Hidden hearing loss is a general term for hearing loss that cannot be diagnosed by a standard hearing test. Cases of hidden hearing loss vary from person to person.
To date, there is no technology that can diagnose or detect hidden hearing loss. Those affected may feel frustrated at the idea of possibly suffering from a hearing disorder. Seeing a specialist only to be told that test results are normal can be particularly confusing.
Let's take a closer look at what hidden hearing loss is, and what you should do if you think you might be suffering from this rare disorder.
Understanding how the ear works
To fully understand hidden hearing loss, it helps to review how your ears work.
Our ears consist of three parts: the outer ear, the middle ear, and the inner ear. These three parts process the sound waves we encounter daily and transmit them to our sensory neurons, where the brain interprets these waves.
The outer ear
The outer ear is made up of the auricle, or pinna. This is the visible part of the ear, the one that is immediately identified as the structure of the human ear. This distinctive shape protects the ear canal.
The middle ear
Moving further into the ear, we find the tympanic membrane, more commonly known as the eardrum. This structure separates the outer ear from the middle ear. The tympanic cavity is an essential structure of the middle ear: it houses three ossicles, the malleus, incus, and stapes.
These three ossicles in the tympanic cavity are extremely important because they are tuned to react to sound waves passing through your eardrum. They play a transmission role: they capture frequencies and send them to the inner ear, before the neurosensory dimension of our hearing intervenes.
The inner ear
Two very important processes occur in the inner ear. Not only does the inner ear participate in hearing and sound processing, but it also plays a major role in our sense of balance.
The cochlea is a structure in the inner ear connected to the nerves involved in hearing. When sound travels through the outer ear, it makes the tympanic membrane (eardrum) vibrate before being transmitted to the middle ear.
These vibrations set the tympanic cavity in motion and specifically activate the malleus, incus, and stapes. The stapes transmits these vibrations to the inner ear, where the cochlea converts them into electrical impulses.
Types of hearing loss
Hearing loss, as we know it, corresponds to an abnormality in the anatomy and process of hearing described above. A person begins to experience hearing loss or impairment according to three types of hearing loss: conductive, sensorineural, or mixed.
Conductive hearing loss
People with conductive hearing loss experience an obstruction in the conduction of sound waves along the natural auditory pathway. This type of hearing loss has multiple causes: earwax buildup, injury leaving a foreign body in the outer ear, or an infection causing an obstruction.
While conductive hearing loss can lead to complications causing significant loss, it is often correctable and represents only a moderate inconvenience to your hearing.
Sensorineural hearing loss
Sensorineural hearing loss specifically affects the inner ear. It can be acquired or congenital. It affects structures like the cochlea, preventing your nervous system from receiving the information needed to correctly interpret sound waves.
Sensorineural hearing loss is often associated with moderate to severe loss, but it can also be mild and progressive.
Hidden hearing loss
Hearing loss is very common in the general population due to its many causes. Anyone can develop hearing loss, as well as hidden hearing loss. Whether it appears naturally with age, due to ordinary stimuli that wear down the organs of hearing over time, or as a result of chronic exposure to loud noises without adequate protection, hearing loss can occur.
Your general practitioner will first refer you to an ENT specialist, who will determine if your hearing loss is correctable or if it is due to a treatable medical condition. You will then consult an audiologist, a hearing specialist, who will perform various tests. These tests assess the extent of your hearing loss, its duration, and the type of loss you are experiencing. However, they cannot diagnose someone with hidden hearing loss.
How do you know if you have it?
The answer is disappointing: to date, there is still no test capable of measuring hidden hearing loss. It is strongly suspected that these disorders have a neurological origin, in the brain.
Doctors base this hypothesis on the observation that when a battery of hearing tests comes back normal, the problem lies beyond the organ of hearing itself.
If your auditory pathways are intact and functional, the problem may lie outside these direct pathways. However, research is actively being conducted to better understand what happens beyond the auditory pathways and to learn how to treat hidden hearing loss.
Symptoms of hidden hearing loss
Symptoms of hidden hearing loss vary from person to person. However, those affected may experience hearing loss phenomena in noisy environments.
For example, if a person has no trouble speaking to a single interlocutor in a crowded room but cannot catch a single word of what they are saying, this may be a sign of hidden hearing loss. It is believed that factors like noise pollution can trigger this disorder and that overstimulation by saturated background noise causes the loss of ability to hear specific elements.
Your ENT doctor may refer to this problem as a speech processing difficulty. Your audiologist can measure its extent by performing a speech discrimination test, during which words are presented to you to assess your degree of comprehension.
How to manage this disorder
What do you do when you suffer from a condition that cannot be diagnosed and whose symptoms do not manifest stably?
Make yourself heard
Our first piece of advice is to advocate for yourself. It can be very discouraging to pay for expensive hearing treatments and consultations only to be told that your hearing is normal.
If you know you are suffering from unexplained hearing loss, continue to demand care and medical opinions.
Develop an action plan
Next, we advise you to take the time to understand how this disorder specifically affects you, then to develop an action plan. If you find that certain environments make listening difficult, you can develop strategies to avoid these trigger situations.
If you notice that very noisy places cause an episode of unexplained hearing loss, avoid environments with high noise pollution.
Surround yourself with a supportive circle
For people with hidden hearing loss, the lack of a precise diagnosis and treatment is nothing new. If possible, take the time to inform those around you so that they can support you. Contact your company's human resources department and ensure they are also informed, to help you overcome the difficulties this disorder can create in your professional life.
Your ENT doctor and audiologist can suggest ways to improve your speech comprehension and your ability to recognize different sounds. Certain techniques, such as learning to pay attention to non-verbal cues, can provide enormous benefits.
CLARIA offers high-quality hearing aids that can help you hear better. If you want to learn more about hearing loss, we have a wide range of resources available.
“Hearing and balance are arguably our most complex and subtle senses, as many factors come into play beyond the structures of our ears.” - Drew Sutton, MD, board-certified otolaryngologist.
Sources:
Anatomy and Physiology of the Ear - Health Encyclopedia | University of Rochester Medical Center
What is hidden hearing loss? | Ohio State Medical Center
Why You May Have Sudden Hearing Loss In Noisy Settings | aarp.org
Hidden Hearing Loss | Houghear.org
Types of Hearing Loss | CDC
Hidden hearing loss | Hearit.org
