The ear is a strange and awe-inspiring thing. It is responsible for our sense of hearing, sure, but its parts and pieces are intricate and delicately balanced; any damage, illness, or ruptured communication between its parts results in the onset of hearing loss and other hearing-related issues. One such issue is conductive hearing loss, one of a group of 3 main types of loss: sensorineural hearing loss, conductive hearing loss, and mixed hearing loss. We will be taking a deep dive into the ins and outs of conductive hearing loss, including what causes it, what can be done about it, and what other hearing issues it may trigger or lead to. Before we do that, however, let’s take a closer look at the ear overall, and how exactly conductive hearing loss occurs within the structure of the ear.
An Introduction To The Anatomy Of The Ear
To fully understand conductive hearing loss, you must first become acquainted with the basic anatomy of the ear. The ear is divided into three different compartments: the outer ear, the middle ear, and the inner ear. Each of these parts has unique structures, and each structure plays an important role in the process of hearing. Any disturbances or damages to these structures can potentially lead to hearing loss like conductive hearing loss, and other issues, such as tinnitus and balance difficulties. The types and functions of the different ear compartments are:
- Outer Ear. This part consists of the pinna (outer ear), ear canal, and tympanic membrane (also known as the eardrum). This is one of the areas most prone to infection.
- Middle Ear. This part consists of the ossicles (the three smallest bones in the body!), the eardrum, the tensor tympani and stapedius muscles, and the Eustachian tubes. Along with the outer ear, this is another part of the ear that commonly experiences infection.
- Inner Ear: Also called the cochlea, the inner ear contains tiny hair cells (stereocilia), auditory nerve fibers, and the semicircular canals which control the vestibular system, essential for our body’s balance function.
Understanding how the inner ear, middle ear, and outer ear work can help lend insight into how conductive hearing loss impairs the ability of these structures to work together and effectively process sound. Now that we have covered the basics of the ears, including the external ear canal, let’s take a look at conductive hearing loss.
What Is Conductive Hearing Loss?
Conductive hearing loss is a condition wherein sound transmission through the outer and or middle ear is obstructed or dampened. Essentially, conductive hearing is impaired. This can be caused by issues with the external ear canal, or issues elsewhere in the ears, but unlike sensorineural hearing loss, it is not related to age related hearing loss, though it can cause mild hearing loss, moderate hearing loss, and severe hearing loss, depending on the nature of the obstruction or damage to the external and middle ear.
Sound is heard through the movement of air particles through sound pressure waves. Those waves then send vibrations down the ear to the eardrum, and through the middle ear–via the ossicles–to the inner ear where sound is processed within the cochlea and auditory nerve. If an obstruction in the outer ear or middle ear prohibits the movement of sound pressure, sound loses volume on its journey through the ear’s canal. By the time sound reaches the innermost portion of the auditory processing system, it is perceived at a much softer volume – a condition is called conductive hearing loss. Conductive hearing loss occurs with a host of issues and conditions, and understanding how the external ear is impairing hearing requires a careful evaluation of an individual’s medical history and an examination of the ears in question.
Common Causes Of Conductive Hearing Loss
Conductive hearing loss may seem simple enough – an obstruction impairs the hearing nerve in its task of receiving and processing sound. However, obstructions are not always as simple as an overabundance of wax or inflammation that causes swelling. Instead, conductive hearing loss can stem from a variety of issues, including:
Middle ear fluid (called “serous”)can accumulate in the middle ear due to colds or seasonal allergies. It is usually watery, and does not usually result in or from an infection. It can, however, cause aural fullness, ear popping, and general ear pain.
There are different types of ear infections, depending on the location within the ear. These types include:
- Otitis Media.
- This is characterized by abnormal fluid accumulation within the middle ear. In a healthy state, the middle ear is filled with air, rather than fluid. When upper respiratory infections, seasonal allergies, colds, the flu, and sinus infections are present, the eustachian tube does not function properly. Inflammation and swelling of the surrounding tissue can cause fluid to build up in the middle ear; because it is small, dark, and warm, it is the ideal breeding ground for bacteria and infection of this portion of the ear can occur. Infection severity differs from case to case, and are more common in children and infants due to the size, shape, and orientation of the eustachian tube in this particular population.
