Are you having trouble hearing? Are you unsure why? Hearing loss can be caused by a number of factors. Let’s delve into some common causes of hearing loss.
First, it’s important to understand the basic anatomy of the ear. There are three major parts of the ear- the outer, middle, and inner ear (as shown in the figure below).
The outer ear contains the ear canal, which is connected to the eardrum. The middle ear contains the eardrum and middle ear bones. This portion of the ear is also connected to the nose and throat by a tube called the Eustachian Tube. The inner ear is where the hearing organ, called the cochlea, sits (along with part of our balance system). Sound travels through each part of the ear until it reaches the cochlea. The cochlea then sends the sound through a nerve, called the auditory nerve, to the brain. Then, the brain decodes the information to determine what is being heard.
When a person has trouble hearing, the issue could be occurring in any part of the ear, including the parts of the brain that are connected to the ear. When a person goes to an Ear, Nose, and Throat (ENT) physician and/or an audiologist, it’s the doctors’ job to determine where the issue is occurring.
Here are some common forms of hearing loss that occur due to problems with the outer ear:
- Earwax - if earwax or any other foreign object occludes the ear canal, it can block sound from getting through and will cause you to feel like your hearing is muffled.
- Solution: Earwax/foreign body removal can be completed at the doctor’s office. We do not recommend using Q-tips for removing earwax, as this can actually push the earwax farther into your ear. You also run the risk of damaging your eardrum when you can’t see what you are doing.
- Exostoses - AKA “Surfer’s ear” can occur when ears are exposed to cold water repeatedly. This constant exposure causes bony swelling in the ear canal, which looks like little “hills” of skin that begin to create a blockage in the ear canal. If the bony growths get too large, they can block sound from getting through.
- Solution: A surgical procedure can remove the bony growths and revise hearing.
- Outer ear infections - AKA “Swimmer’s ear” can occur when fungus or bacteria grows inside the ear. This often happens with swimmers that can’t/don’t get the water out of their ears after swimming, but can occur in non-swimmers, as well. If the infection progresses enough, it can cause muffled hearing, along with its other symptoms.
- Solution: Your ENT or primary care physician can prescribe medication to treat the infection.
- Eardrum rupture - The eardrum, which separates the outer and middle ear, can rupture. Eardrum ruptures can occur in the presence of air pressure changes (like flying on an airplane). Cold, sinus, and allergy issues can also be the cause of a ruptured eardrum when the Eustachian tube is not able to pressurize the ear properly. Eardrum ruptures can also occur from a foreign object in the ear (such as a Q-tip). Holes in the eardrum prevent it from doing its job in the hearing process, which often leads to a temporary hearing loss.
- Solution: Eardrums often heal on their own. However, your ENT may prescribe something to help with the pain and healing process when this occurs. If the eardrum does not heal on its own, your ENT may perform a surgical procedure to patch the hole.
- If the hole cannot be patched, a hearing aid can help you hear in that ear.
- Birth defects can also occur in which a person is born with a malformed outer ear.
- This can often be corrected by surgery.
Here are some common forms of hearing loss that occur due to problems with the middle ear:
- Otitis Media - AKA a middle ear infection occurs when fluid from the nose and throat area travels through the Eustachian tube and fills up the middle ear space. This fluid can be infectious or non-infectious, but will often cause a hearing loss either way as it fills up the space in the middle ear.
- Solution: Your primary care physician can often prescribe antibiotics and other medication to clear up the infection. However, if it persists, they will likely refer you to an ENT. If the infection does not clear up with use of medication, the ENT may suggest pressure equalization tubes (PE tubes) to drain the fluid out of your ears.
- Ossicular chain discontinuity - The bones in the middle portion of your ear are attached to each other. However, they can detach from each other in certain circumstances, such as a trauma to the head. When the bones become detached, they cannot do their job properly and lead to a hearing loss.
- Solution: Your ENT can sometimes perform a surgical procedure to reconstruct the bones. For some, the procedure restores their hearing. However, the procedure does not guarantee that hearing will be restored. Some patients continue to have hearing loss after the procedure.
- For those that continue to have hearing loss after the procedure, or prefer not to undergo surgery, a hearing aid can help you hear.
- Cholesteotoma - A cholesteotoma is a non-cancerous growth of tissue that can form in the middle ear space and block the components in the middle ear from sending sound to the inner ear.
- Solution: Your ENT can perform a surgical procedure to remove the growth. For some people, cholesteotomas may regrow over time and need future procedures to remove new growths.
- For some, the procedure restores the hearing. However, the procedure does not guarantee that hearing will be restored. Some patients continue to have hearing loss after the procedure.
- For those that continue to have hearing loss after the procedure, a hearing aid can help you hear.
- Birth defects can also occur in which a person is born with a malformed middle ear.
- This can sometimes be corrected by surgery, dependent on the extent of the malformation.
Here are some common forms of hearing loss that occur due to problems with the inner ear:
- Damage to the hearing organ - AKA sensory hearing loss, occurs when there is damage to the cochlea. The cochlea contains thousands of little hair cells that are stimulated by sound. These little hair cells will then send the sound to the brain through the auditory nerve. Damage to these hair cells, which prevent the sound from getting to the brain, can occur for several different reasons:
- Age-related hearing loss: over time, many people will begin to lose their hearing as the natural aging process takes its toll on the cochlea and hair cells begin to die off.
- Noise-exposure damage: If a person is exposed to damagingly loud sounds for too long, the pressure from those loud sounds can knock the hair cells over. With repeated exposure, the hair cells will die off completely.
- Birth defects: some people are born with a damaged hearing organ, causing them to be born with hearing loss.
- Physical trauma: traumatic head injuries can sometimes reach the cochlea and cause damage to the hearing organ.
- High fever
- Ototoxic medications: some medications (ex: cisplatin and other forms of chemotherapy) cause irreparable damage to the hearing organ.
- Some viruses and diseases
Hearing loss from damage to the hearing organ cannot be restored (at this time). If your hearing loss is due to damage to the hearing organ, hearing aids (or possibly a cochlear implant) can help you hear better in most cases.
Hearing loss can also have neural origins.
- Neural hearing loss can be caused by:
- Lesions - Lesions on the auditory nerve or near the hearing center of the brain can cause difficulty hearing and processing sound.
- Neuropathy - Auditory Neuropathy Spectrum Disorder (ANSD) refers to disorders in which the inner ear is often healthy and can successfully detect sound. Instead, it is the proper transmission of that sound from the inner ear to the brain that is unsuccessful.
- People with ANSD may show normal hearing on a hearing test, but struggle with understanding speech. Those who show hearing loss may appear to struggle with speech understanding more than the average person with a similar hearing test result.
- Certain diseases and syndromes can also cause neural hearing loss.
Hearing loss with neural origins often coincides with other symptoms aside from hearing loss alone. This type of hearing loss can only be diagnosed by a physician. Depending on the cause, neural hearing loss may be treatable, but may be permanent. Treatment options for neural hearing loss may include surgery, medication, rehabilitation therapy, hearing aids, or cochlear implants.