[TheForge] Hearing aids

Mon Jan 24 19:08:17 EST 2005

I wear a hearing aid. I've had three different types and two 
audiologists. I earn my living as an electrical engineer designing 
amplifiers; this doesn't make me know beans about hearing, but I had a 
long list of questions when I went in to the audiologists.

Short version: I think the largest single factor in success with an aid 
is finding a highly competent audiologist. I don't think you can find 
this by looking at their diplomas (just like any other discipline).

-------------------
Joke: There's a new version of the AID's virus out. It enters the body 
through the aural canal. It is called Hearing AIDS.
(suitable pause until the laughter is just running out)

You get it from listening to too many assholes!
-------------------

The whole nine yards:

First, there are three main categories of hearing aids:
1. Traditional analog
These basically make everything louder. No smarts whatsoever. These are 
the hearing aids your father and grandfather hated. They are also the 
least expensive.

2. Advanced analog
By careful design, some of the tricks the digital aids do can be done 
with analog circuits. I suspect these may not be around any more, 
superseded by the digital ones. These are priced in between traditional 
and digital. You can have a couple of different settings/programs, they 
provide some compressive limiting (see #3).

3. Digital hearing aids
These are a whole different thing from the traditional.
a) Different amplification in different frequency bands
My hearing loss is narrowband (a classic sort of genetic loss called a 
"cookie bite" loss due to the shape on the audiogram). I have a 45 dB 
loss right in the middle of voice frequencies. That makes frequency 
selective amplification pretty important to me (and to many people). A 
secondary importance is that you won't get the best intelligibility with 
a flat frequency response. You want to boost some areas and depress 
others. The goal is not to give you stereo hi-fi, but to give you better 
understanding of speech, quite a different thing.
b) Several programs available for differing conditions
For instance, going back to a), if you are in an area with lots of 
motors (or a noisy ventilation system), you might want a program that 
depresses low frequencies, lower than normal. I use this all the time at 
work to drop out HVAC noise. I like it a lot. You might want a setting 
specifically for speech and one for music (but I prefer to listen bare 
ears to music). I've had three aids; the first advanced analog and the 
other two digital. The first and current aids had three programs; the 
one in the middle had four or five. Whatever it had, it was too many. 
You don't get to go direct to a program, you step through them one at a 
time. Having more than three I found confusing (which one am I on?) and 
cumbersome without any real advantage.
c) Smart control of the audio reaching your ear
If you're in an environment with occasional loud noises, otherwise quiet 
conversation, you have a problem. Do you crank the aid up to hear the 
conversation, only to get a blast when the loud noise comes along? A 
digital or advanced analog aid does this for you automatically. What 
they do is called compression. Quiet sounds get amplified a lot; loud 
sounds don't. Unless a quiet sound happens at the same time as a loud 
one, they come right through. Aid companies have gone so far with this 
that they don't recommend a volume control. I had one like that and 
couldn't stand it, I have to have that volume control. That said, I only 
use it in unusual circumstances.
Smart aids also deftly avoid two horrors of the traditional aid: wind 
noise and feedback screeches. Wind noise with a traditional can be 
extremely loud, with a digital the aid just shuts off for a fraction of 
a second. Feedback screeches are extremely common with traditional aids; 
you have to work at it to make a digital or advanced analog aid screech. 
They're smart. Smart is good, especially if your audiologist is smart 
and can take advantage of it.
d) Additional features
You can get a digital aid with two microphones. This allows you to have 
a setting that makes the aid directional, so that sounds in front of you 
come through with twice the volume of sounds behind you. Really useful 
in a noisy environment. The only reason I don't have it is it was that 
or the volume control.

On my first aid, I got a recommendation--a friend of a friend of a 
friend--to an audiologist in Fort Collins, Colorado (where I was then 
living). "The only PhD in audiology in the area" or some such 
advertising. He could answer most of my technical questions, seemed 
reasonable, so I went with him. He put me in (one) advanced analog aid. 
I liked it a lot, it really worked well. Somehow I lost it to my great 
regret (and great expense). Put contact info in your aid carrying case!