- Otitis Externa.
- Known as Swimmer’s Ear, infections of the external ear are frequently caused by unclean water left behind in the ear canal following swimming or other water activities, which can encourage bacterial growth. Inflammation of the canal can cause sound transmission to waver, particularly in severe cases, which can lead to conductive hearing loss.
- Eustachian Tube Dysfunction
- The eustachian tube connects the middle ear to the nose and throat, and ensures that it receives fresh air at a pressure level equal to the external environment. An infection causing fluid buildup is typically cleared via the eustachian tube. If it is malfunctioning, as is the case with eustachian tube dysfunction, fluid retention may increase, which can cause an infection and other hearing issues to develop and thrive.
- Perforated Eardrum
- An eardrum can be perforated as a result of trauma, repeated infections, and surgical procedures. A perforation does not allow the tympanic membrane to vibrate and transmit sound appropriately, effectively dampening sound transmission. The size of the perforation can also influence the degree of conductive hearing loss experienced, as a large perforation can mean that the ossicles have nothing on which to attach, further impairing sound transmission.
- Benign Tumors
- Tumors, including a glomus jugulare tumor, affect hearing not by attacking the ear as might be the case with a cancerous growth, but by simply obstructing sound waves attempting to pass through the outer ear or middle ear, leading to conductive hearing loss.
- Ear Canal Obstructions
- The two most common types of obstructions include:
- Ear wax. Everyone produces ear wax and it plays an important role in ear health, but it is is a common culprit for conductive hearing loss. When the canals are small (whether naturally that way or small as a result of infection or inflammation), or long-term cotton swab use has led to a build up of wax, a wax blockage can completely plug the ear canal and lead to conductive hearing loss. Ear wax is a lubricant, an antimicrobial, and helps prevent unwanted pests from entering the ear, and is best removed through a dedicated tool or simple wipe of the ear, versus an instrument being inserted within the canal. Common symptoms of ear wax blockages include reduced hearing, itchy ears, crackling sounds within the ears when jaws are moved, and a sensation of fullness.
- Foreign body (object). This conductive hearing loss cause is most often seen in younger children who have inserted something into their ear. Beads, beans, and popcorn kernels are all among the most common items found within the ear canal, but anything that blocks sound waves can lead to conductive hearing loss. That being said, it is possible to see this issue in adults, as well! Hearing aids can lose parts that become lodged in the ear (domes are the most common), cotton swab tips can break off, and earplugs can be lost or forgotten. All are common sources of foreign objects found in the ear and subsequent conductive hearing loss.
- The two most common types of obstructions include:
- Congenital Deformities in the Middle Ear
- Conditions like atresia and microtia, where the outer ear canal may be absent or notably small, are examples of congenital abnormalities that can lead to conductive hearing loss. These conditions are present when someone is born, and surgical intervention can alleviate the complications and hearing loss they incur.
- Otosclerosis is caused by a build up of spongy bone, which calcifies around the middle ear bones (specifically the stapes bone) stiffens, and remains immobile, effectively impeding the transmission of sound. This is another example of a conductive hearing loss cause that may be successfully addressed with surgery.
Treatment Options For Conductive Hearing Loss
Addressing and potentially repairing conductive hearing loss often requires a comprehensive approach, working with both an otolaryngologist (or ENT physician) and an audiologist, to accurately monitor hearing progress along the way. Treatment options may be medical or surgical, but may also rely on the use of hearing aids to remedy issues within the outer ear, middle ear, and inner ear. To determine the type of intervention needed, a hearing professional will administer a hearing test, while a healthcare professional will administer a physical evaluation, and further explore the root causes of hearing loss. Once these workups have been completed, your hearing healthcare team will likely move on to one of the following:
Medical Or Surgical Intervention
The specific cause of the conductive hearing loss dictates the suitable treatment. The most common causes and treatments have been identified below.
- Ear Infections: Typically treated with antibiotics or steroid therapies.
- Ear Wax Blockages: Often manually cleared using curettes or flushed out with water.
- Eardrum Perforations: A surgical procedure known as tympanoplasty is employed to patch the perforated eardrum.
- Otosclerosis: The surgical procedure, stapedectomy, involves the removal of the stapes bone and replacement with a prosthesis.
