Ask Dr. Abonso
5. Why Don't 80% Of Hearing Aids Work Well In Loud Noise Or Music?

Dr. Abonso: That is because 80% of the hearing aids sold last year were "linear" hearing aids. These can work reasonably well in quiet-- certainly much better than nothing can at all -- but are not much good in noise. They are obsolete.

Suspicious Consumer: You sell a different kind?

Dr. Abonso: Actually, I don't sell hearing aids at all except to close personal friends. My job is to make the world a better place by providing information.

Suspicious Consumer: If you are trying to inform, why did your last few columns seem sarcastic at times?

Dr. Abonso: It was an attempt to make them a little humorous, and thus more readable.

Suspicious Consumer: Do you remember my original question?

Dr. Abonso: Yes. I was saying that most hearing aids, even those sold today, are "linear" hearing aids, and I claimed that linear aids were obsolete.

Suspicious Consumer: Why?

Dr. Abonso: Because they provide the same gain for loud sounds and soft sounds, while hearing loss is typically much greater for soft sounds. As a result, they provide so much gain for loud sounds that you are inclined to turn down the volume control, and then you miss the quiet sounds. Worse yet, for loudest sounds linear hearing aids typically overload on the loudest sounds, creating a raucous distortion that destroys intelligibility.

Suspicious Consumer: Destroys what?

Dr. Abonso: Destroys your ability to understand speech, especially in noise.

Suspicious Consumer: Can't I just turn down the volume control some more?

Dr. Abonso: It doesn't help with most of these aids: They distort very loud sounds anyway. Besides, you would have to devote a lot of energy to turning the volume control up and down to handle the range of sounds in the real world. You know how even at the loudest party everyone can suddenly stop talking just as you say something "privately" to someone, so that you end up blurting the secret out to the entire room?

Suspicious Consumer: I guess so. Can we go back to why 80% of hearing aids don't work in noise?

Dr. Abonso: Yes, sorry. The answer is that linear hearing aids typically distort loud sounds, they filter out some of the low frequency and high-frequency speech information, and they can't provide adequate gain for quiet sounds without sudden loud sounds becoming uncomfortable or distorted.

Suspicious Consumer: So?

Dr. Abonso: So the brain is deprived of the information it needs to sort out the speech from the noise (which is quite often the speech of other people). In fact, even people with normal hearing have trouble in noise while wearing those hearing aids.

Suspicious Consumer: Who would dispense such hearing aids?

Dr. Abonso: Well, before we get too righteous, those are the cheapest hearing aids, so a dispenser believing that you would be better off with linear hearing aids you could afford than with better aids you couldn't afford might recommend them. And then some dispensers -- even good ones -- have had trouble with the newer hearing aids and decided to stick with the known problems of the "tried and true."

Suspicious Consumer: You aren't very judgmental. Where is your Ralph Nader instinct?

Dr. Abonso: I can't afford to be judgmental. I make too many mistakes myself. The evidence is now overwhelming, however, that hearing aids with the K-AMP circuit (or the RESOUND circuit in more difficult cases) are far superior for hearing in noise.

Suspicious Consumer: But you say that 4 out of 5 dispensers are still dispensing the much cheaper, old fashioned, don't-really-work-very-well, crummy peak-clipping, head-banging, linear hearing aids?

Dr. Abonso: I love your compound adjectives.

Suspicious Consumer: How do I find the "1 in 5" dispenser?

Dr. Abonso: Choose your hearing professional as carefully as you chooses your physician.

© 1993

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