Presbycusis and Speech Discrimination

September 2006

Editor: Here's a good discussion of presbycusis (age related hearing loss), how it causes loss of speech discrimination, and what you should do if you experience it.

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The results from your latest hearing test may have shown that you were experiencing some form of hearing loss, which, in general, happens gradually as you age. The medical term for hearing loss related to aging is "presbyacusis," and both exposure to loud noises (tools, machinery, or guns, for example) and genetics can contribute to certain types of hearing problems. Less commonly in people over 55, hearing loss can be caused by infections or inner ear injury.

No matter what the cause, hearing problems can take away the enjoyment you have in day-to-day living. When you are suffering from any type of hearing loss, you may not be able to understand friends, family, or co-workers as they speak. You may still be able to hear general sounds, but your ability to understand speech is lessened.

While a hearing aid can reduce your hearing problems dramatically, it does have limitations that you must understand. But being able to accept and enjoy what improvements a hearing aid will provide can bring you better quality of life. A hearing test known as a discrimination test can offer you an indication of what improvements you can expect.

The Causes of Hearing Problems

In your ears, there are hair cells that are responsible for sending sound messages to your brain. The hair cells that are responsible for transmission of sounds that have high pitch energy are very susceptible to damage throughout one's lifetime. When these hair cells are damaged, a person will notice he or she is developing hearing problems and losing the ability to hear consonant sounds clearly. This means that person may be unable to discriminate between different words that have similar sound, although he or she might be able to hear the words enough to make a guess as to their meaning. For example, "What time is it?" and "What kind is it?" may sound the same to someone experiencing this type of hearing loss - questions that require very different answers.

If you notice that you are experiencing hearing problems and having difficulty hearing particular words or sounds, it is important to first visit a local doctor or ENT in order to have any underlying medical issues treated or ruled out. Once those issues have been resolved, and it is determined that you do have hearing problems that need to be corrected, you can take the next step toward purchasing a hearing aid. And that next step should include a hearing test to measure discrimination.

More on this and related topics

What Is a Discrimination Test?

A discrimination test is a hearing test that measures how well you can hear words isolated from the context of a sentence in an ideal situation - the perfect volume, no external noise, no distractions, and so on. This type of hearing test can be helpful for someone experiencing high frequency hearing loss or other hearing problems.

When you have your hearing test, you will be placed in a soundproof booth and you will be given headphones to wear. Next, the person conducting the exam will adjust the volume of the headphones being used so that it is at a comfortable level for you without being too loud or too soft. Then the person conducting the hearing test will read you a list of words, one at a time, from outside of the soundproof area. You will repeat each word back as you hear it, and the administrator will score the percentage of words repeated correctly. You will not have any visual cues to go along with the words, so you will not be able to lip read, and you will not have any context to the words in the way you might in a real world situation. Separate lists will be used for each ear.

At the end of the hearing test, the administrator should take the time to go over your results with you and explain what they mean for your particular hearing problems. While in an ideal world you will score 90 percent or higher on such a hearing test, you may instead find that, for example, you scored only 60 percent on the test and that your hearing loss is more severe.

What does this type of hearing test score mean? It means that in the most ideal of conditions, when you are given individual words in isolation, you will only be able to correctly understand 60 percent of the words you hear. And therefore, that is the best percentage of words that you can expect to be able to hear when you are using a hearing aid. Even with today's improved technology, a hearing aid will never be able to give one with hearing problems a better level of discrimination than was achieved in his or her hearing test.

Your Discrimination Score and Your Hearing Aid

When you know your discrimination score, you will know what you can realistically expect from your hearing aids. With a quality hearing aid in place and calibrated correctly, you will be given back many of the sounds that you might have missed in real world circumstances, like a cricket's chirp or the falling of rain on your window. And, most importantly, you will be given the ability to hear consonants better, so that you will be able to follow conversations more easily than you could without the aid - particularly in noisy or distracting situations.

In addition, new hearing aids are being introduced that have adaptive directional microphones that adjust via algorithms that depend on the level of sound in the room. These microphones can improve the signal to noise ratio and can help to focus someone's voice in a noisy situation, allowing one with hearing problems to hear sounds at the level of his or her discrimination score. If possible, find a vendor who sells these new hearing aids so that you have the best chance at optimizing your hearing.

Conclusion

Having a hearing test administered is one of the most important steps that you can take before you buy a hearing aid to correct your hearing problems. When you go to purchase your hearing aid, you should bring your discrimination scores with you, whether the test has been performed by your physician or by the vendor. If the hearing aid vendor does not offer discrimination testing or does not ask to see your scores, you should reconsider your vendor choice.

Most importantly, you must remember that a hearing aid will never be able to bring your hearing back to what it was before your hearing loss occurred. But when you know your discrimination score and you understand the nature of your hearing problems, you can have a realistic expectation of what the aid can do for you. And, armed with this knowledge, you can find the right hearing aid that can give you enjoyment in your life again.

About the Author

Henry Smith is the founder of America Hears, a leading manufacturer and distributor of hearing aids online for over 26 years. The company recently rolled out its new FreedomAD product line, which utilizes the latest generation of ADRO hearing aid technology. Henry started the company in 1979, following a 15-year career at the Pennsylvania School of the Deaf, including his work as an Acoustic Technician. Henry is a pioneer in the use of computers and the Internet to allow customers to have a hands-on approach to the tuning and adjusting of their digital hearing aids. He strives to be customer-centric in all aspects of his work

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