by Neil Bauman, Ph.D.
A man wrote,
I am 23 years old and I have recently started to believe that I may have a mild hearing loss. I often have trouble understanding other people in noisy environments, such as cars or restaurants, and I seem to be the only one having difficulties. In quieter environments, on the other hand, I have no trouble understanding what the other is saying.
I have tested my hearing many times online, and also with an audiologist. The results showed consistently that I have a normal hearing when there was no background noise—possibly with a slight weakness towards higher frequencies. With background noise, however, my hearing was on the edge between “still normal” and “mild hearing loss”.
I often feel I do not belong to a group because I cannot understand what others are saying. Can you relate to my description of the problem? I read in one of your articles that when hearing loss occurs, one of its side effects is that my ability to differentiate multiple same-frequency noises vanishes, therefore making it impossible for me to understand someone if another is speaking simultaneously. Could you explain why that is so?
You may be surprised to learn that one of the first symptoms of high-frequency hearing loss is exactly what you describe—when you can hear and understand people in quiet places, but cannot understand the same people in noisy surroundings.
Hearing loss is hearing loss—whether you are in noise or in quiet. There is no difference. What is different is how much you understand of what you hear. It doesn’t take too much high-frequency hearing loss to begin to notice you don’t understand as much in the presence of noise—and that is what you are experiencing. The result is that you often feel left out when you are in a group of people all talking at the same time.
Let me explain why a high-frequency hearing loss causes these problems. First, here are three principles you need to know.
1. Low-frequency sounds travel well through air, while high-frequency sounds quickly “drop out” of the air. Thus low-frequency sounds travel much greater distances through air than do high-frequency sounds.
2. Most of the volume of speech is produced by the low-frequency vowels.
3. Most of the intelligence in speech is produced by the high-frequency consonants.
What this means is that because you hear the low-frequency sounds well, you hear people talking with no problem, but because you cannot hear the high-frequency sounds as well now, you don’t hear the high-frequency consonants that carry most of the meaning of speech. Thus you don’t understand as much of speech as you used to.
This condition is exacerbated by increasing distance (you lose more of the needed high-frequency sounds since they do not travel well though air) and by noise (loud low-frequency sounds mask the softer high-frequency sounds needed to understand speech).
Therefore, one solution is to get close to whomever is speaking so you can catch the softer high-frequency sounds, and at the same time, try to cut down the loud low-frequency background noise by shutting open doors/windows, moving to a quieter spot, turning down the volume on any background music playing, etc.
Another solution is to get and wear haring aids that will boost the volume of the higher frequencies. A third solution is to use assistive devices that put the microphone close to the speaker’s mouth, thus capturing the high-frequency sounds before they drop out of the air.