What is Conductive Hearing Loss, Symptoms, Causes, Diagnosis
If you’ve recently noticed hearing problems, you’ve likely done some digging about the types of hearing loss. You might be overwhelmed by the terminology. It’s challenging to make sense of medical jargon and grasp the nuances of conductive and sensorineural hearing loss.
Don’t worry. This guide will break down all the essential facts about conductive hearing loss for you in plain language. Let’s take a look.
Conductive vs. Sensorineural Hearing Loss
Before we do a deep dive into conductive hearing loss, let’s briefly go over the two main types of hearing loss. Hearing impairment is broadly classified into two categories—conductive and sensorineural—based on where the hearing loss occurs.
- Conductive hearing loss is rooted in the outer or middle ear.
- Sensorineural hearing loss signifies a problem in the inner ear or the auditory nerve.
- Mixed hearing loss is when you experience both simultaneously.
Sensorineural hearing loss is primarily permanent and progressive, whereas the most common types of conductive hearing loss are reversible. To learn more, read our Hearing Loss Guide.
Why Is It Called ‘Conductive’ Hearing Loss?
We call hearing loss “conductive” when the conductive component of hearing is affected. In other words, this type of hearing loss involves the parts of the ear that transmit sound from the outside environment to the inner ear, where it’s converted to electrical signals and sent to the brain across the hearing nerve.
Conductive hearing loss occurs when sound can’t reach the inner ear because it is disrupted somewhere in the outer ear or middle ear.
Conductive hearing loss is when the sound gets lost on the first part of its journey, whereas sensorineural hearing loss happens at the final stop.
Understanding the Conductive Component
Your ears are complicated mechanisms. Since conductive hearing loss occurs in the outer or middle ear, familiarizing yourself with the various parts will help you better understand this condition.
- Auricle: Made out of skin and cartilage, the auricle is the part of the ear you can see. It acts as a funnel, capturing sound from the outside and channeling it into the ear canal.
- Ear Canal: The ear canal is a narrow passageway connecting the auricle and the tympanic membrane.
- Tympanic membrane: Commonly known as the “ear drum,” the tympanic membrane is a thin piece of tissue that separates the outer ear from the middle ear. It transfers sound vibrations from the air to the middle ear.
- Ossicles: The ossicles are the small bones of the middle ear. They include the malleus, incus, and stapes.
Conductive Hearing Loss Causes
Most of the most common causes of conductive hearing loss are not serious and can be reversed by simple medical treatments. However, some are caused by chronic conditions and may require surgery.
One of the most common causes of conductive hearing loss is an impaction of earwax in the external auditory canal.
Fluids and foreign bodies can also lodge in the ear canal, causing temporary hearing loss. This is more typical among small children, who put foreign objects like toys inside their ears.
Infections can cause conductive hearing loss, particularly infections of the outer and middle ear (otitis externa and otitis media). Ear infections trigger an immune response, promoting excess fluid buildup and inflammation in the ear canal and middle ear space.
This fluid can impede sound or potentially harm middle ear structures, causing hearing loss.
Chronic otitis media could permanently damage the middle ear. Sinus infections may also affect hearing by clogging the eustachian tube that connects the throat to the middle ear. When the eustachian tube is blocked, fluids can’t drain from the ear.
Ear Drum Rupture
Damage to the ear drum interferes with sound transmission to the inner ear. The ear drum is thin and fragile, so it’s susceptible to tears. Common causes of ear drum damage include:
- Puncture with a cotton swab or other foreign object
- Changes in pressure due to depth or altitude
- Recurrent otitis media infections
Genetic disorders can result in the malformation of the external ear, ear canal, and middle ear. Some examples include:
- Aural atresia: This is a condition where the external ear canal is not fully formed, affecting the ear’s ability to channel sound waves into the canal.
- Otosclerosis: This is a hardening of the middle ear bones. The bones become fixed and do not transmit the vibrations from the ear drum to the inner ear fluid.
Growths inside the external and middle ear can block sound or interfere with middle ear structures. These are generally noncancerous, but they can cause hearing loss if they grow unchecked.
- Cholesteatomas: These benign growths occur on or behind the ear drum preventing it from functioning normally.
- Acoustic neuroma: These tumors form gradually along the balance nerve or auditory nerve. They can cause conductive and sensorineural hearing loss depending on the affected area.
- Glomus tumors: These tumors develop at the base of the skull near the inner ear. If they grow large enough, they can affect both the inner ear and the middle ear, causing conductive, sensorineural or mixed hearing loss.
- Exostoses: People who spend a lot of time in cold water swimming can develop abnormal bone growths in the ear canal. This is also known as “surfer’s ear.”
