More than hearing aids are needed for Speech Intelligibility
You May have purchased your hearing aids to help you to understand speech better, just to discover that you still have difficulty, especially in background noise situations. Here are some of the reasons for this and suggestions that may help.
First, the ability to hear comes from your ears, but your ability to understand speech comes from your brain. There are basically three sections in this process, the ear, the nerves that take the signal from the ear to the brain, and the brain itself.
Some people never have any difficulty hearing or understanding anything until they have a hearing loss. Most permanent hearing loss is due to damage to hair cells in the ear. Picture someone playing a piano with an entire section of keys not working. They're playing a song you should know but you don't recognize it because large segments of the music are missing. Well, that's how your brain is trying to hear if you're missing parts of the speech frequencies. Instead of damaged piano keys, large segments of hair cells missing. Just like the music, words can become unintelligible.
Now we have to get the signal up to the brain. Sometimes people have auditory processing difficulties that make speech difficult to understand when background noise or visual distractions are present. The problem lies in the processing path the sound takes to the brain. Think back to your school days. Some people could study with a party going on and others need it quiet to soak the lesson in. Even with perfect ears, distractions can cause the signal can get sidetracked on its way to the brain.
Finally, there are times when our brains can't interpret speech as well as it can at other times. Has someone ever told you something and you immediately said "what?" and then two seconds later you knew what they said? Our brain's ability to interpret the speech it hears can vary day by day, or even hour by hour. The more stress you're under and the more you're trying to multitask, the more your brain has to process, and sometimes it just can't do it all.
Now you may never know you have any of these difficulties until someone points it out to you and you discover you have a hearing loss.
Hearing aids can do a great job of filling in the gaps that your inner ear is missing (to learn more in detail peruse this website), but they need help from the rest of your auditory system to get the light bulb in your brain to flash on. Considerations that may help you are:
1. Get the right hearing aids for your hearing loss. Although most of the hearing aids available now are good at adjusting for your hearing loss, some are better than others at cutting out background noise or enhancing speech. Find someone you trust to help you make this very important decision.
2. It takes time. Over time the brain loses some of the synapses it needs to interpret the speech signal it's getting. If you learned a foreign language a few years ago but didn't keep up with it, you'll have to re-learn the vocabulary to understand it again. Well, your brain has to relearn the "new sounds" it's hearing with hearing aids, and this can take months, even longer. The more you wear your hearing aids, the better your brain will get at interpreting the signal.
3. Try an auditory retraining CD. These are programs developed to speed up the process of rewiring your auditory system. Two I like are LACe and eARena. They aren't magic, but they've been shown to improve speech intelligibility somewhat if used consistently.
4. Proper expectations. Even the best hearing aid can't fix dead inner ear hair cells or completely get rid of background noise. You may never be able to hear as well as you use to, but the benefit hearing aids will bring can improve the quality of your life.
Let us know if you have ideas that may help others or if you have specific questions regarding hearing aids and intelligibility .

Oct 12, 2009 at 5:38 PM Very well stated. I would also suggest that we may consider FM System's to asssit with distant speech as wella s to reduce ambiant noises. Just a few thoughts. Nicely said Dr. jenkins
Rich
Jan 11, 2012 at 1:58 AM I was born with inner ear nerve damage after being born 3 mths premature and, finally, at 46yo I have just purchased my first set of hearing aides. I've always had difficult with sounding out certain words. I've had them for one day now and am welcoming the improved ability to hear sounds I found so difficult to hear before. But the amazing thing I have discovered, which EVERYONE I know has commented on, is the fact my speech abilities have improved also. They are amazed at how much more clearer I speak now... and not speaking with a "deaf.. hollow.. slurring" sound anymore. The first time someone mentioned this discovery was within an hour I had them in, as if my speech improved as soon as I began wearing the hearing aides. Is this something that happens to others? Why all of a sudden the improvement of my own speech? I think it is amazing and am excited of this new improvement in my speech abilities!
Jan 11, 2012 at 3:59 PM How wonderful for you Theresa!
One of the most difficult aspects of treating hearing loss is that, many times, my patients don't even know how much they are missing. If you can't read something it's obvious that you have a vision loss, but if you can't hear something, you either don't know that you've missed it, or you think that the other person is speaking too softly or mumbling. Once you try on hearing aids, all that changes.
We see it every day in the office. I have had many patients cry because they didn't know what they were missing. One 25 year old female didn't know that pulling kleenex out of a box made a sound. She spent her first few weeks wearing hearing aid just exploring the sounds around her.
The reason you are speaking more clearly now is that you have a "feedback mechanism" in your brain. Now that you can hear your own voice more clearly, your brain can regulate it much better. That's usually most apparent with the high frequency sounds like the "F,S,sh and ch sounds, but it can be any of them.
I'm so happy that you are hearing more clearly now. Enjoy getting to know the sounds around you, and please be an advocate for others who may have hearing loss but don't think that it's important to have their hearing tested. You can now have the pleasure of helping others to hear their best!
All my best to you Teresa,
Dr. Barbara Jenkins
Advanced Audiology.info
Denver, Colorado