Conductive hearing loss is a type of hearing loss that occurs when sound waves are unable to pass through the outer or middle ear to reach the inner ear. In this case, the patient's inner ear functions normally, but it cannot transmit any sound waves to the brain for interpretation, because no sound reaches it from the outer and middle ear. Conductive hearing loss can be temporary or permanent, depending on its cause. In most cases, treating the cause of the hearing loss can restore normal hearing. There are two types of conductive hearing loss: unilateral conductive hearing loss and bilateral conductive hearing loss.
Unilateral Conductive Hearing Loss
Unilateral conductive hearing loss is a type of conductive hearing loss that affects only one ear. The patient has conductive hearing loss on one side while the other ear hears normally. Unilateral conductive hearing loss can be acquired or congenital. Microtia of one ear is an example of congenital unilateral conductive hearing loss. In this situation, one of the child's ears is perfectly formed while the other is malformed or deformed. The malformed ear is often non-functional and requires surgical correction. Unilateral conductive hearing loss can be difficult to detect due to the normal functioning of the other ear. The patient often manages to communicate, hear, and react to ambient noises without difficulty. In most cases, they begin to suspect a problem when they have to orient their good ear toward the source of a sound to hear it. The discreet nature of unilateral conductive hearing loss and the inability to diagnose it early often delay treatment. This is dangerous because the underlying cause has usually caused almost irreversible damage to the ears by the time treatment begins.
Bilateral Conductive Hearing Loss
Bilateral conductive hearing loss is a type of conductive hearing loss that affects both ears. It is also referred to as hearing loss in both ears.
Bilateral conductive hearing loss can be symmetrical or asymmetrical.
Symmetrical Bilateral Conductive Hearing Loss
Symmetrical bilateral conductive hearing loss occurs when the severity of symptoms is identical in both ears. This type of bilateral hearing loss has serious consequences for the hearing and communication of affected individuals. Communication is more difficult for them.
Asymmetrical Bilateral Conductive Hearing Loss
Asymmetrical bilateral conductive hearing loss occurs when both ears are affected but the degree of symptoms differs from one ear to the other. In this case, the hearing loss is more pronounced on one side than the other. Even if the second ear is also affected, the mildness of its symptoms allows the patient to rely on their "good" ear to hear.
Causes of Bilateral Conductive Hearing Loss
Several factors can cause bilateral conductive hearing loss. These causes are either congenital or acquired. Congenital causes are factors that lead to hearing loss before birth. Acquired causes are those that cause bilateral conductive hearing loss after birth. As we have already mentioned, the causes of bilateral conductive hearing loss are always located in the outer ear or the middle ear. The inner ear is not affected. Here are the most common causes of bilateral conductive hearing loss.
1. Earwax Impaction
Excessive accumulation of earwax in both ears can cause bilateral conductive hearing loss. When both ears produce earwax beyond the normal level, the body struggles to expel it. The excess earwax then accumulates, hardens, and forms a blockage in the ear canal. This blockage prevents sound transmission from the outer ear to the middle ear.
2. Swimmer's Ear
Swimmer's ear is also known as otitis externa. It is an infection of the external ear canal. The infection extends from the eardrum to the outside of the head. Swimmer's ear occurs when water remains in the ear after swimming. The presence of water creates a moist environment conducive to the development of bacteria or fungi. Symptoms of swimmer's ear include: redness of the ears, difficulty hearing on both sides, mild to severe pain in both ears, itching, and discharge of fluid or pus.
3. Cholesteatoma
This is an abnormal, non-cancerous skin growth that develops in the middle ear, behind the eardrum, as a result of repeated middle ear infections. A cholesteatoma begins as a sac or cyst that sheds layers of dead skin. Over time, these layers accumulate and the entire mass grows. As it grows, it compresses and destroys the fragile ossicles of the middle ear. This damage to the middle ear structures leads to hearing loss, balance disorders, and facial muscle dysfunction.
4. Eardrum Perforation
The eardrum, also called the tympanic membrane, is a thin membrane that separates the ear canal from the middle ear. A tear or rupture of the eardrum can cause bilateral conductive hearing loss. When it has a hole or a tear, it is said to be ruptured or perforated. An eardrum perforation can be caused by head trauma, the presence of foreign bodies in the ear, exposure to intense noise, rapid pressure changes, or a middle ear infection. Perforated eardrums often heal spontaneously, without treatment. But in some cases, surgical repair or the placement of a patch may be necessary to accelerate healing.
5. Other Causes
Other causes of bilateral conductive hearing loss include: otosclerosis, microtia, middle ear infections, Eustachian tube dysfunction, fluid accumulation in the middle ear, head trauma, serious illnesses, and viral infections.
