programmable hearing aids

Chas in PR chasinpr at aol.com
Sat Dec 21 22:47:17 EST 1996


Dear James,

Resound and several other companies have hearing aids which work very
differently than simple amplifiers.  The Resound hearing aid has what is
called "wide band dynamic compression" which is very different from a
conventional hearing aid that may use a set compression ratio (e.g. 2:1 
For every 2dB input the ouput is 1dB above a minimum level of
amplification). Programming of the aid is done with patient participation-
the patient judges loudness levels of  a series of noise bands at varying
intensity levels centered at 4 test frequencies. The aid is then
programmed so that, depending on the intensity of the input signal,  the
normal speech characteristic will be as faithfully preserved as possible
for each individual ear. That means that soft sounds will sound soft,
normal speech is perceived as being comfortable and loud sounds are kept
loud but below the level where the cause more than mild discomfort.

Does this work? For many patients it is a great solution. I find it
excellent for mild to moderate/severe (less than 85dBHL) hearing losses.
Steeply sloping hearing loss at 1000Hz and above are questionable. 
Oticon, Siemans and others are now producing their programmable and as
audiologists we will have to evaluate them and compare them with Resound.
Phonak has an excellent programmable aid with a directional microphone.

What  does this all mean? Find an audiologist (unless you can get a person
like Paul in Iowa) who has experience with programmables and who you feel
you can trust. Two audiologists can sell the same hearing aid and the
patient can get two entirely different programs, just as he can buy a
conventional hearing aid that will be adjusted differently by 2 different
dispensers. In both cases the aid may be appropiate but the adjustment
great with one dispenser and lousy with another. . 

I don't believe here is one of us (audiologists) who has all the answers
as to what is the BEST hearing aid for an individual. 

Charles Harney



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