- Fluid Build-up from Colds or Allergies: This is commonly addressed with sinus rinses or allergy nasal sprays.
By consulting with an ENT physician, you are increasing your likelihood of finding the best treatment for conductive hearing loss–especially when that hearing loss is addressed using medical or surgical procedures. The issues identified above are not likely to improve without medical intervention and subsequent treatment, making it vital to speak with both a healthcare specialist like an otolaryngologist and a hearing health professional like an audiologist.
Hearing aids are a useful part of any treatment plan, because they are largely accessible to everyone, regardless of health status or personal convictions. Hearing aids offer an alternative to people for whom surgery is not an option, or for whom medical clearance to engage in surgical or medical intervention is unlikely due to other health concerns. Hearing aids are also a useful tool for those who experience residual hearing loss following surgical or medical intervention, as additional surgeries are not always recommended or available to address any remaining hearing impairment.
While many people think of hearing aids as a tool exclusively for those with sensorineural hearing loss–most frequently age related hearing loss–they can be useful for conductive and mixed hearing loss. They function by compensating for any damages to the outer and middle ear structure, amplifying soft sounds, minimizing background noise, and enhancing speech clarity.
Types Of Hearing Aids
There are three main types of hearing aids that can be used to treat conductive hearing loss. Each type is ideal for a specific patient population, based on the cause of conductive hearing loss, and the treatment preferences and additional issues such as tinnitus that the patient in question is experiencing.
Behind-The-Ear (BTE) Hearing Aids
Behind-the-ear hearing aids are among the most common types of hearing aid used for conductive hearing loss. BTE hearing aids provide flexibility in both ear canal coupling (or fit) and amplification power levels and ability. The style of BTE aids varies; some are molded to the ear canal via the ear piece from an open-fit dome, while others are developed with a fully occluded, custom-fit ear mold. BTE hearing aids themselves can be very small, tucked inconspicuously behind the ear, or very large to house more amplification power, for users with severe to profound hearing loss. BTE styles are often preferred by those who do not want the electric components of the hearing aid to be within the ear canal, should the canal become an actively draining ear–a concern common among people with chronic ear infections or a perforated eardrum.
In-The-Canal (ITC) Hearing Aids
In-the-canal hearing aids are more discreet than BTE options, as the entire hearing fits within the ear canal. That being said, these hearing aids are not appropriate for people with perforated ear drums, actively draining ears, or even a history of recurrent ear infection, as they block the entirety of the ear canal and do not allow for air flow and ventilation to the ear canal, further impairing healing. These styles are still able to pack a punch for amplification power, and can be used for severe hearing loss. Many people who opt out of surgery to address otosclerosis turn to ITC hearing aids and consider them a great option.
Bone Anchored Hearing Aids (BAHA)
A bone anchored hearing aid is among the most commonly used hearing aids for those with conductive hearing loss. BAHA are useful for conductive hearing loss because they can bypass disruption of sound in the outer and middle ear spaces by utilizing vibrations sent directly to cochlear hair cells. Essentially, a bone anchored hearing aid is able to replace the function of the middle ear. This type of hearing aid is frequently used for people with a congenital deformity of the ear, such as microtia or anotia, and is also commonly used for single-sided deafness or hearing loss. Bone anchored hearing aids have functions such as Bluetooth streaming and app controls, making them highly functional for the technology expectations of society today.
Treating Conductive Hearing Loss With Treble Health
Conductive hearing loss treatment varies from person to person, based on the health of middle ear structures, the health of the middle ear space, the need to address other concerns, like finding adequate tinnitus treatment, and even the response to the potential for ear surgery. Fortunately, unlike some other types of hearing loss, conductive loss is often able to be addressed and remedied, from removing a foreign body, to speaking with a hearing specialist to be fitted for hearing aids. If you are experiencing hearing problems, we encourage you to schedule a complimentary telehealth consultation with our team of audiologists. During this free, 20-minute Zoom call, you can talk to one of our audiologists about any symptoms that you are experiencing, ask any questions that you may have, and discuss next steps. This call comes with no obligations, and is an opportunity to start managing any symptoms of hearing loss. Schedule your call with our team now to discuss your treatment options, discover any potential underlying causes of your concern, and address that cause to remedy hearing loss, or support hearing health.