14. Are Two Aids Really Better Than One?
Dr. Abonso: Well,
I guess that depends on how good the hearing aids are.
You don't ever give a straight yes or no answer, do you?
Dr. Abonso: No.
With older hearing aid designs, most wearers found two hearing aids were much
better than one most of the time, but not in noise.
Suspicious Consumer: I see this is going to take some time. May I sit down?
Dr. Abonso: Yes, I love an audience.
Suspicious Consumer: Why don't two of those "older aids" work
better than one in noise?
Dr. Abonso: That's
an interesting question, because in the laboratory people nearly always
do better with two hearing aids in noise regardless of the type of hearing
Suspicious Consumer: Why?
Dr. Abonso: Professor
David Hawkins at the University of South Carolina asked the same question. He
speculated that when people had to listen to distorted sound - typically created
by the older types of aids in high-level noise - they preferred to have it in
only one ear. In her Ph.D. study, Dr. Naidoo confirmed that Hawkins was probably
Suspicious Consumer: I'm looking as interested as I can; please go on.
Dr. Abonso: The
majority of Naidoo's subjects preferred one hearing aid in noise when
they were listening to the old-fashioned, crummy-peak-clipping aids (80% of
the aids sold in 1991 were that kind), but when they listened to clean Class
D hearing aids...
Suspicious Consumer: What class did they attend?
Dr. Abonso: Class
D describes a new type of high-fidelity amplifier that can almost eliminate
distortion in hearing aids.
Suspicious Consumer: What happened
to Dr. Naidoo's subjects when they listened to Class D hearing aids?
Dr. Abonso: Nothing
happened to them, but when the sound was clean and undistorted, they
preferred two hearing aids in noise. They could also understand speech
much better in noise with two hearing aids than with one.
Suspicious Consumer: Did Dr. Nadoo
test several kinds of hearing aids? Did one hearing aid give the best results?
Dr. Abonso: I'm
glad you asked. Yes and yes. The K-AMP hearing aids (which include a Class D
amplifier) received the highest average ratings.
Suspicious Consumer: So why would anyone buy the crummy kind of hearing aid?
Dr. Abonso: At most
hearing aid companies, the crummy-peak-clipping aids are still shipped automatically
- they are the cheapest, and presumably because of their simplicity, have the
lowest rate of return for credit- unless something better is ordered. And, sad
to say, some dispensers simply send in the client's ear impressions and hearing-test
results and let the factory pick the aids.
Suspicious Consumer: That doesn't sound like a good approach to me.
Dr. Abonso: I have
to agree. Professor Hawkins once suggested- I suspect only half in jest - that
you shouldn't be given those aids unless you had checked off a box saying "Yes,
I want my hearing aids to hurt and/or sound bad."
Suspicious Consumer: Are there any other reasons to buy two hearing aids?
Dr. Abonso: I think
a better question would be; "Which ear do you want to give up?" Even with older,
less-than-perfect hearing aids, most people report they are much more relaxed,
they localize sound better, and they hear much better in quiet at home. An Army
study of men who had been given only one hearing aid (by the Army audiologist),
and then much later were issued a second one, found the vast majority preferred
two. Over half the men were actually hostile when they came back for
their checkup, because for years they had been denied the second aid by an Army
audiologist who told them they needed only one.
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