Conductive Hearing Loss
There are three key types of hearing loss: sensorineural, conductive, and mixed. The conductive variety is quite common among children but can occur in people of all ages. Here, HearingTracker shares information about the causes, symptoms, and available treatment options.
First, a lesson in ear anatomy
To understand conductive hearing loss, it is first helpful to understand a little the structure of the ear. The ear is made up of three parts—the outer ear, the middle ear, and the inner ear.
The outer ear refers to the part of the ear you can see and the external auditory canal. The middle ear consists of the eardrum, the ossicles (middle ear bones), and the Eustachian tubes, which connect the middle ear with the back of the nose. The inner ear includes the cochlea (which contains the nerves for hearing) and the vestibular system (which contains balance receptors).
All three parts of the ear work together to pass sound waves from the outer ear, though the middle ear and into the inner ear. The auditory nerve sends signals to the brain, where they are translated into meaningful sound. When this flow is blocked, conductive hearing loss results.
What causes conductive hearing loss?
“A conductive hearing loss refers to a hearing loss that occurs at the outer ear or the middle ear, blocking sound from reaching the inner organ of hearing, also known as the cochlea,” said Sarah McAlexander, AuD, a Houston-based audiologist in an interview with HearingTracker. “In the case of a purely conductive hearing loss, the cochlea is functioning, but the sound is unable to reach it due to a malformation or blockage in the outer or middle ear.”
The diagram above depicts an active middle ear infection, also referred to as otitis media.
Conductive hearing loss can be both temporary or permanent, depending on the cause. Some of the most common include:
- Otitis media: Infection of the middle ear, often due to colds or allergies.
- Otitis externa: Infection in the ear canal commonly known as “swimmer’s ear.” This is often due to water exposure or infection in the ear canal.
- Impacted ear cerumen (earwax): Earwax can collect in the ear canal causing a blockage.
- Poor Eustachian tube function: The Eustachian tubes are responsible for draining fluid from the middle ear. If the tubes don’t work correctly, this fluid can stay trapped, causing a blockage.
- Eardrum collapse: Poor Eustachian tube function can lead to a severe imbalance of pressure in the middle ear. This can cause the eardrum to collapse onto the middle ear bones.
- A perforation (hole) in the eardrum: This may be due to trauma, infection, or severe Eustachian tube dysfunction.
- A foreign body stuck in the outer ear: This commonly occurs with young children who put an object such as a bead in their ears.
- Cholesteatoma: Skin or a small lump in the middle ear space, which can grow and cause damage to the tiny bones.
- Otosclerosis: An inherited disease that causes a stiffening of the bones in the middle ear. This disrupts the movement of soundwaves, hindering their journey from the middle ear to the inner ear.
Also worth mentioning, according to McAlexander: “Individuals who have frequent ear surgeries may also experience a conductive hearing loss. There are also some anatomical differences that can cause a conductive hearing loss; for instance, individuals who are born without an outer ear or ear canal (microtia/atresia) would likely have a conductive hearing loss.”
What are some common symptoms of conductive hearing loss?
Since the inner ear is intact, conductive hearing loss typically causes sounds to be less loud than usual, without the clarity being affected. This means that someone with conductive hearing loss can often hear without distortion, as long as the volume is loud enough. Phone calls can be quite challenging.
Sometimes, though, the individual may experience sounds coming through as if he or she is underwater, noted McAlexander. These issues may impact one or both ears.
Other symptoms will depend on the cause of the conductive hearing loss but may include:
- A feeling of pressure or pain in the ears
- Clear or yellow drainage coming from the ears
- An unpleasant odor coming from the ear canal
- Dizziness or problems with balance
What treatments are there for conductive hearing loss?
Fortunately, most cases of conductive hearing loss can be treated medically or surgically, bringing partial or total improvement.
“For ear infections, common treatments typically include antibiotics or pressure-equalizing tubes. For impacted ear wax, professional removal or eardrops to help break down the blockage can work. Additionally, “there are surgeries available for certain types of conductive hearing loss as well,” explained McAlexander.
For conductive hearing losses that cannot be resolved in these ways, hearing devices may help. These include traditional hearing aids or bone-anchored hearing devices. Bone-anchored devices (whether surgically implanted or not) work by sending sound directly to the cochlea, bypassing the malformation or blockage in the outer- or middle-ear space.
When to see a doctor
If you think you may have conductive hearing loss, make an appointment with an ENT specialist or audiologist. These professionals can determine your diagnosis and help you decide which treatment option may work best for you and your lifestyle.