by Neil Bauman, Ph.D.
February 18, 2017
A young lady wrote,
I have a 30 dB hearing loss in my left ear although I still have 100% word recognition. However, my right ear has an 80 dB hearing loss, but only 8% word recognition. My doctor told me that due to this, my right ear is not eligible for a hearing aid. She said even if I hear speech in my right ear, it will be highly unrecognizable and distorted. Is this true?
Does this mean I have severe hearing loss in my right ear and normal hearing in my left?
In crowds, with a lot of background noise, I feel like I can’t hear anything. Also if a phone rings or a baby cries, I can sort of hear it, but I cannot possibly find where the sound is coming from. I was wondering if you knew why this was.
A 30 dB hearing loss is a mild loss. Don’t let the term “mild” fool you. You still miss a significant amount of quiet sounds, although you will still hear louder sounds.
An 80 dB hearing loss is, like you already know, a severe loss. This means you don’t hear much with that ear—only loud sounds. However, you can still hear a “lot”. I have an 80 dB loss in both ears and I still think I hear a “lot”, but I know I miss ever so much more than I hear. Thus, to answer your second question. You have a mild hearing loss in one ear and a severe hearing loss in the other.
Therefore, in order to correct your lack of hearing, you need hearing aids to amplify sounds so you can hear them. Most people only think you need more volume to hear. This is only one aspect of hearing loss.
The second aspect of hearing loss is how much you understand of what you hear—what audiologists call speech discrimination or word recognition. If you have 100% word recognition, you understand everything you hear. 80% word recognition means you understand 4 out of every 5 words you hear. This is still quite good as your brain often can fill in the missing words from the context of the sentence, unless you happen to miss a key word. Then you may miss the meaning of the entire sentence.
Your bad ear only understands 8% of what it hears. This is very poor discrimination. Basically, that ear just gives you gibberish. You’ll only understand every twelfth word. So if you hear someone talking, you’d hear something like this.
“Gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, car, gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, gibberish, dishes.”
Not very edifying is it?
If you wear a hearing aid in that ear, all you’d hear is louder gibberish for the most part with an English word thrown in now and again. Wearing a hearing aid won’t magically make this gibberish into English. Thus, what your doctor said is true.
However, if you are a good speechreader, even with only 8% discrimination, you could still understand a lot more of speech than your level of discrimination would indicate. You will get the cadence of speech via your hearing aid (and the odd word you understand) and this will help you immensely with your speechreading accuracy. Your brain will put together what you hear with what you see (speechread) and surprise—you’ll find you understand quite a bit.
Having said that, you will likely find that if you wear hearing aids in both ears, all the gibberish your bad ear hears and sends to your brain will overpower the good sounds from your better ear. This makes it much harder for your brain to separate the good sounds from the gibberish. The result will be that you won’t understand as much as you would if you only wore a hearing aid in your better ear. Besides, you’ll feel much more tired and cranky as the day wears on.
If you find that this is your case, then you should only wear a hearing aid in your better ear, especially when you are in relatively quiet places.
Now let’s look at why you have so much difficulty understanding speech in noisy places. In order to extract speech from background noise, you basically tell your brain to listen to just the sounds coming from one person’s mouth. In order to do that, your brain has to focus on the sounds coming from that specific location. And in order to do that, your brain needs two separate sound signals of that person talking.
As an analogy, think of the difference between a flat (2D) picture and a 3D picture. In the former—you see the various objects as though they were all the same distance from you (the speech is all inter-tangled with the background noise). You can instantly see this effect by shutting one eye (or ear).
However, if you want to see this same picture in 3D, you need both eyes (ears), each sending a slightly different set of signals to your brain. The result, is that your brain triangulates (focuses) on the person you are wanting to see (hear), and he suddenly stands out from the background.
Since your bad ear can’t hear that person talking, only your better ear sends that sound signal to your brain. Thus your brain doesn’t have the critical information it needs to make that person’s voice “pop” out of the background racket. Essentially, you are only hearing in 2D, not 3D. This makes extracting speech from background racket almost impossible.
If you wore a hearing aid in your bad ear in such cases would just make everything even worse, because now your brain would have to contend with an enormous amount of gibberish as well.
Furthermore, the reason you can’t tell the direction from which sounds are coming is also related to your lack of binaural hearing. You see, in order to locate the source of sounds, a baby crying, the phone ringing, etc., you also need two working ears. Your brain uses the slight difference in the volume of the sounds reaching each ear and the tiny difference in time these sounds reach each ear, to figure out from which direction the sound is coming.
When your brain only has one signal coming in, it doesn’t have the critical time delays and volume differences to triangulate the direction of the incoming sound. The result is that you just hear the sound, but don’t have a clue where it is coming from.
In such situations, you may gain some benefit from wearing two hearing aids. When you wear two hearing aids, as long as both of your ears can pick up the same sound, then your brain has the sound delays and volume differences it needs to calculate direction. Thus, you may find you have your directionality back.
Some people in your situation do wear two hearing aids when out and about so they can hear the direction from which warning sounds are coming—for example, a siren, horn honking, person shouting a warning, etc.
This can work quite well since you don’t have to understand speech in these situations, you just have to hear the sound. Note: this is only going to work when the background noise isn’t so loud that it buries the sound you want to hear.
- In quiet situations, wear a hearing aid in your better ear and not one in your worse ear. This will let you hear the best without amplifying the gibberish your worse ear hears.
- In noisy situations, you may find that even wearing a hearing aid in your better ear doesn’t help, so you may want to take it off and see if you hear and understand better without it.
- When out and about, you may find that wearing two hearing aids will help you identify the direction of warning sounds, but they won’t aid in understanding speech.
- Finally, in all situations, use your eyes. Your eyes are now also your “ears”. Speechread all the time and your brain will put together what your eyes see and what your better ear hears. The result is that you will understand speech much better than you otherwise would. After all, that’s exactly what you want.