2 – Conductive Hearing Loss Causes

Types of Hearing Loss


A conductive hearing loss occurs when there is an obstruction or malformation in the outer ear (pinna, ear canal or tympanic membrane) or the middle ear. If hearing loss is present it is generally temporary, going away when the underlying condition is resolved. However, as with all conditions, one can see a variety of symptoms for each of these conditions. First and foremost medical treatment is needed, since in most instances that will cure the problem. Audiology might be a portion of the medical work-up, however, until a physician declares the underlying medical condition cannot be further treated, hearing aids will probably not be suggested by the audiologist.

Outer Ear

Although problems can happen on the pinna just as with any other part of the body that has skin, cartilage and blood vessels, most pinna conditions do not cause hearing loss. It is possible, however, that pinna disease may signal a systemic illness, which may lead to hearing loss.

The causes of pinna problems may be any of the following: congenital (genetic, structural), infection, trauma, inflammatory, autoimmune, cancer. Pinna problems are most often medical issues to be treated by a physician.

Some pinna problems that may signal audiologic issues are:

Outer ear malformations can be accompanied by ear drum and/or middle ear problems. Many outer ear malformations require surgical intervention and more severe, staged (bit by bit) reconstruction as needed. These individuals may benefit from such surgery but some type of hearing instrument may also be warranted, for example a bone anchored implant.

Earwax and Foreign Bodies

Earwax and foreign bodies cause temporary, conductive hearing loss only when they fully fill up or occlude the ear canal. Physicians can remove wax and foreign bodies; audiologists may remove wax but will refer to a physician for removal of any foreign body in the canal.

Trauma: Fracture of the Outer Ear

Trauma to the head can result in what is called a longitudinal temporal bone fracture, which is a temporal bone fracture that would be through the middle ear, eardrum and possibly in the bony portion of the ear canal. This type of injury usually can have some to a lot of hearing loss, which is primarily conductive. If there is cochlear-based hearing loss with a longitudinal fracture it is typically in the high pitches but may extend to lower pitches. Some type of amplification device is often indicated for a fracture of the outer ear.

Tympanic Membrane

This is an eardrum with the cone of light showing. This is a sign that the eardrum and system are normal.

A healthy eardrum and middle ear.

Eardrum Perforations

The eardrum is actually fairly tough and hard to puncture, but of course it can happen. Bobbie pins, Q-Tips and sticks, for example, can go from outside in. However, fluid build-up inside the middle ear can make the drum burst inside to outside. In many cases the drum will heal on its own. There are some conditions and injuries that make that less likely, for example, if the eardrum gets burned, it may not heal. Otolaryngologists can perform repair surgery on the drum, which the burned individual would want to have done to prevent infectious agents from entering the middle ear space.

With damage to the eardrum, you can usually see whitish, calcium-looking areas on the drums. The white areas are scar tissue and suggest the ears may have had ongoing problems with the drum bursting and healing several times before. Although that scar tissue, tympanosclerosis, may look ominous, most of the time does not cause hearing loss.

The presence of and amount of any hearing loss is based on where the hole is located and how large it is. Smaller holes and holes in the bottom portion of the eardrum often produce no hearing loss while larger holes and those in the top part tend to cause some hearing loss. When the perforation heals, the hearing loss generally goes away.

Middle Ear

Problems in the middle ear that can lead to hearing loss are:

The following are some medical conditions that can cause conductive hearing loss because the condition interferes with the proper functioning of the middle ear system.

Typical audiologic symptoms/findings in middle ear pathology can include the following, in any combination:

See graphics of the typical results of a conductive hearing loss caused by an outer or middle ear disorder.

There can be quite serious complications from untreated otitis media, although in today’s medical environments in the U.S., these do not occur often. Complications include:

Most adults don’t suffer from otitis media, however there are some individuals who do battle otitis media throughout life. For these people medical treatment often can control but not cure the otitis media. These folks may also need a hearing instrument, which may be either an acoustic hearing aid or a bone anchored implant.


Cholesteatoma is a growth that expands within the middle ear space and/or mastoid process that is made up of squamous epithelium mixed with keratin. Keratin is a protein that makes up a large portion of the skin. What happens is that a portion of the eardrum ‘falls into’ the middle ear space and starts to grow. More skin is grown on the eardrum and but encounters the ‘hole’ in the drum and drops in and adds to the growth in the middle ear. Meanwhile, the mucosal lining of the middle ear forms the ‘outside’ of the growth. Enzymes in this mucosal lining can erode the bones of the middle ear and other places that the growth comes into contact with. For example, the skull and brain are immediately above the middle ear space; if the growth erodes the ceiling of the middle ear, the cholesteatoma could invade the brain with serious consequences possible. Surgery is mandatory for cholesteatomas, but an amplification device may also be needed.

Discontinuity of the Ossicular Chain

This disorder refers to the situation in which the ossicles are no longer joined together. Most often the incus and stapes become unattached, although sometimes it is the incus and malleus. The causes of this disorder include congenital defects, trauma (e.g., temporal bone fracture, traumatic tympanic membrane perforation, barotrauma), or recurrent or ongoing middle ear disease (e.g., otitis media, cholesteatoma).

When there is complete disarticulation of the ossicles, the person will have the maximum conductive loss possible, about 60 dB HL, which is in the ‘moderate’ hearing loss range (daily conversation is about 55 dB HL the ossicles may rejoin by fibrous tissue or become fixed by new bony growth. If this happens sound transmission can suffer and we may see a conductive hearing loss. If the rejoining includes the malleus, it’s called malleus fixation. The primary treatment for disarticulated ossicles or malleus fixation is surgery. If hearing is not restored into the ‘normal range’ by the surgery, a hearing instrument and/or assistive device may be considered.


Otosclerosis is a condition in which the footplate of the stapes loses the ability to move, due to new bone growth. The individual will experience a progressive, conductive hearing loss. During some periods the bony growth seen in otosclerosis is gradual, however, heavy endocrine changes, for example during pregnancy, can increase the grow rate.

Although the etiology of otosclerosis is not fully understood, it is known that the etiology is at least partially genetic because about 40-50% of patients report a family history, and as of 2011, seven locations on various genes have been identified with the condition.

We know that otosclerosis occurs more commonly in European Americans than among Asians, African Americans and Native Americans. Otosclerosis also occurs more often in women than men and that women notice hearing loss about a decade earlier than men. People with otosclerosis may begin to have difficulty hearing from their 20s to their 40s. The condition is most often in both ears, though sometimes is found on only one side. It has been shown that having fluoride in the water supply decreases the incidence of otosclerosis. Surgery is one of the main medical treatments available for otosclerosis. Hearing aids and bone anchored implant hearing aids are also treatment choices.

Conductive Hearing Loss Treatments

People with conductive hearing loss often have a medically treatable condition and can benefit from seeing a physician before being treated by an audiologist. In fact, audiologists generally will not provide treatment to a person with a conductive hearing loss without ‘medical clearance’ from a physician.

Some individuals with conductive hearing loss do not benefit from or are not candidates for medical treatment. Because the main complaint of individuals with conductive hearing loss is that sounds are simply not loud enough, hearing aids and other types of assistive devices usually are quite successful in treatment this type of hearing loss.