Conductive Hearing Loss Causes and Treatment

The Middle Ear Bones

The middle ear bones are extremely small. Fixation or malformation of these bones will result in a conductive hearing loss. Here, a stapes bone is shown next to a 10 cent Euro coin.
The middle ear bones are extremely small. Fixation or malformation of these bones will result in a conductive hearing loss. Here, a stapes bone is shown next to a 10 cent Euro coin. | Source

Types of Hearing Loss

There are several reasons a hearing loss may occur. The type of deafness depends on which area of the ear and/or auditory nerves are affected.

A conductive hearing loss occurs when the physical transmission of sound is impeded. The sound waves cannot get to the cochlea (and thus the auditory nerve), so sound is difficult to perceive. The cochlea (hearing organ) and auditory nerves are not damaged.

A sensorineural hearing loss occurs when the delicate hair cells of the cochlea are damaged or missing, causing a hearing loss that may range from mild to profound. This type of hearing loss is generally permanent, but may be treated with hearing aids or cochlear implants (dependent on the severity of the hearing loss).

A mixed hearing loss happens when a person has both a sensorineural and conductive hearing loss.

Auditory neuropathy spectrum disorder (ANSD) happens when the auditory nerve does not send synchronous signals to the brain. The physical transmission of sound and the cochlea are healthy, but the auditory nerve cannot effectively relay information to the brain.

Conductive Hearing Loss Audiogram

A typical audiogram for conductive hearing loss. The "x" & "o" show the hearing for the left and right ears when sound is presented through earphones. When the middle ear is bypassed, however, the hearing level demonstrates normal levels (brackets).
A typical audiogram for conductive hearing loss. The "x" & "o" show the hearing for the left and right ears when sound is presented through earphones. When the middle ear is bypassed, however, the hearing level demonstrates normal levels (brackets). | Source

What is a Conductive Hearing Loss?

When sound waves cannot be transmitted through the outer and middle ear space, a conductive hearing loss is diagnosed. Most causes of conductive hearing loss are treatable, but some people have a permanent condition and will require the use of hearing aids.

The ear is a very complicated sensory organ. Sound is first collected by the outer ear. The sound then travels down the ear canal, and causes the eardrum (tympanic membrane) to start vibrating. The three smallest bones in your body lie just behind the eardrum in an air-filled space– the incus, malleus, and stapes. These three bones conduct sound to the oval window of the cochlea. The cochlea is filled with fluid, so the sound must be coupled from transmission in air to transmission in fluid. The stapes bone directly connects with the oval window, where sounds are amplified more than twenty times what they were when they first struck the tympanic membrane.

A conductive hearing loss occurs when any part of the sound transmission process is interrupted. A problem with the outer ear, ear canal, eardrum, middle ear space, or the middle ear bones may cause a conductive hearing loss.

The actual hearing organ of the cochlea and the auditory nerves are completely unaffected in a purely conductive hearing loss.

Causes of Conductive Hearing Loss

Cause
What is It?
Treatment Options
Earwax
Cerumen, or ear wax, collects in the ear canal. This may block the transmission of sound.
Earwax removal.
Middle Ear Fluid
Fluid collects in the middle ear space as part of an acute or chronic middle ear infection. This is also known as "glue ear." Sound does not travel effeciently because the bones may not move freely.
Antibiotics and/or placement of ventilation tubes.
Microtia/Atresia
A small or missing external ear (microtia) and/or a small or missing external ear canal (atresia)
Surgery or the use of a bone conduction hearing aid.
Tympanic Dysfunction
A stiff, floppy, or perforated eardrum.
In severe cases, a tympanoplasty (eardrum replacement) may be performed.
Ossicular Dysfunction
The middle ear bones are malformed or stiff.
Surgery to replace the affected bones.
Otosclerosis
Mineralization of the stapes, which causes it to become fixed.
Surgery to replace or improve the function of the stapes bone, or hearing aids.
Cholesteatoma
A cyst-like growth of skin tissue which forms a mass behind the eardrum.
Surgery to remove the cholesteatoma and replacement of the damaged middle ear bones. Continued monitoring is necessary.

