlear synaptopathy can be caused by several factors, including aging, noise exposure or side effects of certain medications.

Treating or managing hidden hearing loss may be challenging because there aren't clear diagnostic guidelines. Fortunately, research is ongoing, and hearing healthcare professionals are working on finding better diagnostic tools and treatments.

If you're having trouble hearing, visit an audiology clinic or an ear, nose and throat (ENT) doctor. They may suggest assistive devices like hearing aids, new communication strategies and auditory training exercises to help your hearing.