What is Hidden Hearing Loss?

We’ve all heard of hearing loss and its side effects. What about those people who technically score within “normal” range on their audiogram but still have trouble hearing in louder environments? Hidden hearing loss is a type of hearing loss that goes past the audiogram and into the ear.

Diagnosing Hidden Hearing Loss

When all test results come back within normal ranges, doctors can turn to the auditory brain response. In this test, results missing or showing a diminished wave I could signal a lower number of auditory nerves within the ear. In a recent animal study, mice were exposed to a moderate amount of loud noise. Results showed damaged auditory nerves; however the cochlear outer hair cells remained intact. Oftentimes, hearing loss is diagnosed by the damage of these outer hair cells, but hidden hearing loss is only seen in the damaged synapses. This makes the diagnosis more complex to understand and treat

Symptoms of Hidden Hearing Loss

Those with hidden hearing loss may not realize they are experiencing hearing loss at first. Researchers in Boston at the Massachusetts Eye And Ear Infirmary tested their theories on college-aged adults who regularly exposed themselves to loud sounds. What they found is that those who protected their ears against these loud noises actually had the same levels of hearing sensitivity as those who did not. However, the unprotected group reportedly had trouble hearing in loud environments. Each test subject was fitted with electrodes to measure their auditory nerve response. Those in the higher noise exposure group showed greater damage to their synapses, which causes this hidden form of hearing loss.

While one-on-one conversations in a quiet area hide the hearing loss, crowded settings with competing sounds reveal the issue. Traditional devices such as hearing aids and listening devices tend to be unhelpful for hidden hearing loss sufferers, as they only need aid in very specific situations and need amplification on certain sounds. A hearing aid is extremely helpful for standard hearing loss, but listening devices such as the Solo, that is only intended to be worn from time-to-time, is sufficient for those with hidden hearing loss.

Future for Hidden Hearing Loss

Be wary! Hidden hearing loss can easily lead to greater hearing loss with time and increased noise exposure. If left untreated, it can lead to permanent hearing problems such as tinnitus, ringing in the ear, or hyperacusis, over sensitivity to sound. Because of the hidden nature of this issue, many may not speak to their audiologist, and even after testing the audiologist may be left stumped. The lead researcher involved with the Massachusetts Eye And Ear Infirmary experiment, Dr. Stephane Maison, concluded that further research must be done on the inner ear to establish a reliable diagnosis method for hidden hearing loss. Once there is more information on the subject and a definitive diagnosis method set in place, scientists can work on methods to reverse or halt hidden hearing loss from becoming traditional hearing loss. Just as with the latter, reducing noise exposure and protecting your ears is always a good preventative measure.

By: Diana Michel