Hearing Loss

First signs of hearing loss

I guess you feel that something in your hearing is different lately. You may be thinking that it comes with age. You manage to get along on most situations. You do feel that it’s harder to follow the youngsters on family events. The host on TV also doesn’t seem to speak clearly lately. But since you hear her, you assume she is not speaking clearly.




It might be that she doesn’t speak clearly, but you might be suffering some hearing loss typical to your age...

Some numbers:

  • One on five people above 45 and one of three above 65 got some level of hearing loss.
  • 11% of US population got hearing loss (about 35 million people)
  • Only 28% of people with hearing problems use hearing aids

So, where are all these people?? How come you don’t see hearing aids as one should expect from the numbers above?

It starts with hearing impairment (and not hearing loss)

Well, to begin with, you don’t just wake up one day without hearing a thing. It takes time, the hearing loss comes gradually. In addition, on most cases you start facing problems in hearing on certain situations. It can be where there is a background noise, or on the phone, for instance. But generally speaking, in the beginning, you function perfectly well. You can have fluent conversations, you can hear the TV, no real issue.

Hearing impairment is not hearing loss. With hearing impairment, certain scenarios can be harder than others. You might miss, for instance, high voices (mostly women and kids). Typically, you might feel that you hear your surrounding, but you don’t understand what they say. How can it be? You still understand OK and you still hear OK (you can tell when someone is talking to you). It might be confusing, Maybe it’s your imagination?


Well, it is a perfectly normal process. Here is the explanation:

How does the sense of hearing works (in a nutshell)

Ear parts

image placeholder Click here for detailed human ear diagram

Outer ear
gathers the sounds from the pinna to the hearing canal and to the ear drum. The “hole” in your ear is the outer edge of this canal. The eardrum is the inner edge.

Middle ear
Begins in the eardrum. The eardrum vibrates from the sounds outside. It vibrates three tiny bones in the inner ear. The bones then vibrate the inner ear.

Inner ear
A cochlea, attached to the middle ear bones on the one side. It generates electrical signals and transfers it to the nerve that goes to the brain.

Hearing nerve
delivers electrical signals to the brain where the interpretation takes place.

 

How does it all works

A small example: you walk in the meadow and a cow moos.
  • The sound from her mouth vibrates the air
  • The outer ear gathers the air vibrations and transfers it to the eardrum
  • The eardrum vibrates the hearing bones
  • The bones vibrates the cochlea
  • The cochlea translates the vibrations to electric signals
  • The hearing nerve transmits the signals to the brain
  • The brain interpreter the signals: It’s a Moo. It’s a cow.

Naturally, all this is done automatically. We don't have to think about it. We can hear many kinds of sounds. Sounds with different levels of strength (silent whisper to extremely loud noises). We can also hear various frequencies (low tones like far away thunder to high tones like kid’s voice or birds tweeting)  

Here is a site that covers many other aspects of the human ear...

So, what can go wrong?

What happens on hearing loss (Or hearing impairment, for that matter)

You can have hearing loss from various reasons. Every component in the hearing process can be damaged. The treatment and the rehabilitation way should fit the part that is hurt.

Types of hearing loss (In a nutshell)

Conductive hearing loss
The name indicates the problem. Conductive hearing loss is when there is a problem in conducting the sounds to the inner ear. The impairment  can be a result of many reasons like:

  • Lack or damaged earpiece
  • A hole in the eardrum
  • Some malfunction in the Ossicles (the tiny hearing bones in the middle ear)
  • Fluid accumulation behind the eardrum (quite common with kids)
  • Extra earwax
  • Earwax plug
  • Chronic infection

You can solve some of these problems fully or at least partially using proper treatment or some surgery.


Sensorineural hearing loss
This type origin is in the inner ear. The problem can be:

  • A damage in the part that transfers vibrations to electric signals
  • Some problem in the nerve that transmits the signals from the inner ear to the brain
  • Sensorineural hearing loss can be a result of few factors:
  • Born (Genetic or due to some early infection)
  • Acquired, due to exposure to noise
  • Some tumor on the nerve itself
  • Using ototoxic medicine
  • Age...

