Conductive hearing loss is caused by a problem in the outer or middle ear that prevents sound from getting to the inner ear.
Sound from the environment passes through the outer ear to the middle ear, from where it is transmitted to the inner ear. From the inner ear, the sound is sent to the brain for interpretation.
When a person has conductive hearing loss, this normal hearing process is interrupted. If the problem is from the outer ear, sound from the environment cannot get into the ear. If a problem causes hearing loss in the middle ear, external noise may be received by the outer ear, but the sound is blocked in the middle ear and prevented from getting to the inner ear.
Even though the inner ear is perfectly functioning, the lack of sound input from the outer or middle ear makes it unable to send signals to the brain.
Conductive hearing loss can be bilateral or unilateral. Bilateral conductive hearing loss is hearing loss that affects both ears.
Bilateral hearing loss can be symmetrical or asymmetrical.
Symmetrical bilateral hearing loss is a type of hearing loss where the symptoms of the hearing loss in both ears are the same. A person is said to have asymmetrical bilateral conductive hearing loss if the hearing loss symptoms are severe in one ear than the other.
What is Unilateral Conductive Hearing Loss?
Unilateral conductive hearing loss is hearing loss that affects one ear. In this case, hearing is within normal limits in one ear, but the other ear is affected. Unilateral conductive hearing loss is also referred to as one-sided hearing loss.
People with unilateral conductive hearing loss have one "good" ear (the unaffected ear), and they heavily depend on this ear for hearing. The affected ear may have reduced hearing ability or complete inability to hear out of the affected ear.
Unilateral conductive hearing loss can be mild, severe, or profound. Severe or profound unilateral conductive hearing loss is known as single-sided deafness.
People with unilateral conductive hearing loss have difficulty determining the direction of the sound and often struggle to separate background noise from speech.
Symptoms of Unilateral Conductive Hearing Loss
The symptoms of unilateral conductive hearing loss are often felt in the affected ear. Hearing in the unaffected ear is usually normal. Common symptoms of unilateral conductive hearing loss are:
1. Difficulty Localizing Sound
Most people with unilateral conductive hearing loss have difficulty localizing or identifying where a sound is coming from.
The localization of sounds plays a crucial role in our survival in urban environments. This is because, to a large extent, responding effectively to the environment and other people around is key to survival.
In certain dangerous situations, you need to identify the exact direction a noise is coming from to avoid the danger. Examples of such cases are; an approaching car, an object falling, a building collapsing, animal noise, and gunshot noise. The new electric cars pose new problems those with hearing loss because it may be difficult or impossible to hear a car coming from a particular direction.
Asides from the fact that localization of sounds helps you identify and avoid the direction of danger, it is also necessary for conversations. When a person calls you, your ability to respond to the call quickly is determined by how quickly you can locate the person. If you are looking for something or someone, the sound you hear will help you find the person easily.
2. Difficulty Understanding Group Conversations
Due to the inability to localize sounds, people with unilateral conductive hearing loss find it difficult to understand group conversations.
In group conversations, people take turns to talk, and for a person with unilateral hearing loss, this can be a problem. This is because when the conversation switches from one person to another, the hearing loss patient needs to locate the new speaker.
If the new speaker is not located instantly, they may miss out on the first part of each speaker's contribution to the conversation. This can reduce the hearing loss patient's understanding of what is being said.
In most cases, the hearing loss patient may complain that he has difficulty hearing in meetings. But the actual complaint should be that he has difficulty at meetings because he misses things when trying to locate who is talking.
3. Difficulty Understanding Speech in Background Noise
Background noise is an ambient noise that is not the specific sound you are paying attention to.
A common problem that conductive hearing loss patients have to deal with is the difficulty of understanding speech in background noise.
Even when speech is amplified to increase audibility, this problem is still encountered.
Most hearing loss patients can't communicate effectively if background noise is present because the background noise interferes with the sound they are trying to focus on, making them mishear and misunderstand what is being said.
4. Difficulty Hearing with the Affected Ear
Unilateral conductive hearing loss affects one ear. Hearing in the affected ear may be muffled or non-existent, depending on the severity of the hearing loss.
People with unilateral conductive hearing loss have to turn the unaffected ear toward the direction of a sound to be able to hear well.
If you engage a conductive hearing loss patient in a conversation, you may see him change his position before responding. This change in position is aimed at positioning his good ear in the direction of your voice for clarity.
Causes of Unilateral Conductive Hearing Loss
As already stated, unilateral conductive hearing loss is caused by a problem in either the outer ear or the middle ear. Possible causes of unilateral conductive hearing loss are examined below.
1. Ear Infection
An ear infection occurs when there is an accumulation of fluid in the middle ear. The buildup of fluid is caused by the swelling of blockage of the eustachian tubes.
Eustachian tubes are small tubes that run from each ear to the back of the throat. They are responsible for draining out fluid from the middle ear. When the eustachian tube of one or the ears cannot drain fluid out, an ear infection can occur.
The blockage or swelling of the eustachian tube can be caused by excess mucus, sinus infection, colds, and allergies.
Children are more prone to ear infections than adults because they are more susceptible to eustachian tube dysfunction.
The eustachian tubes of children are shorter and narrower than that of adults, making the draining of fluid out of the middle ear slower. Bottle feeding and the use of pacifiers also increase the risks of middle ear infection in children.
This notwithstanding, adults who are exposed to cigarette smoke, climate change, and altitude change are also prone to ear infections.
Asides from the conductive hearing loss which occurs in the infected ear, the hearing loss patient, may experience other symptoms.