Symptoms of Bilateral Conductive Hearing Loss
Bilateral conductive hearing loss can develop gradually or suddenly, depending on its cause. For example, sudden exposure to very loud sounds can cause sudden bilateral conductive hearing loss, while earwax impaction leads to progressive hearing loss. It is important to note that no two cases of bilateral conductive hearing loss are ever alike, even when the causes are identical. As we have seen, bilateral conductive hearing loss can be symmetrical or asymmetrical. This means that if patient A has symmetrical bilateral hearing loss, their symptoms will not be the same as patient B, who has asymmetrical bilateral hearing loss. Moreover, the repercussions of hearing loss are unique to each patient. No two people react to hearing loss in the same way. While some manage to adapt, others can develop serious emotional and psychological disorders. The symptoms of bilateral conductive hearing loss vary according to the underlying cause. In other words, the symptoms experienced depend on the origin of the hearing loss. If it is caused by an ear infection, the symptoms will differ from those of hearing loss due to eardrum perforation. Despite these differences, some general symptoms are common to people with bilateral hearing loss. These symptoms include:
1. Muffled Speech
With the exception of people with profound bilateral conductive hearing loss, most patients perceive sounds as muffled.
This results from poor sound conduction from the outer and middle ear to the inner ear.
2. Difficulty Hearing in Noisy Environments
Most patients with bilateral conductive hearing loss have difficulty hearing in noisy environments. They hear better during one-on-one conversations and in quiet places. This is mainly due to the ear's inability to distinguish speech from background noise.
3. Feeling of Blocked Ears
Bilateral conductive hearing loss caused by fluid in the ear and Eustachian tube dysfunction is often characterized by a feeling of fullness in both ears. This sensation may be more pronounced on one side, or of identical intensity on both sides.
4. Tinnitus
Tinnitus is the perception of a sound in the ear in the absence of any external sound source. Tinnitus is a common symptom in patients with bilateral conductive hearing loss. Several factors cause it. One of them is the absence of sound signals reaching the brain. Since no sound is transmitted to the inner ear from the outer and middle ear, the inner ear sends no sound signals to the brain. To compensate for this lack of signals, the brain creates its own sound. It is this sound that is perceived as tinnitus in the ear.
Degrees of Bilateral Conductive Hearing Loss
Sound is measured in decibels. The normal hearing range for adults extends from zero to twenty decibels. This low threshold allows people with normal hearing to perceive very faint sounds, such as human breathing, which is around 10 decibels. This is not the case for people with hearing loss. They only perceive sounds within a particular range, above the normal level. Bilateral conductive hearing loss is classified into four degrees. Hearing loss begins when a person is no longer able to hear sounds in the normal range. Here are the different degrees of hearing loss and their characteristic symptoms:
1. Mild Bilateral Conductive Hearing Loss
People with mild bilateral conductive hearing loss perceive some speech sounds but have difficulty hearing soft sounds. These include the sound of dripping water, shuffling feet, whispered conversations, bird song, or rustling leaves. They also struggle to hear sounds or speech at a distance, as well as low or high-pitched sounds.
People with mild bilateral conductive hearing loss can hear and hold a conversation in a quiet environment. The ideal setting for them is one-on-one. However, they encounter difficulties when the environment is noisy, when their interlocutor is at a distance or not facing them. In this case, they can hear the sound without being able to understand what is being said.
2. Moderate Bilateral Conductive Hearing Loss
A person with moderate bilateral conductive hearing loss has difficulty hearing faint voices and whispers. They also struggle to follow speech or conversations at a normal voice volume. In most cases, the interlocutor must speak louder than normal to be understood.
3. Severe Bilateral Conductive Hearing Loss
People with severe bilateral conductive hearing loss are unable to hear speech spoken at a normal volume. Words spoken at a normal voice level are reduced to whispers, and music is perceived only as a faint hum. If the hearing loss is not sudden, sounds first become muffled, then gradually fade. Details of conversations also become blurry. The patient then constantly asks for the volume to be turned up and for things to be repeated. In the long run, they may begin to withdraw from conversations and social activities, due to embarrassment at having to constantly ask for repetitions and fear of misunderstanding and giving inappropriate answers. In addition to difficulties hearing and understanding speech, severe hearing loss can be accompanied by other symptoms depending on the cause. These symptoms include pain in the affected ears, a feeling of blocked ears on both sides, dizziness, and tinnitus.
4. Profound Bilateral Conductive Hearing Loss
Profound bilateral conductive hearing loss occurs when a person cannot hear sounds below 90 decibels in both ears. In some cases, people with profound hearing loss hear absolutely nothing, regardless of the sound level. This is the most severe form of bilateral conductive hearing loss. Affected individuals communicate through reading and writing, sign language, or lip-reading. Patients with this type of hearing loss may benefit from wearing hearing aids. Hearing aids for profound bilateral conductive hearing loss are referred to as high-power or super-power. They are larger than conventional hearing aids and are worn behind the ear with a custom earmold.
Conclusion
Bilateral conductive hearing loss can be very challenging, as it affects both ears. It can significantly impact your daily life. It is therefore essential to consult a healthcare professional. If your emotional and psychological balance is affected, your doctor may prescribe psychological support. Have you ever suffered from hearing loss in both ears? What symptoms did you experience? What impact did it have on your life? Share your experience with us.
