Many people say to their audiologist that they are able to hear fine in a quiet room but the minute there is background noise they are not able to hear well. Sometimes it happens while watching a TV program and the background music suddenly gets louder. Difficulty may arise if a conversation is being held in a large room with echo or reverberation. This comment is true for people who hear normally or people with a hearing loss.
The Physiology of Hearing
All hearing situations are not created equal. There are numerous variables, from the shape of the room to the number of people in the room. The distance you are from the speech you are trying to hear will affect how your brain understands. The pathway of sound from the outside of your head through the canal and into the middle ear space can be altered by earwax, a hole in the eardrum or fluid behind the eardrum. The pathway of sound from the middle ear to the inner ear then through the nerves in the brain to the area of the brain that understands speech may be altered by damage to the inner ear from noise, genetics, medications or trauma. The area of the brain that understands speech may be compromised by blood flow and the speed the nerves can send the signals. It is a complicated system, to say the least.
Why is Background Speech Noise So Frustrating?
In a group of people there is speech sound that you are attempting to ignore and other speech that you want to hear. With a normally functioning auditory system, you can simply “tell” the brain to focus. It is almost an automatic occurrence that you do not need to even think about. However, many people with normal hearing and with a hearing loss struggle to pull the desired sound out of the background. Both the desired sound of the person talking has the same frequencies, timing and modulation as the speech of the people behind you. The two “noises” are very similar. The plethora of filters that control how you process the various sounds may not work well.
The Filters in the Brain
The brain and the ears work together to provide a seamless signal to us. Each side of the brain has its own job depending on the location of the noise versus the desired signal you want to hear. Some brains process the various noises very quickly and other brains like to take their time. Some brains do a great job on one side but for one reason or another have difficulty on the other side. The speed of how you take a sound and send it up the various brain pathways will help determine how well you understand. The pathways in the ear and brain modify some pitches and sound, which help understanding. Researchers are still discovering new “automation” in healthy functioning hearing system pathways. We know that people with two equally hearing ears understand speech better in noise than a person with one good ear and one impaired ear. The brain itself does much of the work but it needs the sound to be clear from both sides without distortion.
How to Improve your Odds to Understand Speech in Noise
There is not a single method of repairing the hearing pathways to function better in noise. We know that people who are exposed to competitive situations often do better than people who avoid noise continually. Practice listening to something enjoyable in a noisy room to help the areas of your brain “remember” what they are supposed to do. Help your brain stay active in how it functions in a variety of situations. When you are stressed your brain does not function with the same fluidity as on days that you are relaxed. Play games with your brain to help it function well so that when your day is not flowing and you become tense you will have enough brain power to work through your situation. Control the noise in the environment for important conversations. Sit near the person you have the most difficulty understanding. Try a pair of hearing aids with noise reduction circuitry and directional microphones. Just because you have to work at understanding speech does not mean you are a failure. It is a sign that you need to expend more energy for some activities than others. Speech understanding in noise is one of them, for all of us.
By Dr. Karon Lynn, Au.D
Trinity Hearing Center is located at 1330 N. Rim Dr., Suite B in Flagstaff. For more information, visit the website at TrinityHearing.net. Karon Lynn is a doctor of audiology with 30 years of experience working with hearing impaired individuals. Dr. Lynn may be reached at 928-522-0500 or at audio@trinityhearing.net.
