When patients come into our office for a hearing evaluation and a consultation it is not usually because they are not aware of sounds. It usually is because they are having communication difficulties with their spouse, significant others, and friends. Hearing and understanding are alike…yet different.
Hearing loss is one of the largest health concerns today and it is related to everything we do in our lives. Often, how well we think we hear is related to how loud sounds are. If you can hear a knock at the door.... you must be ok. Right? If you can hear the microwave beep, go off... you must be ok. Right? Not necessarily.
One of the most common issues that people come into our office with is " I can hear but I can't understand." This can usually be explained quite simply. The hearing hair cells, or Cilicia that line your inner ear / cochlea and transmit sound up the auditory nerve to the brain is positioned within the ear in such a way that the high frequency nerves receive continuous sound pressure at the highest level. As the sounds that we are exposed to travel further into the cochlea the pressure is not as strong and there is not as much "wear & tear" on the hearing nerves. These nerves that are furthest in are lower frequencies and mid frequencies. Therefore, the high frequencies are usually damaged more than the low frequencies. The high frequencies give us about 80% of our speech understanding. Most of the consonants of the alphabet are located within the high and mid frequencies. Take a black marker and blacken out just 50% of the consonants in a couple sentences in the newspaper.... then try and read it out loud while pronouncing only the letters that are available. This is how someone with a hearing loss hears.... or maybe worse. When a person gets a hearing loss, clarity is greatly diminished because of the damage to high frequencies.
The low frequencies give us volume: Power. The ability to hear. Background noise. These are much stronger in sound pressure than high frequencies. So now you "hear" pretty good because these frequencies are better than the speech understanding frequencies. However, you can't "understand" unless you are looking at someone. Add background noise of any kind and even that can be very difficult. Often people feel like they do not have a hearing loss.... that people are mumbling or just speaking too fast. (Because other sounds are loud enough). If someone is cranking up the tv that is an indication that there may be such a loss. They are trying to get the high frequencies louder to understand.
The purpose of hearing instruments is to help people hear and "understand" better. It's mathematical. We must get the speech and noise signal to the brain to be at a 1 to 1 ratio. It’s always about that. That is achieved by stimulating the hearing nerves and controlling the noise through processors. The broader the frequency response of the hearing instrument and the more processors with the greatest speed and flexibility the better the speech understanding. Billions of dollars have been spent on research and development of hearing instruments over the last decade and technology today is awesome! If you or a loved one has communication difficulties, I encourage you to see a hearing health care professional. To Hear Better Is To Live Better!