Hi guys. Cliff Olson,
Doctor of Audiology and founder of Applied Hearing Solutions in Phoenix,
Arizona, and in this video I'm talking about the common causes of hearing loss,
coming up.
There is something that 30 million people in the United States and 1.5 billion
people across the world have in common, and that is hearing loss.
There are lots of things that can cause hearing loss,
but each of these causes leads to only one of three different types of hearing
loss: sensorineural, conductive, and mixed hearing loss. Now,
I am not going to go into great detail about each of the three different types
of hearing loss,
but I will give you a basic understanding of each of the three so you can better
understand the different causes of them.
Sensorineural hearing loss occurs when there's damage inside of your inner ear
hearing organ, called the cochlea, your auditory nerve,
or your brain that processes sound. This is what sensorineural hearing loss
looks like on an audiogram.
When the X's and the O's fall below the normal range of hearing and the angle or
square brackets are in close proximity to them,
you have a sensorineural hearing loss.
This is by far the most common type of hearing loss worldwide.
Conductive hearing loss is when the hearing loss originates in either the outer
ear or the middle ear when the vibration of sound tries to pass through them
into the inner ear.
This is what a conductive hearing loss looks like on an audiogram.
When the X's and the O's fall below the normal range of hearing,
but the brackets fall within the normal range,
you have a conductive hearing loss. And a mixed hearing loss is, you guessed it,
a combination of sensorineural hearing loss and conductive hearing loss at the
same time. This is what you'll see for a mixed hearing loss on an audiogram.
When the X's and the O's fall below the normal range of hearing,
and the brackets also fall below the normal range of hearing,
but there is a gap between them, you have a mixed hearing loss.
If you would like a more detailed explanation of these three different types of
hearing loss,
I will have this video linked in the description for you to check out.
As for what causes each of these three different types of hearing loss,
there are a lot of them,
so let me go ahead and cover some of the more common causes.
When it comes to sensorineural hearing loss,
these common causes include genetics, age, noise exposure,
chemical exposure, head trauma, and in some cases even tumors.
Approximately 50 to 60% of all hearing losses in infants is due to
genetics,
and each one of these causes can potentially lead to one or all three of the
different types of hearing loss. For instance,
Pendred syndrome is the most common form of genetic sensorineural hearing
loss that is caused by a genetic mutation and a chromosome mutation.
This either causes a sensorineural hearing loss or even deafness at birth,
or it leads to a progressively declining sensorineural hearing loss as the child
gets older. Of course,
the most common cause of hearing loss is something that most people are very
familiar with, which is age, and it even has its own name, called presbycusis.
While you probably could call this cause of hearing loss genetic,
it does not have a clear pattern of inheritance. As we get older,
the outer and inner hair cells inside of your cochlea begin to deteriorate.
This often leads to the reduced perception of clarity when people are speaking
to you and difficulty hearing speech in background noise.
Approximately one in every three individuals in the United States between the
ages of 65 and 74 has presbycusis,
and that number goes up to 50% for individuals who are above the age of 75.
Noise exposure and chemical exposure also cause damage to the outer and
potentially even inner hair cells causing a reduction in hearing sensitivity as
well. Noise exposure from loud sounds such as gunfire or even working in a noisy
factory can cause damage to the outer hair cells between approximately 3,000
Hertz and 6,000 Hertz thanks to the human ear canal resonance.
Chemical exposure, often in the form of chemotherapeutic drugs,
typically damages these hair cells in the higher frequency ranges inside the
cochlea.
When it comes to head trauma like you might sustain in a vehicle accident,
you can actually damage the bone of the cochlea or the bone surrounding the
cochlea,
or you could even cause trauma to your brain causing a significant reduction in
your ability to hear and process sound.
Hearing loss caused by head trauma is actually more common than you may think.
However,
a cause of hearing loss that is not very common is a tumor growing on your
auditory nerve that will impede the flow of sound from your cochlea up to your
brain. Or other rare cases such as a sudden sensorineural hearing loss,
which is often thought to be caused by a viral attack or some other unknown
cause,
and this causes a significant amount of damage to the structures inside of your
cochlea. Sometimes it can be recovered and other times it can't.