Unfortunately, this kind of injury is irreversible. You cannot  really fix the problem. You sure can rehabilitate the hearing using a hearing aid.


Mixed hearing loss
Like  the name implies... It involves some damages, Conductive (outer and middle ear) and Sensorineural (inner ear).


In order to define what kind of hearing aid you have, you have to have a hearing test.


Hearing test

Hearing test is a vast domain. I write here only the basic so you’ll get the whole picture.

How do you measure hearing?

First, lets define ‘hearing threshold’. Its the lowest volume that you can hear a sound. In other words, If I decrease the volume even a bit, you won’t hear it. It changes from tone to tone, meaning, you might hear well low tones (bass) and hardly hear high tones (soprano) with the same strength.


How they decide if you hear well

On hearing test, they check what is your hearing threshold for different frequencies (the frequencies indicates how low or how high is the tone). They compare the results to the thresholds of a good-hearing-person. On frequencies that you don’t hear as good as the good-hearing-person you have some level of hearing loss. Another way to put it: On some tones, they had to increase the volume level so you can hear. On these tones, you don’t hear as well as the average person.


How hearing test is performed

hearing test Hearing test

Like I mentioned above, I only describe it here in a nutshell but it should be enough to get the basic idea. 

The basic and most common test is called behavioral test. You’ll seat in a small room, sealed to noises with earphones. The audiologist will seat outside this room, seeing you through a window. He will make a series of tones on different frequencies with different volume levels. The equipment he’s using, buy the way, is called Audiometer. You’ll be asked to raze your hand or push some button if you notice the tone.  Keep in mind that he is looking for your hearing threshold, so you’ll hardly hear it... It’s OK.

In addition, the audiologist will read certain words, on different volume levels, you’ll have to repeat him. It’s OK to guess even if don’t hear it well. This can be either before or after the tones test, it doesn’t really matter.

Another word repeating test is to repeat a single syllable words. here the volume level is much above your threshold. Among others, the purpose of this test is to predict how much a hearing test can help you.

Don’t worry! even if you miss a tone or a word here and there, the test as a whole is taking it into account

Here is a nice clip that demonstrates hearing test, in case you'll need it to evaluate hearing loss.

Did you know? 

You can’t fake a hearing test... a good audiologist can tell after a hearing test EXACTLY how is your hearing. The test is way more sophisticated than just listening to sounds and raising your hand. It got many aspects and the audiologist is looking on many other parameters then what seems obvious. 


The difference between hearing and understanding

Hearing loss is not necessarily not hearing at all. It usually means that you can’t hear some of the frequencies on some level. For instance, if you only have a minor problem hearing high tones (very common) you have hearing loss.

Does it mean you can’t hear? no. It means that you have problems hearing certain sounds and voices on certain scenarios. For example, you might have difficulties to hear s, sh, and z properly. This is why you have the feeling: “I hear, but I can’t understand”.

Remember the TV host from the first paragraph? Well, It’s not her. It’s them frequencies you don’t hear as well as you used to. You do hear her. You simply can’t understand as well as you used to.


Now what?

open fit hearing aid An example of a tiny aearing aid

During the hearing test, the audiologist marks your response on a page or on the computer. He eventually gets a plot of your hearing on both ears. This is called “Audiogram”.

From the Aidiogram, the audiologist can tell if you got hearing loss. It shows how is your hearing on the different frequencies. There are many terms to describe the hearing as it appears on the audiogram.  It can be something like: “minor on the low tones to severe on the high tones”. It can also imply to the curve: “Slooping”, “Unshape”, “corner” and more.

You don’t need to figure it yourself! The audiologist does it for you.

Another thing that audiologist learns from the audiogram is what type of hearing loss you have, conductive,  Sensorineural or mixed. With this info, the audiologist can recommend on further actions (go to see a doctor, do additional hearing tests, fit a hearing aid and more).

If the audiologist recommends so, the door to the wonderful world of hearing aids is opened...

 


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