EDUDEAF: Reading Strategies

Key Words: Instructional Strategies, Language, K-12

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Date: Fri, 4 Oct 1996 04:24:32 EDT
Reply-To: A Practical Discussion List Regarding Deaf Education
Sender: A Practical Discussion List Regarding Deaf Education
Subject: Re: New Member
To: Multiple recipients of list EDUDEAF

Information travels to your brain where it is interpreted (shortened version here) as sound/speech/whatever. Think of what happens when you throw a rock in a pond. Near the site where the rock enters the water, you have very high/deep pronounced ripples (waves). As the waves get farther away from the site of original impact, they become less formed, i.e., not so pronounced, until they eventually disappear to nothing. This is the exact same thing that noise does. At the source of the noise, the sound waves are big, crisp and clear. As they travel through space, they get less sharp, less formed and less easy to interpret. Given enough distance, they eventually disappear. The high frequencies disappear to nothing faster, just like throwing a little rock will make smaller, less pronounced ripples than a larger rock. So, the farther away from the speech signal you are, the less clear the signal will be when it hits your ear and makes your eardrum vibrate to send a signal to your brain. On top of this, throw in some background noise. Now think of throwing two rocks in the water, but you only want to track the ripples of your personal rock (the speech signal you're trying to hear). Well, the ripples/waves cross each other and it's harder to make out which ripples are yours. Throw in about 3-4 more rocks, and you get a scrambled mess. How do you pick your wave/speech signal out of all of the others bouncing around the room.

Now, get yourself an assistive listening device. That puts you right at the center of the point where sound originates. Just as though you're sitting on top of where that rock goes in. So, you'll get the benefit of those high waves that send such a strong signal to make your eardrum vibrate from the noise you're trying to hear. Those other, now quieter noises, are further away now and won't over-ride or mix in with the vibration (as much) because the original signal is so much stronger.

If a child is hearing impaired, then they already have trouble understanding a perfect sound wave. If this sound wave is already weakened, distorted, or mixed in with other sound waves when it gets to that child's ear, then it is just so much harder for them to hear that sound. If they have any loss in the high frequencies, it makes their situation even worse, because the high frequency sounds are the worst ones at making it through. What's the solution? Get that "perfect" sound wave as close to the ear as possible. Then, at least the child is starting out with a clear signal to begin with and can get as much information out of that sound signal as his ears will let him/her.

This is why a hearing aid cannot substitute for an ALD. The sound signal has already weakened, ie, the ripples have spread out and become less clear, by the time the sound signal gets to the hearing aid. The amplification provided by the aid does not reinstate the original signal, it just amplifies the "distorted" signal that has changed by traveling through space to the hearing aid. So, it does not place the child in the same situation as using an ALD. Some children may still be able to "Cope" without an ALD, but my position is why should they in any way have to struggle...they spend enough of their lives struggling to hear in situations where an ALD is not appropriate. Why put the extra stress on them when you don't have to.

Brad, you're our resident audiologist. Am I missing something in this analogy that is making me overemphasize the importance of ALD's?

Linda S

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Date: Fri, 4 Oct 1996 16:23:21 -0400
Reply-To: A Practical Discussion List Regarding Deaf Education
Sender: A Practical Discussion List Regarding Deaf Education
Subject: Re: New Member
To: Multiple recipients of list EDUDEAF

Your explaination was correct. Signal-to-noise ratio is essential for kids with sensorineural loss. BUT even with an ALD, a linear hearing aid can exacerbate the recruitment in the kid's ear. So it's a matter of ALD's PLUS hearing aids that reflect our current understanding of hearing loss.

I am tossing around the idea of establishing a not-for-profit (501c3) foundation that will provide advanced processing hearing aids to kids on a sliding scale based on gross income. I'll let you all know if and when it comes about.

Brad Ingrao
Jax, FL
http://www.aos-jax.com

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Date: Fri, 4 Oct 1996 21:14:57 -0400
Reply-To: A Practical Discussion List Regarding Deaf Education
Sender: A Practical Discussion List Regarding Deaf Education
Subject: Re: New Member
To: Multiple recipients of list EDUDEAF

In a message dated 96-10-04 17:51:31 EDT, you write:

<< By Soundfield FM are you talking generically about using a sound field with a hearing aid or is it a specific name for their FM device. Also, I'm not familiar with the Lombard effect. Also, when you say compresses the frequencies, in what fashion are they compressed and what is the impact of this? >>

I meant generic soundfield FM system.

The Lombard Effect is the tendency for normal hearing people to raise the volume of their voice and increase vocal effort for high frequency consonants in background noise. The listener will shift their attention to the higher frequency speech components and reduces attention for the low frequencies where background noise will tend to mask more.

If a hearing aid compresses the low frequencies, this is great because it compensates for the abnormal loudness perception (recruitment) associatedwith sensorineural hearing loss. But, it the aid also compresses the highs, then the Lombard advantage is lost.

Resound compreses both the lows and highs.

MultiFocus and DigiFocus (Oticon) compress the lows and leave the highs essentially un-compressed.

A head-to-head study found that in quiet, there was a slight preference for Resound, but MultiFocus was preferred in noise.

Brad Ingrao
Jax FL
http://www.aos-jax.com

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Date: Sun, 6 Oct 1996 23:13:18 -0400
Reply-To: A Practical Discussion List Regarding Deaf Education
Sender: A Practical Discussion List Regarding Deaf Education
Subject: Re: New Member
To: Multiple recipients of list EDUDEAF

At 10:03 AM 10/4/96 -0400, Linda Semesky wrote:

>Brad, you're our resident audiologist. Am I missing something in this >analogy that is making me overemphasize the importance of ALD's?

One thing that you left out. There's no question that an FM system is preferred in a school setting by most, IF it is used properly. The FM can do great things as long as the teacher wearing the microphone is constantly aware of a few very important things:

  1. Make sure that the child(ren) with the reciever can see your lips at all times as much as is practical
  2. Remember to turn the mike off or change channel plugs when working with a subset of the classroom
  3. If working in a participatory group setting, try to have the children pass the mike amongst themselves when one is speaking

The point of all this being, the FM does no good whatsoever, and can even be detrimental, if the input coming from the mike is not relevant to all of the children wearing the recievers. At least hearing aids would give a somewhat equal weighting to all sounds in the room, both essential and nonessential.

Chris
<< Chris deHahn.....CdH.....System, Network, CAE Administrator >>
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Uploaded by: Jessica Soltesz/Kent State University/Deaf Education Major