On the theme of the article, sound is a great way to understand what is going on, and I really like how you've used it here. I think some people believe that hearing mainly applies to obvious sounds such as speech and music, but it is, as you demonstrate here, an excellent diagnostic tool. I've personally learned that all of the little sounds contribute significantly to ones mental map / model of the world to the extent that I'm prepared to believe that total deafness would be as devastating, in the long term, as total sight loss.