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.
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
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.
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