Hidden hearing loss is a type of hearing loss that is not detectable using standard hearing tests, which are designed to identify specific kinds of hearing problems.
Because it is hard to identify, no one is sure exactly how many people suffer from this condition, but one study of more than 100,000 patient records over a 16-year period found that nearly 10 percent of patients who visited Massachusetts Eye and Ear for a hearing test had a normal audiogram despite feeling that they could not hear well.
Signs of Hidden Hearing Loss
Unfortunately, hidden hearing loss is not well understood, and there is no established set of guidelines for diagnosing the condition. Some signs may include:
- Preferring quiet conversation settings
- Feeling easily distracted or unable to focus in noisy environments
- Hearing people incorrectly
- Having a strong sense you have hearing loss despite passing a hearing test
What Part of the Hearing System Is Affected?
For people with normal hearing, soundwaves travel through the outer and middle ear into the inner ear and stimulate tiny hair cells called stereocilia. The stereocilia convert soundwaves into electrical energy that is transferred via the auditory nerve, across synapses, to the brain to be interpreted as meaningful sound.
Conductive hearing loss means there is a problem with the outer or middle ear that prevents soundwaves from making it to the inner ear. Sensorineural hearing loss means there is damage to the stereocilia, and soundwaves cannot be converted. Both these types of hearing loss are detectable using traditional hearing tests. Hidden hearing loss, however, is likely due to damage to the synapses, meaning the signal arrives to the brain incomplete.
What Causes Hidden Hearing Loss?
Noise exposure and the natural aging process are likely to blame for hidden hearing loss.
“Most researchers feel that long exposures to even low-level noise may cause hidden hearing loss and most agree that the aging auditory system reveals this problem. We lose some synapses as we age,” explained Dr. Catherine Palmer, Director of Audiology and Hearing Aids at the University of Pittsburgh Medical Center.
Diagnosing Hidden Hearing Loss
Hidden hearing loss is often misdiagnosed as ADHD (attention deficit hyperactivity disorder) or CAPD (central auditory processing disorder).
There are some experimental tools for detecting hidden hearing loss. One measures electrical signals from the surface of the ear canal to determine how well fluctuations in soundwaves are encoded. Another involves the participant wearing glasses that measure changes in pupil size while listening to speech in noise.
For more information about hidden hearing loss or to discuss options, contact the experts at Timpanogos Hearing & Balance.