Here is an article about DAF devices http://www.washingtonpost.com/wp-dyn/content/article/2010/12/20/AR2010122004203.html. I have many posts on forums about people spending money on these things hoping for a "cure" and being so terribly disappointed that they did not work for them, worked only at first, or being so annoying that the thing was put in a drawer to never be used again. One post that really pointed out the problem with using one all the time was about all of the outside noises being played back in the ear making it irritating to use. This post was about talking with someone while walking down the street and the blasted device playing back noises like a bus going past and other street noises. Another post was about how useless it is when worn while in a restaurant and trying to talk fluently while this thing in the ear is playing back all of the clinking of dishes, talking of others, and the music, too! I can see where the only place one might be used successfully is when you are the only one giving a speech and nobody else is talking.