Conductive hearing loss is a type of hearing loss caused by the inability of sound to pass through the outer or middle ear into the inner ear. The inner ear of people with conductive hearing loss works perfectly, but because no sound is being sent to it from the outer and middle ear, it results in hearing loss. This is because no sound signal is being sent from the inner ear to the brain for interpretation.
In a normal functioning ear, the outer ear receives sound from the environment and transmits it through the middle ear’s eardrum. The middle ear then transmits the sound to the inner ear from where it is sent to the brain. People with conductive hearing loss have this normal flow of sound interrupted in either the outer or middle ear.
In most conductive hearing loss cases, the problem is in either the outer ear or the middle ear. Cases of both outer and middle ear malfunctioning at the same time are not so common.
If the outer ear is damaged or the ear canal is blocked, the transmission of sound to the middle ear is difficult. Even though the middle ear is healthy enough to receive and transmit sounds, it cannot do that properly because no sound is being sent to it from the outer ear.
Conductive hearing loss can be unilateral or bilateral. Unilateral conductive hearing loss is conductive hearing loss that affects only one ear. If a person suffers conductive hearing loss in his two ears, it is referred to as bilateral conductive hearing loss.
Bilateral conductive hearing loss can also be symmetrical or asymmetrical. Symmetrical means that the severity of the symptoms in both ears is the same. Asymmetrical bilateral conductive hearing loss is characterized by more severe symptoms in one ear than the other.
Most people with conductive hearing loss have low-frequency hearing loss. This post will take you through all you need to know about low-frequency conductive hearing loss and possible treatments.
What is Low-frequency Conductive Hearing Loss?
Low-frequency conductive hearing loss, also known as reverse-slope hearing loss, is a rare form of hearing loss that occurs more in people with conductive hearing loss than those with other hearing loss types. It is known as reverse-slope hearing loss because of the shape it makes on the audiogram.
Low-frequency conductive hearing loss is defined as the inability to hear low-pitched sounds (sounds that occur in the frequency of 2,000 Hertz (Hz). People with low-frequency conductive hearing loss have difficulty hearing deep sounds like bass sounds in music, men's voices, and thunder. Vowel sounds spoken in low-pitch are also more difficult to hear than low-pitched consonant sounds.
Low-frequency conductive hearing loss is characterized by hearing the volume of speech. If the volume is amplified, the hearing loss patient will be able to hear low-pitched sounds better.
People with low-frequency conductive hearing loss can understand speech normally. They even tend to have excellent speech skills because they are more sensitive to high-frequency sounds.
The only difficulty they experience is with low-frequency sounds, and this is why most of them prefer face-to-face conversations.
Face-to-face conversations enable them to hear better. This is not the case if they are spoken to in crowded or noisy environments.
Low-frequency conductive hearing loss can range from mild to profound. People with mild low-frequency conductive hearing loss do not always know they have it.
It may go undetected for years or until diagnostic testing is done because of how subtle it is. This, however, is not the case for people with severe or profound cases of low-frequency conductive hearing loss. Their symptoms are more profound and easily detected.
Low-frequency Conductive Hearing Loss Symptoms
Just like every other form of hearing loss, low-frequency conductive hearing loss is characterized by certain symptoms.
These symptoms and their severity may vary from person to person because no two hearing loss cases are the same. If you have low-frequency conductive hearing loss, you may experience some or all of the symptoms below:
1. Difficulty Hearing Low-frequency Sounds
As the name implies, people with low-frequency conductive hearing loss are unable to hear low-pitched sounds. This is because the sounds are lower than 2,000 Hertz, which is the frequency that people with this type of hearing loss can't hear.
Examples of low-pitched sounds that low-frequency conductive hearing loss patients can't hear are; voices of men, the humming of a refrigerator, thunder, bass sounds in music, and trucks’ rumbling sound, cars and airplane motors, and vowel sounds.
This hearing loss is only restricted to low-frequency sounds because people with this form of hearing loss are uncannily good at hearing very high-pitched sounds that may be unnoticed by other people. They can easily hear high-pitched sounds like the voices of women and children.
2. Difficulty Following Group Conversations
People with low-frequency conductive hearing loss prefer one on one conversations to group conversations. They have difficulty following group conversations because they create more complex noise environments.
Group conversations involve a mix of different voice pitches and different people talking at the same time. This makes it difficult for the hearing loss patient to distinguish the voices around.
Also, due to the mix of different sound pitches, the high-pitched voices will be heard faster than the low-pitched ones. This may make the hearing loss patient miss out on important information being passed across.
This difficulty in keeping up with the conversation can make the hearing loss patient misunderstand what is being said, constantly ask for repetition, or amplify voice during the conversation. This can be embarrassing to the hearing loss patient, and in most cases, they choose to withdraw from or avoid group conversations.
3. Difficulty Hearing in Noisy Environments
Most people with low-frequency conductive hearing loss have difficulty hearing in noisy environments. Just like group conversations, noisy environments create a complex listening environment for the hearing loss patient.
They avoid engaging in conversations in noisy places or places with lots of background noise such as people speaking, background music, and noise from equipment like coffee machines, refrigerators, and cash registers.