These symptoms include a feeling of pressure in the affected ear, fussiness in infants, discomfort in the affected ear, and pus-like discharge from the affected ear.
2. Earwax Buildup
Earwax buildup is a common cause of conductive hearing loss in one ear.
The ear canal produces a waxy oil known as cerumen or earwax. This wax protects the ear canal from being exposed to microorganisms, foreign particles, and water that can cause infection.
Under normal circumstances, the earwax often drains out naturally from the ear canal into the ear opening. But in some cases, the ear can begin to produce more earwax than it can get rid of.
With time, this excess earwax accumulates and solidifies. Attempting to clean the ear with cotton buds may push the accumulated wax further into the ear canal and cause a blockage.
The earwax blockage in the ear canal prevents sound from passing through to the middle ear, resulting in hearing loss.
If the earwax accumulation happens in just one ear, unilateral conductive hearing loss occurs.
Other unilateral conductive hearing loss symptoms caused by earwax buildup include severe pain in the affected ear, a feeling of fullness in the affected ear, and tinnitus.
If the earwax is not quickly removed, it can cause ear infection and have more severe symptoms like drainage or fluid from the affected ear, dizziness, an odor coming from the affected ear, and fever.
3. Eardrum Rupture
An eardrum rupture is also known as a perforated eardrum. It is a small hole or a tear in the eardrum.
The eardrum is a thin membrane located between the outer ear canal and the middle ear.
The eardrum vibrates when sound waves enter the ear. This vibration is an important aspect of hearing, and if it is not present, the sound will not be transmitted to the middle ear from where it is sent to the inner ear.
When there is a tear or a hole in the eardrum, it can no longer vibrate when sound waves reach it, which causes hearing loss.
The tear or hole in the eardrum can be caused by the following:
When the pressure outside the ear is different from the pressure in the ear, it can tear the eardrum. This is referred to as barotrauma. Activities like direct, forceful impact to the ear, scuba diving, shock waves, driving at high altitudes, and flying in airplanes can cause barotrauma.
Ear infections that cause fluid to accumulate behind the eardrum can make the eardrum rupture. The rupture is caused by the pressure from the accumulated fluid on the eardrum.
Injury or Trauma
Any trauma or injury to the ear or the side of the head can cause the eardrum to rupture. The trauma can be caused by a blow to the head, falling on the ear, inserting objects into the ear, car accidents, etc.
Acoustic trauma is damage done to the eardrum caused by exposure to loud noise. Any form of exposure to loud noise, whether sudden or extended, should be avoided because apart from damaging the eardrum, the hair cells in the inner ear can also be damaged.
Unilateral conductive hearing loss caused by eardrum rupture is often temporary. In most cases, the year or hole will heal naturally within a few weeks.
A ruptured eardrum is accompanied by symptoms like bloody, watery, or pus-like drainage from the affected ear and pain.
4. Outer Ear Infection
An outer ear infection, also known as otitis externa, is an infection of the ear canal and the outer opening of the ear.
A common type of outer ear infection is the swimmer's ear. It is called the swimmer's ear because it is caused by exposure to moisture and prevalent in swimmers.
When you swim or bathe, water gets into the ear. When this water is left in the ear canal, it can create a conducive atmosphere for bacteria to breed.
Apart from the presence of moisture in the ear, an outer ear infection can be caused by damage or injury to the thin layer of skin that lines the ear canal.
The use of headphones, cotton swabs, and constant scratching can range this thin skin. The damaged or inflamed skin can become a breeding ground for bacteria. Skin irritation and eczema can also cause outer ear infections.
Asides from the general symptoms of unilateral conductive hearing loss, people whose hearing loss is caused by an outer ear infection will experience symptoms like swelling and redness of the ear.
Other symptoms include pain or discomfort in the affected ear, excessive fluid drainage, muffled hearing in the affected ear, itching, heat, and discharge of pus.
Microtia is a congenital deformity of the external ear. Children born with microtia have an underdeveloped pinna or outer ear. Microtia is a common cause of congenital unilateral conductive hearing loss.
Microtia usually occurs during the first trimester of pregnancy when the baby’s ear in the womb is developing.
Even though the exact cause is unknown, it has been linked with the use of drugs or alcohol during pregnancy, consumption of a diet low in carbohydrates and folic acid during pregnancy, and the use of acne medication during pregnancy.
Due to the underdevelopment of the affected ear and the severity of the deformity, total hearing loss may be experienced.
Anotia, which means "no ear," is a rare cause of unilateral conductive hearing loss. It is a congenital deformity that is characterized by the absence of the pinna and the narrowing or absence of the ear canal. Anotia is often regarded as a severe form of Microtia.
Just like microtia, the exact cause of anotia is not known. But it occurs during the first few weeks of pregnancy.
The standard treatment for anotia is total ear reconstruction. A team of multidisciplinary specialists often carries out this procedure. The team consists of a plastic surgeon, a speech pathologist, and an otolaryngologist.
Most cases of unilateral conductive hearing loss discussed above are not permanent. This means that hearing can be restored to normal if the underlying cause is treated.
Apart from microtia and anotia, no surgical procedure may be required to treat any of the above causes of unilateral conductive hearing loss.
Some may require some form of medical intervention, while others like eustachian tube dysfunction and ruptured eardrum can heal naturally.
If you have difficulty hearing with one ear, we advise that you see a doctor. Don't try DIY treatments without your doctor's consent. In a bid to solve the hearing loss problem, you may worsen it, so it's best you do everything with your doctor's consent and supervision.
Have you suffered a unilateral conductive hearing loss? What symptoms did you experience?
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