Before I lost that aid, the audiologist called me up one day and ended 
up talking me into trying at no cost a digital aid. I tried it for the 
full 30 days, went in and had it adjusted several times, and in the end 
decided that it really wasn't any different than the analog unit I had. 
I gave the digital one back.

In the course of a few years seeing this first audiologist, I had 
developed some uncertainities about him. Nothing specific, but I wasn't 
convinced he really was on top of things. When I lost my analog aid, I 
went to a different guy in Loveland, Colorado. I don't remember how I 
picked him. He talked me into trying two digital aids (i.e. both ears). 
I worked with him closely, and tried really hard, but I just didn't like 
having something in both ears. I feel like I'm in a box and someone 
could walk up on me without my hearing them. It was useful to have both, 
because I could try just the left or just the right to see what worked 
better. My analog aid I had used in my right ear. I ended up keeping the 
digital aid for the left ear. The audiologist was really surprised at 
some of my testing results--both ears measure the same, but my ability 
to understand words is significantly better in my left ear.

A good friend of mine was looking at getting a hearing aid and I gave 
him the data dump. He asked me a lot of pointed questions about the 
first audiologist and finally asked me who he was. It turns out my 
friend had gone to him and gotten the same idea, that he just didn't 
really know what he was doing.

Find an audiologist that several people recommend if at all possible. I 
think someone who does more than just measure you in the booth is a good 
plan (like someone who reads you lists of words to check 
intelligibility). Try a couple of audiologists and compare, it's your 
money, make sure it will be well spent.

I think all states have a legally required trial period. You should be 
able to get custom fit for an aid and try it out for maybe 30 days. At 
the end of that time, you should be able to return it with no big 
arguments. You may have to pay for the audiologist's time, but neither 
of the guys I saw had that requirement. These things take some getting 
used to; if it isn't comfortable, tell the audiologist. It will take a 
few appointments for them to get it programmed correctly. You MUST NOT 
BE SHY about returning the aid. You're spending a lot of money, make 
sure it works as advertised. If you do return it, the audiologist will 
probably suggest trying a different brand. They all work a little 
differently.

I agree, they cost a lot of money. What it is worth to you is something 
only you can answer. I can tell you that designing a custom chip to go 
in one of those aids is fiercely expensive. The up-front, cash costs to 
make an integrated circuit run $50k minimum. These are complex designs; 
three months after you shell out $50k, you get to find out what mistakes 
you made and maybe spend another $50k. This is the cash expense for a 
boat of wafers and the photo masks to make them; you also have to add in 
maybe a man-year (total) of expensive salary and overhead for a design 
engineer and layout talent. When we do a small amplifier chip (much 
simpler), development costs for the project are maybe $150k. A more 
complex chip can easily be double that cost, all payable before you sell 
the first one. Aid technology changes, how many years do they have to 
make that investment back? Each chip only costs 10-20 cents, but you 
still have to pay for the up front costs. That's why they are so pricey, 
they don't have enough volume.

There is another expense you should ask about. For the price they get, 
you'd think an aid would last forever, but it ain't so. Sooner or later, 
something will break (it should be maybe 10 years, but who knows). If 
nothing else, you'll do something dumb some day like smash it with a 
hammer. If it is 10 years, odds are they may not have parts anymore...

Good luck. I recommend you give them a serious try, an aid can really 
make a difference. Get one for each ear, but try them singly as well 
during the trial period. Your ears really do hear better when both are 
working, but check out all the options.

Steve

PlumDon at aol.com wrote:

> Anyone else out there recently had to purchase hearing aids and might share  
> some thoughts and suggestions with me. It is shaping up as a dreadful expense. 
>  Guess I shoulda started wearing hearing protection twenty years ago,  but...
>  
> I dont really have any psychological or emotional problems about wearing  
> them. But the thought of spending $3000 for both ears is creating great  
> emotional stress. 
>  
> If you respond, write loud. 
>  
> Don Plummer
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