To BTE or not to BTE: That is the question Question:
Aside from cosmetics is the behind the ear aid as
effective or more effective than an in-canal aid?
N.D.
Dear N.D.:
Most of what is priority in fitting style is based
on patient needs and preferences. To me and a good
number of my patients behind-the-ear (BTE)
instruments enjoy some superior features, mostly in
reliability and larger processing capacity over
their smaller custom cousins. Uniformity and quality
control are much tighter in the BTE production than
in custom instrument production, with far fewer
repairs. Certainly, longer battery life, more
digital processing ability and memory are available
in BTE confirgurations.
But that does not mean custom instruments are
intrisically inferior. For some people the
simplicity of a one-piece custom instrument is more
important, and sometimes determines whether or not
they will wear them. Custom instruments also enjoy
better microphone locus in the ear, which in mild
and moderate losses is important for transparency in
amplification. Arguably, in many cases--if feedback
does not compromise acoustic gain--custom
instruments offer better control of loudness growth
in limited dynamic ranges.
However, I believe there are two principal groups of
users for which BTEs are by far the best choice.
They are:
1) Those patients with near normal lows but who drop
off precipitously in the highs, and who need at
least 45-55dB gain at 3KHz or 4KHz without feedback.
Custom instruments are notorious for feedback (and
also resonant distortion) in such cases, while the
greater mic-receiver partition in the BTE provides
lots more gain without feedback or resonant
distortion.
2) Those patients with more severe losses, and who
would like to be able to use assistive devices. BTEs
are really the only choice for most of these, the
lone exceptions when handling an earmold and BTE
setup is too difficult. Then, the compromise by
going ITE may be worth it.
I guess you could say that the amount of
high-frequency gain required to accommodate a given
loss is the deciding factor of which is
electroacoustically superior.
Until recently, everyone and his brother thought the
only way to go was custom instruments. But, alas, a
renaissance in reason has gathered, and BTEs are
capturing a growing share of the market---it looks
as if about 30% of hearing aids for 2005 will be BTE.
And if present trends continue, will likely climb
close to 38% by end of 2006.
Not knowing anything about your particular hearing
needs or expectations I cannot comment on your
particular case. However, hopefully the above
guidelines will help....and, by the way, contrary to
what most people think, the new, smaller BTEs are
really less noticeable than most custom instruments
with the exception of the CIC and minicanal. The key
for success with BTEs often lies with the material
and design of the earmold.
Whatever you do, whatever instrumentation makes you
happy is the one you should go for. Just don't delay
your health, happiness and better hearing any longer
than necessary (smile).
Max Stanley Chartrand, Director of Research
Digicare Hearing Research & Rehabilitation
P.O. Box 706
Rye, CO 81069
(719)676-3277
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