Hidden Hearing Loss

I have heard a similar story throughout my adult life. People say that they have trouble hearing and understanding conversations in a crowded party or other noisy setting. But, when they have their hearing tested, the audiogram does not show hearing loss.

In 2009, a team of investigators at Massachusetts Eye and Ear uncovered a new type of inner ear damage–cochlear synaptopathy–that could explain these hearing complaints.  Cochlear synaptopathy is damage of the nerve cells that connect the inner ear to our brain, and is not identified by traditional hearing tests.  Because of this, the terms “hidden hearing loss” and “hidden hearing disorder” have begun to be used to describe cochlear synaptopathy.

Research is continuing to learn more about cochlear synaptopathy, its causes, and possible treatments.  At this time, it appears that some of the causes include extended exposure to background noise, any loud noise, aging, and certain medications. Some researchers suggest that a combination of these factors are often the culprits responsible for cochlear synaptopathy.  One unexpected cause recently discovered is sound deprivation or underuse of the ear.

It may be impossible to avoid all circumstances that might cause cochlear synaptopathy, but the following can be helpful in protecting the inner workings of our ears and the cellular links to our brain that translate sound waves into what we perceive as conversation, music, or whatever sound is being processed.

  • Wear proper hearing protection (earmuffs, earplugs) when in noisy environments such as: concerts, sporting events, hunting, firework displays, car races, etc. Hearing protection comes in a variety of sizes and textures to provide optimal fit. Custom-made earplugs can be obtained from an audiologist.
  • Set volume limits on your portable devices.
  • Walk away from loud sounds.

At this time, there is not a specific test for cochlear synaptopathy. However, the recommendation for anyone experiencing any sort of difficulties with their hearing—including tinnitus or ringing/buzzing in the ears—is to start with a comprehensive audiological evaluation. Although cochlear synaptopathy might be a culprit, it’s much more likely that a certain degree of traditionally understood hearing loss is in play and can be helped with traditional hearing amplification (hearing aids). At this time, it is estimated that around 5-10% of people with hearing loss may be experiencing cochlear synaptopathy.

The ability to hear is not simply a matter of convenience. Research has found that mild hearing loss doubles the risk of developing dementia, and severe hearing difficulties increase the chance of developing dementia by five times. Other health issues related to hearing loss include difficulty walking and an increased chance of falling. Research has suggested that hearing loss may contribute to an increased rate of atrophy in the brain.

Any difficulty with hearing should be discussed with your physician, and if at all possible, with an audiology specialist. Ongoing research is continually providing a better understanding of how to protect our hearing, the different ways that our ability to hear can be damaged, and how to deal with the damage if and when it occurs.