The most common form of treatment for a sensorineural hearing loss is hearing
aids, cochlear implants, or sometimes even auditory brainstem implants. Alright,
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When it comes to the common causes of a conductive hearing loss,
we often think of things that will block the pathway of sound through the outer
ear or the middle ear,
but these conductive hearing losses can also be caused by genetics.
As for the things that can block the pathway of sound through your outer ear,
middle ear, and into your inner ear, you have earwax, fluid in the middle ear,
a ruptured eardrum,
a disarticulation or ossification of the three middle ear bones called
ossicles, or a genetic condition.
Probably the most common cause of a conductive hearing loss is earwax,
but earwax has to completely block off your ear canal for it to actually give
you a hearing loss.
Some estimates show that approximately one in every 10 children,
one in every 20 adults,
and one in every three seniors has excessive or impacted earwax.
Impacted earwax causes a 30 decibel reduction in hearing
sensitivity,
which is roughly equivalent to you wearing a really good earplug deep inside of
your ear canal. Fortunately,
having your impacted earwax removed by an audiologist can completely remove a
conductive hearing loss and get you hearing normally again.
If you happen to have fluid in your middle ear space behind your eardrum,
it can prevent the vibration of your eardrum and that can also cause a
conductive hearing loss. Unfortunately,
this cause of conductive hearing loss is a little bit more difficult to correct.
Sometimes this fluid will naturally drain through your eustachian tube into your
throat,
and other times you need medical intervention in the form of medications or
sometimes even a pressure equalization tube. Of course,
after this fluid issue is resolved,
the conductive hearing loss typically goes away.
If your conductive hearing loss is caused by a ruptured eardrum like you might
sustain from using a cotton swab too deep inside of your ear canal,
then this fix is not as easy.
For small holes, you may be able to have a surgical procedure called a
myringoplasty that will actually patch the hole, but if the hole is too big,
sometimes individuals have to go the rest of their life with a conductive
hearing loss. If you have a disarticulation,
otherwise known as a disconnection in the joints between the three middle ear
bones in your middle ear space,
then this can also cause a conductive hearing loss. On the other hand,
if you have an ossification of these three middle ear bones where they begin to
fuse together like you might see with otosclerosis,
this also causes a conductive hearing loss because the vibration of sound cannot
pass through those bones properly.
Both a disarticulation and ossification of these three middle ear bones
typically requires surgical intervention for the conductive hearing loss to go
away. Now,
there are some genetic causes of conductive hearing loss as well. One of these
causes is a condition known as atresia,
where an individual has a fully formed cochlea,
but they do not have an ear canal,
and this typically needs to be addressed with surgery to create an ear canal.
In some cases, these individuals may opt to go with a bone anchored hearing aid,
so the vibration of sound can actually pass through the skull into the cochlea
whether they have an ear canal or not. As you can see,
the causes of conductive hearing loss can often be addressed by medical
intervention. As far as the common causes of mixed hearing losses go,
you can use your imagination to combine a cause of sensorineural hearing loss
with a cause of conductive hearing loss. For instance,
if your age is causing a sensorineural hearing loss and you have an earwax
impaction causing a conductive hearing loss,
you my friend have a mixed hearing loss. However,
there are also other conditions that can cause a mixed hearing loss as well,
such as CHARGE syndrome.
CHARGE syndrome is a disorder that affects many different areas of the human
body, including the ear. It is actually an acronym that includes coloboma,
heart defects, atresia choanae, retardation of growth,
genital hypoplasia, and ear abnormalities. In some cases,
it can create a sensorineural hearing loss,
and in other cases it can create a mixed hearing loss.
Just like a conductive hearing loss, the conductive component of a mixed.
Loss often needs to be addressed by medical intervention,
but hearing aids or cochlear implants are often required to treat the remaining
sensorineural hearing loss. Overall,
when we consider all of the different things that can cause one of these three
different types of hearing loss, there are hundreds of them.
With some of these different causes of hearing loss,
time is of the essence and if you wait too long to treat it,
it could make it worse or it could even make it irreversible.
This is why it is so important to have a hearing care professional like an
audiologist test your hearing to identify the cause type and severity of
your hearing loss so they can get you pointed in the right direction for
treatment.