Conductive Hearing Loss Video Explanation

Conductive Hearing Loss Signs and Symptoms

The symptoms of a conductive hearing loss vary with the cause. If the cause is due to atresia, a very narrow (or occluded) ear canal may be observed. Heavy amounts of earwax may be seen with an otoscope in some cases of minor conductive hearing loss. Blood or fluid leaking from the ear may be seen with a tympanic membrane perforation.

Many times, however, there is no visible sign of hearing loss. The following may be encountered:

Ø Feeling as if one is hearing “underwater.” Speech sounds muffled.

Ø Difficulty with clarity: a person may be able to detect, but not understand, speech.

Ø Turning up the television or radio volume on a consistent basis.

Ø A child may not consistently turn to their name when called, particularly if the sound originates behind them.

Middle Ear Ventilation Tubes

Ventilation tubes, or grommets, may be placed in the eardrum to help children with glue ear. This procedure allows fluid to drain down the Eustachian tubes.
Ventilation tubes, or grommets, may be placed in the eardrum to help children with glue ear. This procedure allows fluid to drain down the Eustachian tubes. | Source

Treatments for Conductive Hearing Loss

Most forms of conductive hearing loss are curable through surgery or medication. If a foreign body or earwax is responsible for the problem, the obstruction is simply removed and hearing is restored to a normal state. Fluid in the middle ear (chronic otitis media) may be treated with antibiotics or with the insertion of middle ear ventilation tubes (pressure equalization tubes) to allow the fluid to drain. This generally restores hearing.

Sometimes, the middle ear bones are misshapen or missing, or a person has otosclerosis. In this case, surgery may be required to replace the middle ear bones with prostheses (see “ear surgery for hearing loss,” below).

Occasionally, conductive hearing loss may be a permanent condition and requires treatment with hearing aids.


The Baha (Bone Anchored) Hearing Aid

The implanted Baha offers excellent sound quality for those with conductive hearing losses.
The implanted Baha offers excellent sound quality for those with conductive hearing losses. | Source

Bone Anchored Hearing Aids

In some cases, the conductive hearing loss cannot be treated through surgery or medication. In this case, hearing aids will be required. For a purely conductive loss, bone anchored hearing aids offer the best sound clarity. These devices transmit sound through the the bones of the skull, avoiding the use of the middle ear. The sound is carried through the bones directly to the cochlea, where sound may be perceived in a clear, bright fashion. Bone anchored hearing aid systems (such as the Baha by Cochlear or the Ponto by Oticon) may be worn on a headband or may be directly implanted. The headband system is generally used by children too young for implantation. Adults may try a bone anchored system on a headband first, and decide if they would like the implant. A small fitting is implanted into the mastoid bone and the hearing aid snaps onto the fitting (once the area has healed).

Microtia and Atresia Picture

Microtia and Atresia has many different levels of severity. Surgery or bone anchored hearing aids are required to restore access to sound.
Microtia and Atresia has many different levels of severity. Surgery or bone anchored hearing aids are required to restore access to sound. | Source

Causes of Conductive Hearing Loss: A Poll

What is the cause of your (or your child's) conductive hearing loss?

See results without voting

Ear Surgery for Hearing Loss

The most common surgery for a conductive hearing loss is the placement of tympanostomy tubes (middle ear ventilation tubes or grommets). This short surgical procedure places tiny tubes into the eardrum, allowing fluid to drain into the Eustachian tubes. A hearing test should be performed after this procedure to verify hearing has returned to normal limits.

A stapedectomy is a procedure performed when the stapes bone is no longer able to move freely. A fixed stapes may be caused by otosclerosis or by a congenital malformation of the bone. The stapes bone is removed and a small prosthetic is placed. There is a small risk (1%) of deafness occurring from this procedure, so typically only one ear is operated on at a time.

