Hidden Hearing Loss

It is not uncommon for a hearing center to see a patient complaining of difficulty hearing despite having normal test results. The man who cannot hear in a crowd may hear perfectly well in quiet. A couple complains of poor communication if one walks to an adjacent room. An older woman with a modest loss reports severe difficulty understanding speech.  Is there hidden hearing loss? What can cause this? Can it be helped?

We use the term “hidden hearing loss” for patients whose audiometric evaluation turns up normal hearing, despite complaints. Or severe difficulty is seen with only a mild loss. The condition is “hidden” when we cannot identify the impairment by traditional audiometric testing.

Typical hearing loss caused by aging or noise exposure causes the ears to become insensitive to certain sounds. We see familiar patterns among patients. Mr. Smith can hear certain sounds very softly, however, he doesn’t hear high pitches until they are very loud. This loss is not hidden. It is a deficit that is noticeable to all. Background noise becomes a major problem. The cause is typically damage to the inner ear.

Research has found that sound deprivation, untreated ear infections, noise exposure and toxins, such as chemotherapy, damage the nerve fibers connecting the ears to the brain. This interferes with the brain’s ability to decode the sounds the ears detect. Toxins may act on the inner ear as well as the nerve cells.  Researchers have found similar damage in brain regions responsible for creating new memories.

Patients can improve on this hidden hearing loss with technology, particularly if some loss of hearing is detected in an audiogram. Modern hearing instruments use technology such as directional microphones and remote microphones. These tools minimize the effects of background noise and emphasize speech.  We also recommend protecting the ears from further damage. The first step is a thorough diagnostic exam. We’re here for you. We want to keep you on a clear path to good hearing and ear health.