What is Hearing Loss?Hearing loss effects about 31.5 million people in the United States. That number includes children as well as adults. In fact, hearing impairment is the most common birth defect in the USA. About 17 out of every 1,000 children have some hearing impairment. But for people over 75 years old, about 1/3 are effected. Hearing impairment has a detrimental effect on your quality of life and relationships. How can I know if I have a hearing loss? Click here. The ear is a remarkable organ. The person with normal hearing has an very large "dynamic range". That is, this person can hear very very soft sounds, (a drop of a pin), and can tolerate very loud sounds, (like a very close train whistle). The normal hearing system can also focus on the signal of importance, (or speaker or importance), and block out the surrounding background noise, (such as in a very popular restaurant). The ear with hearing loss becomes less sensitive to soft sounds, making it hard to hear some things even in a quiet environment. The hearing impaired ear also often becomes more sensitive to loud sounds, unable to tolerate the louder sounds in our lives. And, the impaired ear is less able to focus on the important signal. The background noise seems overwhelming. Hearing loss can result from many different causes. Let's take a look at how the ear is made. Here is a brief overview. The outer ear is the part we all see on the side of our head, as well as the opening and canal that leads up to the eardrum. After sound waves enter the ear canal, they impact the eardrum (tympanic membrane),which then vibrates. The vibration is carried on into the middle ear. The middle is the space behind the eardrum and is filled with air. The three small bones, the anvil, hammer, and stirrup, (or the incus, malleus, and stapes) carry the vibrations to the cochlea, the inner ear. Basically, the cochlea is a coiled, fluid filled tube. Running the length of the cochlea are the hair cells. When the fluid is disturbed by the vibrations of the tiny bones (ossicles), the hair cells are also stimulated. This in turn causes a signal to be sent along the acoustic nerve to that part of the brain that interprets sound. Another way to think about it is: Our hearing system is much more intricate and complicated than I have just described it. And something can be abnormal just about anywhere along the way, from the external ear to the brain. For example, often the ear canal can be completely packed with ear wax, which does not allow the sound waves to impact the eardrum. Also, it is not unusual for the middle ear system to be abnormal because of a stapes fixation, not allowing the sound waves through. These kind of problems result in a conductive hearing loss. Often, as we get older, the hair cells in the cochlea do not perform as well as they once did. This results in less sensitivity to soft sounds and, in some cases also results in greater sensitivity to loud sounds. This greater sensitivity to louds sounds is called recruitment. When the problem is in the cochlea, a sensory loss is the result. This is usually called a sensorineural hearing loss. When a patient can hear, but not understand, the processes of sound perception are involved. This involves the subcortical or cortical auditory centers and the central auditory pathway. Depending on where the leison is (past the cochlea), a person can have poor understanding of speech and poor directional hearing. Speech understanding can be affected, while sensitivity to pure tones is not. A comprehensive audiometric evaluation is needed to determine what type of hearing loss you have.
Make an appointment to check your hearing loss with a comprehensive audiometric evaluation. Hearing Care Center 4736 Bryant Irvin Road, Suite 702 Fort Worth, Texas 76132 817 263-1971
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