A stapedotomy is a similar procedure to a stapedectomy, except the stapes is not removed. A tiny hole is drilled into the fixed stapes and a prosthetic that acts like a piston is surgically attached. 90% of patients will have improved hearing after this procedure. Stapedotomy is safer than stapedectomy, as the risk of leaking fluid from the cochlea (perilymph fistula) is greatly reduced.

Ossiculoplasty is the replacement of malfunctioning middle ear bones with titanium prostheses.

Mastoidectomy is performed for patients with cholesteatoma. The entire cholesteatoma must be removed and a “safe ear” created. The middle ear may be reconstructed with the use of prosthetic middle ear bones or a bone anchored hearing aid may be required to restore hearing to the damaged ear.

Microtia surgery is generally required for children who have microtia and atresia. Children with small or missing external ears often have a small or obstructed ear canal and may also have problems with the middle ear bones. A severe conductive hearing loss (40-60dB) may result. Plastic surgery is used to create an external ear and atresia surgery creates or widens the ear canal. Ossiculoplasty may be required to replace the middle ear bones. A bone anchored hearing aid may be used until surgery can be performed. In cases where surgery is not advised, a bone anchored hearing aid may be the treatment of choice.

Hearing With a Bone Anchored Hearing Aid

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Comments 10 comments

meloncauli profile image

meloncauli 4 years ago from UK

Very interesting hub with lots of useful information. My husbad has the baha device and though it works well on the whole, background noises and things like high winds force a noise feedback from the device.


leahlefler profile image

leahlefler 4 years ago from Western New York Author

Wind noise and background noise are problems for every hearing aid user - it can be really tough to hear in those situations! My own son has a mixed hearing loss, though there was a period of time when we thought there was a more significant conductive component and we considered the Baha. He uses air-conduction aids and those are working well for him now. Thanks for the comment, meloncauli!


CassyLu1981 profile image

CassyLu1981 4 years ago from Spring Lake, NC

wow, excellent hub with great information! My husband is mostly deaf in one ear but his is due to deployments and all that comes with those. I couldn't imaging having a baby that doesn't hear well. Great hub! Voted up and shared :)


leahlefler profile image

leahlefler 4 years ago from Western New York Author

Your husband probably has noise induced hearing loss, CassyLu - I hope the hearing in his other ear is safe! We are fortunate that our son's hearing loss was detected early, so we are able to monitor it (it is progressive). Many children struggle with fluctuating, conductive hearing loss or have a more permanent form of conductive loss, so it is an important thing for parents to be aware of.


Deborah Brooks profile image

Deborah Brooks 4 years ago from Brownsville,TX

wow great inflammation here.. You sound like a doctor.. you have done your home work.. so far we have not had this problem but you never know.. great job.. sharing

Debbie


leahlefler profile image

leahlefler 4 years ago from Western New York Author

Deborah, our son has a permanent congenital loss with a conductive component, so we're very familiar with the causes of both sensorineural and conductive hearing losses. Unfortunately, we can't identify a cause of the conductive component in my son's hearing loss, as his middle ear bones appear normal and he has no fluid (he has working middle ear tubes) - so it is a permanent component to his hearing loss!


lindacee profile image

lindacee 4 years ago from Southern Arizona

Great info about conductive hearing loss. I always learn so much from your Hubs. Thank you for sharing, Leah! Voted up useful and interesting.


leahlefler profile image

leahlefler 4 years ago from Western New York Author

Thanks, lindacee. A lot of people think of conductive hearing loss as a temporary problem or just "fluid in the ears." While those problems are significant and need to be addressed, there are also a lot of people who have permanent conductive hearing losses and require hearing aids to hear clearly!


teaches12345 profile image

teaches12345 4 years ago

You have certainly posted a lot of very helpful information on hearing. Your chart is one that I found quite useful, amazing how many different types of hearing loss causes are out there. Voted up and useful.


leahlefler profile image

leahlefler 4 years ago from Western New York Author

There are a lot of different types of hearing loss, teaches. Some people have a permanent form of hearing loss caused by damage to the hair cells in the cochlea - others have a temporary conductive loss caused by fluid. Still others have a permanent form of conductive loss, or a mixed loss consisting of both components!

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