Noisy environments like clubs, bars, coffee shops, and restaurants usually have a mix of different sound pitches. The hearing loss patient is more likely to pick the high-pitched sounds around than low-pitched sounds. If they are being spoken to by a person with a low-pitched voice, they may not be able to hear what is being said.
They have difficulty filtering out competing sounds and focus on following a conversation. To communicate effectively with them in noisy places, you may need to talk face-to-face with a loud voice. Calling them aside to a more quiet place for a one on one conversation is also really helpful.
4. Difficulty Hearing Phone Conversations
Telephone calls are one form of conversation that people with low-frequency conductive hearing loss find difficult to have. This is because most phone conversations (whether make or female voices) are delivered on low or middle frequencies.
The hearing loss patient may constantly ask for repetition or ask the person on the other end of the line to speak. The majority of the conversation is lost because the hearing loss patient can only hear bits and pieces of what is being said.
This is why most of them prefer one on one conversations to phone conversations. If one-on-one conversations are not possible, they may prefer to communicate via text messages.
Causes of Low-Frequency Conductive Hearing Loss
Low-frequency conductive hearing loss is often caused by problems in the outer or middle ear. Below are the two most common causes
Otosclerosis is the abnormal hardening of body tissue in the ear caused by bone remodeling the middle ear. Bone remodeling is a natural process that happens throughout life. It is a process in which bone tissue renews itself by replacing old tissues with new ones.
Otosclerosis occurs when there is an abnormal remodeling that disturbs the ability of sound to travel from the middle ear to the inner ear.
The bones of the ear affected by otosclerosis are the stapes.
The stapes vibrate when sound is sent to them, but otosclerosis causes the stapes to be stuck in one place, which prevents them from vibrating. The stapes' stiffness or lack of vibration makes it impossible for sound to travel through the middle ear to the inner ear; this results in conductive hearing loss.
The exact cause of the stapes’ stiffening is unknown, but some studies have suggested that it could be linked with immune disorder, previous measles infection, and stress fractures to the bony tissues around the ear.
Hearing loss caused by otosclerosis is often gradual and starts in one ear. Hearing loss often starts with the inability to hear low-pitched sounds. It is also accompanied by symptoms such as tinnitus or noise in the ear, dizziness, and loss of balance.
Otosclerosis can be treated with surgery and hearing aids. The surgical procedure, which is known as stapedectomy, entails inserting a prosthetic device into the middle ear to bypass the abnormal bone and create room for sound waves to pass through to the inner ear.
Hearing aids can also be used to amplify sound if the otosclerosis is mild. Currently, there is no medication for otosclerosis.
2. Secretory Otitis Media
Secretory otitis media is the fluid that accumulates behind the eardrum caused by an incomplete resolution of acute otitis media or the obstruction of the eustachian tube without an infection.
Secretory Otitis Media is more common in children aged three months to three years, and it is often caused by a blocked eustachian tube or a previous ear infection.
Secretory Otitis media is rarely accompanied by pain, but it can have other symptoms like feeling of pressure or fullness in the ear and low-frequency conductive hearing loss.
Even though the patient may not notice any pain, the eardrum or tympanic membrane often has an amber or grey color upon examination. Mild to severe retraction, displacement of the light reflex, and accentuated landmarks will be noticed. Air bubbles or an air-fluid level may also be visible through the tympanic membrane. The doctor can only see all these.
Most cases of Secretory Otitis Media resolve without any form of treatment. Hearing often returns to normal within two to three weeks.
If there is no improvement after about one to three months, there is a procedure that involves the insertion of a tympanoplasty tube into the middle ear.
The middle ear is ventilated three to four times a minute. This is to open up the eustachian tube and absorb oxygen into the middle ear mucous membrane’s vessels.
When the accumulated liquid has been gotten rid of, the eardrum can vibrate normally to allow the transmission of sound.
Low-frequency Conductive Hearing Loss Treatments
There is no one-size-fits-all treatment for low-frequency conductive hearing loss. In most cases, the hearing loss is resolved by treating the root cause of the problem.
If low-frequency conductive hearing loss is caused by otosclerosis, treating the otosclerosis through surgery can restore hearing to normal. The same is true for low-frequency conductive hearing loss caused by secretory otitis media. Secretory otitis media often disappears without treatment, and once this happens, hearing returns to normal.
If, however, the low-frequency loss appears to be irreversible, hearing aids will be prescribed. Hearing aids are the standard treatment for low-frequency conductive hearing loss that lingers for too long.
The hearing aids help to amplify low-pitched sounds while keeping high-pitched sounds at the normal sound level.
Hearing aids are medical devices and should only be fitted by an experienced audiologist. Because no two hearing loss cases are the same, all hearing aids are customized to fit your unique hearing needs.
Due to the complex nature of low-frequency conductive hearing loss and its rarity, the hearing aid’s fitting and programming may be done more than once before it fits the exact specification for your hearing loss.
Even though low-frequency conductive hearing loss is not as damaging as high-frequency hearing loss, it still has an impact on the life of the hearing loss patient.
This is why it is important to seek medical help. Due to the rare nature of low-frequency conductive hearing loss, only an audiologist will have the perfect solution for you.
Have you suffered a low-frequency conductive hearing loss? How did it affect your communication abilities?
Share your experiences with us in the comment section.