Symptoms Of Conductive Hearing Loss
The symptoms of conductive hearing loss may vary depending on the cause, but here are a few.
You may have the following problems hearing:
- Difficulty understanding conversations
- Inability to distinguish between consonant sounds
- Friends and relatives tell you to talk softer or turn the volume of your devices down
- Speech and other sounds are muffled
- Trouble hearing soft sounds
Depending on the cause, you may show other related symptoms, such as:
- Dizziness and vertigo
- Ear pain
- Leakage of fluid from one ear or both
- Facial paralysis
- Fullness or pressure in the ears and sinuses
Diagnosing Conductive Hearing Loss
When you start to notice signs of hearing loss, your first step is to see a general practitioner or an ear, nose and throat doctor. The cause of conductive hearing loss is rarely a severe or chronic condition, so they’ll be able to treat you in most cases.
Seeing a Doctor
When you go to the doctor, they’ll typically go through a few standard diagnostic steps, including:
- A review of your medical history and medications
- A screening interview for underlying conditions
- A full physical examination
- An ear exam with an otoscope to check for obstruction and ear infection
- A basic hearing test
If your doctor can’t develop a diagnosis or wants more information about your condition, they will refer you to an audiologist or other specialists for more testing.
Conductive hearing loss is diagnosed by testing how well someone hears sounds transmitted through the air relative to those sent through the bones.
Using a tuning fork or a tone generator, the audiologist will send sounds through the outer ear and the bone to see which is easier to detect. They’ll chart the responses on an audiogram and compare the results.
People with normal hearing should be able to hear the sounds sent via air conduction than those that pass directly through the bone. If bone conduction is better, then they have conductive hearing loss.
Other tests include speech audiometry and impedance audiometry. The first measures how well you understand speech. The second checks your middle ear’s ability to transmit sound.
If a doctor suspects your hearing loss is caused by cholesteatomas or abnormal bone growth, they might order a CT scan. Magnetic imaging is also helpful for diagnosing some tumors.
However, these are uncommon causes, so your doctor will rule out more typical conditions before referring you for testing.
Most causes of conductive hearing loss can be treated medically, but the treatment depends on the underlying condition.
Treatment for many common types of conductive hearing loss includes medication and minimally invasive outpatient remedies, while others can be reversed through surgical procedures.
Removal of Obstruction
If your hearing loss is due to impacted earwax, at-home treatment is effective in most cases. You can purchase over-the-counter medicated drops to break up the wax and flush it out with warm waters. A doctor can handle a stubborn impaction with suction.
A medical professional must remove foreign bodies blocking the ear canal with the help of an otoscope.
Reconstruct the Tympanic Membrane
Minor scratches and punctures of the tympanic membrane will usually heal on their own within six weeks. If it doesn’t, you may require one or both of the following surgical procedures:
- Myringoplasty closes the hole in the ear drum
- Tympanoplasty reconstructs the tympanic membrane to deal with any scarring
If neuromas, glomus tumors, cholesteatomas and exostoses are causing significant hearing loss, you’ll need to have them removed surgically. A doctor generally recommends this surgery when the hearing loss is greater than 25 decibels.
Hearing loss caused by ear infections like otitis media and otitis externa is treated with antibiotic, antiviral and antifungal medications, depending on the infection. They may also drain the ears of excess fluid that has accumulated.
If your hearing loss is due to a problem with your middle ear bones, you have a few treatment options depending on the specific cause. Ossicles that have become disjointed due to trauma can be repaired through a surgery called ossiculoplasty.
In the case of otosclerosis, doctors will usually wait before starting treatment if the hearing loss is minor.
A surgery called stapedectomy is recommended if the hearing loss exceeds 20 decibels.
Hearing aids might also be an option. Though they won’t correct the fundamental problem, they can compensate by boosting the sound going into the middle ear.
Conductive hearing loss is typically reversible in most cases, but people with permanent hearing loss can get hearing aids.
A standard hearing aid is more appropriate for people with sensorineural hearing loss due to damage in the inner ear, but those with conductive hearing loss often need specialized hearing aid technology.
Bone-anchored hearing aids are surgically implanted in the bones, so the sound can bypass the damaged part of the middle or outer ear and directly stimulate the sensory parts of the inner ear.
Conductive hearing loss is one of the two main types of hearing loss. Now that you know how conductive hearing loss works and what causes it, you can distinguish it from sensorineural hearing loss. Knowing the type of hearing loss you have is the first step to treating and managing it.
Even though you might have a solid idea about your condition by now, you can’t diagnose yourself. Talk to your doctor before you get yourself fitted for a hearing aid. They can provide medical advice about your treatment options.
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