What did you say?
I can hear them talking, but I can’t understand what they are saying.
Through the years I have heard a reoccurring theme as hearing impaired patients try to describe their own hearing problems. The title of this article is the one I hear the most, “I can hear them talking, but I can’t understand what they are saying.” The reason this is their perception has to do with where their hearing loss is located on a graph called an audiogram.
This graph is marked as they respond to signals and tones played both on their head and in their ears. The tones on their head are through a bone conduction oscillator that is placed on the mastoid bone behind the ear. Everyone has a bump behind the ears. That is the mastoid and is like a helmet over the inner ear, the cochlea. This device sends vibrations into the inner ear actually bypassing the outer and middle ear. The best example of bone conduction hearing is when you chew crunchy food with your mouth closed. Few people stop to think about it, but if our mouth is closed while we are chewing that peanut brittle or granola then there is no sound escaping our mouth to go back into our ears, yet we hear it and almost cannot hear anything else while we chew it. That is the bone of our jaws and connected skull conducting the sound into the inner ear by vibration. The sounds played into the ear are called air conduction as this is the primary way we hear with sounds coming through the air into the ear drum, then through the bones of the middle ear, then into that inner ear.
As a patient responds to the sounds first on the head and then into the ear, the hearing professional charts the responses onto a box graph. In one direction loudness is measured and in the other direction we measure frequency, pitches, or tones.
Unless a patient has had their ears injured by disease or some kind of accident, the typical human hearing loss is in the high frequencies. High frequency loss can be speeded up through exposure to very loud noises such as military or industrial noise and even very loud music. By the way, the iPod generation with have massive hearing loss earlier in their lives than their parents by the volume their music is played into their ears. It is only a matter of time before tens of thousands of them turn to professionals like me for hearing help.
That having been said, high frequency is where the soft consonants ride in speech recognition. There are scientific reasons related to energy, time duration, and origin of the sound on the teeth and lips instead of resonating up through the larynx, but the simple issue is that high frequency loss equals missing soft consonants. When that happens the speech of family and friends starts to muddle and the patient defines it as hearing but not understanding. When that is happening you should get help.
Hearing care is health care. If you have the symptoms of hearing loss let a professional help you find out why. The hearing professional will help you sort out the technology level to meet your need, your budget, and answer your hearing need questions.
Jeffrey L. Bayliff, NBC-HIS, is the owenr of Hear the Birds Hearing Aid Center, Lock Haven, Pa.